( ) Foreword Steel Sector has been facing a lot of Challenges. Indian Institute of Plant Engineers (IIPE) has been instrumental in creating platform for the professionals The Indian in various industries and also for cross industry exchange of views that have been instrumental in Plant Productivity. A seminar in Nov 2005 on “Approaches to Zero Break Down Maintenance at Steel Plants” attended by over 150 delegates gave an overwhelming response and the recommendations of the seminar have become Industry guidelines. This seminar was not possible without the support of SAIL, Bhilai Steel Plant. A seminar titled “War on Waste”, inaugurated by Dr V Krishnamurthy, was organized in Sept 2006, which covered Waste Management in various sectors. During the valedictory function, chaired by the then Min. of State for Steel, it was recommended that the Industry speciﬁc Waste Management should be organized at Plant locations. This seminar in Iron & Steel Sector is the ﬁrst in the chain of such Seminars to be organized eventually in all industrial sectors including Oil & Gas, Fertilizers, Power (thermal, nuclear, hydro etc) Mining, Textiles, Chemicals etc. With the active support of SAIL (RSP), the present Seminar being organized at Rourkela, will have Technical papers form all over the world including those from developed and developing nations. The overwhelming response from Steel Entrepreneurs, throughout the world, has already been demonstrated with participation of delegates from USA, China, Nepal, Pakistan etc. I am personally grateful to the Management of SAIL in general and the Managing Director, RSP in particular for their wholehearted support. J.S. Saluja National Vice President, IIPE & Chairman IIPE (Delhi) Editorial World Competitive standards, Rising input costs, Scarcity of raw materials, Wastes generated like in other Sectors, have compelled Mining, Iron & Steel Manufacturing Companies, to have a re-look into their respective operations for all inclusive development and sustainability in the operations. The Iron & Steel Industry is undergoing a phase of uncertainty, volatility and speculation. Waste Management in the Mining, Iron & Steel Industry has gained importance in view of these dimensions. The rapid advancement in technology, has made it possible to realize the task of Waste Reduction, recycling in the Iron & Steel Industry on a sustainable basis. This jointly organized by Steel Authority of India (SAIL) & Indian Institution of Plant Engineers (IIPE) seminar, has been planned to share the experience, propagate and recommend Waste Management potential of Raw Materials, socio economic and political factors, which may have direct and indirect impact on the growth dreams of the Industry among other relevant issues of strategic importance. The strategy of Wastes generated at the Womb –the mine to the Tomb - the Salable Product is to be conceptualized in total. The papers presented are a product of extensive and in depth analysis with incredible amount of time spent by various writers. An attempt has been made to highlight some of proven and established technologies, systems, processes, and attitudes etc., which are essential for continuous world wide efforts being made towards achieving Waste Management Practices available for further improving the same. The contributions from experts and practicing professionals have great potential for implementing these practices. YP Chawla, Program Director National Jt .Secy. IIPE International Seminar “Waste Management in Iron & Steel Industry, 9-10 May, 2008, Rourkela Program Registration of Delegates - 9th May 2008 Friday 0800-1000 Hrs International Seminar “Waste Management in Iron & Steel Industry, 9-10 May, 2008, Rourkela Inaugural Session 9th May 2008 Friday 10.00-10.15 Welcome address J S Saluja 10.15-10.30 About the Seminar NP Singh ED Works RSP 10.30-10.45 Key Note Address BN Singh MD RSP 10.45-11.00 Inauguration SK Roongta – Chairman, SAIL 11.00-11.10 Vote of Thanks SS Mohanti- ED (MM) , RSP International Seminar “Waste Management in Iron & Steel Industry, 9-10 May, 2008, Rourkela Panelists for Panel Discussions: 10th May 2008 BN Singh – MD RSP- Head of Panel Ms. Rita Singh – MD Mesco R P Singh- Ex MD Bhilai Steel Plant , CEO JIndal Steels PR Tripathi – Ex CMD NMDC, Om Narayan – Sr.Vice President Tata Steels PC Aggarwal Chairman / Hira Singh – MD Ashok Steels , Nepal SK Jain – ED (O), SAIL Ashok Kumar – ED (W), B S P Dr. Xia Sheng- Director Engg. Bao Steel, China Oommen, Dilip- CEO / A K Das – GM , Essar Steel JS Saluja – National Vice President, & Chairman, IIPE, Delhi. Valedictory Function 10th May 2008 Saturday 1620 -1655 Hrs 16.20-16.30 Welcome Balbir Singh ED P&A , RSP 16.30-16.40 Summing up NP Singh , ED Opns. RSP RSP 16.40-16.50 Journey Forward J S Saluja National Vice Pres. IIPE 16.50-16.55 Vote of Thanks YP Chawla National Jt. Secy IIPE & Program Convener Program of International Seminar on Waste Management in Iron & Steel Industry 08.00 10.00 Registration Registration of Delegates and Paper Presenters 10.00 11.10 Inaugural Please See Inaugural Program Details Session 11.10 11.25 Tea 11.25 12.45 Session 1 Present Practices:An Overview * Please see Paper Details. 12.45 13.30 Lunch 13.30 15.30 Session 2 Wastes in Iron & Steel Industry * Please see Paper Details. 15.30 15.50 Tea 15.50 18.00 Session 2 Wastes in Iron & Steel Industry * Please see Paper Details. Contd Cultural Program & Fellowship Dinner Day 2 10th May 2008 Saturday 0900 10.30 Session 3 Solutions to Wastes in Iron & Steel Industry * Please see Paper Details. 10.30 11.00 Session 4 Business Opportunities in Waste Reuse in Iron & Steel Industry * Please see Paper Details . 11.00 11.20 Tea 11.20 13.00 Session 5 Success Stories 13.00 14.00 Lunch 14.00 16.00 Panel Discussions Please see the List of Panelists 16.00 16.20 Tea 16.20 16.55 Valedictory Please see Valedictory Program details Technical Paper Topic Author Session 1.0 Base Paper YP Chawla Present Practices – An Overview 1.1 An Overview on Waste management In Steel industry V K Dhawan 1.2 Zero Waste Journey at ESSAR Steel Dr. A.K Das. T Bhaskar Session-1 1.3 Need for Indian Iron & Steel Industry R.K.Agrawal A.Sengupta 1.4 The Waste Management and Integrated Utilization Ming Kang, Bin Liu Wastes in Mining , Iron & Steel Industry 2.1 Use of Sub-Grade Ore- A case study N.K. Mayson, A. Mukerji 2.2 Benefaction of Low Grade Iron Ore Fines S Madhavan, Saroj Jain 2.3 Waste management efforts in Iron Making zone (BF) Sajeev Varghese 2.4 Solid Waste Management in Coke ovens S Roy Choudhury 2.5 Effective Biological Treatment of Coke Oven Byproduct Dr. B N Das, Plant’s Effluent For Removal of Ammonia, Cyanide & B Vaidyanathan, Phenol K K Manjhi, Dr. S P Kalia, Session-2 2.6 Waste Utilization & Minimization- BF DD Patra, DM Srivastava, S.Ranade. 2.7 Recycle Management of Waste Refractory S.K.Bandopadhyay, P.K.Ray Choudhury, D.Ghosh, S.K.Vadher, S.Chandrasekaran 2.8 Management of Solid and Liquid Wastes at Coke Oven K.K.Sanyal and By Product Plant 2.9 Challenges and solutions for upgrading indian iron ores Satyabrata Mishra to optimize mining and steel production Solutions to Wastes in Mining, Iron & Steel Industry) R.P. Singh 3.1 BF Slag and SMS Slag utilisation R.G. Segaran S.Nanda, Management of Splinters in SMS 3.2 D. Mohapatra, Md. Islamuddin , Session-3 Effective Solid Waste Management in Dr. B N Das, 3.3 Iron & Steel industry V V R Murty Recycling of Wastes from Iron Steel Industries for Safer B. Sankar R.K.Dutta 3.4 Environment & better productivity P.K.Pani Navin Kumar 3.5 Waste Lubricating Oil Management VK Srivastava, AK Oli Business Opportunities in Waste Reuse in Iron & Steel Industry 4.1 EAF Dust Recycling Through Vitrification John H. Buddemeyer 4.2 Recovery and use of steel mill In-Plant Wastes TC Inc. Session-4 Use of Plastic Waste in Iron and steel Industries – An R.B. Gupta, 4.3 Approach for Energy Reduction G.C Pattnaik INDIAN INSTITUTION OF PLANT ENGINEERS Office Bearers (2007-2008) - National Sl. Position Name & Address Phone (O) Fax Phone (R) Designation IIPE Lt. Gen. SS Apte E-506, Soma Vihar Appts, 9810310233 011-26854525 011-26105997 1 Patron PVSM (Retd) RK Puram New Delhi- 110 022 011-26168627 Past NP, IIPE IIPE Shri CK Varughese E-218, Mayur Vihar, 9868553045 011-22779856 2 Patron Past NP, IIPE Ph-IInd, New Delhi-91 IIPE- Shri NP Gupta President Desein Indure Group, Greater 011-29211185 3 Patron Kailash II, New Delhi 110048 011-29219566 President Shri Rakesh Nath CEA, Sewa Bhawan, RK Puram, ND i 011-26102583 011-22150630 4 Chairman National Shri J S Saluja Director ,Essar Group 0120-6626666 0120-6626690 011-26942660 5 Vice Pres. Director Project A-5, Sector-3, Noida-201 301 9811101181 National Shri YP Chawla Zoom Developers (P) Ltd 011-46591105 011-46591100 011-25262517 6 Jt. Secy CEO A-9 A , Ground Floor, 011-25279434 . Green Park, Aurobindo Marg , ND 16 Office Bearers - Delhi Sl. Position Name & Address Phone (O) Fax Phone (R) Designation Chairman Shri J S Saluja Director Essar Group 0120-6626666 0120-6626690 011-26942660 1 Director Projects A-5, Sector-3, Noida-201 301 9811101181 Secretary Shri YP Chawla Zoom Developers (P) Ltd 011-46591105 011-46591100 011-25262517 2 CEO A-9 A , Ground Floor, Green Park, 011-25279434 . Aurobindo Marg , New Delhi-110016 Secretary Shri Satish Bahadur Business Combine, 9811916962 011-23710822 3 (Fin) 13 Babar Road, New Delhi- 110 001 23319962 Manager Shri A Bhatnagar IIPE, 664 Kamaljit Sandhu Block, Asian 011-26493252 011-26493974 011-22629546 4 Games Village N D- 110 049 9811319198 Steering Committee – Intl’ Seminar on Waste Management in Iron & Steel Industry Sl. Position Name & Address Phone (O) Fax Phone (R) Designation Chairman Shri NP Singh., ED Rourkela Steel Plant , Rourkela – 0661-2510641 1 (Works), Orissa 769011 Vice Shri SS Mohanti, -do- 2 Chairman ED - MM Incharge Shri RK Mathur, HRD, address as above 3 Co-ordn. Sr DGM Resource Shri S Ranadey , Iron Dept, address as above 2523241 2642111 4 Person GM , Chairman Shri J S Saluja Director Projects ,Essar Group 0120-6626666 0120-6626690 011-26942660 5 Director A-5, Sector-3, Noida-201 301 9811101181 Progm. Shri Y P Chawla, Zoom Developers (P) Ltd 011-46591105 011-46591100 011-25262517 6 Director CEO A-9 A , Ground Floor, Green Park, 011-25279434 Aurobindo Marg , New Delhi-110016 Coordinating Committee – Intl’ Seminar on Waste Management in Iron & Steel Industry Sl. Position Name & Designation Address Phone (O) Fax Phone (R) Chairman Balbir Singh ED P&A Rourkela Steel Plant , Rourkela – 0661-2611140 1 Orissa 769011 Incharge Shri JC Mohapatra, 0661-250050 2646306 2 Co ordn COC, --Do-- 94370-85885 3 Member Shri GN Mathur Ex. CBIP 011-25079178 Shri P. Bansal, SAIL --Do-- 4 --Do-- HQ Shri Mahesh Rep RSP Delhi 22531226, 98685 14255 5 --Do-- Takhtani, 2240 3564 In charge Shri Narayan Pati – 0661-2510920 094370 47402 0661-2642 6 Reception DGM – COP 402 Committee In Charge Shri BB Mishra 0661 2511288 094379 63741 7 Seminar Task Force 8 --Do-- Shri A M Pujari 0661 2510395 094379 63732 Shri Satish Bahadur, President, Business Combine 9811916962 011-23710822 9 --Do-- 23319962 Shri P Varshney, Power Trading Corp., New Delhi 98101 53223 10 --Do-- Vice President, Technical Committee – Intl’ Seminar on Waste Management in Iron & Steel Industry Sl. Position Name & Designation Address Phone (O) Fax Phone (R) Chairman Shri SK Jain – ED SAIL HQ Ispat Bhavan Lodi Rd. 2222388 2241777 1 (Opns) New Delhi 110 003 2221023 2242339 2 Member Shri GS Bhatia, Rourkela Steel Plant 3 --Do-- Shri MR Diwakar, GM Rourkela Steel Plant 4 --Do-- Shri D Pal GM , Rourkela Steel Plant 2510359 2646326 --Do-- Shri Mohan Hirani, D-II /2449, Vasant Kunj, ND-70 011-26138209 5 Ex-GM, NTPC --Do-- Shri SK Jain, Vice Essar Group 6 President, A-5, Sector-3, Noida-201 301 --Do-- Shri L N Sharma, GM In charge SAIL Burnpur 7 SAIL AMMP-Division Sl. Position Name & Designation Address Phone (O) Fax Phone (R) Chairman Maj Gen S K Sharma ADG, EME (ESM) AHQ, New Delhi 011-23011423 011-23018608 011-25691904 1 ADG R-256, D.S., Arjun Vihar, Delhi Cantt. 9350040427 V. Shri Mohan Hirani D-II/2449, Vasant Kunj, ND-70 011-26138209 2 Chairman Secretary Brig Kuljeet Singh DDG EME (ESM) , AHQ, ND 011-23019478 011-23018461 011-24677784 3 Advisory Board Members Sl. Position Name & Designation Address Phone (O) Fax Phone (R) Member Shri Rakesh Mehta Chief Secy Delhi 1 A. Board --Do-- Shri Rakesh Nath CEA Sewa Bhawan, 011-26102583 011-26109212 011-22150630 2 Chairman RK Puram, New Delhi --Do-- Dr PS Rana 9810131406 011-26493129 3 Ex-CMD, HUDCO 4 --Do-- Shri Y. Prasad Cmn. Utrakhand Jal Vidyut --Do-- Shri Chandan Roy NTPC Ltd SCOPE Complex 011-24360232 011-24363478 011-24692543 5 Director (Oprn) Core V Lodi Road ND-3 --Do-- Shri U C Misra CMD, BBMB 0124-4043679 6 Director (Pers) --Do-- Shri K K Khanna SAIL , Ispat Bhawan, Lodhi Road, 011-24367105 011-24367250 011-26492434 7 Director (Tech) New Delhi 110 003 --Do-- Shri S K Roongta SAIL , Ispat Bhawan, Lodhi Road, 011-24368094 011-24367015 011-26493004 8 Chairman, SAIL New Delhi 110 003 --Do-- Shri PC Aggarwal Ashok Steel Inds. Ltd Bhagmati 9771-243148 009-771- Chairman Chambers Milan Marg. Kathmandu 9771-242395 4226477 9 PO-121112, 009- KA-2-2/18 7753520155 --Do-- Shri V S Verma Sewa Bhawan RK Puram, 011-26102583 011-26197267 011-26492024 10 Member Sec-I, New Delhi-110 066 --Do-- Shri K Ravi Kumar BHEL , Siri Fort, Asian Games 011-26001001 011-26492043 011-26493933 11 CMD Village, ND-110049 --Do-- Shri J Mehra Essar Group A-5 Sector 3, Noida 0120-6626602 0120-6626690 12 Director --Do-- Brig AK Adlakha AIREA ,81/2, Adchini, Sri Aurobindo 011- 51071555 011-51070555 0120-2430769 13 Executive Director Marg, ND – 110017. 51072555 9810039364 --Do-- Shri NP Gupta Desein Indure Group , Greater 011-29211185 011-29219566 14 President Kailash-II, New Delhi-110 048 9810096139 15 --Do-- Ms Rita Singh MD , Mesco --Do-- Dr A K Lomas Mineral Exploration Corpn Ltd., 0712 2510289 0120-4260204 16 CMD Nagpur 0712-2510338 Vice Chairman Sl. Position Name & Designation Address Phone (O) Fax Phone (R) 1 --Do-- Shri RC Gupta Desein Indure Group Greater 011-29223761 011-29218393 011-26132279 Vice President Kailash-II, New Delhi- 110 048 9810019907 011-26132193 2 --Do-- Shri HL Tayal PGCIL, Corporate Centre 0124-2571957 0124-2571956 011-26894118 th Exe. Director 7 Floor, Plot No-02 Sec.29 9811612124 Gurgaon- 001 4 --Do-- Shri V K Dhawan SAIL, Ispat Bhawan, Lodi Road, 011-24366740 011-24366470 0120-2771278 ED (Operations) New Delhi nd 5 --Do-- Srhi P Varshney PTC, 2 Floor, NBBC Tower 15 011-51659132 011-51659145 011-26277936 Vice President Bhikaji CamaPlace ND 66 98101053223 6 --Do-- Shri Digvijai Nath Office of ED Subanisiri Basin 03788-225832 0129-2428574 ED Projects NHPC Ltd, Ziro, Arunachal 09436068834 Pradesh-791 120 7 --Do-- Dr GS Yadava IIT Hauz Khas 011-26591272 011-26591615 New Delhi & Chmn. Institution of 9891334151 26856058 Engineers Delhi 26861834 Standing Committee-Industrial Sector’s Conveners S. Category Name & Designation Address Phone (O) Fax Phone (R) No 1 Convener Dr. KK Govil 132 Vasant Enclave 9811165557 011-26147514 Power Ex- Dir (P), PFC New Delhi- 110 057 Sctr. 2 Convener Shri G Ojha Director SAIL, Ispat Bhawan, Lodi Road, 011-24367259 011-24367250 011-264925174 Steel ND-110003 Sectr. Executive Committee S. Category Name & Designation Address Phone (O) Fax Phone (R) No 1 Member Col Mahesh Mathur AHQ 9810843739 011-25089974 2 --Do-- Shri YK Mattoo Simon India Ltd., Devika Tower, 9810492884 011-26843281 Sr Adviser Nehru Place, ND-19 3 --Do-- Shri Ashish Jain ONGC Limited New Delhi 011224064651 0135-2720278 Dy. S.E. 4 --Do-- Shri SK Kaila Kaila Technical Services 011-27941082 011-27941082 Consultant 24/C-9, Sec-8, Rohini , ND 85 6 --Do-- Shri SK Goyal National Fertilizer, Dy. GM (Mech) Panipat 7 --Do-- Shri L N Sharma SAIL, GM Incharge 8 --Do-- Shri A B Agrawal NHPC Ltd.,Salal Hydroelectric 01991-255433 011-22624985 General Manager Project PO Jyotipuram, Vai Reasi, Dist Udampur J&KK 9 --Do-- Shri AG Ansari NHPC Limited Sector-33 0129-2258834 0129-2272806 9810546695 Chief Engineer Faridabad-121 003 10 --Do-- Shri S Majumdar PGCIL, Corporate Centre 0124-2571955 0124-2571956 011-26890926 th Executive Director 7 Floor, Plot No-02, Sec.29, (DMS) Gurgaon-122 001 11 --Do-- Shri LC Jain M/s Flowmore Pvt Ltd A-292, 011-30623740 011- 011-26511605 Vice President (P) Mahipalpur Extension, N.H.-8 9313980341 26783278, New Delhi - 110037 26781483 International Seminar on Waste Management in Iron & Steel Industry Jointly organized by: INDIAN INSTITUTION OF PLANT ENGINEERS Co Sponsored by : BeeKay Engineering Corporation www.beekaycorp.com Knowledge Partners: SailCon Rourkela Bokaro Bhilai Pacific Sterling Inc. USA A Premier Project Development Company Base Paper [1.0 / 1 ] Base Paper: YP Chawla CEO Zoom Developers P Ltd. National Jt .Secretary IIPE Iron Pillar Erected by King Ashoka before Christ This paper is intended to give some inputs and data that has been collected for reference by our Paper presenters , delegates to work out the Strategies intended to be developed in this seminar and come up with recommendations that will make this Industry self sustained to the extent possible targeting Zero Waste. The reports and data referred in this paper might have gone changes at the time of Seminar. These have been updated at the time of Compilation and are intended for giving direction to the process of interaction and to be referred as base paper during the Seminar. The Steel Industry is presently vibrant due to demand as well as volatile due to high cost of inputs. The World Steel industry has entered a new phase. Finished steel consumption in the five years since the start of the millennium has increased by 233 million tonnes - an average annual rate of around 6 percent. This compares with a 1.2 percent average yearly rise in the previous three decades to 2000. Large Steel inventory building has occurred around the world. The talk of shortages of raw materials has possibly prompted buyers to carry higher stock levels than previously considered necessary. Fluctuating interest rates at moderately low level the world over (barring India) have made inventory building exercise less painful than in the past. On the other end, Chinese government is deliberating on avoiding overheating of Chinese economy by attempting to reduce growth in key industrial sectors, including steel. Overall, the World has not seen so much demand in last 20 years as it is now. The global steel demand is seeing the rise on the back of accelerated infrastructure activity in China, CIS and India, housing boom in USA, and white goods resurgence in Europe. During the recent recessionary phase, the industry has consolidated in terms of ownership as well as mothballing of inefficient capacities. And the Steel prices continue firming up. The Demand of Steel in India, China and other Asian countries is led by emphatic investment activities in infrastructure. While, the reconstruction work in Iraq is expected to fuel further demand for steel over the next few years. China is consuming steel like never before for its infrastructure with investments such as Three Gorges project on Yangtze as well as part of its build up to the Beijing Olympics in 2008 and the Shanghai Expo in 2010. Base Paper [1.0 / 2 ] In Europe, there is demand from housing and white goods industry which is on buoyancy, according to industry estimates. The global metals and mining industry grew by 17.5% in 2007 to reach a value of US$1,457.4 billion. In 2011, the global metals and mining industry is forecast to have a value of $1,600 billion, an increase of about 12% since 2007. The demand supply gap is expected to increase driving the steel prices northwards, even as the global steel industry is not prepared for this demand onslaught. Approx. 90 percent of global steel demand growth over the next two years will take place in the emerging or developing nations of the world. Steel is an input for Global Industry. Steel Sales account for 67 % of the global industry’s value. The challenges that the Industry faces today are the requirement of a sustainable development by meeting the needs of our present generation without compromising the ability of future generations to meet their own needs. The Industry is required to understand the importance of a sustainable approach to the operations of any company across the entire value chain, from the extraction of raw materials from the Mine through to the manufacture of finished steel products and the distribution to our customers. (Womb to Tomb Approach) Steel is an integral part of our developing world, both now and into the future. As one of the most common materials we come in contact with everyday, it is difficult to imagine a world without steel. The reason for this is steel’s strength, versatility and ability to be recycled. Steel can be used many times over with re-processing techniques maintaining properties and qualities, something that makes it unique from other materials. Base Paper [1.0 / 3 ] The Challenge of the high energy Cost (Iron and Steel sector is the largest energy consuming sector in the world, devouring 15% of world industrial energy) coupled with a pressure on the Carbon emissions and, the employing Competitive Specific Energy consumption pattern is the challenge to the Technology Providers. The benchmarking of Energy Consumption is another challenge by India being a net importer of Crude Oil. In India, average specific energy consumption in steel making is in the range of 6.2 –8.2 GCal/TCS (vis-à-vis international value –4-4.5 GCal/TCS) Similarly benchmarking Co2 emissions, the average CO2emission is in the range of 2.2 –3.2 T/TCS in India(vis-à-vis international value of 1.5 – 1.7 T/TCS) CO2emissions in steelmaking stem from the intense consumption of fossil fuels –for thermal energy, coke making, process requirement and electrical energy mainly is another task to be considered. Carbon dioxide emissions from steel production, which range between 5 and 15% of total country emissions in key developing countries will continue to grow as these countries develop to cater to global steel demand Reducing energy intensity is therefore not only beneficial in saving scarce resources but also in reducing carbon emissions and thus mitigating global climate change. With increasing energy prices, diminishing reserves of conventional forms of energy, and increasing GHG emissions, it is a need of the hour for the iron and steel industries of the developing world to a take sustainability approach for utilization of the limited fossil fuel reserves of the earth. Base Paper [1.0 / 4 ] GHG emission reduction in iron and steel manufacturing facilities can be done through different routes like replacement / switching of CO2 intensive fuel (e.g. oil to gas, coal to gas), energy efficiency in the process technology, waste processing, waste heat recovery projects including power generation, energy savings by elimination of reheating processes. Such technological initiatives for curbing GHG emissions, requires substantial capital investment, because of which India, with its mixed bag of plant and machinery (power + industrial) in terms of old, outdated industrial and power generation equipment coexisting with the latest, most modern machinery, is widely seen as a key CER supplier under CDM Some steel companies in India have initiated ‘Climate Change initiatives’ towards improving its energy performance through fuel substitutes, modernization, recovery & reuse of by-product energy. In integrated steelmaking, a major source of energy and CO2 emissions is from the manufacturing of coke consumed in the blast furnaces. With continuous inflation in global steel demand and supply, there will be a necessity for increasing amount of coke production In this Context the Waste Management in Iron & Steel Industry becomes important , covering the complete cycle of Process from Mining Ore to Saleable Product has been planned to debated on transiting the process from ‘end - of - Pipe approach’ to Reduction, Recycle & Reuse i.e. Cleaner Production leading ultimately to Zero Emissions’ in continuing with Zero Philosophy . Zero Defect – (Total Quality Management) ; Zero Inventory- (Just in Time Production) Zero Emission – (Total Productivity): Reengineering of the Manufacturing Processes for fully Utilize the resources within Industry for higher Revenues and Jobs. Zero Emissions extend as under : Base Paper [1.0 / 5 ] End-of Pipe Cleaner Production Zero Emissions approach (Reduce, Recycle, Reuse) (Total Productivity) Adding New Industry in Up Stream, Minimizing effects on Down Stream Utilizing Wastes in existing Industry Minimize Waste Value Addition Cost Reduction Revenue Increase Continuing with Developing Industry Cluster for using Existing Modifying the Existing Unit Waste as Input to next Industry Production Process Process Measures at the Outlet of the Input- Output Analysis Output- Input Connection process. Water, Energy, Waste Minimization through Wastes Production Process Integrated Approach- Holistic Approach Modification Industry is presently Transit Stage to next stage Ultimate Goal focused on the above Wastes Recycling will lead to Minimization of exploitation of Natural Resources The factors that require Measurement of the industries’ sustainability are to: Develop indices of benchmark Develop “successful” standards and labeling programs To learn “best-of-kind” operation To build a kind of “Energy Code” Base Paper [1.0 / 6 ] To facilitate technology deployment by gathering information on “State-of-the- Art” technologies The Technology of Manufacture is required to be examined for better productivity. o 40 per cent of the world’s steel production takes place through the EAF route, which manufactures steel from scrap metal. o Steel recycling is common practice and scrap steel has become a valuable commodity because there is a technology that can accept it. Engineers and Scientists to take on exciting route to develop technologies and processes to be able to take into account all Waste Materials. The possibilities are endless! o Enhancing existing processes to be able to use all kinds of Waste resources to make the Sustainable Materials Processing, including recycling of waste in steelmaking, lowering of energy and emissions in processing, iron and Steelmaking technologies. While debating various issues, the Industry Recent High Lights on the Resource Position may also be examined: o India's iron ore resources can increase significantly as per ICRIER o Iron Ore reserves can increase significantly from the current estimated level by increasing investment & exploratory efforts. o Concerns over reserves in view of the proposed capacity additions need to be dispelled, as significant share of steel gets recycled and efforts will made through improvement in technologies and waste recycling , demand for iron ore is to be attempted to be stable. The studies have indicated that in the current scenario, export restrictions will make it difficult to take care of excess fines. Restrictions on trade in iron ore will also restrict the economies of scale to Indian mining Companies and they may remain inefficient in global comparison forever. Such restrictions could also lead to closure of some of the mines, leading to loss of direct and indirect jobs. India's iron ore production in 2006-07 was around 181 million tonne, which was in excess of the consumption level. India exported about 93 million tonne during that fiscal, which is expected to come down to about 88 million tonne in the current fiscal. Nearly 80% of exported ores are fines, because those are not adequately used in India. India's competitiveness in the Chinese market has already started falling, the study points out. Base Paper [1.0 / 7 ] World Scenario on Steel Sl Country 2007 Share each Sl Country 2007 Share each Total 15.3 1 Japan 3.364 22.00% 22 Chile 0.034 0.20% 2 Brazil 2.418 15.80% 23 Saudi Arabia 0.027 3 US 1.551 10.10% 24 Sweden 0.022 4 Belgium 1.539 10.10% 25 Tanzania 0.022 5 India 0.977 6.40% 26 Argentina 0.021 0.10% 6 Pakistan 0.687 4.50% 27 Indonesia 0.016 7 Turkey 0.64 4.20% 28 Malaysia 0.015 8 Holland 0.509 3.30% 29 Philippines 0.008 9 UK 0.481 3.10% 30 North Korea 0.008 10 France 0.451 3.00% 31 Norway 0.007 11 Taiwan 0.384 32 UAE 0.006 12 South Africa 0.382 2.50% 33 Egypt 0.006 13 South Korea 0.382 34 Morocco 0.006 14 Iran 0.376 35 Russia 0.005 0.00% 15 Kazakhstan 0.27 1.80% 36 Mexico 0.004 16 Italy 0.213 1.40% 37 Bengal 0.003 17 Canada 0.169 1.10% 38 Burma 0.002 18 Germany 0.096 0.60% 39 Algeria 0.002 19 Viet Nam 0.082 0.50% 40 Hong Kong 0.001 20 Australia 0.073 41 Sri Lanka 0.001 21 Thailand 0.038 0.20% 42 Mozambique 0.001 SUMMARY OF APPARENT CONSUMPTION (Million Tonnes) OF FINISHED STEEL 1998 to 2008 Region 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 European Union 152.9 160.0 156.5 156.7 154.4 162.1 164.1 167.0 167.3 166.5 European Union 128.6 132.6 129.5 127.4 137.4 144.1 145.4 146.9 146.9 146.2 Other Europe 18.2 22.1 20.6 20.7 24.1 26.0 27.0 28.0 29.7 30.5 Former USSR 31.0 38.8 41.2 38.3 43.4 47.0 50.0 52.0 53.5 55.0 NAFTA 142.4 149.2 132.1 135.1 132.9 152.5 153.5 157.5 157.5 155.5 S America 24.8 28.1 28.4 27.4 28.1 31.5 32.5 34.5 35.5 36.5 Africa 15.4 15.0 16.3 17.4 17.1 17.5 18.0 18.5 19.0 19.0 Middle East 16.6 18.4 19.1 20.9 21.6 23.5 25.0 26.5 27.5 28.5 PR China 122.6 124.6 153.4 185.6 230.8 257.4 291.4 302.0 310.0 322.0 Japan 68.9 76.1 73.2 71.7 73.8 75.5 76.5 76.8 77.0 76.8 Other Asia 109.0 119.5 118.9 129.5 133.3 141.0 143.5 145.7 147.0 149.2 Oceania 6.7 6.4 6.3 7.1 7.5 7.5 8.0 8.0 8.5 8.5 WORLD TOTAL 708.5 758.2 766.0 810.4 867.0 941.5 989.5 1016.5 1032.5 1048.0 Region 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 Totals may not be arithmetically correct because of rounding Base Paper [1.0 / 8 ] Ref : MPES UK Governmental Interventions on Iron & Steel: China began to levy a 5% export duty on coke in November 2006. It raised the tax rate to 15% on June 1st 2007. As the world's largest coke producer and exporter, the country has a say in pricing for coke on international markets. Foreign buyers chose to bear price rises based on the 15% export duty. India : Govt. of India in order to cool down the surge in steel prices in India by improving availability is planning to duty cuts on raw and finished material and the inflation and with a view to controlling prices exports would be disincentivised with levy of export duty. Imposition of export tax , Reduction of custom duty on Iron & Steel ,Abolishing Countervailing duty on re bar imports etc. Prospects for International Steel Industry Present status of the International Steel industry Steel is primarily a raw material based industry as for the production of one tonne of steel, an integrated plant consumes 4 tonnes of raw materials. India with its abundant availability of high grade Iron ore, the requisite technical base and cheap skilled labour for the development of steel industry and to provide a strong manufacturing base for the metallurgical industries. India presently accounts for less than 5% of the global output of Finished Steel and 1% of global trade. The per capita consumption of 27 kg. is also well below even the Asian average of 128 kg. China on the other hand shall consume 280 million tonnes of Steel, including 30 million tonnes through imports against the total consumption of 30 million tonnes by India. Chinese Steel and metallurgical industries have provided a major thrust to the economic development, GDP growth and generation of massive employment opportunities. In India , Non-integrated or the secondary producers accounting for over 50% output of the Finished Steel but without any captive mines have not gained much due to the sharp rise in the prices of Melting scrap, Sponge Iron, Coke, Iron Ore and other inputs. The growth has been mainly export based, boosted by the high global prices and liberal export incentives. The current status of the Indian Steel industry amply reflects the vast potential for the future growth of steel and allied industries through integrated planning to exploit the potential and the Indian steel is indeed poised for a quantum jump in the next decade. Base Paper [1.0 / 9 ] Structure of Indian Steel Industry Indian Steel Industry comprises of several interdependent and interlinked segments for value addition, broadly classified as the integrated or the majors producers and non-integrated or the Secondary Producers. India has played a pioneering role in the recycling of scrap for the production of Steel through EAF/Induction Furnaces and the rolling of both the Long and the Flat Products in Mini/Midi Mills at highly competitive prices. The Secondary Sector accounted for over 50% of the total indigenous output of Finished Steel The Secondary Producers focus on the production of high grade steels and specialty products to meet the specific requirements of the industry and the development plans must include the strengthening of the Secondary sector along with the major producers. Ample scope for the reduction of production costs by the Secondary Sector through the technological up-gradation, particularly by the Electric Arc and the Induction Furnace Producers, through the conversion of Electric Arc Furnaces to Twin shell Furnaces. Technological developments in the past decade, the non integrated producers and the integrated compact Mills have emerged as low cost producers of Finished steel due to low capital investment and breakeven points intense customer orientation and flexibility in altering the product wise. The Sponge Iron/Mini/Midi Rolling Mill route appears to be the appropriate for a large country like India and the requisite support be provided to the Secondary Producers on merits, for the modernization and expansion projects and these Mills adopting Waste Recycling Techniques. Key role of the domestic market The expansion of the domestic market in a huge country like India holds the key to the future growth of the steel industry and the basic input like Steel should obviously be utilized for the industrial and the economic development of the country. Besides, the export prices and markets are subject to wide ranging fluctuations triggered by economic and political developments in different parts of the world. Targets of the Seminar The major responsibility for the implementation of the development plans and strategies shall however rest on the industry through (i) Benchmarking with the leading global steel producers in term of the production costs, quality and service, to meet the global competition in the low tariff regime. (ii) Customer orientation and collaborative research and development with the metallurgical industries, to develop cost effective products for the domestic and export markets and to develop India as a low cost global Base Paper [1.0 / 10 ] manufacturing base for the metallurgical products. (iii) Development of rural markets and providing requisite infrastructure support for fabrication and after sale service in the rural areas. (iv) Promote construction of steel intensive commercial buildings and domestic housing in collaboration with Architects and town planners. To Resolve Protection of the Biosphere We will reduce and make continual progress toward eliminating the release of any substance that may cause environmental damage to the air, water, or the earth or its inhabitants. We will safeguard all habitats affected by our operations and will protect open spaces and wilderness, while preserving biodiversity. Sustainable Use of Natural Resources We will make sustainable use of renewable natural resources, such as water, soils and forests. We will conserve non-renewable natural resources through efficient use and careful planning. Reduction and Disposal of Wastes We will reduce and where possible eliminate waste through source reduction and recycling. All waste will be handled and disposed of through safe and responsible methods. Energy Conservation We will conserve energy and improve the energy efficiency of our internal operations and of the goods and services we sell. We will make every effort to use environmentally safe and sustainable energy sources. Risk Reduction We will strive to minimize the environmental, health and safety risks to our employees and the communities in which we operate through safe technologies, facilities and operating procedures, and by being prepared for emergencies **** Present Practices – An Overview [1.1 / 1 ] AN OVERVIEW ON WASTE MANAGEMENT IN STEEL INDUSTRY V.K. Dhawan ED (SAILCON) Steel Authority of India Limited New Delhi 1. Waste Management: For Sustainable Development Development of an industry in the present age of ‘Sustainable Development’ is synonymous with the concern for environment along with its social and economic goals. Steel is the driving force of economic progress. The intrinsic ability of steel to be completely recycled offers good prospects for ‘Sustainable Development’ of the steel industry. The challenge for steel in the new millennium is no longer to prove its capacity to create growth, but to show that it is a material with a future, resolutely adapted through recycling /reuse of wastes to the integrated concept of ‘Sustainable Development’. When the steel industry is to remain committed to ‘Sustainable Development’, there is no option for the industry other than gainful utilisation of all the wastes. One of the major concerns of world steel industry is the disposal of wastes generated at various stages of processing. The global emphasis on stringent legislation for environmental protection has changed the scenario of waste dumping into waste management. Because of natural drive to be cost-effective, there is a growing trend of adopting such waste management measures as would convert wastes into wealth, thereby treating wastes as by-products. This has led to aiming at development of zero- waste technologies. The technologies developed to economically convert wastes of steel plants into wealth provide new business opportunities for prospective entrepreneurs. Such technologies are divided in two categories, namely technologies for gainful utilization of wastes in manufacture of conventional products and those for gainful conversion of wastes into altogether new products. 2. Waste Management Waste management is the collection, transport, processing, recycling or disposal of waste materials, usually ones produced by human activity, in an effort to reduce their effect on human health or local aesthetics or amenity. A subfocus in recent decades has been to reduce waste materials' effect on the natural world and the environment and to recover resources from them. Waste management can involve solid, liquid or gaseous substances with different methods and fields of expertise for each. Present Practices – An Overview [1.1 / 2 ] Waste management practices differ for developed and developing nations, for urban and rural areas, and for residential, industrial, and commercial producers. Waste management for non-hazardous residential and institutional waste in metropolitan areas is usually the responsibility of local government authorities, while management for non- hazardous commercial and industrial waste is usually the responsibility of the generator. 3. The Waste Hierarchy The waste hierarchy refers to the "4 Rs" reduce, reuse and recycle, restore which classify waste management strategies according to their desirability in terms of waste minimization. The aim of the waste hierarchy is to extract the maximum practical benefits from products and to generate the minimum amount of waste. The waste hierarchy remains the cornerstone of most waste minimization strategies. In general by reducing or eliminating wastes an industry can: • Solve the waste disposal problems created by land bans • Reduce waste disposal costs • Reduce costs for energy, water and raw materials • Reduce operating costs • Protect workers, the public and the environment • Reduce risk of spills, accidents and emergencies • Reduce vulnerability to lawsuits and improve its public image • Generate income from wastes that can be sold. Present Practices – An Overview [1.1 / 3 ] 3.1 Waste Minimization Techniques Waste minimization includes any source reduction and/or recycling activity undertaken by a waste generator (i.e. any business that produces waste through their operations). These activities result in a reduction of waste produced and/or a reduction in the toxicity of the waste. Some examples of waste minimization techniques are listed below. 3.2 Source Reduction Techniques • Change the composition of the product to reduce the amount of waste resulting from the products use. • Reduce or eliminate hazardous materials that enter the production process. • Use technology (including measuring and cutting) to make changes to the production process; equipment, layout or piping; or operating conditions. • Purchase what you need to avoid waste from unwanted materials. • Good operating practices such as waste minimization programs, management and personnel practices, loss prevention, and waste segregation help to reduce waste at their source. 3.3 Recycling Techniques • Return waste material to original process. • Use the waste material as a raw material substitute for another process. • Process waste material for resource recovery. • Process waste material as a by-product. • Investigate contractors to recycle waste material. 3.4 Waste Management In Steel Industry Metallurgical industry is both capital and energy intensive and its production volumes are very high. Process chains within the industry are long. Many different technologies are applied and the industry has a significant impact on the environment. Steel industry is a mature industry with overcapacity as well as the strongly cyclic nature is a problem. In the future, the competitiveness of the steel industry depends on reducing the production time-to-market time, lowering the production costs, increasing the performance of products and minimizing the environmental impacts. One of the major concerns of world steel industry is the disposal of wastes generated at various stages of processing. Because of natural drive to be cost-effective, there is a growing trend of adopting such waste management measures as would convert wastes into wealth, thereby treating wastes as by-products. This has led to aiming at development of zero-waste technologies. The technologies developed to economically convert Present Practices – An Overview [1.1 / 4 ] wastes of steel plants into wealth provide new business opportunities for prospective entrepreneurs. On an average about 400 Kg of solid by products is generated in the steel industry per tonne of crude steel and the world steel industry in 2006 had produced about 1.239 billion tonne of crude steel, thereby generating huge wastes. Major share of this (70- 80%) consists of Blast Furnace Slag and Basic Oxygen Furnace Slag. These wastes are an ecological hazard. The total steel production in India in 2006 was about 44 million tonne and the waste generated annually was around 14 million tonne with associated ecological problems. There remain opportunities in utilization of the generated wastes into commercial products. Technologies have been developed in most of the developed nations of the world for utilization of the generated wastes. In India though utilization of wastes has begun it is still quite some time before there is total utilization. The objective of this paper is to bring out the scope of waste management in steel plants through waste auditing, yield loss improvements and by implementing zero waste programs in respective areas for waste minimization and match with the corresponding figures in the developed world and again identify measures to minimise generation of wastes, maximise utilisation of generated wastes and achieve ‘zero waste’ status. Integrated steel plants usually consist of Coke oven, blast furnace, sinter plant, steel melting shop and rolling mills. In addition to the above the plants may have auxiliary units like oxygen plant and power plant and Engineering shops for their own uses. In India, Steel Plants are facing the challenge to make and process steel without adversely impacting the environment, from complying with the requirements of the law to adopting environmentally friendly, clean technologies. The Ministry of Steel has been emphasizing on the importance of solid waste management. More than 30 per cent of solid waste generated in the country’s steel industry is being economically used and it needs to be further improved. Solid waste arising from different major shops: Sl no Major Shop Major Solid Wastes 1 Co & BPP Coke & Coal Dust, Tar sludge, Sulphur Muck, Acid sludge, Refractory waste 2 Sinter Plant GCP, Sludge 3 RMP Lime fines, ESP dust 4 BF BF Slag Flue dust, BF GCP Sludge, Refractory wastes 5 SMS LD Slag, GCP sludge, Refractory wastes 6 Rolling Mill Mill Scale, Scrap, oil sludge Present Practices – An Overview [1.1 / 5 ] Typically, in an integrated Steel Plant, to make one tonne of crude steel even with good quality raw materials and efficient operation requires 5 tonne of air, 2.8 tonne of raw materials and 2.5 tonne of water. These will produce in addition to one tonne of crude steel, eight tonne of moist dust laden gases and 0.32 tonne to 0.5 tonne of solid waste. A Glance to typical Solid Waste utilization in a SAIL plant ‘000T 2006-07 2007-08 Solid Waste Actual Plan Gen % Utilization Generation Utilization % Utilization BF Slag 1743 41 1890 984 52 BF Flue Dust 62 100 55 55 100 LD Slag 397 78 485 403 83 Lime Fines 25 100 30 30 100 Mill Scale 76 100 80 80 100 Refractory 12 50 15 7.5 50 Carbide 3.5 100 3.5 3.5 100 Sludge Taking clue from the waste utilization being done as shown above a holistic view point on waste management in iron & steel industry is being conveyed in this paper. 4. Scope of Management of Steel Plant wastes involves • Waste Audit-- Quantification, characterisation and management of all types of wastes in a steel plant, analysis of the wastes and characterisation of hazardous wastes,related Ecological problems • Yield loss improvements--Reduce, Reuse, Recycle and Restore- The Four R’s, Reduce, Reuse, Recycle and Restore, all contribute to saving energy and natural resources • Zero waste program- Present practices of steel plant waste management vis-à-vis best practices, Envisage new products from wastes, their market scope, project cost estimate for implementation, preliminary evaluation of order of investment and running cost of implementation of a feasible technology. • R&D opportunities:- Technology development efforts required to be carried out with special context to the wastes from steel plants Present Practices – An Overview [1.1 / 6 ] 4.1 Waste Auditing A waste audit: • Defines sources, quantities and types of wastes generated; • Identifies where, when, how and why these wastes are produced; • Identifies areas of wastage and waste problems; and • Establishes targets and priorities for waste reduction. The waste audit can be used to: • ensure external regulatory compliance; • develop base-line data; and • evaluate alternatives to minimize wastage of resources To conduct a waste audit, the following steps may be followed: • List all generated wastes • Identify the composition of the waste and the source of each substance • Identify options to reduce the generation of these substances in the production or manufacturing process • Focus on wastes that are most hazardous and techniques that are most easily implemented • Compare the technical and economic feasibility of the options identified • Evaluate the results and schedule periodic reviews of the program so that it can be adapted to reflect changes in regulations, technology, and economic feasibility. 4.2 Yield Loss in the Steel Industry From the available information, in a typical year, the U.S steel industry consumes approximately 120 million tonne of raw materials and ships approximately 100 million tonne of products. Roughly 53% of these shipments are produced by integrated steelmakers, i.e. blast furnace and BOF operators, and 47% via the electric furnace route. This represents a total yield loss of about 20 million tonne each year. The losses are realized throughout many different operations in a steel mill. They appear in the form of “home” scrap and waste oxides; integrated producers also lose a small percentage of coal and coke. Yield losses also reduce the overall energy efficiency of steelmaking. The steel industry consumes about 18.1 million Btu per ton of product, 22% more than the practical minimum energy consumption of about 14 million Btu/ton. These energy losses – about 4 million Btu/ton – are a result of the energy “embedded” in yield losses and process inefficiencies. Additional losses are generated in the use of Present Practices – An Overview [1.1 / 7 ] steel as it is manufactured into steel products. Examples of these “intrinsic” losses are excess scrap generated because of quality rejects, poor or inconsistent steel properties, or corrosion; excess material consumption due to excessive corrosion and safety factors; the misapplication of materials; and manufacturing rejects and excesses from manufacturing operations. For example yield loss improvements can be achieved through use of dusts, scales and sludge as an input material in converter process but it has its own merits & demerits. 5. What Steel Industry should do for yield loss improvements The steel industry should strive to make improvements in yield losses in order to become more competitive through better waste management. Yield loss in steelmaking is a function of waste oxide production, slag formation, and in-plant scrap returns. In addition, any off-specification steel that may be returned from the customer will be a substantial yield loss. Finally, the yield loss associated with the use of finished goods cannot be ignored; improvements in steel processing techniques that improve steel quality and the development of new materials and their implementation by customers have the potential to save up to substantial amount of energy required to manufacture the steel used in the product. The steel industry needs more precise knowledge of steelmaking processes, feed stocks, and products in order to address the complex combination of inefficiencies that lead to yield losses. Better understanding and control of iron making and steelmaking manufacturing processes will help reduce these inefficiencies. Advanced technologies, operating practices, and materials that increase steelmaking productivity and yield will also generate sizeable energy savings. Improvements in operating techniques and practices can reduce the yield losses associated with in-house scrap returns, waste oxide production, excess slag formation, lower throughput, and reworking. In-house scrap and the produce that returns due to non conformity of specifications from customer must be reprocessed. Both kinds of scrap represent significant yield loss since the energy consumed in the production of these is lost. The operation of electric arc furnaces, for example, presents an opportunity for improving yield by optimizing charging practices, reducing furnace heat time, and optimizing operating cycles. The productivity of many finishing processes can also be increased by minimizing process times and adopting practices that reduce defects. Other examples are scaling due to improper atmosphere control and excess soaking time in the reheat and annealing furnace. Lack of chemical control produces excess slag volume and iron losses in the blast furnace, BOF, and EAF. Present Practices – An Overview [1.1 / 8 ] 5.1 A Step Towards a Zero Waste Plant Globally, steel industry has made tremendous efforts in the past decade to drastically reduce its operating costs and to comply with environmental requirements. Given this situation, the promotion and acceptance of a "zero waste" philosophy in environmental circles may appear to be an unwelcome challenge for the industry, involving more up front exploratory work than continued operation with a pollution control/compliance philosophy. 5.2 The Zero Waste Concept A zero waste approach should - 1. Be a structured approach to minimize -waste generation, energy consumption, emissions 2. View wastes & emissions as potential raw materials to be conserved or reused rather than wasted. 3. Clearly identify appropriate manufacturing processes and ensures bottom line cost savings. 4. Implement the identified projects which • reduce process wastes, • convert waste to economically beneficial material • develop new processes that eliminate waste. For example, the value of EAF steelmaking slag is greatly increased if it is modified for use in cement-making operations. Redesign or develop a process which produces no unusable by products. For example, the COREX iron making process eliminates the need for coke making and coke oven gas byproduct recovery plants. 5.3 Potential Zero Waste Process for the Steel Industry Economics for every plant is uniquely determined by its location, age, product mix, equipment, cost structure among other factors. It is neither reasonable nor economical to attempt to make every process within a steel plant into a zero waste process, since the thermodynamics and kinetics of some reactions mitigate against achieving absolute zero waste. Some zero waste approaches and technologies in these areas are provided below. 5.4 Coke making • Waste can be minimized by improving up the operation and maintenance of existing processes. Present Practices – An Overview [1.1 / 9 ] • Zero waste option to develop new coking processes that reduce emissions at the source. • Non-recovery coke making processes are technically viable for a lower quality of Coking coal. • The combination of COREX and a Non-Utility Generator NUG is a reasonable option in areas with an inadequate power supply grid 5.5 DRI Production Iron oxide fines generated during the screening of ore and pellets are a process waste for which there is no current economic use. Many DRI plants buy pellets and it is not economical to return fines to the pelletizing plants that supply their raw materials. A DRI technology that uses iron ore fines is a zero waste complement to the two DRI technologies widely used. There are several processes like the DIOS coal based process (Japan) uses iron ore fines, which are pre-reduced in a fluidized bed, to produce liquid iron from a bath smelting reduction process. The FIOR natural gas based process (Venezuela) uses 100% fines in a multiple stationary fluidized bed. The Lurgi Circofer (coal based) and Circored (hydrogen based) processes use iron ore fines to produce DRI. 5.6 Slags • Evaluation of slag reuse is a low cost, high value option for steel plants. • Opportunities for waste minimization include the reduction of slag volume through better control of lime input to the furnace and improved control of silicon and sulphur in blast furnace hot metal. • The technology for reducing slag volume and increasing its value to other industries exists. It is dependent more on steelmaking chemistry and operating practices than on capital investment • Blast furnace slags are used for the manufacture of cement, road base, railroad ballast, light weight concrete block, glass and artificial rock. Recycling it to the blast furnace may raise the hot metal phosphorus content to undesirable levels. • The processing of steel slags for metals recovery is important for reuse at the steel plant and is also important to facilitate the use of the nonmetallic steel slag as construction aggregate. • Slag processors to be developed in the vicinity to handle a variety of materials such as steel slag, ladle slag, pit slag, and used refractory material to recover steel metallics. Present Practices – An Overview [1.1 / 10 ] • segregate spent refractories at the source of generation, use them for less critical applications after necessary conditioning and use them as constituents in manufacture of new bricks/mortars 5.7 Hot Rolling The hot rolling operation generates scales and sludges with high iron content, contaminated with significant amounts of oil and grease. The zero waste approach in this area may have three elements: • Minimize Scale Generation. Direct rolling or hot charging and good reheat furnace • management can reduce scale loss. • Reduce Oil Contamination: One of the primary sources of oily scale is leaking bearings. Reductions in oil losses through the use of sealed bearings, thus reducing maintenance, operating costs, and the quantity of oil in sludge. • Oil Separation. Oily sludge is slurry of water, oil and metallic which is difficult to separate. It has been significantly demonstrated by North American Steel Industry improved separation of the constituents can be obtained using microwave technology and specially developed oil release agents. 6. R&D opportunities in Waste Management in Steel Industry The steel industry can improve its fuel efficiency and productivity by capturing the heat value of by-product gases and optimizing its mix of fuels and feedstock. In a similar fashion, efficient use of iron and steelmaking by-products can improve yield by maximizing the industry’s use of its iron-bearing feedstock. Recycling scrap may consume less than half the energy required for iron ore reduction. R&D to increase recycling includes improved measurement technologies to classify scrap and processes. The reliance of iron making on coke is a productivity barrier that can be overcome by increased use of coke alternatives such as coal and natural gas. Research have shown Iron-bearing by-products generated within the steel mill can also be used as feedstock to the blast furnace. Waste oxides contain iron units plus lime, coal and coke fines. Research leading to increased internal recycling of these residues will increase the steel industry’s primary yield while reducing disposal costs and saving energy. Advanced refractories and other improved materials can reduce the frequency of both scheduled and unscheduled downtime for furnaces and ladles. The development of Present Practices – An Overview [1.1 / 11 ] rolling and finishing technologies with reduced maintenance requirements or faster operating speeds can eliminate bottlenecks that inhibit productivity in these stages. R&D in the Material properties can optimize steels in ways that minimize the yield loss in manufacturing. For example, appropriate alloying, rolling, and heat treating practices must be determined as well as weld ability, forming, and annealing schedules. R&D opportunities to improve microstructure control and reduce defects include better sensors for chemistry, cleanliness and defect detection systems. Half of the Waste oxide generation in steelmaking furnaces contains iron. A major barrier to reducing this loss is maintaining reliable process control and furnace stability. Potential R&D opportunities to overcome this barrier include sensors for critical chemical and physical parameters in the BF, BOF, and other furnaces; real-time chemistry adjustment technologies; and advanced combustion control systems. 6.1 Viewpoint It is proposed that to ensure Zero Waste in steel industry, waste management departments should be created mandatory in every steel industry and then steel industry should have an apex body comprising of personnel of waste management department/environment/safety with a mission to promote steel as the material of choice and to enhance the competitiveness of steel industry by targeting for sustainable waste management programmes through more and more R&D in this area with an ultimate aim for zero waste implementation in steel industry. As part of its strategy for achieving the goals, the body should create an extensive high-risk R&D program to develop new technologies and reduce the lead time between discovery and commercialization. The program should be highly leveraged by steel- producing companies, steel users, and equipment suppliers. Because the waste management apex body R&D accomplishes a public purpose as well as the industry’s objectives, the local/central Government may share cost of the R&D projects taken up by this body. The other part of the strategy of this body should be to ensure the implementation of Zero Waste program. The waste management apex body and steel companies in individual capacity and Steel sector as a whole will share several common goals, including maintaining a globally competitive manufacturing sector, increasing energy efficiency, reducing environmental impact, and creating and saving jobs. The numerous benefits of this collaborative partnership of the industry and Government are summarized below. • Increasing Energy Efficiency and Improving the Environment: • Leveraging High Risk Research Present Practices – An Overview [1.1 / 12 ] • Maintaining Globally Competitive Manufacturing • Delivering Safe, Low-Cost Consumer Goods • Utilizing Government Resources and Expertise • Accelerating Technology Development Based on the discussions in this paper some of the key R&D Opportunities that may be taken up for Yield Improvements by the industry are given below. The lists of opportunities are not meant to be exclusive; rather, they are representative of the kinds of activities that could be included in the overall pathway for yield improvements. • Modeling, Measurement, and Control • Operating Techniques and Practices • Process Equipment • Fuels, Feedstocks, and Recycling • Material Properties and Manufacturing Technologies 6.2 Zero Waste Implementation Waste minimization and recycling is widely perceived to require more initial exploratory work. An organized approach to waste minimization is required to identify and economically justify opportunities to reduce environmental costs and/or make a valuable product from waste. A zero waste program will be successful only when it has five key factors: 1. Total commitment from the highest levels of management. 2. Cross discipline teamwork. 3. Clear-sighted identification of areas which provide environmental and economic opportunities. 4. Objective process evaluation. 5. A continuous improvement outlook. 7. Conclusion? Waste Management requires a new attitude. Traditional thinking places all the responsibility on a few experts in charge of for it. The new focus shall make waste management everyone's responsibility. Waste management may be a new role for production-oriented managers and workers, but their cooperation is crucial. It will be the workers themselves who must make waste management succeed in the workplace. Management commitment and employee participation are vital to a successful waste management program. Management can demonstrate its commitment to pollution prevention and encourage employee participation by: Present Practices – An Overview [1.1 / 13 ] • Training employees in waste management techniques • Encouraging employee suggestions • Providing incentives for employee participation • Providing resources necessary to get the job done. Waste management projects may be selected & strategies developed for new installations right from the design stage during the expansion/modernization going on in the Steel industry.A systematic approach will produce better results than piecemeal efforts. An essential first step is a comprehensive waste audit. Areas that pose a significant problem with respect to environmental compliance and/or costs are good places to start. The zero waste concept can be applied to both integrated and mini-mill steel plants. Waste Management does not end with project implementation, follow-up and continuous improvements are crucial to waste management. Measurement and reporting of waste reduction and cost saving goals achieved will help to justify future projects and indicate areas for further work. Present Practices – An Overview [1.2 / 1 ] ZERO WASTE JOURNEY AT ESSAR STEEL Dr. A.K Das Senior Vice-President Essar Steel Limited 1. Introduction Essar Steel Ltd., Gujarat (India), is part of the Essar Group of Companies which has established roles in other fields like Shipping, Oil, Power, and Communication. It is involved in manufacturing of Hot Briquetted Iron (HBI) and Hot Rolled Coils (HRC), through the ‘Direct Reduced Iron (Hot Briquette Iron) – Electric Arc Furnace (DC) – Ladle Furnace – Vacuum Degassing / Vacuum Carbon Deoxidation - Continuous Slab Caster – Hot Rolled Coil – Cold Rolling - Galvanizing’ route at its Hazira operation 1. The steel plant generates by-products such as slags, fines and dust. Essar steel is aiming to achieve the status of a “Zero Waste Company” through recycling and reducing the by-product generations. 2. Global trends of waste utilization The iron and steel industry represents one of the most energy intensive and waste generative sectors within the Indian economy and is therefore of particular interest in context of both local and global environmental discussions 2. The present day scenario demands a balance in the productivity as well as the reduction in the wastes expelled from the Industry. Hence there is a great drive among steel giants as to find a way for proper utilization of various wastes and energy in order to maintain a “clean sheet” in the global market. Scrap is one of the primary waste materials which are now being effectively recycled. Recycled iron and steel scrap is a vital raw material for the production of new steel and cast iron products. Recycling of scrap plays an important role in the conservation of energy because the remelting of scrap requires much less energy than the production of iron or steel products from iron ore 3. Blast furnace flue dust is a solid waste material from the integrated steel plant. The flue dust is a mixture of oxides expelled from the top of the blast furnace, whose major components are iron oxides and coke fines. It also contains silicon, calcium, magnesium and other minor elemental oxides in lesser amounts. The direct recycling of flue dust is not usually possible since it contains some undesirable elements (like zinc, lead and alkali metals) that can cause operational difficulties in the blast furnace. As these undesirable elements are in very low quantities it is not economically feasible to extract them on an industrial scale.. The same is seen in Electric Arc Furnace dust also called Fume Extraction System (FES) dust, which contains a large amount of iron oxide. Present Practices – An Overview [1.2 / 2 ] These dusts are first processed for extraction of zinc and other metals (if scrap is used during charging) and later pelletized. Research has found that it could be used as a source of lime and phosphorous in fertilizers. Slag produced during the processing of iron and steel poses risk as its utilization possibilities are limited. Blast Furnace slag, due to the lower iron content and its glassy nature has found bulk use in the production of slag cement and pozzolanic cement 4. Basic Oxygen Furnace (BOF) slag has the useful components like CaO, MgO with high basicities (CaO/SiO2) of above 3.0. BOF slag therefore has high fluxing capacity and is being charged in the blast furnace due to easy melt and better utilization of calcium values. In the European countries, 30% of such slags are recycled into the blast furnace. However, the most harmful components in the BOF slag is Phosphorous which needs to be accounted for before use either in sintering plant or blast furnace. Electric Arc Furnace (EAF) slag owing to its high crystallinity and high iron content has presently no well established method for potential recycling. The Basicity Index (BI) of the slag is generally between 1.2-1.8 which comes under the low hydraulic Merwinite group. Also the Grindability Index, which is a measure for the energy required for grinding a particular material to a given size, is high due to high Iron oxide content. This makes the further grinding and processing of EAF slag energy intensive. Research is presently focused on investigating the partial replacement of clinker with EAF slag for the production of slag cement. Some other researchers have tried to substitute standard sand with EAF slag and have reported benefits like increase in the compressive strength and lower consumption of water. Ecomaister Co. Ltd. of Korea has invented, patented and commercialized Slag Atomization Technique (SAT) by means of which molten slag is converted to small round balls which is later used as a blasting material or in cement admixtures 5. Most of the materials of sludge and dusts from steel industries are recycled through sinter making. The recycled wastes also have some effect on sinter quality, strength and productivity. The recycling is generally controlled depending on the analysis of the waste material. The process byproduct of mill scale from the rolling process containing >70% Fe is generally recycled into the sintering plant. Generally, 70–100% mill scale containing high iron is being recycled through either briquetting or sintering route with out any difficulties. In some cases, de-oiling of the material is required. Rolling mill sludge contains fine particles, which take the oil portion along with the rolling cooling water. Recycling of these particles are challenging due to very high oil content. The reduction of oily mill scale sludge along with blast furnace flue dust in laboratory experiments and in a pilot plant rotary kiln has indicated that it is possible to reduce oily mill scale sludge to sponge iron in the rotary kiln. Present Practices – An Overview [1.2 / 3 ] 3. Scenario at Essar Steel Essar Steel Ltd. With a current capacity of 4.6 million tones per annum, generates various materials as by-products from the steel melting plant and other plants. Some of the major by-product generations are given in the Table 1. Electric Arc Furnace slag and Ladle Furnace slag are the predominant by-products that need immediate attention. Understanding this, the management as well a key professionals have focused their attention and also have chalked out several projects for their effective utilization. Table 1: By-product generation at Essar Steel Ltd. Source of By-product Generation Lime fines Lime plant Dolime fines Dolime plant Slag (Electric Arc Furnace & Ladle Steel Making Plant Furnace) Fume Extraction System Dust Steel Making Plant 4. Waste utilization at Essar Steel A Sinter plant with a capacity of 1.32 million tons located on an area of 120 m2 has been commissioned. The main function of this plant would be to sinter the iron ore fines generated from the calibrated lump ore degradation as well as from the broken pellets. A 12 ft diameter disc pelletizer is a part of the plant. Essar is planning to utilize the sludge pond fines, mill scale and fume extraction system dust for making micropellets using this pelletizer and hence increase the amenability for these materials to sinter. The sinter produced would be then utilized for making hot metal in the blast furnaces and later charged in the Electric Arc furnaces. EAF slag generated at SMP after necessary characterization with respect to the chemical and physical properties has been effectively utilized for filling the low lying areas in and around the plant. The slag has also been used as an effective aggregate for road making within the plant premises as well as in surrounding areas. Trials have been completed in joint collaboration with Surat Municipal Corporation and Reliance Industries Ltd. Essar has also initiated collaborative research work along with Central Glass and Ceramic Research Institute (CGCRI) Calcutta to make vitrified ceramic tiles from the slag. Prototypes have been prepared; field trials of the tiles will be taken up shortly. Trials of recycling ladle slag as a source for lime is also being carried out. Characterization studies of Fume extraction system dust is being carried out to find other potential route for its recycling/reuse. Present Practices – An Overview [1.2 / 4 ] Steel Making Plant (SMP): SMP generates various by-products such as scraps, skulls, lime fines, dolime fines, slag and Fume Extraction System (FES) dust. Scrap, skulls, all metallic wastes are directly being utilized/recycled for use in the Electric Arc Furnace for steel making. Lime fines generated during lime making process are binded along with pulverized coal and fed to the Electric Arc Furnace. Trials of making pellets out of lime fines and pulverized coal has been completed. These pellets will be part of the feed mix to Electric Arc furnaces. Slurry made from lime fines is also used to coat pellets before charging in the Hot Briquetted Iron (HBI) modules to prevent clustering at high temperatures inside the module during operation. 5. References 1. “Electric Arc Furnace (EAF) Slag - An excellent substitute for materials of construction in Essar Steel Ltd” – Internal report, Essar Steel Ltd. 2. B.P.Radhakrishna, “Boom in India’s Iron and Steel Industry”, Current Science, Vol: 92, No.9, May 2007. 3. Michael Fenton, “Iron and Steel scrap”, U.S Geological Survey, Mineral Commodity Summaries, January 2003. 4. B. Das, S. Prakash, P.S.R. Reddy and V.N. Misra , “An overview of utilization of slag and sludge from steel industries”, Resources, Conservation and Recycling, Volume 50, Issue 1, March 2007, Pages 40-57. 5. “Slag Atomizing Technology (SAT): Strategic management of electric arc furnace slags”, Global Slag Magazine, June Issue. 6. Luckman Muhmood, “Slag utilization possibilities at Essar”- Internal Report, Essar Steel Ltd. Present Practices – An Overview [1.3 / 1 ] NEED FOR INDIAN IRON AND STEEL INDUSTRY R.K. Agrawal & A.Sengupta E-mail: firstname.lastname@example.org Abstract Indian steel industry is, though nearly 100 years old, has not been able to cross the crude steel production figure of 100 MTPA even though the country has vast reserves of iron ore, coal and other minerals. Of the total crude steel production around 45.1 MTPA (2005-2006), nearly 49% production is from primary steel producers and balance 51% from secondary steel producers. With the total liberation of industry sector since 1990s, the country is aiming to achieve 100 MTPA crude steel production within a span of 12 to 15 years, based on clean technologies, at par with the world standard. A large number of new process technologies for iron making is presently available in the world, particularly in the developed countries. The relevance of these modern clean technologies with regard to the conventional technologies and their feasibility for introduction/adoption in India have certain limitations in Indian conditions:- Absence of suitable technologies for beneficiation of Indian raw materials , specially iron ore and coal, Tata Steel has adopted their coal beneficiation technology to bring down ash level to 14%; but more reduction is required. Coal, based DRI is forced to use high ash coal of 25 to 40%. VM content in coal is high and fixed carbon in coal is low . Hence, they are limited to be used even in the alternate clean route of iron making by COREX process in India. Several Indian steel plants have adopted some of the modern technological innovations such as pre and post-carbonisation techniques. Stamp charging for coke making as well as partial briquetting are also being tried to use inferior quality coal. Non-recovery coking with heat recovery is finding nowadays much preferred option. Jindal Steel also has installed Non Recovery type coke oven. As most of Indian iron ores are combination of hematite-goesthite and hematite-limonite, the sintering technology has to be developed for high fusibility characteristics of iron ore. Energy efficient sintering process technology having least emission is in demand. India requires low capacity cost-effective pelletisation plant. For iron making, in Blast Furnace area, coke rate has been brought down to 475kg /thm from earlier 550 kg/thm. This is an important area for Indian steel plants as Present Practices – An Overview [1.3 / 2 ] coking coal stock is very limited. Technological innovations on BF are continuing by modernisation. In the secondary sector, DRI (Direct Reduced Iron) based steel Plants are coming in the area where coal and gas availability is abundant. To day India is the highest producer of DRI in the world. Jindal’s COREX plant is one of the pioneers of Iron making by smelting reduction process. In the steel making process, many technological development have been taken place through out the years including secondary refining, still a lot more to be done to be competitive in the world. On line sampling of steel, installation of secondary de- dusting facilities, maximising continuous casting, etc are the emerging trend now. Electric Arc Furnace Steel Making sector, there is wide variation in the technological profile . Few Indian plants are of world class but others still suffer with technological obsolesces . Electrode consumption of the order of 1 kg/ton needs to be adopted. Fume emission control devices need improvement in accordance with national environment policy-2006. Steel makers around the world are switching over to continuous casting. In India Steel Production through continuous casting route is only 66% which is much less compared to the world average of 91%. India also need to enhance the continuous casting facility, Thin Slab casting etc. Utilisation of Rolling Mills sludge and oily Mill Scales also need to be increased . For Energy/GHG Emission Reduction, Energy Audit for all the plants has become almost mandatory. All the steel plants, particularly, primary steel producers, are striving hard to bring down the energy consumption level by waste heat recovery from all the practicable sources . Energy savings has government bearing on the operational cost of the plant. The report of the expert committee on integrated energy policy of planning commission has recommended for creation of national energy fund to finance energy research and development which inter alias include technology up gradation as well as to reduce energy and GHG emission. In accordance with the National Environmental Policy-2006 and for the sustainable growth of the society, Indian steel industry being one of the core contributors towards GDP, technological-cum-financial assistance are needed in some of the key areas like quality improvement of prime raw materials, utilisation of inferior quality of raw materials, dust pollution reduction to a level of 1 kg per ton of crude steel or even below, SOX /NOx pollution reduction to a level below 1.2 to 1.5 kg per ton of crude steel, complete treatment of phenol, cyanide, ammonia and other eco-toxic materials from the wastewater of the steel plant, comprehensive energy recovery and GHG emission reduction. Present Practices – An Overview [1.3 / 3 ] KEY WORDS: DRI, COREX, STAMP-CHARGING, NON-RECOVERY COKING, GHG, TRT, CONARC, CONTIARC, SCOPE-21, COKE DRY QUENCHING, CDI, CREP, EAF 1. Introduction Steel in its many forms plays a crucial role in shaping modern industrial society. It is a decisive factor for the economic and social development of our global society. However, in this global and highly competitive environment, we have to continue our efforts to produce steel at less cost, fulfill the stricter quality demands and find solution to the limitations of energy and raw materials as well as environmental constraints. A time existed when there were limited options for producing liquid steel. This situation has changed with recent technological advancements. Many technological routes have been identified for making hot metal at different parts of the world to avoid high capital cost of conventional Blast Furnace and make use of different types of available raw materials to produce steel at lesser cost - depending on the regional advantages, market demand and techno - economics. While many processes are under pilot or demonstration scale, few of them have come up as commercial plant. 2. Current National & International Scenario Global crude steel production during the year 2006 accounts to 1240 Million Tonnes, which shows a growth of 8.8 % over 2005. China accounted for most of the Present Practices – An Overview [1.3 / 4 ] incremental production. Further growth in Production / consumption is expected to come from BRIC (Brazil, Russia, India & China) countries. Cost / availability of raw materials (mainly iron ore & coal ) are areas of major concern. India is the 7th largest steel producing country in the world with crude steel production of 45 MT in 2006. In India, the producers of Iron and Steel have been divided into two broad sectors, namely the Primary and the Secondary, depending on the technological process used in production. The sectors using the various routes are given below: 1. Primary Sector - Coke Oven - Blast Furnace - Basic Oxygen Furnace 2. Secondary Sector - Scrap based Electric Arc Furnace (EAF) steel making 3. DRI based EAF steel making 4. Mini Blast Furnace based plants 5. Induction Furnace ( IF)based plants At present, the primary sector consists of public sector integrated steel plants under Steel Authority of India Ltd. (SAIL), Rashtriya Ispat Nigam Ltd. (Vizag Steel Plant) and the private sector Plant of Tata Steel. In the secondary sector, major steel is being produced through the Electric Arc Furnace route with some of the new generation plants having captive DRI (Direct Reduced Iron) & COREX facilities. In addition, there are a couple of induction furnace units for producing steel ingots. There are a few lone DRI producing units also, who produces sponge iron as input material for the Electric Arc Furnaces as substitute for scrap. While the integrated steel plants in the primary sector have downstream rolling facilities, the secondary sector has innumerable small, medium and large rolling facilities which produce finished steel, using feed materials of semis from the primary sector, EAF and IF units. However, there are many Induction Furnace and Electric Arc Furnace units who have there own downstream rolling facilities. Present Practices – An Overview [1.3 / 5 ] Crude Steel Production in India shows an exponential growth in last few decades which shows more than 100 % increase of production in last 10 years. Growth in steel demand is highest in developing world. In India present per capita consumption of finished steel is 30 kg/annum compared to world’s average of 170 kg /annum. Per capita consumption in India shows a growth of about 46% in last 7-8 Years. The reason for increase in demand is due to more urbanisation and subsequent change in life, style. This has subsequently lead to infrastructure development, demand in automobiles and transportation sector. 3. Raw Materials Major raw materials used for Iron & Steel making industry are iron ore and coking & non-coking coal. As per National Steel Policy, to produce 110 million tonnes of steel by the year 2020, iron ore & coal (coking & non- coking) requirement will be around 190 million tonnes and 100 million tonnes, respectively. Keeping this in mind, review of our raw material resources, particularly iron ore and coal have gained utmost importance. Though India has abundant reserves of iron ore, beneficiation of ore to improve the quality and increased recovery of Iron Ore fines are necessary for effective & sustainable use of the resource. For this, various techniques like use of hydro-cyclones, flotation, magnetic separation, jigging etc., can be used. Indian mining industry requires modern washing and beneficiation techniques for effective utilization of our resources. Presently most of the fines generated in Indian mines are being exported or stocked at the mine site, as there is no demand from the Indian steel industries. Pelletization of these fines can be done for direct use of fines as a feed material for iron making. In the pelletization process, the iron ore fines are initially agglomerated into green pellets by adding a binder, usually powdered bentonite. The green pellets are hardened by drying & heating in an oxidizing atmosphere in the furnace / kiln. India Present Practices – An Overview [1.3 / 6 ] needs low capacity pelletization plant for effective utilization of ferruginous wastes like iron ore fines / dust etc. India has also huge coal reserves, but significant portions of the coal reserves are characterized by high ash content. The estimated coking coal reserves in India is only 32 billion tonnes which is about 13% of the total coal reserves of our country, and having high ash content. Hence Indian steel industry are mostly dependent on import of coking coal, containing low ash. For effective utilization of the Indian coal reserves, high efficiency coal beneficiation and washing methods are required which includes cleaning of coarse coal in Jigs, Barrel or Heavy Media Bath and cleaning of fine coal using flotation technique or Cyclone /Hydro cyclones, with closed circuit water recovery. This will not only improve the utilization of the Indian coal but also reduce the dependency on the import as well as less environmental problems. 4. Coke Making Most of the recovery type Coke Ovens of Integrated Steel Plants in India (except few like RINL) were set up during 1950s to 1970s and were subsequently expanded and modernized. During those days, the pollution control facilities were installed basically aiming at process requirements rather than control of pollution. There were no emission/ discharge standards except the standard of CO emissions (3 kg/ton of coke) and Stack PM emissions standard. (50 mg/Nm3). In 1997, Govt of India notified the Present Practices – An Overview [1.3 / 7 ] environmental standards for coke making. Subsequently there was a Industry Regulatory Authority charter on CREP (Corporate Responsibility for Environmental Protection) which emphasizes on the fugitive emissions control from Coke Ovens and a specific time bound rebuilding target of the batteries. In due course of time, several other technological developments and initiatives have been taken place in Indian steel industries for the manufacturing of coke. However, for rebuilding, due to absence of indigenous Coke Oven designers and the equipment / technology suppliers, Indian coke makers are facing difficulty in achieving the time bound rebuilding target. Most of the phenolic water treatment plants (BOD Plants) are facing problems in meeting the effluent discharge quality standards. These units also need revitalisation keeping in view of the existing regulations. However shifting from wet quenching to dry quenching serves the dual role of energy efficiency and pollution control. Emerging technologies for coke making with less impact on environment & energy efficiency includes Coke Dry Quenching, Stamp Charging , Taller Coke Ovens Battetries, Scope - 21 Process etc. 4.1 Coke Dry Quenching CDQ charges hot coke produced in a Coke Oven into a chamber by lifting device and cools it with circulating gas (inert gas) which is heated to the temperature of 900- 950oC by heat exchange with hot coke. This heated circulating gas, after passing through the primary dust removing device, is conveyed to a boiler to generate steam. Approximately 0.58 tonnes of steam per tonne of coke is generated in the boiler, and the steam is supplied to the steam network power generation system for power generation. Circulating gas is cooled down to around 200oC in the boiler and then recycled into the chamber to quench the next shift of hot coke. CDQ (Coke Dry Quenching) facility exists in Rastriya Ispat Nigam Limited- 3 MTPA Plant in India and is giving satisfactory result. However most of the new Coke Plants at green field sites are planning for CDQ installations in future. 4.2 Stamp Charging Of Coal Charge Stamp charging is a process where the entire coal charge to the coke oven is stamped or compressed and then pushed into the oven for coking. It is one of the effective way of densification of coal charge. The stamping process brings the coal particles into more intimate contact with each other which enhances the coking property. This technology has tremendous potential for improving the coke quality for inferior coking coal. In India, TATA Steel has Stamp Charged Batteries. Present Practices – An Overview [1.3 / 8 ] 4.3 Scope- 21 Process For Coke Making This is innovative coke making, developed by Japan, allows greater use of poor quality coal and provide higher productivity and less polluting coking process. Keeping in mind, the demand and supply of coal, it is anticipated that there may be a shortage of quality coal, unless a new economically viable and environmentally acceptable coke production facilities are installed. However, application of this technology in India needs further research depending upon the quality of Indian coal and quality of coke in demand in the down stream of steel making process. SCOPE -21 eliminates the problems of limited choice of coal sources, associated environmental pollution and high energy consumption in conventional recovery type Coke Ovens. Present Practices – An Overview [1.3 / 9 ] 4.4 Non Recovery Type Of Coke Ovens Large scale Non Recovery Coke Plants are not much prevalent in India. except at Jindal Steel Works, at Karnataka. However, this technology is being considered by number of coke makers during future installations in the green field areas. In the areas of coke making, technology transfer is solicited in the areas of coke oven rebuilding / design, modern and improved design of battery machines, pushing and charging emissions control, improved askania control, modern quenching tower with quenching emissions measurement facility, facilities for smooth functioning of BOD Plants etc. 5. Sinter Making Sensible heat recovery from the main exhaust gas from the Sinter Machines and Sinter Coolers have got great potential for energy conservation in steel plants. This facility is available in some of the new generation Sinter Plants in India, however, Sinter Plants of first generation (1960- 70s) are unable to recover this sensible heat due to logistics and space problems. A suitable technology/design supplier for retrofitting the same in the existing layout would definitely yield less pollution and less energy cost for steel production. Effective utilisation of iron bearing dusts and sludge by agglomeration process using rotary hearth furnace has been developed by Japan. The pellet produced in this process can be directly fed as sinter feed or directly in Blast Furnaces. 6. Iron Making Iron Making through Blast Furnace route includes capital cost for a new Coke Oven Plant and a new Sinter Plant. To avoid such high capital investment and to utilize low grade coal and iron ore fines. Alternative iron making technologies have had been tried and tested in India and were found successful. Some of the alternative Iron making Present Practices – An Overview [1.3 / 10 ] technologies are through Direct Reduction, Smelting Reduction along with combination of EAF or BOF for production of steel. 6.1 Direct Reduction Processes Presently India ranks 1st, amongst the producers of DRI, with an annual production of 15 MTPA, (25 % of the world out put) followed by Venezuela 8.6 MTPA and Iran 6.9 MTPA. India’s Ispat Industries Limited (IIL) is one of the leading integrated steel makers and the largest private sector producer of hot rolled coils in India through DRI process. It produces world-class sponge iron, galvanised sheets and cold rolled coils, in addition to hot rolled coils, through its two state-of-the art integrated steel plants, located at Dolvi and Kalmeshwar in the state of Maharashtra. It’s 1,200 acre Dolvi complex, houses the 3 MTPA Hot Rolled Coils Plant, that combines the latest technologies - the Conarc Process for steel making and the Compact Strip Process (CSP) - introduced for the first time in Asia. The complex also has a 1.6 MTPA Sponge Iron (DRI) Plant, which was commissioned in 1994 as the world's largest and most efficient gas-based single mega module plant. Moreover, the Dolvi complex has a 2 Million Tonne Blast Furnace. Ispat is the only steel maker in India and amongst a few in the world to have total flexibility in choice of steel making route, be it the conventional Blast Furnace route or the Electric Arc Furnace route. Its’ dual technology allows Ispat the freedom to choose its raw material feed, be it pig iron, sponge iron, iron ore, scrap or any combination of various feeds. It also has total flexibility in choosing its energy source, be it electricity, coal or gas. 6.2 Smelting Reduction Process The new smelting reduction processes are based on the use of coal together with pellets or lump ore. One objective of these processes is to eliminate Coke Ovens and Sinter Plants. Another goal is to achieve non agglomerated fine ore. The smelting reduction processes can be divided into two groups, the indirect reduction or “inbed” process and direct reduction or “inbath” process, which includes COREX, HISMELT, ROMELT, DIOS etc. Compared with the traditional hot metal production through Blast Furnace route, only the COREX process offers the possibility of produceing hot metal without BF quality coke on industrial scale. The operation results achieved from the operating COREX plants at POSCO, SALDANHA and JINDAL STEEL, India confirm this. JINDAL’s COREX Plant has 2C-2000 modules. Module -1 was commissioned in August 1999 and Module -2 was commissioned in April 2001. This process has greater flexibility in operation and uses various types of non-coking coals as a primary fuel and requires raw materials of less stringent quality. The gas generated from the process is Present Practices – An Overview [1.3 / 11 ] used for power generation for the pellet plant and as a fuel in the integrated plant complex. The special features of COREX hot metal are; high temperature (1480 - 1510o C), low sulphur, low nitrogen and least amount of impurities. Finally, it is more eco- friendly compared to the conventional Blast Furnace route due to exclusion of Sinter Plant and Coke Ovens. 6.3 Conventional Blast Furnace Route In the field of Conventional Blast Furnace route, emerging technologies are direct injection of reducing agents, energy recovery from top gas pressure, Cast House De- dusting and Cast House Slag Granulation Plants etc. 6.3.1 Direct Injection Of Reducing Agents Direct injection of reducing agents (hydro carbons) in place of coke, in the furnace at the tuyere level, reduces the need for coke, reduce overall pollution and energy demand as well as avoid emissions at the Coke Oven Plant. Hydrocarbons may be in the form of heavy fuel oil, tar, granular or pulverised coal, natural gas or plastic wastes. Since coke acts as a mechanical medium as well, certain amount of coke is still necessary to allow proper Blast Furnace operations. 6.3.2 Coal Injection Theoretical maximum rate for coal injection at the tuyere level is @ 270 kg/thm For every kg of coal injected, approximately 0.85 - 0.95 kg of coke production is avoided. At an injection rate of 180 kg/ton of hot metal, energy savings amount to 0.68 GJ/ thm or 3.6% of the gross energy consumption of the Blast Furnace. This saving is Present Practices – An Overview [1.3 / 12 ] achieved indirectly due to reduced coke consumption. The use of CDI along with oxygen enrichment, saves coke and increases productivity of Blast Furnace. 6.3.3 Energy Recovery From Top Gas Pressure High top pressure Blast Furnaces provide an ideal opportunity for recovering energy from the large volume of pressurised top gas generated by means of an expansion turbine, which is installed after the top gas cleaning device. The electricity generated is reported to be as much as 15 MW in a modern Blast Furnace with a top gas pressure of 2 - 2.5 Kg / cm2. Energy saving is estimated up to 0.4 GJ/thm for a 15 MW turbine. SAIL, in its Corporate Plan 2012 has envisaged the installation of TRT in new Blast Furnaces. For the old furnaces it has been planned during furnace up- gradation/ relining, keeping in mind the logistics and space. 7. Steel Making The performance of the technological routes of steel making in the steel plants of our country is considerably inferior as compared to the technology at the advanced countries. The inferior performance is due to the inefficient /obsolete use of technology, mismatch of Indian input materials with imported qualities --- all leading to low productivity of capital and labour. Though the production of steel through secondary refining has been increased over years in India but the quantum has been comparatively low with respect to other advance countries. Technology is crucial to long term competitiveness. Some of the Cleaner technologies for Steel making are energy recovery from the BOF gas, on-line sampling and analysis of steel, secondary de-dusting, dust hot briquetting & recycling, treatment of wastewater from wet de-dusting and treatment of wastewater from continuous casting. Present Practices – An Overview [1.3 / 13 ] 7.1 On -Line Sampling And Steel Analysis Oxygen steelmaking is a batch process. Every charge of pig iron has to be refined until the required steel quality is achieved. In order to monitor progress, samples are taken from the steel bath for analysis. The result of the analysis is used to determine the additional time of oxygen blowing needed to achieve the required steel quality. In modern plants, samples are taken on-line during oxygen blowing by means of sub lance. This shortens production cycle times and so increases productivity. Emissions are lower compared with the previous sampling method as the position of the BOF is not changed. All modern plants apply on line sampling. 7.2 De-Dusting Of Secondary Off-Gases Sources of secondary off-gases result from reladling and deslagging of hot metal, BOF charging, tapping of liquid steel and slag from BOF (Converters) and ladles, secondary metallurgy and tapping operations handling of additives, continuous casting etc. Until the early 70s, oxygen steelmaking plants were built without secondary dust collection equipment. As a result, most of today’s secondary and subordinate primary source dust collecting installations are retrofitted. The efficiency of such systems is highly dependent on local conditions. These play an important role when it comes to the choice and design of the recovery system (enclosures, hoods, etc). Determination of the waste gas flow rates often depends on local conditions and on the available space for installing piping systems together with the possible size of the pipe cross-sections. Present Practices – An Overview [1.3 / 14 ] As per the CREP charter, Ministry of Environment and Forests, all the integrated steel producers to install secondary de-dusting facility at the Steel Melting Shops by 2008. 8. Electric Arc Furnace Steel Making In the steel industry, the arc furnace is mainly used for the melting / refining of steel which mainly eliminates undesirable components such as phosphorous, hydrogen & oxygen from the material through different chemical reactions including decarburization, dephosphorisation, desulphurization and de-oxidation, in order to obtain the desired physical and mechanical characteristics while adjusting the major components such as carbon so that steel with good qualities can be obtained. Through out the world, various arc furnace technology like Energy Optimizing Furnace, CONARC, CONTIARC etc have been developed where the off gas from one furnace can be utilized for pre-heating of other furnace. 8.1 Conarc Process combines conventional Converter process with Electric Arc steel making in a furnace with two identical shells. The furnace is equipped with one set of electrodes which are connected to transformer and can be slewed alternatively to each of the two shells. Oxygen is injected through water cooled lance which also can be slewed between the furnaces. The process is split into two processes, Converter process during which the liquid iron is de-curburised by injection of oxygen and Electric Arc process where electrical energy for melting of the solid charge and for superheating of the bath to tapping temperature is used . 8.2 Contiarc Mainly consists of a melting reactor with an inner electrode, holding and guiding system inside a central water cooled shaft, which serves to protect the electrode. In this process the off gas from the furnace is used to preheat the charge . In the Indian context, there is a wide variation in the technological achievements in the Arc Furnace Technology. There is limitation in the development of Electric Arc Furnace Technology due to high energy cost and poor availability of scrap. However, few secondary producers in India have done considerable progress (refer Ispat Industry in the Iron making section) in this regard. Installation of proper secondary emission control system, utilization of EAF dust & slag and control of high noise in the EAF steel making processes have further scope of improvement . Electrode consumption of Electric Arc Furnace need to be reduced to 1 kg/thm from the existing level of 6.1 – 6.9 kg/thm (Reference Plant: Alloy Steels Plant, SAIL) . Present Practices – An Overview [1.3 / 15 ] 9. ROLLING MILLS Ingot casting is an obsolete technology and steel makers all over the world are switching over to continuous casting. Continuous casting eliminate the primary mills and produce much superior quality material with high surface finish. It saves about 20% energy. Rolling Mill can be categorized as Hot Rolling and Cold Rolling operations. Pollution from a Rolling Mills mainly includes mill scale, oily mill sludge, oil emulsion, pickling acid sludge, emission from reheating furnaces, Noise etc. 9.1 Mill Scale contains approximately 70 % Fe content. Presently approximately 100 % of the total generation is either recycled or sold. Hence little pressure is there to develop further technological improvement for the utilization of mills scale. Rolling Mill sludge which generally comes out of the secondary treatment from the effluent from mills mainly contaminated with oils and inorganic particles. As the mill sludge are fines bonded with grease and oil, its’ utilization is difficult and presently being dumped in most of the units. Technology to utilize this in the annealing zone of sinter bed has been developed by Burns Harbour, technology transfer in this aspect is solicited as oily mill scale have a great potential for air pollution. 9.2 Thin Slab Casting The important thin slab flat rolling technologies developed in the world are Compact Strip Production (energy savings 50% over conventional Hot Strip Mill) and In- line Scrap Process (energy savings 40% over conventional HSM). This is being installed in the new generation Rolling Mills wherever feasible. 10. Waste Utilisation In an Iron & Steel Plant, about 85 % of the wastes is slag from Blast Furnace and Steel Melting Shop. Hence utilisation of slag is an area of concern. Cement Plants can take Blast Furnace Slag as a input material in it’s blend. High capacity Steel Plants can install captive cement plants for the utilization of BF Slag. This will also attract CDM benefit. Technology option for the utilization of other ferruginous and non ferruginous wastes includes various pelletisation and rotary hearth furnaces. Fastmet process is one such example. 10.1 Fastmet Process Fastmet is a coal based DRI (Direct Reduced Iron) process developed by Kobe Steel Ltd. and Midrex Technologies, Inc. Iron bearing materials viz. virgin iron ores and waste oxides are thoroughly blended with a reductant like coal or waste carbon and rapidly heated in a Rotary Hearth Furnace to produce 85-92% metallised DRI in 6-12 Present Practices – An Overview [1.3 / 16 ] minutes. This DRI is directly charged to Electric Arc Furnace to produce hot metal. The hot metal produced in this process is same as conventional hot metal produced through Blast Furnace route. This process utilizes metal bearing wastes both ferrous and non- ferrous. Integrated steel plants find it difficult to process this waste and achieve zero waste concept. The waste which can be processed through this technology include residue from iron oxide screening, bag-house dust, mill scale, ESP fines, radial settling sludge. This process can also utilize stockpiled metal bearing fines from various mining and processing operations. This is a cost effective, energy conservative and environment friendly process for recycling of steel plant wastes. This process is one of the Best Available Technologies – converting Waste to Gold. 11. Energy / Green House Gas Emissions Reduction And Pollution Control Steel industry is one of the highest consumers of energy. It is evident that even slight improvement in energy consumption in the Iron and Steel sector would mean considerable saving of money from national point of view. The last two decades have witnessed an unprecedented increase in the prices of energy available for steel industry. This has initiated a renewed impetus for introduction of energy efficient process technology as further energy conservation measures. The major energy inputs in a steel plant are through Coal (coking & non coking, both), Electricity, Petro- fuels and Steam, etc. The Indian Steel plants accelerated their focus towards energy conservation since the oil crisis in 1973. Various energy conservation measures have been adopted progressively in the Indian Iron & Steel plants. With the expansion plan of Iron & Steel Industry, more thrust for energy consumption / conservation is solicited. Fig: 13 FASTMET Process Present Practices – An Overview [1.3 / 17 ] The industry has made significant reduction in energy consumption, pollution control and resource conservation, over the decade. However, specific energy consumption at Indian steel plants is still in the range of 6.2 – 8.2 G Cal/tcs compared with the global average of 4.5 G Cal/tcs. Particulate emission (PM) rate matter varies from 1.6 to 2.5 kg/ tcs and water consumption varies from 3.9 to 7.6 m3/tcs, at the Indian steel plants, compared to the best achieved figures of 0.5 kg /tcs and 5- 10 m3/tcs, respectively. Improvement in energy conservation and pollution prevention & control at the Indian steel plants can be achieved through adoption of more efficient and cleaner technologies. Energy consumption can be brought down by adopting various techniques like Coke Dry Quenching (CDQ), injection of coal dust / tar / natural gases, Top Pressure Recovery Turbines, more efficient & modern BOF process with continuous casting, strip casting etc. In addition to these, energy efficiency of the steel industry can be improved through recovery of sensible heat from high temperature flue gases, improved recovery of furnace gases, better sealing & insulation of ovens / furnaces, elimination of reheating processes, computerized combustion & process controls, etc. All these modifications / measures not only conserve energy but also reduce the CO2 emission and can get benefit from Clean Development Mechanism (CDM) under the Kyoto Protocol. Energy audit at all plants have become mandatory in Integrated Iron & Steel Plants. The report of the expert committee on Integrated Energy Policy of planning commission has recommended for creation of National Energy Fund to finance Energy Research and development which inter alias include technology up-gradation as well as energy conservation & GHG (Green House Gas) emission reduction. Reduction in water consumption and effluent discharges can be achieved by intensifying localized and centralized recycling systems. Adoption of dry cleaning of fuel / flue gases in place of wet cleaning will not only reduced the water consumption & effluent discharge but also increase the recyclability of the dusts/fines. For improving the air quality, de-dusting systems for capturing and cleaning the fugitive emissions generated from the various operations like Cast House De-dusting Systems at Blast Furnace & dog house at BOF can be installed. As per the National Steel Policy, steel production in India will increase from the present level of 45 million tons to 110 million tones by 2020. During expansion, major thrust will be given for adoption of best available technologies for further reduction of specific energy consumption and pollution control. 12. Conclusion Indian Steel Industry is poised for a massive transformation, credit goes to the significant change in the Indian Economy. Steel is the backbone for infrastructure Present Practices – An Overview [1.3 / 18 ] building and engine for development. Simple calculation reveals that even to catch up the world average per capita consumption of 170 kg of steel, India’s production falls short by 132 MT annually (which is almost three times of the present annual out put). To achieve global competitiveness, major expansion/ modernization and new installations of Indian Iron and Steel Industry is underway. This steel making process is associated with severe environmental impacts, from mining through production process. With increasing concern at global and local levels on environmental degradation, existing regulatory measures are being tightened and new regulations are on the anvil. Project proponents of the expanding steel industry, when contemplating new installations or expanding/modernization of the existing facilities, must have to plan environmental safe guards to meet the more stringent pollution norms. The proposed technologies must envisage Quality improvement of prime raw materials, maximizing utilization of inferior grade of raw materials, total recycling of other ferruginous and non ferruginous wastes, maximum thrust of energy saving and reuse, reduced GHG gas emission, complete control of secondary emission and low particulate and gaseous emission from the stacks through superior air pollution control systems. THE ULTIMATE OBJECTIVE IS, EVERY TONNE OF STEEL PRODUCED MUST AIM AT IMPROVING THE QUALITY OF LIFE FOR EVERY ONE, NOW AND FOR FUTURE GENERATIONS. IN ONE WORD SUSTAINABLE. 13. Acknowledgement The author acknowledges with thanks to the management of Steel Authority of India for the valuable support that have been provided for publishing this paper. 14. REFERENCES 1. Agrawal R.K. and B.M.K. Bajpai (1999), “Solid Waste Recycling, Reconditioning and Reuse”, in Proc. of REWAS 99 Global Symposium on Recycling Waste Treatment and Clean Technology, eds. I Gaballah, J Hager and B.Solozabal, Vol 2, San Sabestian, Spain, pp. 1638-1646. 2. AISI, 2001. American Iron and Steel Institute, Steel Industry Technology Roadmap, AISI Report 3. Ameling D (2000), “ New Developments in Integrated Steel Making in Europe”, MPT International, December-2000, 6, 36-42 4. Balajee S R, P E Callaway, L M Jr Kelman and L J Lohmen (1995), “ Production and BOF recycling of waste oxide briquettes containing steel making sludges, grit and scale at Inland Steel”, Iron and Steel Maker, 22, 8, 51-55. Present Practices – An Overview [1.3 / 19 ] 5. Ban B C and B M Lim (1994), “ EAF-Dust Treatment by DC-Arc Furnace with Hollow Electrode and New Concept of Dust Recycling ”, SEAISI Quarterly, 23, 1, 54-66 6. Cartwright D and J Clayton (2000), “Recycling oily mill scale and dust by injection into the EAF”, Steel Times International, 24, 2, 42-43. 7. Degel R and O Metermann (2000), “Redsmelt, An Environmentally Friendly Iron Making Process”, Steel Times International, 24, 2, pp. 30-33. 8. Fruehan. R J (1998), “Future Iron Making in North America”, in Proc of ICST/Iron Making Conference, ISS, Toronto Canada, pp. 59-67 9. Griscom F, J T Kopfle and M Landow (1999a), “ Don’t waste Waste-it could mean Profit”, Steel Times Inernational, 23, 1, 72-74 10. Griscom F, J T Kopfle and M Landow (1999b), “Fastmet-your Waste to Profit”, Steel World, 4, 2, 20-24. 11. Heinz J, Lehmkuhler and G Rath (1999), “Red Smelt: A Virgin Iron Making Process for Production of Low Residual Steel in Mini Mills”, Steel Times International, 43, 1, 56-61. 12. Hoffman G E (2000), “Waste Recycling with FASTMET”, Direct from Midrex, 4th Quarter, in house publication, 15-17. 13. Holmes AT and D Greenwalt (1997), “Saldanha Steel Project – the Zero Emission Philosophy”, in Proc Iron Making Conference, Chicago, U.S., pp.451-457 14. Kinzel J, O Pammer, W Gebert, W Trimmell and H Zellner (1997), “Successful Application of the Top Layer Sintering Process for Recycling of Ferrous Residuals Contaminated with Organic Substances”, in Proc.Iron Making Conference, Chicago U.S.,pp 377-383. 15. Landlow M P, J F, Torok, T P Barrett, J F Crum and J Nelesen (1998), “ An Overview of Steel Mill Waste Oxide Recycling by Cold Bonded Roll Briquetting”, in Proc ICSTI/Iron Making Conference, Toronto, Canada pp. 1237-1242. 16. Ministry of Environment and Forests, Govt. of India, Notification dated the 6th January 2000 of Hazardous Wastes (Management and Handling) Amendment Rules 2000. 17. Vancini F (2000), “Strategic Waste Prevention”, OECD Reference Manual, OECD. 18. Young Do Pest (1999), “Waste Oily Material Injection Technology of Foundry BF in Pohang Works”, SEAISI Quarterly, 28, 1, pp 27-29. Present Practices – An Overview [1.4 / 1 ] THE WASTE MANAGEMENT AND INTEGRATED UTILIZATION IN BAOSTEEL GROUP Ming Kang, Bin Liu Baosteel Group, Shanghai,China Email:email@example.com Abstract: On the basis of sustainable development, environmental protection and ecological equilibrium are considered on the top of the list in Baosteel Group. The integrated utilization strategy is carried out to industrialize the wastes or biproducts of steel production such as slag, ash, water, gas, oil. The waste management in Baosteel Group has formed three levels: The first level is to treat the waste as raw material of related industry on the base of avoiding secondary pollution, which ensures regular operation of steel making and avert the stack of wastes. The second level is to build up series of integrated utilization programs, form the industry system technologies and products system of waste management. The third level is to develop technology- focused competitive products based on deep processing of wastes and by-products. Key Words: waste management, integrated utilization, sustainable development, recycling economy 1. Introduction The harmonious development of resource, environment, energy and population is a key social problem in China even in the whole world. Environmental protection and ecological equilibrium are considered on the top of the list in Baosteel Group on the basis of sustainable development. In the implementation of the strategy as “quality steel production”, it is also put forward as a integrated utilization strategy that carry out the environmental protection policies, industrialize the wastes or biproducts of steel production such as slag, ash, water, gas, oil. It has been making great progress in the management of waste in Baosteel Group during 10 years of unremitting efforts. The integrated utilization ratio of the waste is close to 100%. The integrated utilization of slag, ash, mud and oil is developping toward the specialization and industrialization. 2. Waste management is a path to the Recycling Economy Recycling economy is a new type of practical model to promote the sustainable development in the current international society. It emphasizes the greatest efficiency in the utilization of resources and also in the protection of the environment. Recycling economy is different from the linear developing form of traditional large-scale industry, it Present Practices – An Overview [1.4 / 2 ] follows the "3R" principal of reducing, recycling and reusing, which makes the economic activity as a close cycling system of "resource – producing – consuming – reclaimed resource" and achieves a "win-win" result of the economy, enviroment and the society. Therefore, the nature of the recycling economy is ecological economy, the core is the integrated utilization of resources. The integrated utilization is the key part of the recycling economy and it is also a path to the recycling economy and sustainable development. Baosteel as a example of metallurgy industry in China, attaches great importance to environmental protection and integrated utilization of resources. We recycles wastes through internal and external ways, minimizes waste discharge to achieve the "zero release" for years, We make it true that the “so-called waste” is very the “resources in the wrong location”. 3. The discharge and management of wastes in Baosteel Discharge Of The Waste It is produced more than 20 million tons of steel annually in Baosteel. With the expanding and extending of the scale, the wastes hsve increased in both varieties and volume, which reaches more than 10 million tons a year. According to the characteristics of metallurgical waste, the industrial waste in Baosteel is divided into two categories: ferrous wastes and non-ferrous wastes. The ferrous wastes include iron in the metallurgical slag, oxide iron skin of rolling steel, gray iron dust, etc; non-ferrous wastes are mainly fly ash, quenched blast furnace slag, dry blast furnace slag, Bessemer steel slag, electric furnace slag, iron containing dust, waste refractory materials, and other industry waste. As to statistics, in 2006 Baosteel discharged industrial wastes with the amount of 11,667 thousand tons, including the slag, steel slag, iron containing dust, iron oxide scales, waste acid, fly ash and other industrial waste. Especially, the utilization ratio of such wastes as blast furnace slag, steel slag, fly ash reached nearly 100 percent, more than 80 percent of the wastes was utilized by various ways of utilization. The integrated utilization of the main wastes in Baosteel a) Development and Utilization of Slag Fine Powder As is the largest amount of metallurgical slag resources, blast furnace slag was mainly sold to the cement company in before. It is used as high-performanced concrete admixture as slag fine powder based on scientific research as guide. We have also learnt advanced experiences from foreign countries and through many years of scientific development. Specialized company was established to produce slag fine powder and the company has participated in the formulation of national standards “the granulated blast furnace slag powder used in cement and concrete ” (GB/T18046- Present Practices – An Overview [1.4 / 3 ] 2000), which plays a guiding role on the development of the blast furnace slag powder in China. At present, we have set up two grinding lines which produces 1 million tons of slag fine powder each, the production has been widely used in many projects such as bridges, Shanghai Grand Theatre, the Maglev project, and overhead roads. Blast furnace slag fine powder promotes the utilization of wastes, not only greatly ease the pressure of scarce resources, reduce the cost of concrete project, but also significantly improved the performance of concrete in working ability, strength, durability and other properties. b) Development and Utilization of Dry Slag To enhance the application value of the dry slag, the dry slag products have been widely used in concrete roads, floors and blocks, three slag roadbed material, cement admixture, new fossil cotton products and so on after many years of experimental research and market development. Dry slag has many advantages such as stable performance, small density, high strength and high temperature endurance, which can be used as concrete aggregate. c. Development and Utilization of Steel Slag As a large kind of waste, steel slag has a great amount and many varieties. We has made great progress in the use of recycling the steel slag in the plant. It is recycled about 170,000 tons of steel slag stablely per year. We also make the utilization from general back filling to apply to the cement production, road embankment material, concrete projects and soft ground handling. Balance has been made between Emission and utilization. The sesearch of steel slag has made great progress in the application of composite admixture, dry-mix mortar and so on. Compared with the traditional techonology on piles and bottom, the application of steel slag works as a low cost and high allowable bearing pressure. The resistance to wear of the floor material using steel slag is higher than that of ordinary aggregate concrete. The utilization of steel slag is developed from simple working to the profound processing of resource utilization and product orientation. d) Development and Utilization of Fly Ash The comprehensive utilization of fly ash in Baosteel Group has come through more than 20 years by continuous research and productive practice. On the base of breakthrough in high-capacity utilization and multi-channel exploration, fly ash has been developed into several varieties as dry ash, wet ash, wetness adjusting ash, grinded asd, compound ash and so on. These products are widely used in project backfilling, road engineering, concrete or mortar projects, wall materials and insulating materials especially that the grinded ash and compound ash has become the essential components of the pump concrete because of its excellent flow ability and low hydration heat. By 2003, we have made use of more than 600 million tons of fly ash, the utilization Present Practices – An Overview [1.4 / 4 ] ratio has been 100% for 13 years in series. The integrated utilization of fly ash is gradually on the way of resources recycling. e) Development and Utilization of Waste Oil It generates thousands of tons of various waste oil every year in Baosteel Group. In order to avoid environmental pollution and enhance the value of the use of waste oil, we introduced waste oil processing equipments from the United States and set up 700- ton recovery line of waste oil. The quality of the reproduct reaches the standard of the clean oil. At the same time, we have made much research to develop numerous technology and patents. f) Development and Utilization of Iron-Containing Dust Iron-containing dust is a waste of the most varieties and with the most components. It includes: the mud from blast furnace gas, the converter mud, dedusting ash of converter, electrical furnace, the mud of cold-roll or hot-roll, graphite mud in pipes and so on. At present, the low zinc mud (such as the mud from blast furnace gas, the converter mud ) is used for recycling. Other dust is simply disposed and then sold as raw materials for cement plants and steel plants. . g) Development and Utilization of Waste Refractories It generates about 50,000 tons of refractories every year in Baosteel Group mainly including: magnesia-carbon brick, magnesia-chrome brick, converter ladle brick and others. There are seven major categories and dozens of varieties. In recent years, We has increased the comprehensive utilization of waste refractories through scientific research and market development. Some waste refractories are processed into particles to mix with homogeneous new refractories products. We successfully developed the technology as "the technology of making magnesia-carbon brick into renewable raw materials", "the recycling technology of quartz sand". Thses technologies are applied into the production. However, the utilization level of waste refractories in the Baosteel is still relatively low in general. h) Development and Utilization of Desulfogypsum Baosteel, as a giant steel enterprise, has a relatively low emission of SO2 per ton of steel. But, the total amount of emission reaches 35,000 to 40,000 tons / year, in which the SO2 emission of self-owned power plant accounts for 80 percent. To reduce pollution on the environment, Baosteel has been carrying out flue gas desulfurization of the power plant and also the sintering system. Desulfurization devices have been put into use in the power plant. We also set up a production line for wall plaster to suit the market of surrounding aeras, which is prepared for deep processing and utilizatin of desulfogypsum. Present Practices – An Overview [1.4 / 5 ] 4. Conclusion and Expectation Generally speaking, the waste management in Baosteel Group has formed three levels: The first level is to treat the waste as raw material of related industry on the base of avoiding secondary pollution, which ensures regular operation of steel making and avert the stack of wastes. The second level is to build up series of integrated utilization programs, form the industry system technologies and products system of waste management. The third level is to develop technology-focused competitive products based on deep processing of wastes and by-products. All that we do for waste management is to insure clean production, helps to decrease pollution and increase the ratio of utilization, which simultaneously brings in a new point for the economic growth for the enterprise itself. It is certain that there are a lot to do in the aspect of integrated utilization according to the demand of recycling economy. It is essemtial to strengthen international exchange and cooperation. We can exchange successful application as well as practical experience through communication. Let’s make great effort to make the waste management a prospective career. Waste in Mining, Iron & steel Industry [2.1 / 1 ] USE OF SUB-GRADE ORE A CASE STUDY Shri N.K. Mayson, ED (Mines) & A. Mukerji, DGM (Tech.) Mines Organisation Bhilai Steel Plant Synopsis The global increase in demand for steel has caused a corresponding increase in steel demand in India. To cope up with the demand players in both the Private and Public Sectors are planning to increase steel production both through brown field and green field expansion. Addition of new capacities of more than 100 Mtpa are proposed in the next few years requiring an additional 160 Mtpa iron ore. At this rate a 20 to 25 year balance life of Indian Iron Ore beyond 2020 surely is a major concern for the steel industry. The steady depletion of high grade, lump yielding ore reserves, accumulation of large quantities of sub grade fines and tailings are compounding the problem further. The need of the hour is to meet the challenge head on and devise technology to beneficiate and agglomerate the tailings and sub grade fines. Bhilai Steel Plant has already initiated proactive steps to utilize more than 11.5 Mt of tailings and 12 Mt of low grade generated fines through suitable beneficiation and Pelletisation. 1. Complete Paper Steel Industry in India is on an upswing because of the strong global and domestic demand. India's rapid economic growth and soaring demand by sectors like infrastructure, real estate and automobiles, at home and abroad, has put Indian steel industry on the global map. According to the latest report by International Iron and Steel Institute (IISI), India is the seventh largest steel producer in the world. The announcement of the 'National Steel Policy' in 2005 set’s out the Government's vision for future growth of the sector. The policy largely aims to develop a modern and efficient steel industry of world standards, catering to the diversified steel demands. It focuses on achieving global competitiveness not only in terms of cost, quality and product-mix, but also in terms of global benchmarks of efficiency and productivity. It seeks to enhance indigenous production of steel to 200 million tonnes (mT) per annum by 2019-20 from the 2004-05 level of 38.1 mT. This implies a compounded annual growth of 11.5 percent per annum. Waste in Mining, Iron & steel Industry [2.1 / 2 ] India is the 4th largest producer of iron ore, producing around 154 million tonnes annually, which is nearly 12% of the global output. India’s proven iron ore reserve at 25.2 billion tonnes is 7% of the world total at around 370 billion tonnes (of which high grade >65 % Fe hematite is about 14 %). India's largest iron ore deposits are located in Jharkhand-Orissa belt, which accounts for 44% of the total reserves, followed by Karnataka-Goa (32%) and Chhattisgarh – Maharashtra (16%). Of the many problems that beset the steel industry, one is that India is deficient in raw materials required by the steel industry. Iron ore deposits are finite and there are problems in mining sufficient amounts of it. This problem can be tackled by optimum processing of raw materials, search and use of low grade ores, beneficiation and sintering/pelletisation of iron ore etc. The National Mineral Policy, 1993 has outlined certain key objectives in the area of mineral conservation and use like • As minerals are exhaustible and non-renewable resources, their exploitation has to be done keeping in view not only the present but the long term needs. • The best use of available mineral resources shall be ensured by adopting, during mining operation, effective measures for conservation and beneficiation, recovery of associated minerals and later by efficient processing of minerals. • Conservation of minerals shall be construed not in the restrictive sense of abstinence from consumption or preservation for future use, but as a positive concept leading to augmentation of resource base through improvement in mining methods, beneficiation and utilisation of low grade ore and rejects, recovery of associated minerals, reduction in the requirements of minerals per unit of material output, etc. • Utilisation of low grade minerals, mineral wastes and rejects shall also be encouraged through appropriate incentives. Bhilai Steel Plant, an integrated ore based steel works, was commissioned in 1959 with production capacity of 1.0 mT of steel. In successive phases, capacity was enhanced to 2.5 and 4.0 mT in the year 1962 and 1984 respectively. Figure depicts facilities available with Bhilai Steel Plant for 4.0 mt production. As of now this is the largest steel plant in India with present capacity utilisation more than 100%. Waste in Mining, Iron & steel Industry [2.1 / 3 ] Bhilai’s share in the 26 mT hot metal production earmarked for SAIL in 2009 -10 is 7.5 mT. The iron ore requirement in 2009 -10, vis-à-vis its current requirement is tabulated below Iron Ore Requirement of BSP YEAR 07-08 08-09 12-13 17-18 Hot Metal 5700 5800 7500 7500 Sinter Production 7100 7100 9700 9700 Skip Sinter 5652 5652 8245 8245 Pellet 900 900 Net Lumps Required 4768 4847 3323 3323 Net Fines required 5176 4952 7813 7813 Mines Potential Lumps 4196 4465 4032 3324 Fines 4932 4604 6156 8399 Surplus / Shortfall Lumps -505 -382 709 1 Fines 2630 1641 -1656 586 % SINTER 58.0 57.6 67.5 67.5 %LUMPS 42.0 42.4 25.2 25.2 %PELLET 7.4 7.4 Note: For 2007-08 & 2008-09 short fall in the requirement of fines will be met from old fine stocks. The iron mines at Dalli-Rajhara have been in production since 1958 and have so far produced more than 207 mT of iron ore. With nearly 50 years of mining the ore reserves have started dwindling giving rise to numerous constraints in mining thereby creating a shortage of iron ore to meet the future requirement of the steel plant. The current reserve position is tabulated below 1.1 Constraints in Mining • Depletion of Ore Reserves at Iron Ore Complex • Exhaustion of Ore reserves of Dalli Manual. Jharandalli & Mahamaya Mines by 2009-10, 2010-11 & 2011-12 respectively. • Dalli Mech. Mine will be exhausted by 2014-15 • Working at lower horizons in Rajhara Mech. Mine below ground water table. Pit likely to go 130 m below water table. • Increase of Silica & reduction of Lump yield with depth as we are nearing the BHQ basement Waste in Mining, Iron & steel Industry [2.1 / 4 ] Mineral Reserves as on 01.04.2007 Mines Reserve (in MT) Fe % SiO2 % Al2O3 % Rajhara Mech Mine 20.67 67.31 1.76 0.84 Dalli Mech. Mine 32.87 64.09 4.38 2.26 Jharandalli Mine 9.97 63.44 4.36 1.90 Dalli Manual Mine 4.05 62.33 4.71 2.61 Mahamaya Mine 4.32 62.00 5.00 2.90 Dulki 7.66 63.67 3.60 2.76 Total 79.54 64.88 3.48 1.83 1.2 Bhilai Steel Plant’s initiatives to use Sub-grade ores In order to supplement supply of iron ore along with a view to gainfully utilize the accumulated slime (waste) & generated fines and facilitate environment management, BSP is in the process of installing following two model projects. • Reclamation and up gradation / beneficiation of low grade generated fines into sinter grade fines. • Installation of Slime Beneficiation Plant along with down stream Pellet Plant for utilization of the tailings. 1.3 Beneficiation of Generated Fines 12 million tonnes low grade fines (-8 mm) have accumulated at Jharandalli, Mahamaya and Dalli Mines which have been termed as “Generated Fines”. These low grade fines are having about 57-58% Fe content and contain 12-14% +10 mm fraction. It is proposed to reclaim / utilize these Generated Fines dumps by processing through the existing Dalli Crushing, Screening & Washing Plant with certain modifications. 2. Benefits • Gain-full utilization of low grade fines for iron making after beneficiation. The yield of beneficiated fines shall be about 60 – 65 % having +63 % Fe. • Reductions in the dumping load at mines to an appreciable extent & reduce the influx of fine grained washouts which cause land degradation. • The slime generated from beneficiation process can be further utilized as input to the beneficiation pellet plant being installed at mines. Waste in Mining, Iron & steel Industry [2.1 / 5 ] • In future all the regular generation of low grade fines shall be directly diverted to the proposed unit instead of dumping. 2.1 Slime beneficiation & down stream Pellet Plant Dalli Mechanized Mine has crushing, screening and washing facilities which generates slimes beside washed lump and fines. The slimes are accumulated in a tailing pond where solids settle down and clarified water over flows through weirs to down stream water bodies. The pond is now almost full with 11.7 Mt slimes with an additional generation of 0.78 Mtpa from day to day washing activities. The average Fe content of the slimes is about 49% with size below 100 mesh. • The proposed installation includes a slime beneficiation plant which will produce ore concentrate of 64% Fe grade with approximately 50% yield (Annex.-I). • This concentrate will be the feed material for the Pellet Plant which would employ Grate Kiln – cooler process of pellet making (Annex. – II). Pulverized coal will be used as fuel for kiln firing. The pellet thus produced will be used in blast furnaces. The quality of BF grade pellets is envisaged to be as follows:- Fe content : 63.50 (Min) Size : 9 -16 mm CCS : 250 Kg/p (Min) Reducibility : 70% (Min) Swelling index : 18 (Max) 2.2 Benefits • Disposal of current slurry generation from the existing washing facilities and also gradually reclaim slimes from Hitkasa tailing pond. • Gainful utilization of waste material (slime) for iron making in the form of pellets. • Pellets will directly replace lump ore with additional advantage of improved productivity and reduced coke rate at Blast Furnaces. • Recycling of huge quantity of water which is otherwise going as waste at present. • Waste disposal load after ore processing/washing shall further reduce by about 50% - better waste management. Waste in Mining, Iron & steel Industry [2.1 / 6 ] 3. Conclusion Such initiatives will not only meet the Objectives of the National Mineral Policy but also establish the techno-economic feasibility of use of tailing and other sub-grade ore for iron making thereby opening avenues for installation of similar units in India attached to iron ore processing/washing plants. Beneficiation and use of such type of low grade (Fe) hematite slime lying unused at various mining units will lead to benefits like - • Sustainable and gainful utilisation of mineral resources • Recovery of economic value from wastes • Better solid waste management • Creation of space for tailings generated in the future • Reduction of pressure on primary mining • Reduction in the dumping load at mines to an appreciable extent There are possibilities that the rejects of beneficiation plant may also be utilized gainfully in the form of new products. This needs to be explored. Alternatively the rejects after slime beneficiation having very low Fe content can be reclaimed and used for back filling of exhausted mine pits with subsequent afforestation. Waste in Mining, Iron & steel Industry [2.1 / 7 ] Waste in Mining, Iron & steel Industry [2.1 / 8 ] Waste in Mining, Iron & steel Industry [2.1 / 9 ] About the Authors 1. N. K. Mayson Executive Director (Mines), Bhilai Steel Plant had joined Durgapur Steel Plant in 1971 after completing B.E. (Metallurgy) from Nagpur University. Worked in different capacities in rolling mills at Durgapur before assuming charge of ED (Mines) in Oct. 2006. Awarded the National Metallurgical Day Award. Has visited different countries like USA, UK, France Germany, Italy & Finland. 2. A. Mukerji Deputy General Manager (Tech.) Mines HQ, Bhilai Steel Plant had joined BSP in 1980 after completing M. Tech. (Applied Geology) from Saugar University. Qualified Lead Auditor for ISO 14001. Has visited Australia and China. Waste in Mining, Iron & steel Industry [2.2 / 1 ] BENEFICIATION OF LOW GRADE IRON ORE FINES S. Madhavan & Saroj Jain, Essar Group Synopsis: Till date Indian Iron & Steel Industry had luxury of using High Grade Ores for making Iron & Steel. With the increasing mining activity and exports of high grade ores; high grade reserves are slowly & steadily getting depleted. Moreover, existing high grade reserves are not readily being made available to new steel projects due to a number of policy and procedural issues. With the ever increasing prices of iron ore in the international markets as well as non-availability of high grade reserves for new steel making capacities, it has become essential to look at low grade reserves as an alternative for sourcing Iron bearing material for the production of iron and steel. It has become economical and essential to go for Agglomeration Techniques like Sintering or Pellets making process to utilize the Iron Ore Fines after following suitable Beneficiation Techniques for the low grade ores containing high proportion of Alumina, Silica as well as slimes. It is a challenge for the Beneficiation plants to adopt a suitable process to achieve a proper liberation as well as keep the slime level under control. Essar has adopted a process to Beneficiate Low grade Iron Ore fines of about 58 % Fe Content from Joda Sector to convert it to a suitable Pellet feed of about 64 % Fe Content. The Beneficiation Plant will be set up at Dabuna, Joda Sector & the Beneficiated Concentrate will be transported by a long distance Slurry Pipe Line to a Pellet Plant being set up at Paradeep. The Paper Explains the process being adopted by Essar Steel Orissa Limited for the Beneficiation for up gradation from 58 % to 64 % Fe. It also explains the Eco Friendly & Economics of Slurry Transportation of Iron Ore Concentrate. 1. Introduction India is a fast developing economy with GDP growth rate exceeding 8% during last 4 years. This growth rate is likely to be sustained for the next 10-15 years. Steel is the basic material for industrial development. Finished steel consumption is likely to go to 74 Mtpa by 2012 and to a level of 120 Mtpa by 2018 from a level of 47 Waste in Mining, Iron & steel Industry [2.2 / 2 ] Mtpa in 2007. Production of 74 Mtpa finished steel would require about 125 Mtpa of Iron Ore. India has reserves of about 12 Billion tonnes of iron ore. However, with the increasing mining activity and exports of high grade ores; high grade reserves are slowly & steadily getting depleted. Moreover, existing high grade reserves are not readily being made available to new steel projects due to a number of policy and procedural issues. Appropriate planning is required to have a consistent supply of Feed Material of 63.5+ Fe %. If we continue to consume High Quality Iron Ore Lumps, the resources in the country will get depleted in a very short period. It is essential to utilize the fines to full extent. The utilization of fines alone may not solve the resource problems. Hence Beneficiation of Low grade fines is a must for sustaining steel industry in India. Essar Steel Orissa Limited is putting up 8 Million Ton Iron Ore Beneficiation Plant at Dabuna in Joda Sector to utilize the Low Grade fines of about only 58% Fe to up grade to 63.5+ Fe% using Beneficiation Techniques. Essar Steel has already put up a 8 Million Ton Beneficiation Plant at Kirandul, Bailadila, Chattisgarh to produce 67+Fe % Direct Reduction grade high Quality material from Ore of 62-63% Fe %. 2. Need For Beneficiation The Low Grade fines of 58% Fe% cannot be directly fed to Blast Furnace or DR plants since it will be highly uneconomical due the presence of Gangue materials like Silica & Alumina to the extent of 10%. This increases the Slag Volume abnormally & demands high amount of Limestone & Dolomite as flux for maintaining basicity which ultimately increases Coke consumption. Al2O3 also has a negative effect of increasing reduction degradation Index & decreases productivity. Hence it is essential to reduce the Alumina Content in the cold stage itself at a lower cost by proper Beneficiation Techniques. 3. Normal Beneficiation Techniques The following techniques are common for Mineral Beneficiation: • Gravity Separation which uses principle of the difference in Specific Gravity between the valuable mineral & Gangue • Magnetic Separation which uses the magnetic property of one material with Respect to other. • Flotation which depends on surface characteristics of minerals. In this case certain chemicals will be added to modify the surface of one mineral which tends to float due tob surface tension & other material will sink. Waste in Mining, Iron & steel Industry [2.2 / 3 ] • Electrostatic Separation which works on the principle of one material is conductive to electrical charge & other non conductive/less conductive. According to the nature of Ore, the quality of final product required, the value of the ineral & the overall economics one technique or combination of techniques are being followed by different mineral industries. 4. Iron Ore Beneficiation Magnetite (Fe3O4) , Hematite (Fe2O3) & Geothite (Fe2O3.H2O) are common minerals for Iron Ore. If the ore is contains Magnetite the process generally adopted is Low Intensity Magnetic separation. The number of stages depends on the Nature of Ore , Feed Quality & Product Quality. If ROM is a mixture of Magnetite, Hematite & Geothite the process followed is Low intensity Magnetic Separation followed by Gravity Separation. If very high Quality is needed then Flotation is followed after Magnetic as well as Gravity separation. In case of only Hematite & Geothite are present then Gravity separation followed by High Intensity Magnetic Separation is normally the Beneficiation Route. 5. Iron Ore Beneficiation In India Kudremukh Iron Ore Company Ltd.: Kudremukh Iron Ore Company (KIOCL) is the first company in India to install a 7.5 Million Ton per annum Iron ore Beneficiation Plant for the beneficiation of low grade magnetite ore to High Quality concentrate for BF as well as DR feed material with the consultancy help from MS Canadian Met Chem Inc., Canada as a 100% Export Oriented Unit to supply concentrate to Iran. Due to political changes in Iran, the country could not lift material in 1980 & the Concentrate was first exported to many other countries since the same is a good feed material for sintering & Pellet. KIOCL, which started Iron Ore Beneficiation & commissioned the Beneficiation plant way back in 1980 & the plant was beneficiating Low Grade Magnetite & Hematite ore from 38% Fe content ROM to 67% Fe Concentrate. The process adapted was Low Intensity Magnetic Separation followed by Spiral Gravity Separation. The plant added Flotex density separators after Spirals followed by Mechanical Flotation & Column Flotation Cells after second stage Low Intensity Magnetic Separation. The Beneficiated concentrate was transported through a 67 KM long slurry pipeline from the Beneficiation plant at Kudremukh to the Pellet plant at Mangalore for further process. Waste in Mining, Iron & steel Industry [2.2 / 4 ] The company’s Beneficiation Process stopped from 1-1-2006 after Hon. Supreme Court verdict to stop Mining operations. That was the only Magnetite deposit in India being mined. Essar Steel Ltd. (ESL) Essar Steel Limited has put up 8 Million ton Beneficiation Plant at Kirandul (Bailadila Sector) to upgrade 62-63% Fe content Hematite Ore to produce 67% + Fe content Direct Reduction Grade Concentrate. This is the only second plant in India for Iron Ore Beneficiation & the fist plant in India for Hematite Beneficiation. The Concentrate produced in the plant is pumped to the Pellet Plant at Vishakapatnam through 260 Km long Slurry Pipeline. This is the longest distant pipeline in India passing through three states in difficult terrain. The process adapted is Gravity separation by Spirals & Magnetic Separation by High Gradient Magnetic Separation. For the liberation of the ore & for grinding the material suitable for Pipeline Transportation, Ball Mills are installed. Challenges in Beneficiation for Orissa Ore The Low Grade Iron Ore Fines in the Orissa is having higher Alumina Content & combined water. The alumina distribution & Geothite distribution is spreading in all Size ranges. Hence it is the real challenge for Mineral Beneficiation with this type of material. The common mineral Beneficiation methods are: • Gravity Separation • Magnetic Separation • Flotation All the above methods requires de-slimed material as well as Liberation. In Mineral Beneficiation, slime & liberation are two faces of the same coin. General Size Distribution of Orissa Ore The Coarser fraction of as received sample (+1mm ) fraction consists of Higher Fe % than the average Fe % of the ore. But this fraction is not liberated. Only if this fraction contains Fe % more than 63 + Fe % the same can be taken as Final Product. Only if ROM Fe % is in the range of 60% & above the + 1mm fraction is having 63+ Fe %. In case of 58% Fe in ROM the + 1 mm fraction is only 60 to 61 % Fe content which requires liberation & further Beneficiation. The ultra fines of below 20 microns contains only 45 % Fe content which can be taken out as waste slime before grinding. The above constitutes 10% of ROM. Size distribution of typical are as follows for 58 % Fe in ROM. Waste in Mining, Iron & steel Industry [2.2 / 5 ] Size in mm % Retained Fe % - 10 +6 1.1 61.5 - 6 +2 37.5 60.5 - 2+ 1 18.2 60.0 - 1 +0.5 12.6 59.5 -0.5 +0.21 6.6 60.5 -0.21+0.1 5.7 58.0 -0.1 +0.053 2.7 57.0 -0.053+0.02 5.6 50.0 -0.02 10.0 45.0 The minus 0.02 mm finest fraction which is only Slime with 45% Fe. The coarse fractions needs grinding to liberate the material first at 1mm & below for Gravity separation & below 150 microns for Magnetic Separation. The grinding should generate least slime for better yield & to improve the efficiency of Beneficiation equipments. Process at Essar Steel Orissa The Process to be adopted in Essar Steel Orissa for Beneficiation is enclosed in the form of flow sheet which shows the equipments and their sequence. The process sequence is: Beneficiation Plant • Screening at 10mm & Crushing the + 10 mm in close circuit with Screen. • Classification of minus 10 mm fraction to separate slime at 100 microns • De sliming Cyclones to reject minus 10 micron slime as overflow. • Magnetic separation of De sliming cyclone Under flow. • Screening of Classifier Coarse fraction at 1mm • Primary Grinding of + 1mm Screen oversize in Ball Mill in close circuit with Screen. • Gravity Separation of minus 1mm fraction. • The concentrate of Gravity Separation is one part of Final Concentrate. • Treat the Gravity Separation Tail in Magnetic separation along with de sliming cyclone under flow. • Magnetic Concentrate is other final product. • Magnetic tailings is final tailings. • Regrinding of Concentrates in Secondary Ball Mill in close circuit with Hydro cyclones to produce final size at 99% passing 150 Microns & 70 to 75 % passing 45 Microns suitable for Pipe line transportation in Slurry form. • Pumping of Concentrate through 253 km long Slurry line. Waste in Mining, Iron & steel Industry [2.2 / 6 ] Slurry Transportation Taking advantage of finer grinding our company decided to Transport the concentrate in Slurry Form through 253 Km long Slurry Pipe line of 20” diameter. This is a Eco Friendly way of transporting the concentrate. The advantages of this transportation are: • Transportation is Underground & no disturbance to people & traffic. • No air pollution during Transportation. • Conservation of Energy since no Fuel is required. • The transported water is recovered in Pellet Plant after filtration & the same is used in Pellet Plant as make up water. • The method is economical compared to other transportations. Pelletisation The Concentrate will be filtered at Paradeep & mixed with Bentonite & limestone to produce pellets which is called as Green Pellets. The Green Pellets are heat hardened in Indurating machine at 1320 Deg. C using Low Sulphur Oil as Fuel. The pellet produced is to be used in Blast Furnace as a feedstock. 6. Conclusion • It is possible to produce good quality Blast Furnace feed material Using Low Grade Iron Ore Fines using proper Beneficiation techniques. The Concentrate produced can be transported in Slurry form in an eco friendly & economical way. The agglomeration techniques of Pelletisation helps to produce material of correct size & strength material for Blast Furnace. • Processing of low grade iron ore to high grade facilitates utilization of otherwise waste material. This low grade fine ore is presently not usable and is occupying space and causing environment hazards. • Utilization of low grade is also in the larger National interest. By utilizing low grade ores, better quality material is being preserved for future generations. Waste in Mining, Iron & steel Industry [2.2 / 7 ] RO Scree Roll crushe +1 Screw Scree Intermediate Hydrocyclone thickener Hydrocyclone Rougher Magnetic Spiral separator Cleaner Spiral Concentrate thickener Conc. Tailings thickener Tails Flowsheet for iron ore beneficiation Waste in Mining, Iron & steel Industry [ 2.3 / 1 ] WASTE MANAGEMENT EFFORTS IN IRON MAKING ZONE OF BHILAI STEEL PLANT Sajeev Varghese Manager Blast Furnace (Operation) Bhilai Steel Plant The Blast Furnace (BF) is likely to continue as the main production process route for hot metal in large integrated steel plants in the foreseeable future. The steel industry wherein the quantum of raw materials, resource, energy utilization is high in magnitude and which undergoes extensive processing, do certainly calls for greater management and control efforts to minimize pollution, waste arising and optimize resource utilization. Specific consumptions of natural resources and emissions / discharges to the environment are mainly dependent upon the quality of raw materials, technologies, type of pollution control equipments etc. Some of the waste management efforts of iron making zone in BSP have been described below. 1. Waste Heat Utilization From Stoves Of BF-6 The flue gas from stoves is being used for drying of pulverized coal to bring down the moisture level less than 1% in grinding system of Coal Dust Injection (CDI) for BF - 6&7. As the temperature of flue gas in stoves is about 180-200 degree centigrade, it is further heated in hot gas generator with BF gas to attain the temperature required for drying of coal. By using stove flue gas the size of HGG (hot gas generator) & its peripheral are smaller in size and consumption of BF gas is less. Another distinct advantage of using stove flue gas is less consumption of nitrogen gas, which is used for inertization of grinding system. Fig. 1. Pulverised Coal Dust Injection System Waste in Mining, Iron & steel Industry [ 2.3 / 2 ] Fig. 2. Grinding System using stove off gas 2. Reduction of SiO2 in iron ore fines Blast furnace route permits operations with high gangue materials at reduced productivity. Carrying gangue through the high temperature steel making thermal cycle has a huge environmental impact, compared to beneficiation of raw material at ambient temperature before subjecting it to the iron and steel making temperatures. In Dalli mines of Bhilai Steel Plant, work has been carried out to decrease % SiO2 in the sinter fines from 4.4 to 3.9% to improve the functioning of the thickeners. It was observed that the existing classifiers at crushing screening and washing plant can reject fine silica particles through its overflow by operating with higher solid to water ratio. Operating classifier at 20-25% pulp density increases the slime loss from existing 14% to 19% and decreases silica content in iron ore fines by 0.5%. Increased slime loss was also causing jamming of Radial settling tank and production loss. In order to reduce silica content in iron ore fines & reduce slime loss, it is proposed to modify the Fluidized Bed Classifier (FBC) system so that classifiers can be operated at higher pulp density without thickener jamming. This modified system was able to recover iron fines concentrate with 63% Fe with about 4% SiO2. FBC system was stopped due to failure of dewateriser screen. Now the Waste in Mining, Iron & steel Industry [ 2.3 / 3 ] damaged screen will be replaced by a slow speed spiral classifier (SSSC) unit to recover the fine iron concentrate from the slime. It will thus ensure the slime loss to remain at 14% level but improving the quality of sinter fines by decreasing 0.5% silica content. As the faster settling iron particles would be recovered from SSSC unit, the thickener jamming problem will be solved & clear process water will be recycled to the Crushing Screening &Washing plant from the Radial Settling Tank pumping station itself. Annual consumption of sinter in blast furnaces is 7.1 million tones for the year 2007-08. A reduction in SiO2 of .5% can reduce slag rate by 2kg/t of hot metal. Thus annually we can save around 4000t of slag generation. The process flow diagram of FBC and the proposed modification is given in Fig. 3. The civil work of the proposed modification is almost complete & unit may start by Jan. 2008. -10 mm ore fines Slime –0.2 mm Fe:50% SiO2-14% Duplex Spiral -10 +0.2mm Sinter fines (avg.SiO2-4.4 %) Fluidised Bed Classifier (FBC) Slime beneficiation system Slurry Pump Recovered fines: 50T/hr Hydro cyclone Fe: 63% SiO2 < 4% Slow Speed classifier Conveyor Belt Existing Fines Conv. Belt 3. Use of LD slag in sinter & blast furnace The converter slag contains substantial amount of lime & iron. This slag is crushed & screened at a separate place. The fines fractions are sent to sinter plant, which is then used in sinter making to replace limestone. The lump fraction is sent to blast furnace & is charged to the furnace as a replacement of limestone. This way we are recovering the lime & Fe content of LD slag which otherwise goes as a waste. 4. Covered Cast house troughs in BF-7 It helps in substantial energy saving by preventing drop in overall hot metal temperature during delivery to steel melting shops and also helps in controlling fugitive emissions in cast house. Waste in Mining, Iron & steel Industry [ 2.3 / 4 ] 5. Water cooling system A Closed loop demineralised water-cooling system has been installed at BF -7, which is helping us in optimum usage of water. Apart from this the data generated by the flow meter and temperature measurement devices are helping us to reduce the heat losses of the furnace and making the furnace more energy efficient. 6. Energy recovery from top gas BF-7 uses high top pressure for the improvement of productivity and the reduction of coke rate. This high top pressure also provided an ideal opportunity for recovering energy from the large volume of the pressurized gas generated. A project is in the pipeline to tap this energy by means of an expansion turbine, which is installed after the top gas-cleaning device. With this BF-7 can generate as much as 10 MW of electricity. These are some of the work done in the area of waste management & there is still scope for improvement in reduction of waste & our ultimate target is to achieve zero waste discharge. We all know that there is great impact on environment & efficiency of the system for carrying high ash in coal & alumina in iron ore through the steel making cycle. An additional 0.8 G calorie energy is consumed & 375 kg of carbon dioxide is discharged for every ton of steel produced as a penalty for using high ash coal (say 17% ash) coal & high alumina iron ore fines (2-5% alumina) compared to an energy efficient practice (say 10% ash coal & 1% alumina iron ore). In SAIL beneficiations of raw materials particularly in high ash coals & high alumina iron ores should be taken up on priority basis. Waste in Mining, Iron & steel Industry [ 2.4 / 1 ] SOLID WASTE MANAGEMENT IN COKE OVENS OF BHILAI STEEL PLANT S. Roy Chowdhury (Asst. Gen. Manager) Co. & Ccd Bhilai Steel Plant, Steel Authority Of India Ltd. Bhilai, (C.G.) 1. Introduction Metallurgical coke making in by product recovery oven is one of the major source of solid waste generation in an integrated steel plant where coke& coke oven gas are the major source of energy. Right from the receipt, unloading handling, crushing carbonization and subsequence coke handling dust & breeze is generated. The process of coal charging of inside the oven, pushing & coke quenching operation generates lot of waste into kind of hot air forms, dust, breeze, coke smaller freedom. Energy requirement of this Steel Plant for heading purposes is mostly supplied by coke oven gas, tar & pitch mixture. In the early nineties environmental regulation for coke oven emission was non- existent, except for co emission (3Kg / ton of coke) & particulate emission (50Kg / m3). 1. Waste Generation Sources 1.1 Coal preparation Plant In Bhilai steel plant, presently 15000 Ton / Day of coal of different grades & different varieties are handle to cater the demand of production of coke 8000 Ton / Day (Dry basis). Apart from unloading of coal, nearly 15000 Ton / Day coal is handling in two area of coal preparation in coke oven BSP through stacker cum reclaimer & gantry crane. In this area waste generated are mainly 1. Coal dust generated during Coal crushing. 2. Coal spillage from conveyer & chute areas. All the waste generated are being reused in situ. 1.2. Actions Taken For Reducing Waste Generation 1. Dust suppression system is being reintroduced in Coal crushing area. 2. Conveyor belt spillage reduction in Conveyor belt trough angle has been changed from – 25o to 35o. Waste in Mining, Iron & steel Industry [ 2.4 / 2 ] 3. Conveyor protective devices particularly, belt sway system are re Commissioned & chute jam limit switch has been installed for reduction of coal spillage. 4. All chute has been changed from mild steel to stainless steel for better flow ability. 2. Reduction Of Dust Emission On Through Moisture Addition Factors like bulk density of Coal charge, energy requirement for Coke making and flow ability of coal charge guide the extent of moisture in coal blend. Studies have revealed that the bulk density of the change for the desired crushing level (80% through 3.0 mm) is more or less the same at a moisture level of 7.5 – 8.5%. At Bhilai Steel Plant water sprays have been installed in the Coal tippling station and under each silo dozing the Coal for blend preparation. Sprinklers were also installed in the open yard storing of Coal. Moisture addition was controlled automatically with the help of solenoid valves & the blend moisture was maintained at 8 – 8.5% as against the earlier figures of 6-6.5%. The above measures resulted in significant improvement in working environment & operation in the Coal preparation Plant and Coke oven batteries. On line coal moisture analyzer has been installed for better control & monitoring the system. 3. Coke Oven Batteries In Bhilai steel plant there are 10 coke oven batteries out of which Battery no 1,2,3,4,7,8 are 4.3 m high & are running, battery no. 5 & 6 (4.3m height) are under rebuilding stage & coke oven battery no. 9 & 10 are 7m high & are also running & present production of coke is 750 oven / day. (7900 ton B.F. Coke Dry Basis per day ) In BSP coke oven batteries coal of quantity 16.5 ton (dry basis) are being charged inside the oven (oven effective volume is 21.6 M3). The process of carbonization takes place at a very high temperature 1200 – 1250oC in an air tight chambers. The coke formation from coal takes about 17 to 19 hrs and after that coke is pushed from oven through coke guide car into a quenching station where it is quenched with (phenolic effluent came from coal chemical department for better environment). Quenched coke is then stabilized in initially at wharf for steam removal & is sent through conveyers to coke screening plant where particular size fraction (+25mm to –80mm) send to blast furnace & other fraction send to sinter plant.(1,2,3) 4. Sources Of Solid Waste Generation In Coke Oven Batteries The main processes which causes generation of waste in coke oven batteries affects environment are listed below. Waste in Mining, Iron & steel Industry [ 2.4 / 3 ] 4.1 Charging of coal in coke oven Drawing of coal from coal tower to charging car bunker & as well as charging of coal (16.5 ton / oven dry basis in 4.3m batteries, 30 ton / oven dry basis in 7m batteries) into inside the oven, both these cases lot of coal spillage occurred due to lack of automation in the system. 4.2 Coking Process Coal to coke conversion is the utmost important technology in coke oven & maintenance of thermal regime & maintaining proper temperature in heating walls by burning coke oven / blast furnace gas in heating flues is of utmost importance to achieve proper carbonization, coke yield and coke quality. Improper heating leads to green pushing, over coking, wastages to heating gas & may lead to sticker oven. Green pushing (where coke mass temperature is not sufficient, i.e. coking not completed result in evolution of thick black smoke to the atmosphere during pushing. 4.3 Oven Pushing After the carbonization cycle completed, in oven both side door needs open for pushing out of coke from oven, as soon as quenching car is ready for receiving hot coke. After pushing out of coke from oven, coke spillage occurred in front of both side of oven. Improper mechanization of machine causes wastage of coke during pushing. Pushing of coke from oven to quenching car also produces lot of emission called pushing emission. These emissions contain lot of ash, & coke dust, which increase ambient SPM level. 4.4 Quenching process of Coke: In Bhilai Steel Plant hot coke is being quenched by phenol water effluent from coal chemical department. During quenching lot of wastage are being generated in the form of coke breeze at quenching pond & emission are produced during the quenching process of coke in quenching station. It has high particulate matter contains coke dust & ash particle. 5. Coke Sorting & Coke Screening Plant In coke plant, coke spillage, coke dust & disintegrated coke have always been not only a nuisance but also play an importance role for hindering the performance of plant. Important places where there particulate matter escapes out of the system are as follows: 1. Transfer point of material at conveyors. 2. Coke culture & 3. Coke screen houses. Waste in Mining, Iron & steel Industry [ 2.4 / 4 ] 6. Controlling Of Waste Generation In Coke Oven In order to control the generation of waste from coke oven batteries following steps are needed. 1. Reduce / generation of wastage eliminate. 2. Effective management of wastage . 3. Reuse of wastage. In batteries for reducing solid waste generations following actions are taken in different areas. Areas Cause Action 1. Charging car Bunker Spillage 1). All pocket opener for drawing coal are in automode & 2).All Pocket opener are interlocking with long travel of m/c. 2. Charging car telescope Spillage at oven top P/S & C/S telescope bunker charged at a time & then middle bunker coal changed & in middle bunker sleeve with ring provided for reducing spillage. Timer introduced in middle bunker pocket opener for full charging of oven. Pusher car Spillage of coal 1). All pusher car Leveling System in auto mode has been installed. 2). All pusher car spillage chute tie rod system provided for reduce of coal spillage, earlier counter chain system in flexible chute are there. 3). Leveler bar stand straightened was done so that during leveling of each. Oven, spillage coal came out (nearly300kg) in coal spillage bunker for reuse, which eliminates coal spillage. Door Extractor machine Dust emission Battery no. 10 Door Extractor during pushing machine (DE-3&4) hoods are modified for dust emission control. Spillage of coke chain system has been provided in cage of door extractor. In coke oven Battery NO-3 both coal charging cars, screw feeder charging system has been installed for complete elimination of coal spillage at oven top level. Waste in Mining, Iron & steel Industry [ 2.4 / 5 ] 6.1 Combustion control of coke ovens Efficient combustion control system are being introduced in BSP coke oven Battery – 3,9,10, 4 for proper combustion & heat control of coke oven. The system measures end coke mass temperature with the help of infrared sensor located near. Door extracter / Quenching tower. Correlation has been developed between temperature & the actual coke mass temperature in the oven. This data is used to adjust the gas flow rate to attain proper flue temperature in the heating walls. This saves not only heating gas but eliminates green pushing, sticker formation & improves Coke quality also. 6.2 Modification in quenching process In coke oven Battery 9 & 10 quenching process has been modified in the following areas. a). Quenching car & wagon modification. b). Quenching tower nozzle position modification. Quenching car operator cabin has been modified by changing window portion for better visibility of operator and for better receiving of coke in quenching wagon. 6.3 Quenching wagon and Quenching nozzle modification All the holes for air circulation has been plugged & separate perforation has been made in shutter gate of wagon, accumulates for few seconds & coke gets washed, breeze are removed & more over due to high amount water in wagon for smaller time, coke disintegration reduces drastically due to high thermal resistivity of coke due to flood style quenching. Quenching tower nozzle angle has been changed from 900 to 1350 for smooth & uniform quenching. Earlier water sprayed from nozzle couldn’t quenched the coke in wagon receiving side & as water didn’t reach the spot. By changing the angle, problem has been rectified. All the quenching route material has been changed from Mild Steel to Stainless Steel for better life. In this way Quenching pond breeze generation has been reduces from 48 Dump car to 40 Dump car in Battery 9 & 10 per month. 7. Coke Sorting Plant All the transferring point of coke conveyor chute has been modified to Box type chute from inclined chute so that direct impact of coke (which causes generation of coke dust, coke breeze & nut coke) has been eliminated, diabase lining has been done in all chutes. Waste in Mining, Iron & steel Industry [ 2.4 / 6 ] In screening area all 25mm grizzly 12 rolls has been provided for better screening & in continues vibrating screen, double spring has been installed & angle of screen has been changed from150to 221/20, for better screening. More over the convergent of grizzly chute has been modified for effective utilization of grizzly rolls & as well as at the end of grizzly roll, socket has been provided for eliminating coke breakages (which causes coke disintegration. In these specific area by modifying CSP equipment BF grade coke generation has been increased by 1%, and in Bf coke bunker coke fines has been decreased. More over coke (-25mm) size fraction has been decrease from 3.3 T/Oven to 2.26 T/oven. All conveyers width has been increased from 1200mm to 1400mm & trough angle has been changed from 250 to 350 & some leveler arrangement has been installed for complete elimination of coke Spillage. Special type scrapper has been provided for separating coke fines from conveyor (non carrying side). In Tripper care for coke feeding in Bf coke bunker limit switch has been installed for complete elimination of break down & Spillage of coke. 7.1 Management of Waste In coke oven starting from coal to coke feeding, waste of different type are managed differently. 7.2 Waste in Coal Plant All solid waste generated in coal plant has been reused in cycle by cleaning manually 7.3 Waste In Coke Oven Battery Solid waste generated in coke oven Battery has been reused in two ways. Mechanized / manually mode used in battery area Manual mode in coke sorting area. Manual cleaning has been done for coal Spillage, & coal dust & reuse them in coal plant. Mechanized mode like coke thrower used in coke pusher & JCB are being used for coke Spillage occur during coke production, which is recycle with coke at stock yard. 7.4 Manual cleaning Process 4 truck each having 6 Ton capacity regularly engaged for total territory cleaning specially coal / coke dust / breeze, coke particle. Nearly 4x6x5 = 120 Ton coal dust are being generated & reused in their system. Waste in Mining, Iron & steel Industry [ 2.4 / 7 ] Different size fraction of coke are handling in different areas. Fraction CSP-1 CSP-2 CSP-3 +25 mm to –80 mm BF 1 to 4 Bf 4,5/6 BF-7 & 6,5 +20 mm to 25 mm SP-3 SP-3 Sp-3 -20 mm SP1 SP-2 SP-3 Quenching pond breeze. Soaking pit BBM Soaking pit BBM Soaking pit BBM Sintering Plant I Sintering Plant I Sintering Plant I Coke dust K-0 K-0 K-0 Coal dust CHP CHP CHP Coke particle Coke Stock Yard-2 Coke Stock Yard-2 Coke Stock Yard-2 7.5 New screen provided in coke stockyard – 2 In coke stock yard –2 two conveyor belts 24 C1 & 24C2 which fed coke to BFs & as well as coke loading facility has been introduced with a new conveyor belt 24AC2 screen has been introduced for separation coke smaller size –25 mm & +25 mm. 7.6 New coke screen at CHP –I New screen has been installed at CHP –I area for coke particulate separation of – 25 mm & +25 mm. This is for exclusively the coke fines generated from Blast furnace coke bunker. As Blast furnace –7 coke screen size is +35mm so-35mm size coke generated from Bf-7 is reused for screen & coke fines are sent to SP-3 & +25mm fraction of coke is used in CSP-I for feeding to blast furnace. 8. Conclusion Coke oven Batteries are considered to be one of the major contributors towards waste generation & atmospheric pollution in the Steel industry. The coal preparation, oven charging, pushing & quenching & coke screening operation causes lot of wastes in kind of dust, coke particles, coal spillage, coke breeze, coke fines, that are considered to be the harmful to the human system & this generation & their handling also considered to be prime important for smooth production of coke oven. Due to large number of emission sources, their transient nature, long life of coke oven batteries etc. Control of emission from coke oven is a difficult task. Waste in Mining, Iron & steel Industry [ 2.4 / 8 ] Over the years a large number of different type control measures in the coke oven have been introduced by the SAIL BSP in the different areas of coke oven Batteries to improve significant working environment in the operating batteries. 9. Reference 1. Bandopadhyay s.s et al 1992 Modification of coke oven doors with heat shield to reduce gas emission. 2. nashan G (1987) Coke making international volume no. 1 1987. 3. Mr. Ghosh. RDCIS in EFCI, 2002 Production of BF Coke in Cleaner Environment. 4. Abhijit Misra, in EFCI, 2002 Coke plant at Tata steel a technologies model for environment construction. Waste in Mining, Iron & steel Industry [ 2.4 / 9 ] POST CARBONIZATION TREATMENT OF COKE PRESENT STATUS COKE FLOW DIAGRAM BATT-1 BATT-2 BATT-3 BATT-4 BATT-6 BATT-7 BATT-8 BATT-9 CSP-1 CSP-2 CSP-3 SY-1 BF-1 BF-2 BF-3 BF-4 BF-5 BF-6 BF-7 SY-2 BSP “ICS NORM OF COKE IN BHILAI STEEL PLANT” Coke Quality CSP-1 CSP-2 CSP-3 2006-07 2006-07 2006-07 M10 (MAX) 8.2 8.2 8.0 M40 (MIN) 80.4 80.4 80.4 CSR (MIN) 64.8 64.8 64.8 S (MAX) 0.55 0.55 0.55 CRI (MIN) 22.0 22.0 22.0 MOISTURE (MAX) 4.0 4.0 4.0 +80 mm(MAX) 8.5 8.5 8.5 -40 mm 22.0 22.0 22.0 BSP Waste in Mining, Iron & steel Industry [ 2.4 / 10 ] POST CARBONIZATION TREATMENT OF COKE PRESENT STATUS COKE QUALITY COKE Quality CSP-1 CSP-2 CSP-3 2006-07 2006-07 2006-07 M10 8.0 7.9 8.0 M40 80.7 80.9 80.5 CSR 65.4 65.3 65.3 CRI 22.6 22.7 22.7 MOISTURE 3.5 3.6 3.8 +80 mm 8.6 8.1 7.9 -40 MM - 17.0 21.8 SULPHUR 0.51 0.51 0.51 MEAN SIZE 54.6 - 54.0 BSP “EQUIPMENT USED IN POST CARBONIZATION PROCESS” INSTALLED EQUIPMENT STATUS EQUIPMENT CSP-1 CSP-2 CSP-3 80 MM GRIZZLY 5 5 10 NO.OF ROLL 80 MM CRUSHER √ √ √ 25 MM GRIZZLY 6 6 12 NO. OF ROLL CONTINUOUS 28.5 MM 28.5 MM 28.5 MM VIBRATION SCREEN SIZE IVS SCREEN 20 MM 20 MM 20 MM BSP Waste in Mining, Iron & steel Industry [ 2.4 / 11 ] POST CARBONIZATION TREATMENT OF COKE PRESENT STATUS COKE QUENCHING PROCESS QUENCHING BATTERY BATTERY BATTERY SYSTEM 1-8 9 10 CONVENTIONAL TOP QUENCHING √ √ √ (STAGGER) SIDE QUENCHING --- √ --- BSP POST CARBONIZATION TREATMENT OF COKE PRESENT STATUS COKE SIZE IN 2006-07 SIZE FRACTION AVERAGE % +100 MM 2.1 +80 MM 10.2 +60 MM 19.4 +40 MM 40.1 +25 MM 19.8 + 10 MM 5.6 - 10 MM 2.9 BSP Waste in Mining, Iron & steel Industry [ 2.4 / 12 ] POST CARBONIZATION TREATMENT OF COKE PRESENT STATUS SKIP COKE ANALYSIS 2006-07 (PERCENTAGE) SIZE CSP-1 CSP-2 CSP-3 +100 MM NIL NIL NIL +80 MM 8.4 8.6 7.4 +60 MM 25.5 25.6 23.1 +40 MM 43.8 43.0 45.9 +25 MM 21.2 21.0 22.5 +10 MM 1.1 1.0 1.1 BSP POST CARBONIZATION TREATMENT OF COKE PRESENT STATUS POST CARBONIZATION PROCESS CSP-3 CSP-1 CSP-2 CSP-3 EQUIPMENT CHANGING FREQUENCY 80MM GRIZZLY 6 MONTH 6 MONTH 6 MONTH ROLL 80MM CRUSHER 6 MONTH 6 MONTH 6 MONTH SEGMENT 25MM GRIZZLY 2 MONTH 2 MONTH 40 DAYS ROLL CVS SCREEN 3 MONTH 3 MONTH 3 MONTH IVS SCREEN 3 MONTH 3 MONTH 3 MONTH COKE MOISTURE --- --- INSTALLED & ANALYZER WORKING BSP Waste in Mining, Iron & steel Industry [ 2.4 / 13 ] POST CARBONIZATION TREATMENT OF COKE FUTURE PLAN FUTURE PLAN BATTERY – 5 1) SUBMERGED QUENCHING SYSTEM (TOP & BOTTOM). 2) WHARF – 3 AUTOMATION DRAG PLOUGH SYSTEM. 3) CSP-2 PLC BASED CONTROL SYSTEM 4) A) DRYFOG SYSTEM FOR DUST SUPPRESSION B) WHARF BELT (HOSCH MAKE) SCRAPPER 5) MOTORISED WHARF BELT CHANGING FACILITY BSP POST CARBONIZATION TREATMENT OF COKE FUTURE PLAN FUTURE PLAN BATTERY – 11 1) COKE DRY QUENCHING 2) WHARF AUTOMATION 3) PLC 4) DE SYSTEM BSP Waste in Mining, Iron & steel Industry [ 2.4 / 14 ] POST CARBONIZATION TREATMENT OF COKE FUTURE PLAN COKE QUALITY BATTERY – 5 MOISTURE 3.5%(MAX) VM 0.8 M 10 8.0(MAX) M 40 81 (MAX) CSR MORE THAN 63.5% BSP SIX SIGMA FILTER CONE 25 factors received from I/O sheet 12 factors filtered from c & E Metrix 6 factors filtered from FMEA 4 inputs for DOE Waste in Mining, Iron & steel Industry [ 2.4 / 15 ] PHASE-4 – CONTROL RESULT BEFORE PROJECT AFTER PROJECT MONTH MOISTURE % MONTH MOISTURE % NOV’04 5.8 JAN’06 4.7 DEC’04 5.6 FEB’06 4.8 JAN’05 4.3 MARCH’06 4.9 FEB’05 5.01 APRIL’06 4.6 MARCH’05 4.81 MAY’06 4.5 APRIL’05 5.06 JUN’06 3.9 MAY’05 4.66 JULY’06 3.8 JUN’05 5.29 AUG’06 3.8 JUL’05 6.03 SEP’06 3.8 AUG’05 5.32 OCT’06 3.7 SEP’05 5.26 NOV’06 3.7 OCT’05 5.24 DEC’06 3.7 NOV’05 5.5 JAN’07 3.7 DEC’05 5.58 FEB’07 3.7 MARCH’07 3.6 APRIL’07 3.6 MAY’07 3.7 JUN’07 3.8 BSP Waste in Mining, Iron & steel Industry [ 2.4 / 16 ] REDUCTION OF BF COKE SIZE (- 40MM) IN CSP-3 OF BATTERY – 9 & 10 CO & CCD BHILAI STEEL PLANT, BHILAI BSP STATUS IN 2005-06 - 22.3% (MONTHLY AVERAGE) TARGET - 21.5% (MONTHLY AVERAGE) RESULTS (DEC.06 – MAY 07) - (MONTHLY AVERAGE) LOCATION - COKE SORTING PLANT –3 METHODOLOGY APPLIED - SIX SIGMA TIME OF COMPLETION - SIX MONTHS OF PROJECT BENEFITS : - 1. IMPROVEMENT IN BF COKE YIELD. 2. IMPROVEMENT IN BF OPERATION PRACTICES. 3. IMPROVEMENT IN BF PRODUCTION. 4. LESS HANDLING OF –40MM COKE. 5. COKE SIZE IMPROVED. BSP Waste in Mining, Iron & steel Industry [ 2.4 / 17 ] BEFORE PROJECT AFTER PROJECT MONTH 40MM MONTH 40MM Oct’ 05 23.5 Oct’06 22.5 Nov’05 21.8 Nov’06 22.3 Dec’05 21.8 Dec’06 21.3 Jan’06 21.8 Jan,07 20.6 Feb’06 21.4 Feb’07 20.7 March’06 23.2 March’07 20.7 April,06 23.2 April’07 21.1 May,06 22.8 May’07 22.0 June’06 22.8 July’06 22.1 Aug’06 22.2 Sept’06 22.2 BSP Table: Comparative productivity figures for different size ovens Parameters Small Large oven Huckingen Prosper Kaiser oven (Orghishima) Stuhl III Dimension (Usable),Height,m 4.50 7.65 7.85 7.10 7.63 Length, m 11.7 16.4 17.2 15.9 18.0 Width, m 0.450 0.435 0.550 0.590 0.610 3 Useful volume m 22.1 52.2 70.0 62.3 78.9 Productivity, Coke/Oven, t 12.7 32.0 43.0 39.8 48.7 No. of ovens 322 123 120 142 120 Total oven openings 2898 984 1080 1278 1080 Length of sealing faces, Km 10.5 5.1 6.0 6.2 5.5 No. of pushing/day 430 171 128 138 115 Total of opening cycles/day 3870 1368 1152 1242 1035 Length of sealing faces to be 14.0 7.0 5.0 6.6 5.3 cleaned Km/day (Capacity: Coke, 2Mt/year) Waste in Mining, Iron & steel Industry [2.5 / 1 ] EFFECTIVE BIOLOGICAL TREATMENT OF COKE OVEN BY PRODUCT PLANT’S EFFLUENT FOR REMOVAL OF AMMONIA, CYANIDE & PHENOL WITH A SPECIAL REFERENCE TO ROURKELA STEEL PLANT * Dr. B N Das, GM (Env. Management) * B Vaidyanathan, AGM (Coal Chemicals Department) * K K Manjhi, Sr. Mgr. (Env. Engg.Dept) * Dr. S P Kalia, Dy. Mgr. (Env. Engg. Dept) Rourkela Steel Plant, SAIL, Rourkela 1. Introduction The Iron & Steel Industry in general is one of the major contributors of environmental pollution due to the complex and diversified nature of raw materials and by-products handled and various waste products, discharged into the surrounding eco- system. Starting from mining of iron ores and fluxes and their beneficiation to coke making, iron making, steel making and rolling, various solid, liquid and gaseous pollutants are liberated which contribute to air, water, land and noise pollution which call for proper treatment and disposal for better environmental management. One of the major pollution problem encountered in steel industry is treatment of wastewater generated from various process. The waste water generated from Coke Oven By Product Plant is the most polluted water arising from any Integrated Steel Plant. This wastewater contains toxic chemicals like Phenol, Cyanide & Ammonia, which are harmful to receiving water bodies when discharged, untreated. Rourkela Steel Plant is an integrated Iron & Steel Plant which was set up in the year 1959 and modernised in early 90s to a production capacity of 1.9 MT of crude steel. About 5000T of coal is carbonised daily to produce coke, which is an important raw material for making hot metal along with iron ore. While making coke, lot of raw gases are generated in Coke Ovens which will be cleaned and number of by products like Tar, Benzol, Naphthalene, Carbolic acid, Pitch, Anthracene oil are separated in Coke Oven By Product Plant commonly known as Coal Chemicals Department. The cleaned coke oven gas is used as a main source of energy for various operations in the steel plant. Lot of water is used in various operations in Coal Chemicals Department for purification of coke oven gas and production of various byproducts. During the process, wastewater is generated to the tune of 150 to 175 m3/hr. This wastewater is highly toxic and contains high concentrations of Phenol, Cyanide & Ammonia. Waste in Mining, Iron & steel Industry [2.5 / 2 ] There are various methods to treat the wastewater arising from Coal Chemicals area. The various processes can be categorised into two i.e concentration process and oxidation process. In concentration process the pollutants are removed from the effluent by concentration of pollutants into a small volume of waste that itself requires same form of treatment of disposal. The concentration processes include adsorption of the pollutants on activated carbon or ion exchange media, osmosis solvent extraction. In oxidation process, the pollutants are oxidized to relatively harmless end products by either chemical or bio-chemical means. Chemical oxidation includes, oxidation by ozone, chlorine, electrolytic action. Biochemical oxidation methods include oxidation of pollutants by using microorganisms. Biological oxidation is the most widely practiced method and is generally followed by some other processes as a Polishing step. For complex wastes generated in the carbonisation process, it is difficult to find a single process that offers complete treatment. BOD (Biological Oxidation and Dephenolisation) is the most common and preferred root through out the world because of its simplicity in operation and easiness in maintenance. In all steel plants including SAIL plants, the BOD plant was is being operated which was installed earlier and revamped recently. There is certain variations in process and equipment in different steel plants but the essential principle is the same. Principle of BOD plant: The pollutants present in the waste water are removed due to oxidation/digestion by micro organisms. A common BOD plant consists of various units and its flow chart of BOD plant is given in Annexure-1. The waste water arising from Coal Chemicals department generally consists of various pollutants viz., tar, oil, phenol, cyanide & ammonia. The microorganisms are highly sensitive to shock loads. To eliminate shock loads, equalisation tanks are provided generally to make the influent, homogeneous. These equalisation tanks also act as a place for settling tars and other suspended solids present in the influent. The presence of oil in influent badly inhibits the growth of microorganisms. Oil is first removed by means of dissolved air floatation (DAF) system before putting in for biological oxidation. The wastewater, which is uniform in nature, is admitted into first stage aeration where oxygen is supplied by means of mechanical aerators. The required nutrients like phosphorous is supplied by addition of 5% phosphoric acids and Nitrogen portion of nutrients are met through ammonia present in the wastewater. The presence of Pseudomonas bacteria in aeration tank where sufficient oxygen is maintained (>4 mg/lit) by aerators, help in multiplying their population by taking phenol as food and come to an equilibrium as per food to mass ratio (F:M) of 0.4 so that no nitrification can take place in the first stage aeration. After reduction of Phenol in first stage, the liquor is admitted into a clarifier where the sludge is allowed to settle and the supernent liquor is send to Trickling filer for removal of Cyanide. Waste in Mining, Iron & steel Industry [2.5 / 3 ] The liquor is sprayed on filter media and allowed to pass through it. During passing through the filter media, Cyanide and thiocyanide are oxidised by the microorganisms present on the surface of the filter media and form into a layer called slime layer. The microorganisms will grow by taking Cyanide as food oxygen from the ambient air. The microbial growth will increase thickness of the slime laver on the filter media till the inner most layer of the microorganisms will die due to non availability of oxygen. This will lead to slashing of the slime layer and the dead microorganisms will fall down along with flowing water. The liquor is recycled to maintain sufficient hydraulic loading on Trickling filter. After removal of Phenol, Cyanide & Thiocyanide, the liquor is treated in second stage aeration, where Ammonia is removed. The ammonia is converted into nitrite by Nitrosomonous microorganisms and nitrite is converted into nitrate by Nitrobacter microorganisms. The nitrification reactions tend to make the medium highly acidic which inhibit the growth of microorganisms. The growth of microorganisms is given in Annexure-2. NITROSOMONOUS 2 NH4+ + 3O2 2 NO2- + 4H+ + 2H2O NITROBACTOR 2 NO2- + O2 2 NO3- NITRIFIERS NH4+ + 2O2 NO3- + 2H+ + H2O Waste in Mining, Iron & steel Industry [2.5 / 4 ] STATIONARY PHASE GROWTH CURVE OF MICRO ORGANISMS 3.5 3 LOG (BACTERIAL DENSITY) 2.5 2 1.5 1 0.5 0 1 1.75 4.25 5 7 TIME Alkali is dosed to maintain pH in the range of 7-8.0 and orthophosphoric acid as a nutrient for better growth of microorganisms. The liquor is taken to second stage clarifier where the mixed liquor suspended solids are allowed to settle down. The bottom settled MLSS is recycled to second stage aeration tank to maintain optimum concentration of bacteria in aeration tank. The supernent liquid is finally taken to clear water sump and recycled back to Coke Ovens/Coal Chemical Department for reuse. Inherent problems with BOD Plant: Pre-treatment of tar & oil are essential otherwise bio-organisms are destroyed by them. Inconsistent and high shock loads also kill the microorganism and wash out occurs due to any problem in the plant operation. Physio chemical condition like pH, flow rate, temperature, and retention time are very critical to sensitive microorganism. The culture once destroyed is to be replenished by fresh organism and they must be made acclimatized to the particular operating conditions. The process also demands strict operational and technological discipline otherwise washouts can occur frequently. This is also a slow kinetic process requiring high residence time 2. Bod Plant In Rourkela Steel Plant Biological Oxidation and Dephenolisation plant was set up to treat the waste water arising from CCD in February, 1994 with an investment of Rs.8.32 Crores. Different types of microorganisms in BOD plant treat the pollutants. The organic carbon present Waste in Mining, Iron & steel Industry [2.5 / 5 ] in toxic substances viz., Phenol, Cyanide & Ammonia are bio chemically oxidised by uni/multi cellular organisms like autotrophic bacteria, crustaceans by consuming part of it to build their own cell tissues and part of it to produce energy for their survival and producing CO2 and water as end products which are harmless to environment. The BOD plant has the following units for treatment of wastewater in stages; a) Equalisation tank b) Dissolved air floatation unit for removal of Tar & oil c) First stage aeration tank (AT#1) for removal of Phenol d) First stage clarifier e) Trickling filter for removal of Cyanide f) Second stage aeration tank (AT#2) for removal of Ammonia g) Second stage clarifier h) Sludge thickener i) Sludge drying bed Biological Oxidation and Dephenolisation is a near natural treatment of wastewater by various types of microorganisms like Pseudomonas bacteria for removal of Phenol, Nitrosomonous & Nitrobacter for removal of Ammonia. The oxidation/digestion of the pollutants take place in aeration tanks where oxygen is made available to microorganisms from air to breakdown the toxic substances. This is a techno-economically viable solution for treatment in confirmation to IS2490-1982. The BOD plant was designed for influent water with the following characteristics. Over a period of time the influent wastewater characteristics were changed due to closing down of some units in CCD. This resulted in irregular feed of wastewater to BOD plant which badly affected the growth of microorganisms and efficiency of treatment of BOD plant. The design data, present level of pollutants at inlet and outlet of BOD plant with norms are given below; INLET PRESENT LEVEL NORM SN. PARAMETER DESIGN (mg/L) ATINLET (mg/L) 1. Waste water flow (m3/hr) 150 - 175 80 - 100 - 2. Ammonia 300 - 350 157 50 2. Phenol 400 - 500 167 1.0 3. Cyanide & Thiocyanite 100 - 150 1.5 & 150 0.2 4. BOD 1700 410 30 5. Tar & oil 30 - 40 Traces 10 Waste in Mining, Iron & steel Industry [2.5 / 6 ] The wide difference in design data and the present influent characteristics resulted improper growth/inhibited growth of microorganisms at various stages of treatment in BOD plant. This has resulted in improper reduction of Ammonia and cyanide and failed to meet the statutory norms. 3. Problems Faced In Bod Plant Of Rourkela Steel Plant 1. Reduction in hydraulic loading 2. Shock loading of Ammonia in the influent 3. Improper mixing in equilisation tanks 4. Improper operation of DAF system and coagulation 5. Insufficient contact time in Trickling filter 6. Low pH at second stage aeration 7. Very low presence of microorganisms in second stage aeration. 4. Study For Enhancement Of Effectiveness Of Bod Plant, Rsp The problems were studied in detail and an action plan is formulated for complete revamping of the BOD plant so that all the pollutants are treated properly and statutory norms are met. The various steps being under taken to set right the BOD plant are; 1. Constant pumping of waste water from all 3 catch pits of CCD to maintain constant hydraulic feed to BOD plant - The pumps are maintained properly and constant vigil is kept at all catch pits for continuous pumping of waste water to BOD plant. 2. Extending the inlet of equilisation tank up to its bottom for thorough mixing & equilisation. Earlier the inlet and outlets of equalisation tanks are at same horizontal plane which resulted in short circuiting and the main purpose of equalisation tank was defeated. The extension of inlet up to the bottom of equilisation tank, made uniform mixing of liquor in the tank and short circuiting is prevented. 3. Revival of DAF unit and using FeSO4 as coagulant in place of alum. - The presence of Cyanide & Thiocyanide prevents growth of Nitrosomonous and Nitrobacter micro organisms. Ferrous Sulphate removes Cyanide present in the wastewater. Earlier Alum was used as coagulant for removal of suspended solids. Now alum is replaced by Ferrous Sulphate, which acts as coagulant as well as helps in removal of Cyanide. It is established that cyanide is removed with the dosage of Ferrous Sulphate with a dosing rate of 15 ppm. Waste in Mining, Iron & steel Industry [2.5 / 7 ] The reaction of Ferrous Sulphate with Cyanide is given below; Fe+2 + 2 CN- Fe (CN)2 Fe(CN)2 + 4CN- [Fe(CN)6]4- [Fe(CN)6]4- + 2Fe2+ Fe3[Fe(CN)6)] 1. Low pH of liquor in second stage aeration - The nitrification reaction makes the liquor highly acidic which inhibits growth of Nitrosomonous & Nitrobacter. A highly alkaline waste water source is located at Steel Melting Shop #2 and the alkaline water is brought to BOD plant by closed pipe line and added to maintain optimum pH. 2. Culturing microorganisms using cow dung and adding in second stage aeration tank to maintain sufficient level of microorganisms - Washing out of microorganisms at second stage is a common phenomenon observed. To maintain sufficient MLVSS concentration, processed cow dung liquor dosing is being exercised which has given good results. 5. Results Of The Study The action plan for revamping of BOD plant of RSP has been implemented. The results show, there is considerable improvement in all parameters as well as good microbial growth. The pollutant parameters concentration at the outlet before and during implementation of the action plan are given below; POLLUTANT CONCN. (mg/L) NORM SN PARAMETER BEFORE TRIAL DURING TRIAL (mg/L) 1. Phenol 0.06 - 0.32 0.06 - 0.10 1.0 2. Cyanide 0.08 - 0.70 0.14 - 0.20 0.2 3. Ammonia as NH3-N 24.2 - 236 1.28 - 35 50 4. Tar & Oil NOT TRACEABLE NOT TRACEABLE 10 5. COD 70 - 143 65- 137 250 6. Conclusion The removal of Phenol is very good. Cyanide and Ammonia reduction is achieved first time since inception after implementation of the action plan. Dosing of Ferrous Sulphate at inlet to DAF, maintenance of optimal pH & MLVSS concentration at second stage aeration were given maximum thrust to improve removal of Cyanide & Ammonia so that statutory norms are met. The treated effluent is recycled back to Coke Ovens for quenching purpose there by there is no discharge from BOD plant to drain. Waste in Mining, Iron & steel Industry [2.6 / 1 ] WASTE UTILIZATION & MINIMISATION AT RSP BLAST FURNACES: AN OVERVIEW Shri DD Patra, Shri DM Srivastava, Shri S. Ranade. Rourkela Steel Plant, SAIL,Rourkela-769001 Abstract Blast Furnaces being a processor of mineral, generates a number of waste material during production of hot metal, Slag being the major waste product. Actually something is termed as waste as long as it has not found a use. Since the ages several mountains of slag has been created in absence of a viable use. But now not only BF Slag (granulated) has been an important raw material for Portland slag cement but also it has found use in several other areas such as marine aquaculture, construction industry& for insulation purpose (as ground granulated slag). Similarly another waste product of BF process, the flue dust, recovered during cleaning of BF top gas is used in basemix the feed for sinter making. A number of actions were taken at R.S.P Blast Furnaces to minimize waste generation as well as in recycling the waste. Use of imported coal in blend, increasing HBT, installation of HTP and improving process parameters to name a few have resulted into lower waste generation where as installation of CHSGP, Belt Press Filter and improvement in GCP has improved the recycling of the waste generated. RSP is also implementing an ambitious modernization plan where waste generation shall be further reduced and all the waste shall be recycled. 1. Introduction Any industrial unit using natural resources generates a byproduct during processing which is termed as a waste as long as an use is not found for this product. It is a fact that no system can be perpetually perfect to prevent generation of a waste, but the system can be improved to reduce the waste generation to a bare minimum level. Further, effort must be made to find a use for the byproducts of the system, so that they can be used as a resource for some other product. Blast Furnace is a major consumer of natural resources such as Iron Ore, Coking Coal, Lime stone, Quartzite etc., besides Air for its Oxygen requirement. It also uses millions of gallons of water for its process. BF slag is one of the major waste products of BF, which comes from the gangue material of Iron Ore & Ash of coke. Also the fines carried over by BF gas & Cooling water is another waste product of BF. Since the ages, no body knows how many mountains of Iron Ore the Blast Furnaces have swallowed Waste in Mining, Iron & steel Industry [2.6 / 2 ] world over and how many mountains of environmentally detrimental slag mountains they have created. But the scenario is now changed, natural resources are fast depleting and no one can have the liberty to throw any thing to the surrounding affecting our environment. As the old saying goes, “necessity is the mother of invention” or scarcity brings austerity, soon people have started taking up a number of measures for optimum utilization of resources, minimum generation of wastes or waste recycle measures and finding a number of use for its waste products. Rourkela Steel Plant Blast Furnaces have also done its part in minimising waste generation or recycling of its waste products. A large number of measures were undertaken at BF shops in minimizing production of slag or otherwise converting the slag to usable form to be used as a resource for cement plants. Also measures were taken to minimize & recover the solid waste lost through BF gas & from Cooling water to the maximum possible level. All attempts have been put to minimize & re-circulate the cooling water in such a way that the unit is almost self sustaining on water requirement. A number of actions were also taken to minimize the return fines arising from the raw material conveying system and recycling of the same through the system. Details of waste generation, minimization measures & their recycle are enumerated in this paper. 2. Blast Furnace Wastes Although a number of minor waste is generated in BF process the only major waste is the BF slag which is at present generated ~ 395 Kg/THM at RSP. The flue dust separated from BF gas ~ 5 – 10 Kg/THM, gas cleaning plant clarifier sludge and filter sludge ~ 0.3 – 0.5 kg/THM are the other BF waste of some prominence. The BF gas which is another byproduct of BF process is never considered as a waste because it is fully utilized in an integrated steel plant because of its fuel value. However, minimizing losses of this gas or optimum generation of this gas is part of waste management system in Blast Furnaces. Belt return fines and D.E system fines are though very less, still considered as a waste in BF unless recycled through a proper handling system. Under this back drop BF department adopted a 3 prong waste management system in the shop such as: a) Reducing the waste generation; b) Converting the waste into recyclable form; c) Recycle the waste. Waste in Mining, Iron & steel Industry [2.6 / 3 ] 3. Efforts to reduce waste generation at Blast Furnace A number of steps were taken over the years to reduce generation of various wastes such as BF slag, Flue Dust, BF gas & spillage water etc.are elaborated as under: a) Reduction in generation of Blast Furnace Slag: The amount of slag generation per ton of Hot Metal depends on mainly the coke rate (coke ash being the major contributor to slag generation) and the gangue material in iron bearing materials such as Iron Ore lump and sinter used for Iron making. Therefore, a large number of steps have been taken at RSP Blast Furnaces to reduce coke rate, important among them are (1) increasing the Hot Blast Temperature (2) using more imported coal in the blend to get coke with lower ash (3) optimizing & improving furnace operating parameters (4) improved cast house practice (5) use of 100% screened iron ore & sinter (6) introduction of high top pressure & oxygen enrichment in BF #4. The coke rate at RSP has been reduced considerably from 680 Kg/THM to 580 Kg/THM over last decade ( see Fig.1). The other factor contributing to reduction in slag generation is the gangue content in iron ore & sinter. Ore beneficiation at mines, blending, bedding & screening at our OBBP has helped reducing the gangue content in the raw material as shown in Fig.2. Coke rate Trend (Kg/THM) 700 675 650 625 600 575 550 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 Coke Rate 678 663 668 656 647 611 633 633 607 577 578 Figure-1 Waste in Mining, Iron & steel Industry [2.6 / 4 ] % GANGUE INPUT TREND 50 49 48 47 46 45 44 43 42 41 40 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 Gague 47.8 48.4 48.6 48.1 48.1 46.2 46 47.7 45.1 43.6 44.57 Figure-2 The above efforts have resulted into reduction in slag generation (slag rate) per ton of hot metal to ~ 395 Kg/THM from ~ 410 Kg/THM over the years as shown in Fig.3. (b) Reduction in generation of flue dust : The amount of flue dust carried over by the out going BF top gas depends on the dust content in the input materials, strength of the input materials and efficiency of the furnace operation besides the top pressure of the furnace. After installation of high top pressure system in BF # 4 in Sept.2005, the generation of flue dust from BF # 4 has come down considerably from 10 Kg /THM in 2005-06 to 3 Kg/THM in 2007-08. To minimize the fines/ dust input into the furnace we have ensured use of 100% screened ore lump and ~ 99% screened sinter. Dumping of direct iron ore lump from mines in BF High Line have been stopped since 2005. Up-gradation of sinter screens and improved maintenance practice has ensured use of ~ 99% screened sinter in our burden as shown in Fig.4. After installation of I.C. Screens for coke screening, coke screening efficiency has gone up resulting into lower coke fines into the furnace. Another modification done to improve coke screening is installation of coke fines feeder which not only enable utilization of full screen area but also avoids launder jamming by feeding Waste in Mining, Iron & steel Industry [2.6 / 5 ] the coke fines to launder by a vibrator. Improving the strength & hardness of input materials particularly that of coke & sinter reduces fines generation thereby reduces the flue dust carried over by the outgoing BF top gas. Use of more imported coal in blend and use of PBCC has helped us to improve the coke hardness ( i.e. M10 value) over the years. Similarly, improvements in sinter plants has resulted into sinter having good strength ( DTI value). The coke M10 value & sinter DTI value over the years are given in Fig.5 &6. SLAG RATE TREND (Kg/THM) 430 405 380 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 slag rate 400 410 414 409 432 411 404 402 393 394 406 Figure-3 % SINTER SCREENED 110 105 100 95 90 85 80 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 %Sint Screen 82.8 84.1 95 96.25 97.68 93.85 95.94 98.73 98.37 98.99 99.21 Figure-4 Waste in Mining, Iron & steel Industry [2.6 / 6 ] COKE M-10 VALUES 9.4 9.2 9 8.8 8.6 8.4 8.2 8 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 M-10 8.85 9.05 8.84 8.67 8.67 8.44 8.57 8.76 8.56 8.44 8.65 Figure-5 SP-I DTI VALUES 75 74 73 72 71 70 69 68 67 66 65 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 DTI 70.2 70.1 70.1 71.9 71.5 71.3 73.1 71.1 70.7 70.7 71.3 Figure-6 Efficiency of the furnace operation such as steady blowing, prevention of hanging & forced slips, and minimizing down-time can reduce the flue dust losses through BF top gas. Improved equipment availability & input materials, better cast house practice Waste in Mining, Iron & steel Industry [2.6 / 7 ] introduction of mix charging system and furnace movement control by differential pressure control has helped us to improve furnace operation & contribute to lower generation of flue dust as shown in figure-7. RATE OF FLUE DUST RECOVERED (Kg/THM) 35 30 25 20 15 10 5 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 Fluedust 26 20 30 18 15 18 15 7 9 7 7 Figure-7 c) Reducing loss of BF gas: Theoretical generation of BF gas per ton of skip coke burnt is ~ 1.2 times of Air blown in Blast Furnaces. The more nearer to this value one is, the more is the efficiency of operation i.e. less loss of BF gas. There is a steady increase in BF gas generation per ton of skip coke in RSP BF implying reduced loss (See Fig.8). It is the result of a number of systematic actions taken to improve gas yield & reduce gas losses. Among the important ones are; installation of BLT charging systems with excellent sealing arrangement, replacement of aging goggle valves, bifurcation of gas lines to facilitate maintenance without shut-down of all furnaces, monthly inspection of leakage points & its liquidation during shut down days. Timely cleaning of gas lines & repair of GCP units has also contributed to improved gas yield. Improved furnace operation & optimization of furnace operation also contributed considerably to improved gas yield. As per the losses on account of bleeding, modifications in power plant boiler burners, cleaning of Waste in Mining, Iron & steel Industry [2.6 / 8 ] clean gas line and increasing gas pressure in stove gas line has contributed to increased consumption of BF gas & less bleeding. BF GAS YIELD(NM3/TSC) 3000 2950 2900 2850 2800 2750 2700 2650 2600 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 BFG Yield 2628 2719 2706 2900 2811 2893 2826 2630 2734 2883 2879 Figure-8 d) Reduction in water consumption or reducing the water loss at BF: Blast Furnace requires around 13,000 m3/hr cooling water for cooling the furnace lining, tuyer coolers, Hot Blast Stove Valve coolers, GCP scrubbers & for ESP flushing requirement etc. An excessive requirement of makeup water to the tune of 1200 to 1400 M3/hr was required in the water circulation system of GCP due to inadequate cleaning of return water in the Filter House, non availability of required number of cooling towers, overflow & leakage at a number of points, which had led to excess requirement of make-up water during the 1990’s. But a number of steps have been systematically taken over a period of times to minimize water losses and now BF department is almost a self sustaining closed loop unit requiring ~ 300 m3/hr to 400 m3/hr makeup water to take care of the losses including the evaporation losses. The trend of make up water requirement over the decade is shown in Fig.9. Waste in Mining, Iron & steel Industry [2.6 / 9 ] MAKE UP WATER REQUIREMENT (m3/hr) 1500 1300 1100 900 700 500 300 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 Makeup water 1438 1276 1037 801 794 559 480 431 411 401 377 Figure-9 Among the major initiatives taken for reducing water losses is, the installation of highly efficient and environment friendly Belt Press filter in place of vacuum disc filter for filtering the clarifier underflow water. Efficient removal of sludge by belt press filter has eliminated frequent draining of clarifier underflow water thereby substantially reduced the water losses on this count. Revamping & up gradation of 6 cooling towers in last 2 years has gone a long way in reducing additional water requirement as well as minimizing the losses also. After connection of a pipe from BF cooling tower inlet pipe to High Pressure pump # 1,2 & 3, excess water overflow from BF cooling towers could be diverted and overflow/wastage avoided. This has resulted into saving of substantial mount of water wastage. Besides the above steps, replacement of leaking valves & repair of leaking pipes was carried out regularly to save water. Efforts to convert the waste into a recyclable form : As mentioned above earlier, as soon as a waste finds an user it is no more a waste, it has become a resource. Therefore, it shall be a beauty if all the waste is converted into a resource & is put to use. With this philosophy in mind, all tempts have been made to convert our major waste i.e. BF slag into granulated slag which is a major raw material for cement plants. The actions taken at our plant over the years to increase the percentage of slag granulated is detailed below: Waste in Mining, Iron & steel Industry [2.6 / 10 ] 1. Increasing % of slag granulation: Upto the 1990’s BF liquid slags were carried in steel slag pits to external slag granulation plant, ~3 KM away from the cast house & poured there for granulation. % of liquid slag granulated was ~ 50 only. The pouring method had the handicap of several bottlenecks such as hard crust formation on top of the slag pot, a number of problems in slag cars making the pot unsuitable for pouring and inability to pour the entire slag in the slag pot. Moreover, due to various logistic problems & poor availability of slag pots for casting, many a times slag pots were directly dumped out-side instead of pouring at slag granulation plant leading to lower % of liquid slag granulation. A systematic action plan has been implemented over the years to improve % of slag granulation. First among the project implemented is the installation of cast house slag granulation plant of BF#4 in 1995 followed by BF#1 in 2005. It is worthwhile to mention that due to lack of experience in running & maintaining a Cast House Slag Granulation Plant, various furnace problems, absence of a good cast house practice and few major breakdowns of INBA #4 equipments, availability of BF#4 CHSGP was not satisfactory until 1997. But thereafter, availability of CHSGP remains more than 90% and ~ 95% of the liquid slag generated from BF#4 is granulated. With good experience of running & solving of problems faced in INBA #4, we could commission & stabilize BF #1 INBA CHSGP quickly in Aug.2005. By Sept.2005 liquid slag granulation from INBA CHSGP exceeds 90% from the level of 60% in the 90’s.The results are shown in Fig.10. % OF SLAG GRANULATED IN CHSGP 100 95 90 85 80 75 70 65 60 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 %chsgp 62.15 89 99.4 94.5 94.1 97 94.2 97.3 87.8 97.8 88.1 Figure-10 Waste in Mining, Iron & steel Industry [2.6 / 11 ] Liquid slag from BF #2&3 still continues to be sent to external SGP for granulating the slag. A number of action have been taken to improve the % of slag granulated at SGP from a level of 40 to 50 during the 90’s to ~ 70% in 2007-08. Introduction of water dumping of skull slag pots instead of knocking, has brought in revolutionary changes in improving slag pot availability, providing clean slag pots for casting, avoiding cracking of slag pots & damage to slag cars & their tilting drives . This has facilitated availability of pots for proper lime coating & enhanced slag pot carrying capacity resulting into more slag pouring per pot at SGP. Besides the above, introduction of super finish steel slag pots and & improved lime coating by using CP#II lime fines and 5 coats of lime instead of earlier 3 coats has increased the % of slag poured at SGP considerably. Introduction of CHSGP at BF#1 & #4 also ensured quick disposal of slag loads to SGP (because of few slag load generation) thereby minimizing hard crust formation & maximum pouring. Dumping of cast house mucks in slag pots has also been discontinued since 2004 which helped in preventing hard crust formation & the slag loads are now easily pourable at SGP. Improved cast house practice such as minimum 3 casts/shift, minimization of slag pot pushing during castings and higher metal/slag temperature has helped in avoiding hard crust formation and therefore, more % of slag pouring at SGP.The trend of % slag granulated at SGP in the last decade is shown in Fig.11. It is heartening that the above actions have yielded good dividend and % of over all liquid slag granulated at BF has been increased to above 80% & that of INBA at SGP to more than 95% as shown in figure-12. % OF SLAG GRANULATED IN SGP 100 90 80 70 60 50 40 30 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 SGP 36.5 41.3 57.5 54.4 42.9 44.7 45.5 49 57.7 81.7 70.6 Figure-11 Waste in Mining, Iron & steel Industry [2.6 / 12 ] % OF TOTAL SLAG GRANULATED IN B.F 100 90 80 70 60 50 40 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 %slag granulated 48.3 57.2 74 72.1 64.4 62.4 60.2 63.2 70.9 89.4 87.5 Figure-12 2. Increasing flue dust recovery: The flue dust recovered from the BF top gas contains ~ 40% coke fines & 25-30% iron bearing material thereby making it suitable as a raw material for sinter-making. But because of handling problems associated with this material, this was simply thrown outside the plant as a waste prior to installation of our ore bedding & blending plant. After commissioning of OBBP in 1997, preparation of base mix, the prime feed for sinter making, started using a mix of iron ore fines, coke fines, lime stone & dolo fines. This has rendered excellent scope for recycling of the flue dust recovered at BF by mixing along with the base mix feed. Therefore, the more flue dust recovered from the top gas means more utilization of wastes which otherwise would have been lost through top gas or return water. A large number of measures have been taken in BF GCP to recover the flue dust to the maximum extent possible from the top gas and return water. Important among them are modification & replacement of high efficiency scrubber nozzles for efficient washing of top gas, regular drying of dust catchers to prevent higher dust carry over along with top gas, systematic capital repair of ESPs & cooling towers to improve the efficiency, replacement of raw gas & clean gas goggle valves for enabling capital repair of ESPs etc. The dust content in the BF clean gas is the indicator for efficient recovery of flue dust from top gas. Over the years the dust content in our clean gas has come Waste in Mining, Iron & steel Industry [2.6 / 13 ] down considerably from 15-16 mg/Nm3 to 5 mg/Nm3. Similarly, whatever flue dust was washed through washers / scrubbers & ESPs is also recovered by settling in clarifiers & then by filtering. The efficiency of recovery of dust from the clarifier water has been enhanced by introduction of chemical dozing along with installation of Belt Press filter in place of vacuum disc filter. Recovery of dust from Belt Press filter is now 15T/day in comparison to 5T/day in case of Disc filter. Revival of clarifier #3which was down for several years by in-house innovative method has also helped in the effort for recovering more dust from washing water and has also enhanced clarifier availability. Strict implementation of clarifier cleaning schedule ( i.e. cleaning of each clarifier once in a year) has also helped us in increasing the dust recovery. The trend of cleanness of BF gas & dust recovery is given in Fig.13 which reveals that there is tremendous improvement in recovery of flue dust from top gas. DUST CONTENT IN BF CLEAN GAS(mg/Nm3) 19 17 15 13 11 9 7 5 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 BFG Dust 12.6 14.8 11.7 8.7 7.8 9 15.9 7.7 7.6 6.9 5.8 Figure-13 4. Measures to recover & recycle the wastes in stock house The common wastes in raw material handling system & stock house are the belt return fines and the D.E system recovery dust. Fixing of modified scrappers & a reliable fines handling system enabled us to recover the belt return fines which is then recycled through base mix feed in OBBP.In absence of an effective DE system, lot of dust is lost by polluting the air. Revamping & upgradation of DE system in our BF #4 stock house in 2005 has not only helped us to recover substantial amount of dust but also made it easier to re-use in base mix feed. This year too the DE system of BF#1,2 &3 Stock House has been revamped & made effective. While the proposal for installation of dry Waste in Mining, Iron & steel Industry [2.6 / 14 ] fog system for suppression of dust in stock house is under implementation the proposal for implementation of cast house de-dusting system is under active consideration of management. 5. Measures to recover & recycle the Cast House runner losses & metal kishes Cast house waste generation is largely due to the runner loss and muck generated while preparing the Cast House. Metal kisses generated during casting is also another metallic waste. The earlier practice at Rourkela had been to collect all the iron jams in scrap boxes and rest of the generation in muck boxes. Iron jams were taken by dumpers to scrap & salvage unit for processing the same to be used in SMS, whereas the muck boxes were either emptied into slag pots for dumping outside the plant or taken by tippers to be dumped in Scrap & Salvage unit. The practice of sending mucks through slag pots has been stopped since 2004; all the iron jams and slag mucks generated in Cast House is sent to our Scrap & Salvage department where metallic portion is reclaimed from the waste and used in Blast Furnaces as BF fines. While effort is made to recycle the Cast House wastes a number of steps have been taken to reduce muck generation of Cast House. Important among them ; use of high life trough mass which made it possible to repair the trough once in a month in comparison to 2 to 3 times in a month earlier. Holding of bypass continuously for over a month has eliminated bypass runner losses. Use of castable iron runner, and tilting runner in BF 3 & BF #4 has reduced iron runner losses to almost zero. Splash guards are provided by the side of iron tracks to catch metal splashing which is then recovered in large pieces to be used as scrap. Metal kisses on the Cast House or from the ground is dosed and sent to SSD for reclamation. 6. Future Plan for Waste minimization With installation of BF#5 having modern state of the art technology, reconstruction of BF#1 with high top pressure & CDI in BF 1 & 4 Slag rate can be reduced to as low as 300 Kg/THM from today’s 400 Kg/THM. Installation of cast house slag granulation plant in all furnaces shall ensure 100% granulation means full utilization of the slag in cement plant. RSP is also shortly building a cement plant with joint venture to take care of the entire granulated slag produced from BF. In addition to this commissioning of closed loop demineralised water circuit, power full D.E systems in material handling section, use of runner covers, castable troughs & cast house de-dusting system shall minimize waste generation substantially by 2012 at RSP BF. ***About the Authors: The authors are Sri D.D.Patra AGM BF(O), Sri D.M.Srivastava DGM BF(O) and Sri S.Ranade GM I/C (Iron) SAIL,Rourkela Steel Plant,Rourkela-769001. Waste in Mining, Iron & steel Industry [2.7 / 1 ] RECYCLE MANAGEMENT OF WASTE REFRACTORY AT ROURKELA STEEL PLANT S.K.Bandopadhyay, P.K.Ray Choudhury* D.Ghosh, S.K.Vadher, S.Chandrasekaran (*The author is from SAIL, R&D Centre for Iron & Steel, Rourkela Centre Others are from SAIL, Rourkela Steel Plant, Rourkela) The refractory materials are generally multiphase ceramic products which, in industry, are subjected to severe conditions of use (high temperatures, severe thermal shocks, etc.). By definition, a material having the ability to retain its physical shape and chemical identity when subjected to high temperatures is called refractory. The iron and steel industries are the principal consumers of refractory products. The structure of a refractory material is composed of a mixture of aggregates whose size ranges from micron to several mm, surrounded by a matrix, containing finer grains (of size lower than 0.1 mm) and eventually a binder. Different types of refractory materials are used for different application, specific to the condition of use. The life time in service varies from few hours to more than twenty years. The specific consumption of refractories per tonne of steel in our country varies from 10 to 20 kg. This gives an idea of the importance of this kind of materials and the activities which surrounded them. In iron and steel industry, refractories are present at each step of production (e.g. lining of ladles, converters reheating furnaces etc ) and some of them contain carbon. In the past, refractories producers and consumers thought of spent refractories on a disposable commodity – once removed from service, the material was simply land filled. The lack of environmental awareness coupled with the low cost of disposal, inexpensive raw materials, uncertainty about the quality of recycled products and the complexity of recycling operations led to the widespread belief that recycling was just not cost effective and too troublesome to worry about. However, more recently due to use of costly raw material in refractory product coupled with increasing disposal cost and stringent environmental issues forced the industry to take a deeper look into the problem. Moreover, established resources are being exhausted and discovery of new ones are getting harder and more expensive. The capacity of the earth to assimilate more waste is also nearing its limits. The increase in production of steel in a sustainable fashion will only be possible with the circulation of resources. The concept of refractory recycling involves 3Rs (Reduce, Reuse and Recycle). Reduce refers to decrease refractory consumption per tonne of steel means, reduce refractory wear while use. “Reuse” refers to the utilization of spent refractories in Waste in Mining, Iron & steel Industry [2.7 / 2 ] production process e.g. Magnesia-Carbon spent refractories as slag conditioner in electric arc furnace steel making or as a patching material for the eroded portion of BOF lining (charge pad). “Recycle” refers to the reuse of spent refractories after processing. Mostly the recycled grain thus generated are used along with virgin material and then used either as monolithic refractories or repair material or as shaped product in non vulnerable areas of metallurgical vessel lining. Several kinds of refractories are present in every furnace. When these refractories are subjected to demolition, they are discharged in a mixed state. In this mixed condition, spent refractories are not suitable for recycling. The demolished spent refractories are sorted for example, into MgO type or Al2O3 type refractories. After sorting, the clean materials are reduced in size by traditional crushing, grinding and screening operations. During the entire sizing process, the materials undergo conditions magnetic separations. Samples are then taken and extensive quality control tests conducted to determine chemical and physical compliance with previously established standards. The materials are then packed by type and particle size range and stored for future recycling/ reuse depending on their type. In Rourkela Steel Plant, continuous efforts are being made towards reduction in specific consumption of refractories per tonne of steel by improving the lining life of two major refractory consuming units e.g. BOF and steel ladle. In BOF, lining life increased from 995 (Avg. life of 2001-2002) to 4001 heat (Avg. life of 2007-2008) with in-house pitch bonded MgO-C bricks and thereby total number of campaigns per year decreased from eight to three and hence generation of waste refractory decreased by more than 60%. In the case of steel ladle, lining life increased from 60 heats to 100 heats with purchased MgO-C bricks on performance guarantee basis from different suppliers. Here also the requirement of total refractories per year decreased significantly for the same level of production. Another area, where generation of waste refractories has been reduced drastically is in 140T hot metal ladle. The number of relining and repair per annum decreased from 28 to 11 and 213 to 178 respectively when compared 2005- 2006 data with 2007-2008 till date, although the production of hot metal increased from 1.77MT(2005-2006) to 2.2MT(likely to achieve for 2007-08). Regarding “Reuse” of spent refractories only a portion of dismantled MgO-C lining is used as a patching material to take care of the localized preferential wear areas of BOF. Rest of the spent MgO-C refractories is sold outside. The bricks dismantled from safety lining of different metallurgical units are also reused after proper sorting where ever possible. Attempts were made to reuse waste slide gate plates as impact pad of tundish. The lack of space and quick equipment turn around times in most cases, selective lining dismantling is usually not feasible and sometimes not even local sorting can be Waste in Mining, Iron & steel Industry [2.7 / 3 ] done due to lack of available space and manpower. Moreover, all generated spent refractories of different suppliers are to be stored separately and also dealing of unknown material for recycling may be difficult. In the absence of dedicated recycling plant at RSP, most of the spent refractories generated are either sold or dumped outside. Waste in Mining, Iron & steel Industry [2.8 / 1 ] MANAGEMENT OF SOLID AND LIQUID WASTES AT COKE OVEN AND BY PRODUCT PLANT OF BOKARO STEEL PLANT K.K.Sanyal Astt.General Manager Bokaro Steel Plant The waste management is an industry makes it cost effective and its productivity increases by recycling wastes. Thus approaches to ‘ZERO ‘ WASTE. By proper waste management pollution reduces & in turn helps social & economic development. Various liquid and Solid Waste (Hazardous and non-hazardous) are being generated in CO & BPP of Bokaro Steel Plant. The secured engineering landfill ( Fig – 1) of 125 meters x 30 meters x 4 meters has been made for disposal of hazardous wastes of CO & BPP and mill area. Liquid wastes are Ammoniacal liquor generated during coke oven gas condensation and waste water generated during scrubbing of C.O gas in other units of By-product Plant. Ammonia rich waste water is treated in Ammonia still to take out free ammonia which goes into saturator for enhancing Ammonium Sulphate production. Other waste water with ammonia, phenol , cyanide, tar oil and grease is treated in B.O.D plant & treated water is used in coke quenching. Thus waste water is re-used fully in the coke making process only. Table 1 & 2 shows the characteristics of waste and treated water of B.O.D plant. In Table –3 solid waste materials gives an idea of solid wastes management system either by re-cycling/ re-using and earns revenue by selling to outside parties, thus approach to ZERO Waste. For some wastes , market is being explored. Damaged conveyor belts generated are cut into small lengths & sell to market . Metallic wastes are being charged in Steel making system in SMS converter. Refractory bricks generated are being used inside plant for some secondary purposes. We have developed lubricating oil recycling system where no waste generated & it also satisfies ISO 14001 : 2004 EMS guidelines. ( BSL already certified ). Thus we the collectives of CO & BPP of Bokaro Steel Plant are improving in wastes management system, we will continue till we achieve ZERO WASTES. Waste in Mining, Iron & steel Industry [2.8 / 2 ] Table-1 Ammonia : 400 mg/liter Tar & grease : 500 mg / liter Cyanide : 2 mg / liter PH :8-9 Phenol : 400 mg/liter Table-2 Ammonia : ≤50 mg/liter Oil & Grease : ≤ 5.0 mg/liter Cyanide : ≤ 1.0 mg/liter PH : 7-9 Table-3 S.no Wastes Qty/Yr Management Rev. MT System (Rs.in Lakh) 1. Decanter sludge 6000 Mixed with coal ---- blend 2. Acidic Tar from Amn. 2400 Sale to parties 12 .00 Sulphate plant 3. Regenerated Acid 250 Market to search - sludge 4. Tar muck with Sand 1200 Disposal to HAZ. W. - PIT 5. B.O.D 1200 Nos. Return & re-se No waste POY JAR 6. Sulphur sludge 300 MT To HAZ W. PIT - 7. Used Conveyors Recycle through No ------ store for auction Waste 8. Used electrical cables Re-use for plant No ----- purpose Waste 9. Used rubber hose pipes 48,000 Kg Can be sold to party for re-use --- 10. Spent alkali (2-3 %conc ) 360 MT Used in HAZ .W PIT - to maintain pH of pit water. 11. Used lubricating oil ---- Re-cycled fully No Waste 12. Pond Breeze 2000 Used in Sinter Plant No MT & B.F. Waste Waste in Mining, Iron & steel Industry [2.9 / 1 ] CHALLENGES AND SOLUTIONS FOR UPGRADING INDIAN IRON ORES TO OPTIMIZE MINING AND STEEL PRODUCTION Satyabrata Mishra Abstract: Mineral processing is characterized by a constant adaptation to changing raw materials and market conditions. It is the link between the mined raw material and a marketable product. As a lot of high grade reserves are exploited, a steady deterioration of raw material quality can be observed. At the same time, the customers requirements for product purity and consistent quality increase. This general scenario has been well addressed on various occasions in respect to indian iron ore, e.g. that less than 10 % of the reserves are high grade lumpy reserves as well as the economic benefits of using high grade, low silica and alumina concentrates in blast furnaces. So beneficiation techniques for iron ore are becoming very important in order to achieve a maximized utilization of ore resources and to optimize the down stream value chain. Allmineral has been engaged in hematite iron ore beneficiation with its gravity separators for more than 10 years. Various installations with jigs for lump and fines as well as upstream separators for fines are in operation in Australia and South Africa. Low grade run of mine and/or dump ores are being processed with alljig®- and allflux®- separators as the core equipment. The biggest of it´s kind in South Africa with 4.000 tph capacity and 24 alljigs installed. The lecture describes the technology in use, the beneficiation characteristics of various Indian iron ores with special respect to ores from the south indian Bellary area and the impact of their characteristics on the process technology and achievable grades and yields. In comparison with Orissa ores southern Indian ores are typically finer disseminated, which results in the need for finer grinding before being separated. Although the initial capital and operating costs are relatively high, at actual and expected future price levels it´ s still a very economical process . The data presented show the specific advantages of jigs and upstream separators on iron ore upgrading due to the possible high gravity cuts and the easy and low operating costs. WHIMS are an additional option for the recovery of ultrafine Hematite . These technologies provide a value addition to the development of the Indian Iron Ore Industry, including the southern parts. Waste in Mining, Iron & steel Industry [2.9 / 2 ] Challenges Solutions 1 steel production is projected to - adaption and development of technologies double within next 10 – 15 years for providing steh steel industry with the in India required iron ores, both in quantity and quality 2 consequently iron ore production - maximize the utilization of the ore reserves has roughly to be doubled in this period 3 only 10 % of the reserves are - the key to success, mineral benefication high grade (lumpy) reserves 4 provide the steel industry with the - follow the required “classical” steps demanded quantity and quality 5 quantity becomes an issue in - mineralogical characterization respect to sustained reserves 6 quality becomes one keypoint for - evaluate the results regarding possible improving the productivity of steel quality and yields as well as associated costs making 7 - lab (and pilot plant) test work 8 - make business plan Solutions to Wastes in Mining, Iron & Steel Industry [3.1 / 1 ] “BF SLAG” AND “SMS SLAG” UTILISATION IN BOKARO STEEL PLANT R.P. Singh & R.G. Segaran Environment Control Department Bokaro Steel Plant Steel Authority of India Ltd Abstract Environmental legislation and regulations and the economics of disposal are directing the steel industry to look for ways of minimising the generation of wastes and maximise recycling and reuse of collected wastes. The biggest part (about 70% - 80%) of solid waste arisings in an integrated steel plant, is metallurgical slag, which is utilised to a large extent in the cement industry and for road and civil constructions. At BSL , presently the 51 % BF slag is granulated and sold to nearby cement industries. However , nowadays the cement industries prefer dry flyash fom power plants for making blended cement, to cut the cost of grinding of Granulated BF slag . Thus there is a need to look for other alternative routes for increasing BF slag utilization. Production of “Ground Granulated BF Slag” (GGBFS) and Air cooled BF slag aggregates for construction industry are the promising avenues for enhancing the BF slag utilization. Government should encourage everyone; Steel Industry , ready-mix concrete companies, builders, contractors, engineers, and architects; to use GGBFS, thus producing better concrete as well as saving energy and reducing the CO2 emissions in the environment. BSL has achieved 96 % utilization level in SMS slag . BSL is processing the SMS Slag in various fractions. 0-5 mm slag is being charged into Sinter Plant replacing equal amount of flux . Similarly 10-40 mm size are being used in SMS and BF. The entire road of Plant and Township are being repaired by 5-10 mm and 10-40 mm size LD slag. BSL is having around 400 Kms of Railway Track for which 20-65 mm size LD slag is being spread replacing conventional stone ballast . BSL is also supplying processed LD slag to IISCO Steel Plant, Burnpur which is being charged in Blast Furnace, inturn cutting down fresh flux consumption. Directions to the concerned in Central Govt and in State Govts. Agenicies like CPWD, PWD, NHAI, Railways , etc, to specify the use of Slag Cement / GGBFS/ BF Solutions to Wastes in Mining, Iron & Steel Industry [3.1 / 2 ] and SMS slag aggregates, etc; in construction activities, will go a long way in meeting the utilization targets of metallurgical slags from Integrated Steel Plants in India. 1. Introduction Environmental legislation and regulations and the economics of disposal are directing the steel industry to look for ways of minimising the generation of wastes and maximise recycling and reuse of collected wastes. The biggest part (about 70% - 80%) of solid waste arisings in an integrated steel plant, is metallurgical slag, which is already utilised in the cement industry and for road and civil constructions. The chemical analysis of the above stated Metallurgical Slags (BF slag and SMS slag) are given in Annexure-1. The Generation and Utilization of Solid Waste in the financial year 2006-07 at Bokaro Steel Plant is given in Table-1. Tabe-1 Solid Waste Generation and Utilisation in BSL ( 2006-07) Solid Wastes Generation (T) Utilisation (T) % Utilisation BF Slag 17,43,345 7,11,471 41** SMS Slag 3,97,420 3,30,631 83** Mill Scale 76,393 76,393 100 ESP Dust 25,377 25,377 100 Flue Dust 62,205 62,205 100 Acetylene Sludge 3,546 3,546 100 Coke Breeze 3,92,053 3,92,053 100 Refractory waste 12,000 6,000 50 ** Note : Utilization of SMS slag & BF slag has reached to 96% & 51 % in Nov 2007. 2. Blast Furnace Slag Slag generation rates at Indian Steel Plants are comparatively higher than that of developed countries, mainly due to inherent adverse quality of raw materials like high ash in coal, high alumina and silica in iron ore ,etc . Efforts are made at BSL to reduce coke ash % by judicial blending of different indigenous and imported coals and increased use of washed low alumina Iron Ore in Sinter Plant and in Blast Furnaces, so as to reduce the Metallurgical Slags from the process units. Coke rate also reduced by introducing Coal Dust Injection (CDI) and Coal Tar Injection (CTI) system in BF which not only reduces specific energy consumption but also reduces BF slag arising and also reduces environmental pollution in coke ovens by reducing the coke making requirement for the given hot metal production. BSL has Solutions to Wastes in Mining, Iron & Steel Industry [3.1 / 3 ] CDI installed in BF 4 & 5 and CTI in BF 1 . Rest of the Furnaces will be fitted with CDI in phased manner . This will also help to reduce BF slag arisings, appreciably in the coming years. BSL has on site “Cast House Slag Granulation Plant “(CHSGP) in BF 4 & 5. BSL is also having Offsite Slag Granulation Plant for granulating BF slag from BF 1, 2 & 3. CHSGP will be installed in BF 1, 2 & 3 in phased manner, which will help in increasing BF slag utilisation . At present the Granulated BF slag is sold to cement industry which produces Portland slag cement (PSC). PSC is obtained by mixing Portland Cement Clinker, gypsum and granulated slag in suitable proportions and grinding the mixture to get a through and intimate mix between the constituents . It may also be manufactured by separately grinding portland cement clinker, gypsum and granulated slag and then mixing them intimately . The resultant product is a cement which has physical properties similar to those of ordinary portland cement . In addition, it has low heat of hydration and is relatively more resistant to soils and water containing excessive amounts of sulphates of alkalied metals, alumina and iron, as well as to acidic waters, and can, therefore, be used for marine works with advantage . Mass concrete works like large foundations, dams, port-and-harbor structures such as jetties, break-waters, warfs; floating structures, sewerage and underground structures, pipe lines and mines, also can be built using slag cement. It is also suitable for shore protection works such as blocks, tetrapods, machine foundations, piling, caissons, piers, wells, effluent and sewerage treatment plants, buildings, industrial structures, cooling towers, silos and storage structures. Slag being available in Eastern India, Slag cement is quite popular in Eastern India and many important structures like Second Hoogly Bridge, Underground Metro system at Calcutta, etc. have used Slag cement. At BSL presently about 51% BF slag is granulated and sold to near by cement industries. However cement industries in and around Bokaro area are very few, leading to stock piling up of granulated BF slag happens, particularly since the cement industries prefer dry flyash for making blended cement, to cut the cost of grinding of Granulated BF slag. Thus there is a need to look for other alternative routes for increasing BF slag utilization at BSL. Production of Ground Granulated BF slag (GGBFS) and Air cooled BF slag aggregates for construction industry are the promising avenues for enhancing the BF slag utilization at BSL. Solutions to Wastes in Mining, Iron & Steel Industry [3.1 / 4 ] 3. Ground Granulated Blast Furnace Slag With the advancement of technology and research in the field of concrete and slag utilisation, a change came, and in year 2000 the BIS permitted the use of flyash and Ground Granulated Blast Furnace Slag (GGBFS), as mineral admixture from the consideration of “Durability criterion” (IS 456-2000). In the United States, the production and marketing of ground granulated blast furnace slag (GGBFS) has seen extraordinary growth since its introduction in 1982. Used as a partial replacement for portland cement, this byproduct of the steel industry can significantly improve the durability of ordinary portland cement concrete and, at the same time, have a positive impact on the environment. GGBFS is produced and used widely in advanced countries like USA, Japan, Australia, Europe, UK , etc . 3.1 Environmental and Energy Conservation Aspects of GGBFS: The use of GGBFS as a partial Portland cement replacement takes advantage of the energy invested in the slag making process and its corresponding benefits with respect to the enhanced cementitious properties of the slag. Grinding slag for cement replacement requires only about 25 percent of the energy needed to manufacture Portland cement. Investigations show that one tonne of normal Portland cement production discharges about 0.9 tonne of CO2 into the atmosphere, which is the major green house gas. GGBFS typically replaces 35% to 65% portland cement in concrete. Thus, a 50% replacement of each ton of portland cement would result in a reduction of CO2. Typical CO2 Emissions for Portland Cement and GGBS Production. (Figures in kg per tonne of output) Solutions to Wastes in Mining, Iron & Steel Industry [3.1 / 5 ] On one hand, utilization of slag in cement / concrete conserves the energy, minimizes the CO2, emission problem to the extent of its proportion in cement / concrete, on the other hand, it reduces the accumulation of slag. GGBFS is a 100% recycled material, using significantly less energy at reduced levels of CO2 emissions during production as compared to portland cement. Because of this environmental posture, GGBFS is included in the list of recommended materials in the National Institute of Standards and Technology study entitled Building for Environmental and Economic Sustainability. GGBFS also has been recommended by the U.S. Green Building Council's program called Leadership in Energy and Environmental Design. The US - EPA recognizes the environmental and energy-saving values of GGBFS by favoring its procurement and use in federally funded projects (EPA 40 CFR Part 247). Government should encourages everyone Steel Industry , ready-mix companies, builders, contractors, engineers, and architects) to use GGBFS, thus producing better concrete as well as saving energy and reducing the CO2 emissions in the environment. 3.2 CONSTRUCTION PROCEDURES FOR “GGBFS” Material Handling and Storage: GGBFS (or cement containing GGBFS) is handled and stored like conventional Portland cement. Mixing, Placing, and Compacting: The same equipment and procedures used for conventional Portland cement concrete may be used to batch, mix, transport, place, and finish concrete containing GGBFS. Curing: The slower strength development of concrete containing GGBFS may require that the moisture be retained in the concrete for a longer period of time than what is normally required for conventional concrete. Scheduling of pavement construction should allow adequate time for the specified strength gain prior to the placement of traffic loads, the onset of freeze-thaw cycles, and the application of deicing salts. Quality Control: The same quality control procedures used for conventional Portland cement concrete can be used for concrete containing GGBFS Solutions to Wastes in Mining, Iron & Steel Industry [3.1 / 6 ] 4. Steel Melting Shop (SMS) Slag In the field of SMS slag utilization, Bokaro Steel has done a pioneer job . BSL is processing the SMS Slag in various fractions such as 0-5 mm , 5-10 mm, 10-20 mm 10-40 mm, 40-45 mm and 10-100 mm for various consumers. 0-5 mm slag is being charged into Sinter Plant replacing equal amount of flux . Similarly 10-40 mm size are being used in SMS and BF. The entire roads of Plant and Township are being repaired by 5-10 mm and 10- 40 mm size LD slag . BSL is having around 400 Kms of Railway Track for which 20-65 mm size LD slag is being spread replacing conventional stone ballast . BSL has not purchased any stone ballast for maintaining its railway tracks in past few years BSL also supplying processed LD slag to IISCO Steel Plant, Burnpur which is being charged in Blast Furnace. With the above mentioned recycling efforts, around 96% of LD slag is being recycled / consumed within BSL which is highest among Indian Steel Plants. 6. Conclusion With growing shortages of energy and materials, waste is now seen as a potential resource. Environmental legislation and regulations and the economics of disposal are directing the steel industry to look for ways of minimising the generation of wastes and maximise recycling of collected wastes. Environmental Friendly Slag Cement ( made using BF Granulated slag and Steel Making Slag ), Ground Granulated BF Slag (GGBFS) for using in Construction Industry should be preferably promoted in India by necessary economic incentives and legislative mechanism by MoEF in line with US EPA’s scheme and should be enforced by Administrative Set up in India. Government should encourage everyone; Steel Industry , ready-mix concrete companies, builders, contractors, engineers, and architects, etc, to use GGBFS, thus producing better concrete as well as saving energy and reducing the CO2 emissions in the environment. Directions to the concerned in Central Govt and in State Govts. Agenicies like CPWD, PWD, NHAI, Railways , etc, to specify the use of Slag Cement / GGBFS in construction activities , will go a long way in meeting the utilization targets of metallurgical slags from Integrated Steel Plants in India. About the Authors Shri R.P. Singh, DGM, ECD, BSL. Shgri R.G. Segaran, Sr. Manager, ECD, BSL. Solutions to Wastes in Mining, Iron & Steel Industry [3.1 / 7 ] Annexure-1 CHEMICAL COMPOSITION OF STEEL PLANT WASTES PARAMETERS BF Slag BF Slag SILICA 32.89 14.70 ALUMINA 13.54 3.25 OXIDE OF IRON 21.40 22.20 FeO 1.28 12.71 LIME 25.16 36.15 MgO 0.81 1.50 LOI 0.60 4.21 Solutions to Wastes in Mining, Iron & Steel Industry (3.2 / 1) MANAGEMENT OF SPLINTERS IN SMS S. Nanda, AGM (M), SMS-II D. Mohapatra, AGM (M), SMS-II Md. Islamuddin, DGM, Design 1. Introduction Prevailing conditions affecting splinter (dust) generation Like most of the BASIC oxygen furnace shops operating in India, SMS II department of Rourkela Steel Plant has also adopted the conventional way of making steel that is desiliconisation, dephosphorization, decarbonization, and some desulphurization is done upto the removable levels of the individual constituents in the converter alone. Hence, generation of total dust is affected inside the converter only. As the hot metal received from blast furnace normally contains silicon, phosphorus, and sulphur on the higher side as well as manganese in small amounts, available lime of largely compromised quality is used in higher quantities. Other constraints of converter operation like lining protection with shortage of scrap etc. have imposed the adoption of the use of iron ore and dolomite in optimum quantities. Briefly, we make steel in the condition of slag in higher viscosity and the liquid metal with lower surface tension. We also blow with a six-nozzle lance for improving the process of steel making. All these factors facilitated the process of dust making in higher quantities. That is why against the normal expectation of 3.5 to 4 tons of dust generation per blow, all our previous assessments have shown a generation level in excess of 4.5 tons in slurry form only i.e. excluding higher size grits. 2. Dust Management In RSP, a Gas Cleaning Plant designed and commissioned by DAVY MCKEE LTD. UK manages dust. It is a modified form of OG(Off Gas/ Oxygen gas) process developed in Japan in 1975. As usual, it has two functional sections: Cooling section. Cleaning section Cooling section is an absolutely necessary and problematic section in all BOF gas cleaning plants just to facilitate safe use of water as the cleaning medium owing to the following parameters: Solutions to Wastes in Mining, Iron & Steel Industry (3.2 / 2) 1. Wet scrubbing system is suitable for BOF gases as no strong acid forming gases are generated during steel making. Hence, rapid corrosion does not take place due to use of water for scrubbing. 2. Only the venturi type wet scrubbers have the capability and reliability to perform in severe fluctuations of dust quantity and size. The size distribution varies from 0.008 µm to 250. µm under normal conditions and upto 500 µm or even beyond under abnormal conditions, but about 60% dust by mass remains in 1 to 60 microns range by the time it reaches the cleaning section. 3. Water cannot be sprayed to gases directly when gases are at temperatures far beyond 800 °C as water in steam phase at 800 °C (water gas) may dissociate forming explosive hydrogen. Thus, gases have to be cooled from about 1700 °C at converter mouth to about 900 °C. 4. The cooling section also serves the most important function of dust preparation and separation. It flocculates most of the fine dust to bigger agglomerates and returns back many bigger/heavier particles to converter. Right from the converter vessel mouth, gasses along with all splinters are guided through the skirt to cooling hood. Dust is mechanically entrained upwards along with the gases. Turbulences inside the hood are avoided by design upto the cleaning section so that flocculation is facilitated. In RSP, the cooling section has some special features uncommon to many others. 1. System has been designed for atleast 50% more gas load than normally working. 2. Much care has been taken in all the equipments to minimize erosion and ensure smooth flow of fluids. 3. Pressure drop in fluid flow has been ensured to be bare minimum with adequate compensation. 4. All the susceptible pockets have been adequately taken care of against locked in hazardous gases. 3. Cleaning Section In the cleaning section, two stages cleaning has been provided. The first stage cleaning starts with a quencher which cools the gases and dust from about 900 °C to about 75 °C. The quencher is designed to trap all the heavier particles and some of the smaller particles. The quencher is followed by the primary venturi scrubber and the primary separating elbow where contaminated water is collected and drained off to the flume. The gases with residual fine particles are then guided to the secondary cleaning stage, which is provided with a high energy venturi scrubber. The secondary scrubber is supplied with clarified water from wastewater treatment plant, which gets partially Solutions to Wastes in Mining, Iron & Steel Industry (3.2 / 3) contaminated after cleaning. This partially contaminated water is then separated from the gas stream at the secondary separating elbow just below the secondary scrubber venturi and pumped to quencher for final use before sending to waste water treatment plant. The wastewater contains dust particles almost of all sizes starting from submicron to about 500 microns. Almost 99.5% of the dust generated in the converter basin are captured by the inside gas cleaning plant and the flare stack normally exhausts some dust in the invisible or mild color sizes. 4. Sludge/Slurry Management The wastewater treatment plant (WWTP) receives highly contaminated water by the flume (launder). The flume discharges water to a screw classifier where a few seconds settling time is available. Almost all the bigger particles and granules settle on the floor and swept by screw classifier. These granular dusts is then conveyed and discharged for onward utilization in sintering plants. The slurry/contaminated water is then subjected to chemical treatment in a flash mixer compartment and discharged to thickener/clarifier for sludge settling. The contaminants normally settle completely in the thickener. The outlet condition of the water from the thickener is P.H – 12.5 (11.5 to 12.8) Total Harness – 300 to 1000 Total suspended solids – 25 to 35 milligram/litre In the original system, sludge was being drawn from the center of the thickener by underflow pumps to sludge holding tanks. From sludge holding tanks, it was pumped at the desired rate to drum filters for final cake formation and disposal. As usual the low reliable drum filters continued to pose problems. They were rarely able to cope up with slurry generation rate and thickener level used to swell up. The cakes were never very dry or suitable for transportation. Spillages were rampant in the area. It used to flow along with water to drains during rainfall or otherwise. The ground remained muddy all around and vehicular movements on dried or wet sludge were contaminating a larger ground area and even the air above it. Higher rate of production only worsened the matters. In order to save the environment from this menace, the slurry-handling project was taken up and it was decided to transfer the slurry to pits on the ground level. Three pits were made with earthen embankments and facilities for dry slurry disposal was also Solutions to Wastes in Mining, Iron & Steel Industry (3.2 / 4) incorporated so that while one is in operation, the other two can be left for drying/ disposal as per requirement. The pits have been constructed at an average distance of 1200 meters from wastewater treatment plants. The ground was leveled and earthen embankments of 2.6 meter height were constructed. NB125 size slurry handling pipes (2 lengths) have been laid for discharging slurry at the rate of 75 m3/hour. Originally, the scheme was to draw slurry from thickeners to sludge holding tanks from where it was to be pumped to the pits. The scheme was found to be facing some capacity mismatch problems for pumping. Higher temperature and fluctuating density of the sludge in the sludge holding tanks led to operational problems for the pumps. It was decided to try direct pumping from under the thickeners so that slurry density remains quite low and higher positive suction is ensured irrespective of temperature. The trial was successful and consistent behavior of the pumps was observed. The project has been running successfully since March 2006 and that is the major reason why we have been able to cope up with high level of production. Now the system is running for only three hours every shift and still able to manage the whole dust load. 5. Observations Some of the observations in the system are noteworthy. 1. After about two hours of operation in every shift, the slurry density at discharge point is very low indicated by a drop in discharge line pressure as well as color of the slurry. 2. Sludge buildup in the thickener has never taken place. 3. The settled sludge made a gradient of almost 1 in 125 in the pit whereby the sludge touched the discharge pipe while covering half the length of the pit only. It has necessitated multiple feed points per pit for full utilization. 4. Water has never overflowed on the weir provided on the embankment opposite to the feeding point. It has always passed through the embankments to surroundings apart from normal evaporation. Retained water level is always quite low. 5. Permanent water accumulation has occurred in the unused pit which were previously drier. Minor leakage has also been observed on the base of one side embankment. The water quality of the leakage is surprisingly very good (compared to water after sedimentation). Solutions to Wastes in Mining, Iron & Steel Industry (3.2 / 5) 6. PH – very near to 10 7. TH< 10 8. Turbidity - .5 NTU max 9. Some snakes and small insects have been found swimming in this water. 10. It may be one consolation that even the ground water may not be getting polluted owing to this project. 11. Pit no. 3 which is much deeper compared to other pits has become a lake with clear water of the above quality. We may think of using this water for suitable purposes. 6. Conclusion Seepages through embankments or ground may require some changes in layout etc to ensure drying of the sludge in pits when nearby pit is in operation. Use of dried BOF sludge is normally a challenge for conventional sintering plants. Many steel plants prefer to make briquettes by using PVC, polyethylene or polypropylene as binders and use them in blast furnaces. Process of direct use in BOF converters after briquetting is also available. Portland cement has never been successful in binding the sludge for making bricks and the last use as land filler is neither economical nor devoid of other controversies. In this situation, many steel plants have adopted processes, which have reduced generation of total dust by about 50%. We may have to resort to some similar ways in the future. Solutions to Wastes in Mining, Iron & Steel Industry [3.3 / 1 ] EFFECTIVE SOLID WASTE MANAGEMENT IN IRON & STEEL INDUSTRY WITH A SPECIAL REFERENCE TO ROURKELA STEEL PLANT *Dr. B N DAS, General Manager (Env. Management), ** V V R MURTY, Sr. Mgr. (Env. Engg. Department) Sail, Rourkela Steel Plant, Rourkela Synopsis The quantity of waste generation and its quality are the indicators of Steel Plant’s operational efficiency and quality of input raw materials. Waste generation is a threat to environment protection and sustainable development. Basically two types are wastes viz., ferruginous wastes (iron bearing) and non ferruginous wastes are generated from different processes during the Iron & Steel making. The ferruginous wastes can be gainfully utilized by proper recycling, back to process, for steel making where as proper method of usage is to be identified for the non ferruginous wastes for maximization of their utilisation . The principle of 4R (Reduce, Reuse, Recover & Reuse) is adopted as baseline for Solid Waste Management in Rourkela Steel Plant . Disposal of wastes confirming to statutory requirements is a last resort in effective solid waste management. No one is waste in this nature. It is the responsibility of the technocrats to identify the various alternate uses of the wastes to make them as by products. Recovery, recycling and reuse of wastes in steel making not only earn revenue in terms of saving of basic raw materials replaced but also conserves natural minerals from depletion. Recycling and reuse of wastes have their own limitations hence disposal of wastes has become inevitable. Disposal of wastes on land is a big threat to environment. Use of different slags as pavement material, railway ballast and use of fly ash in cement manufacturing are already established by research organisations. Government’s support and stringent directives are the need of the hour to support steel industry in effective management of wastes . 1. Introduction In an integrated steel plant, 5 tonnes of input raw materials in the form of Iron Ore, Coal, Fluxes, Ferro alloys & Refractory are required for making 1 tonne of Crude Steel . In the process of steel making around 3.5 tonnes of wastes like slags, dusts, sludges, Solutions to Wastes in Mining, Iron & Steel Industry [3.3 / 2 ] fly ash, mill scales etc., are generated. The general flow of materials in iron and steel making is given in Fig.(1) . The main reasons for high quantity of waste generation are poor quality of raw materials i.e., Iron ore and Coal. High alumina content in Iron ore and poor coke quality lead to high coke rate in hot metal production resulting in high quantities of Blast Furnace slag generation. High ash content in boiler coal results in high fly ash generation in captive power plants. ORE BEDDING & OXYGEN COKE BLENDING PLANT PLANTS (TOP#1 OVENS (OBBP) & 2) SINTER SINTER PLANT#1 PLANT#2 BLAST FURNACES PIG CASTING MACHINE STEEL MELTING SHOPS (# 1 & 2) PLATE HOT STRIP MILL MILL SWPP ERWPP CRM SSM Fig (1) Flow of materials in Steel Making The comprehensive qualitative analysis of different solid wastes help in identifying the areas where the wastes can be recycled back and gainfully utilised. The wastes coming out from steel making can be broadly divided into two categories i.e., Ferruginous wastes and Non Ferruginous wastes. The iron bearing ferruginous wastes are generated from steel making viz., mill scale, flue dust, sludges from Gas cleaning plants of Blast Furnaces and Steel Melting Shops, Blast furnace slag and SMS slag. These ferruginous wastes can be recycled after suitable processing. The non ferruginous wastes are lime fines, broken refractory bricks, broken fire clay bricks, acetylene plant sludge etc. These are reused for various purposes viz., lime fines for Solutions to Wastes in Mining, Iron & Steel Industry [3.3 / 3 ] neutralisation of acidic water, broken refractory bricks for pavement making, and acetylene plant sludge for white washing. 2. Ferruginous Wastes The iron bearing wastes, generated at different stages of steel making are suitable for recycling back to steel making process and reusing in place of raw materials after suitable processing. The recycling of ferruginous wastes back to process is not only replacing iron ore but also other raw materials like Iron Ore (Fines), Lime stone and Coke breeze (coal) . The different types of ferruginous wastes generated at different stages of steel making in Rourkela Steel Plant, their quality and quantity of generation is given in Table-1. 2.1 Mill Scale The mill scale which is nothing but oxides of iron, is generated when the hot slab, plates, coils are cleaned with water during rolling. Mill Scale is generated from Steel Melting Shops, Hot Rolling Mills and Cold Rolling Mills. Mill scale is generated at a rate of 2% of steel rolled in rolling mills . The mill scale coming along with wastewater is separated in wastewater treatment plants. As mill scale is nothing but iron oxides having Fe upto 98.5%, its recycling back to Ore bedding and blending plant is replacing Iron ore (fines) to an extent of 115% . All the mill scales generated in Rourkela Steel Plant are recycled back 100% and gainfully utilised. 2.2 Blast Furnace Flue Dust The dust coming along with Blast furnace gas is first separated in dry form at Dust Catchers, is called Blast Furnace Flue Dust . The BFc. Flue dust is generated at a rate of 50 gms per one Tonne of Hot Metal production. The chemical composition of BFc. flue dust shows that these wastes can replace Iron Ore (Fines) and Coke when it is recycled back for making base mix . Recycling of 1 T of Blast furnace flue dust is replacing 0.63 T of fresh Iron Ore(Fines) and 0.37 Tonnes of Coke . All the Blast Furnace Flue Dusts are recycled back and gainfully utilised in Rourkela Steel Plant for making base mix. 2.3 BFc sludge/SMS Sludge The micro fine particles separated from Blast Furnace Gas and BOF gas at Gas Cleaning Plants in the form of sludge is called BFc sludge/SMS sludge. The rate of generation of sludge is 0.018 T of Tonne of crude steel . The composition of sludges shows that, they can replace Iron Ore (fines) and Lime Stone, when the sludges are recycled back for making base mix in Ore Bedding Blending Plant. One tonne of sludge replace 0.62 T of Iron Ore(fines) and 0.38 T of lime stone, when it is recycled back for making base mix for sinter making. Solutions to Wastes in Mining, Iron & Steel Industry [3.3 / 4 ] Handling and transportation of sludges are posing environmental problems. The spillages on roads during transportation, is the main problem with recycling of Sludges . Recycling of these sludges throughout the year is not possible, particularly during rainy season, as the sludges become wet and cause jamming in unloading facilities . In Rourkela Steel Plant, the BF sludges are mixed with BFc flue dust and transported back to OBBP for making basemix. In Rourkela Steel Plant, the BFc sludges are utilized 100%. SMS sludge, in the form of slurry, generated from Waste Water Treatment Plant is transported to sludge ponds in pipe lines for drying. ponds have been constructed for storing and drying of SMS sludges. One pit is always in operation, another pit is under drying and the third one will be under reclamation. The dried sludge is excavated and recycled back to OBBP for making base mix . 2.4 SMS Slag The impurities present in raw materials and hot metal come out as slag during crude steel production in Basic Oxigen Furnace. The rate of slag generation in SMS is 0.18 T per one tonne of crude steel production. The SMS slags are very rich in calcium content to an extent of 45-50% (as CaO), iron content to an extent of 20-22% (as FeO) . The calcium content in SMS slag can replace addition of lime stone when it is added for base mix making . Recycling of 1 T of SMS Slag replaces 1 T of Blast furnace grade limestone . It is also established by studies conducted by Central Road Research Institute (CRRI) that SMS slags can be gainfully utilised for road making as pavement materials and concreting . Research works carried out by RDSO, of Indian Railways established that SMS slag (40-60 mm) can be used gainfully as rail ballast . The SMS slags can be utilised for various purposes only after proper processing. After proper crushing and segregation, the SMS slags of size <5mm can be used for base mix preparation for sinter making as a substitute for lime stone. The SMS slags of size 5-20 mm can be used for concreting purposes in pavement making. SMS slags of size ranging from 20-40 mm can be used directly in Blast furnaces in place of Blast furnace grade Lime stone . The sizes above 40 mm & <60 mm can be used as rail ballast. All the railway tracks inside Rourkela Steel Plant (190 Kms) are laid on SMS slag ballast. SMS slag is used for making all roads inside the Steel Plant and in Townships in Rourkela. Rourkela Steel Plant is gainfully utilising SMS slags upto an extent of 45- 50% only. The high volumes of SMS slag generation is leading to its disposal on ground. 2.5 Blast Furnace Slag In the process of making Hot metal in Blast Furnaces, the impurities present in raw materials are forming into slag and coming out along with hot metal. The slag generation rate is 400 kg/tonne of hot metal produced . It is established that Blast furnace slag is a good raw material for making slag cement only after proper Solutions to Wastes in Mining, Iron & Steel Industry [3.3 / 5 ] granulation. Granulation is 100% only if the slag is granulated immediately after production; otherwise slag gets solidified and will not be fit for granulation. The un- granulated slags are air cooled and disposed on ground. Installation of in-house slag granulation facilities in Blast furnaces will solve the problem of slag solidification and facilitate 100% slag granulation. Rourkela Steel Plant is having inhouse slag granulation facilities at 2 blast furnaces, BFc#1 & 4. A separate slag glanulation plant is installed to take care the slag coming out from BFc.#2 & 3. The present rate of overall slag granulation is 90-92% and is gainfully utilized 100% for cement making. The use of granulated slag is replacing lime stone in cement making. Utilisation of BFc. Granulated slag is not only saving the precious lime stone but also reducing the green house gas emissions on account of lime stone usage. The use of BFc granulated in place of lime stone in cement making is reducing the green house gas emissions to an extent of 936.4 kg of CO2 / Tonne of BFc slag utilized. 3. Non Ferruginous Wastes In Iron & Steel making, different non iron bearing wastes are generated from various operation like, refractory lining in converters & furnaces, making of acetylene, calcinaion of lime and dolomite & boiler coal for captive power generation. These are called Non Ferruginous Wastes. They are; • Used Refractory bricks • Used fire clay bricks • Acetylene sludge • Lime fines • Dolomite fines • Fly ash The quantity of generation and their utilisation are given in Table-1. 3.1 Used Refractory Bricks 60000 T of refractory bricks are used every year in RSP. Out of which 1500 T of used refractory bricks are salvaged for reuse and rest consisting mainly magnesite and chrome-magnesite bricks are being sold . The rejected refractory bricks are used for pavement making in RSP. 3.2 Acetylene Sludge Rourkela Steel Plant has two number of Acetylene plants for production of acetylene gas from Calcium Carbide. About 1700 T of acetylene sludge is generated from these plants. This sludge is highly alkaline in nature and can be used for Solutions to Wastes in Mining, Iron & Steel Industry [3.3 / 6 ] neutralisation purposes. This sludge can also be used for white washing purpose. Presently the acetylene sludge is being sold out. 3.3 Dolomite & Lime Fines In Calcining Plant#2 & LDBP of Rourkela Steel Plant, lot of dolomite & lime fines are generated during calcination of dolomite and lime stone. These fines are mostly arising from material handling operations, screening and are captured in various dust extraction systems in the plant. The CaO content of these lime fines is ranging from 85- 87% and can be gainfully utilised for neutralisation purposes as well as for white washing. These lime fines are also gainfully utilised as trimming addition in Sinter Plant. The lime fines are also being used for neutralisation purposes in water treatment plants for township, neutralisation units of Cold Rolling Mill . All the fines are gainfully utilized to 100% in Rourkela Steel Plant. 3.4 Fly Ash RSP is having a coal based Captive Power Plant. The ash generated during the burning of coal, called fly ash is disposed off by dry & wet methods. The fly ash generation is 36000 T/month . Presently most of the fly ash is disposed off in wet condition in Ash ponds. The disposed fly ash is presently used only for raising dyke height of ash ponds . Dry fly ash is also disposed to cement manufactures from MP boiler#3 presently. Arrangements are being made for direct disposal of dry fly ash from captive power plant HP boilers of RSP. 4. Plan & Prospects Of Solid Waste Management Rourkela Steel Plant has started effective management of Solid Wastes in the year 1998. The solid waste utilisation has increased form a level of 55.3 % in the year 1999- 00 to a level of 73% in the year 2006-07. The utilisation of solid wastes is not only earning revenue to the company but also reducing the consumption of precious natural resources. It is planned to increase overall utilisation of solid wastes to 80% in the year 2007-08. It is planned to further increase the solid waste utilization in RSP by increasing the recycling of SMS slag fines back to OBBP for base mix preparation. Consistent operation of in-house slag granulation facilities at BFc#1 & 4, strengthening of Slag Granulation Plant‘s efficiency will further augment the Blast furnace slag granulation and increase the overall utilisation of solid wastes in the coming years. 5. Conclusion The management of Solid wastes from steel making is a major environmental issue to be tackled properly as the quantities are very large . Consistent efforts are required to maximize the utilisation of these solid wastes. Whatever unuilised wastes are left behind are to be properly disposed on the ground in a systematic way. The Solutions to Wastes in Mining, Iron & Steel Industry [3.3 / 7 ] dumping sites are also developed systematically. Devising means to reduce, recycle recover and reuse of solid wastes can only solve the problem. While substantial progress has been made during last few years these areas, yet much more remains to be done. Table-1 Solid Wastes Generation & Utilisation in Rourkela Steel Plant QUANTITY OF SOURCE OF UTILISATION SOLID GENERATION SN GENERA- QUALITY (%) WASTE (T) TION 2006-07 (2006-07) Fe= 46-52-%; CaO= 22-30%; Blast 1. BFc slag 827575 MgO= 4-10%; MnO= 2-6% & 90.75 % Furnaces SiO2 = 26-31% Steel Melting Feo= 18-21%; Sio2= 16-18%; 2. SMS slag 366933 47.92% Shop CaO= 47-53% C=16.6-33.4%; LOI= 19.4- Blast Blast furnace 43.6%; Fe= 30-40.5%; SiO2 = 3. furnace 14883 100 % dust catcher 7.4-11.6%; CaO= 2.3-4.6; flue dust MgO= 0.5-1.2% Waste Water C= 2.13%, Fe= 51.8% ; MgO= SMS 4. treatment 35919 2.0; S= 0.21%; SiO2= 2.1; 0.39 % sludge plant of SMS CaO= 12.8; LOI = 6.7% Rolling Mills waste water 5. Mill Scale 37836 Mixture of iron oxides 100% treatment plants Acetylen Acetylene SiO2=4-6%; Al2O3= 1-3% 6. 2244 100% e Sludge plants CaO= 60-70% Calcined Calcination Cao=70-80%; MgO=3.5%; 7. lime Plant#2 & 32231 100% SiO2=1.7%; Al2O3= 3.5% Fines LDBP Used From relining refractory of converters, Basically CaO, Al2O3 and 8. 2946 100% / fire clay furnaces and traces of Fe2O3 and MgO bricks ovens Total Steel Plant 1321722 77 % Solutions to Wastes in Mining, Iron & Steel Industry [3.4 / 1 ] RE-CYCLING OF WASTE FROM IRON STEEL INDUSTRY FOR SAFER ENVIRONMENT AND BETTER PRODUCTIVITY Mr. B. Sankar, Dy.Manager - Mr. R.K. Dutta, Asst. Manager - Mr. P.K. Pani, Production Superintendent OCL Iron & Steel Ltd. Introduction With the revival of Industrial scenario all over the world, the Iron steel plants are growing anything like mushroom, with the emergence of no of plants also posed a big challenge among the manufacturer to recycle the waste coming out of the process. It is not only the disposal of the waste but it has a necessity also to keep the environment clean as well as increase the productivity. The rapid growth along with their technological limitations a severe problem is being faced by the industries in the area of environmental pollution leading to ecological imbalance for the society. The problems become much grimmer as they are placed in a situation of stiff competition with enormous quantity of generated waste and their handling, disposal, elimination or re- utilization. As day-by-day the Govt. of India become more conscious about the environment we all have to think seriously about the above matter. With the growing price of steel the raw materials cost is also going high so by recycling of the waste will help in bringing the production cost down. Steel industry has been transformed into a dynamic industry within many fundamental ways the steel is produced, fast to adopt new technology and at the same time these changes have made new challenges to be solved. Even though steel makers traditionally had recycled a good amount of by-products they produce .A new process a better social awareness and more restrictive legislation have generated new ideas and new technologies for better re-using of all of them. Most of the times, compliance with environmental regulations has been a burden for the steel makers, adding extra cost to steel products .It seems that only economic solutions to the environmental problems are when the by-products are considered as raw material for some other process, thus obtaining an economic value and not been considered as waste product. The most common and economical route for making steel with low initial investment is Induction –caster route with own sponge iron plant and captive power plant many of the mini steel plant have this set up .The major waste material generated in this set up are Sponge Iron plant (i) Iron ore fines (ii) coal fines (iii) bag filter dust (iv) Waste flue gas (v) Accretion material (vi) Sponge iron Fines Solutions to Wastes in Mining, Iron & Steel Industry [3.4 / 2 ] (vii) Char Power plant (i) Fly Ash (ii) Esp. dust Steel Plant (i) Slag (ii) Mill Scale Waste Mangement The disposal of waste generated from the industrial processes is the major concern Reduce, reuse and recycle philosophy and efficient waste management has to be prompted. The material generated in a process which is unused and rejected in that process is considered as a waste. Iron ore fines and Coal fines Iron ore and coal are the two major raw materials for the Iron & steel industry but the process required certain size of raw material. There fore crushing and screening is required. During crushing of iron ore lumps normally 30% fines (-3mm) are generated of total lumps ore. From chemical analysis it has been seen that it contain >65% Fe (T). Similarly in case of coal. The generation of coal fines is very high in dry season as compare to the cosumption. These excess fines coal are required to be disposed off in dry season. 2 to 5 mm of the ore can be used in rotary kiln sponge iron process directly by adjusting coal size and process parameters. 0 to 2 mm ore fines can be used by pelletisation in other iron making process such as BF-BOF route, Oxicup, gas based sponge iron process. Bag filter dust High capacity bag filter are installed in dust emission area the dust generated from bag filters are considered as waste .The dust generated from coal bag filters have the proximate analysis report VM=2%, ASH=75%, FC=23% similarly the iron dust also contain .65%Fe (T). It could be used in the AFBC of the power plant. It could also be used in the brick-manufacturing unit for construction job for which they are using the top soil of the earth Waste flue gas In rotary Kiln sponge iron process exit gasses are called waste gas. These gases contain high heat value. Chemical composition of this is as follows Solutions to Wastes in Mining, Iron & Steel Industry [3.4 / 3 ] CO2 = 19% H2O = 17% O2 = 1% CO = 0.5% SO2 = 0.05% CH4 = 0.8% N2 = 61.65% The temperature of the flue gas can be utilized in power generation through waste heat recovery boiler Accretion Material Accretion materials which we are getting out of the kiln are mainly comprised of:- Al2O3 + SiO2 = 70-78%, Fe2O3 = 20 – 28%, rest is TiO2, CaO, MgO, Fe (M). It can be used in the Oxicup furnace. It can also be used in the land filling in the mining areas It can also be thought of to extract the 30% hematite from the amount through the mineral beneficiation process. Sponge iron fines(-1mm) Sponge iron fines (-1mm) generated is approximately about 20%. Which are normally creating several problems in melting. Sponge iron fines can be processed for production of electrolytic Iron powder of Ultra high purity, high strength P/M parts, higher productivity and this process is Useful for production of high and medium density PM parts and high quality welding electrodes. Char Char generation in the rotary kiln is approximately 25%to 30%. Having proximate analysis report of: V.M = 1% to 2%. ASH = 68 %( Approx.) FC = 30% (Approx.) Solutions to Wastes in Mining, Iron & Steel Industry [3.4 / 4 ] CV = 2000 Kcal/Kg Chemical analysis of char: LOI = 31.72 SiO2 = 38.64 Al2O3 = 17.12 Fe2O3 = 10.67 CaO = 1.13 MgO = 0.15 Na2O = 0.09 K2O = 0.48 Char can be utilized in AFBC for power generation. And its chemical composition suggests it can well be used as a cement raw material replacing siliceous material having potential heat value around 2000 Kcal/Kg, which can save some fuel during burning in cement kiln also. Slag Slag is a by-product from the foundry process. The type of slag produced by a foundry will depend on the Processes used. Common ferrous foundry slag includes: n cupola slag (air-cooled or water-quenched); n induction furnace slag; n electric arc furnace slag; n desulphurisation slag. The physical and chemical characteristics of slag make it ideal for re-use in a range of applications. Its chemical Composition makes it suitable for use as a source of various minerals. Physically, its mineral-like properties make it particularly suitable as an aggregate replacement... Use Of Iron & Steel Making Slag Reuse of iron & steel making slag largely depends on slag chemistry and the methods used for it’s cooling. With increase in production of steel, production of slag also increased significantly. So, several new areas have been explored for reuse of slag. Slag has been used since ancient time for construction purposes. Solutions to Wastes in Mining, Iron & Steel Industry [3.4 / 5 ] The use of slag increased significantly in asphalt blends for smooth road paving. Air-cooled blast furnace slags are used for road construction after crushing and screening. Water cooled blast furnace slag are widely used for cement making because of its cementations properties which develops with lime and water. Reuse of slag generated from foundry process 1.) Cupola slag: The air-cooled cupola slags are used in asphalt, ballast, bricks, mineral wool, and road base construction. The water-cooled cupola slags are used in blockmaking, bricks, mineral wools, soil modifier, and abrasives running surfaces. 2.) Induction furnace slag : Road base construction, abrasives. 3.) Electric arc furnace slag : Ballast, road base construction. 4.) Desulphurization slag : Soil modifier, slaked lime replacement, blast furnace slag, and Cement manufacture. Mill scale Mill scales are the oxides of iron produced during hot fabrication of the steel. During continuous casting of near about 0.6 -0.7% of mill scale generated of the finished steel billet. Mill scale having composition of Fe (T) = 70 %( Approx.) , Oxygen by weight 25% Other gangue material = 8% Sulphur = 0.1% VM = 4.5% The use of mill scale as an oxidizing agent results in improving the yield of process but it needs thermal energy to dissociate it self and make oxygen available for refining reaction. These materials can be utilized as oxidizing agent in the melting furnace, which can remove phosphorus as P2O5 and reduce the carbon content in the molten bath also this can be used in thermit welding process. Fly Ash Fly ash is generated in the AFBC boiler and it is about 70% of the charge into it .Fly Ash is composed of: - Solutions to Wastes in Mining, Iron & Steel Industry [3.4 / 6 ] Al2O3 = 20-25% Fe2O3 = 8-10% TiO2 = 1-1.5% CaO = 1-1.5% MgO = 1%(Approx.) SiO2 = 60-65% Na2O = 0.05% K2O = 0.5 -1% Fly ash can be used in the cement plant for making PPC.This fly ash can also be used for bricks making for building construction ESP Dust The residual dust particle from flue gas exited from the kilns are collected by the TR set of Electrostatic precipitator are receipted in the hopper. These dust particles are termed as ESP dust. The ESP Dust generated could be used for brick manufacturing. It could also be used in the AFBC boilers as a potential fuel. Modern Recycling technology Environment-friendly and Energy optimized technologies for Competitive iron and steel making As the production of steel is increasing, the generation of wastage is also going high. Though, lots of work has been done in the area of recycling of waste generated from the steel plant, further research work is still going on. Oxi-cup is a very good process in which we can minimize the waste generation as low as to zero level. This process is based on self-reducing agglomerates containing iron oxide fines and carbon in the form of brick. These bricks are made up ESP Dust, Skulls/ rubble, Iron ore fines, coal fines, Skulls, Processed sags, Mill scale sludge, Mill scale, Flue Dust Esp. dust, Sponge iron fines, Acrietion materials, Bag filter dust. Which are Charged into a shaft type furnace called Oxi-cup for smelting to deliver sustainable hot metal to EOF/BOF shop. Solutions to Wastes in Mining, Iron & Steel Industry [3.4 / 7 ] The advantages of this process: - (i) Agglomerations of coal fines in a cold bond process. (ii) Smelting and melting from one heat. (iii) Minimum lump coke consumption Conclusion Steel production is one of the most important indicators and indices of economic development of a country. Much belatedly the concern for ecological degradation has cautioned the mindset of steel producers. The steel producers are gradually phasing out the obsolete and energy intensive technology to efficient one. For its more survival and growth in this era of stiff competition and stiff hike in input costs, the industry has no better option. By doing so benevolence to the society can also be established since it not only gives wealth to the industry but conserving the natural resources to a greater extent and hence maintaining the ecological balance and health of the society at large. Let us have an oath to save the earth to provide us a healthy; clean, and congenial society to live in by converting the waste in to a raw material for recycling for better productivity, which is the right solution in the right time. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 1 ] AMERICAN EAF DUST RECYCLING THROUGH VITRIFICATION This Paper was presented to Iron & Steel Society Electric Arc Furnace Conference, Dallas, Texas December 9,1996 Local Reps. In Asia: Zoom Developers P Ltd Status Of Eaf Dust Recycling Through Vitrification John H. Buddemeyer V.P. Engineering and Operations Inorganic Recycling Corporation (Taken over by Pacific Sterling Inc. Paper Printed with Permission from Pacific Sterling) Introduction Inorganic Recycling Corporation (IRC) has developed and commercialized a method for recycling EAF dust that is: - Environmentally sound - Inherently economical - Inherently reliable - Commercially proven IRC is the only dust handling system capable of offering a strong potential for reduced fees over the next ten years, with product improvement and development, rather than increased fees. Using silicate chemistry, IRC's process converts once environmentally hazardous EAF dust into friendly commercial products of lasting value. Products are in the glass-- ceramic family of materials. (See Figure 1 and Figure 2) They are typically used as an ingredient in the manufacture of many other commercial products. Examples are: roofing granules, ceramic floor tile, abrasives and architectural applications. IRC supplies glass-ceramic products to users who require products with more consistent or more customized properties than are available through naturally occurring materials now used. EAF dust provides low cost feedstock materials which are of great value in achieving desired product properties. Low feedstock costs enable IRC to sell recycled products at highly competitive prices that remain predictable over the contract period. An IRC recycling facility is normally located on a steel mill's site and accepts dust directly from the bag house, thereby eliminating transportation costs and risks. In the Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 2 ] IRC process, dust is mixed with other raw materials, melted, then cooled and formed into recycled products that meet customer specifications. Arkansas Black Glass Specimen #1 Fig. 1 400X magnification of current IRC product showing various crystal forms. Fig. 2 400X magnification of Annealed IRC product showing growth of crystals Once recycled, EAF dust looses the "liability trail" normally associated with hazardous waste operations. Both Inorganic Recycling and the steel mill are thoroughly and completely isolated from hazardous waste liability. IRC's recycling services are provided on a low risk, pay for services rendered, basis. Dust is recycled in return for an agreed price for each ton recycled. Facility design, installation and operation is at IRC's expense. No capital investment is required by the steel mill. Theoretical Basis For The IRe Product Technically, a glass is any solid material that does not have long-range order (periodicity) in its atomic structure. A ceramic is any inorganic, nonmetallic material. comprised of a single crystal or of many small crystals (polycrystalline). In practice, glasses and ceramics are often interrelated. This is possible because the same material composition can often be fabricated as a glass, a ceramic, or a combination of the two, Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 3 ] depending on the way the material is thermally treated. Glasses are, generally speaking, super-cooled liquids of extremely high viscosity. When heated to a specific temperature, glass becomes low enough in viscosity that the atoms cannot order themselves sufficiently to become crystalline. However, if cooled slowly enough, they can become ordered (crystalline), as shown schematically in Figure 3. The most common glasses, e.g., window glass, in use today are based on a silicate structure (Si02), the same material used in many ceramics, e.g., dinnerware. Silicon dioxide in pure form can make a very fine optical glass called fused silica; unfortunately, the temperature required to form it is very high, restricting its use to areas where a very low thermal expansion material of high optical quality is required. The more common glasses use fluxing agents, like Na20 or K20, Figure 4, which reduce the processing temperature, making the glass easier to form. Silica has often been referred to as the universal solvent, by glass and ceramic manufacturers, due to its ability to accept most other ions into its structure while remaining quite stable in the presence of water, acids and bases, HF being the exception. Additions of other oxides are made to glass for many reasons; however, they are generally added to increase resistance to chemical corrosion, increase or decrease optical transmission, to obtain various colors, and to vary mechanical properties. Glass is also used as a coating for other materials to provide environmental protection or provide a decorative effect. Glass coatings on a metal are called enamels and on ceramics, they are referred to as glazes .. In each, relatively large amounts (1-10 weight percent) of transition metal ions are added to give a particular color and/or opacity. (1a) (1b) Fig. 3 Schematic representation of (a) ordered crystalline form and (b) random network . glassy form of the same composition (Kingery, 1960). Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 4 ] Si++ O 2- Na + or Metal Ions Fig. 4 Schematic representation of the structure of a sodium silicate glass (Kingery, 1960). In the schematic shown in Figure 4, the Na or Si ions could be replaced by a transition metal ion. The transition metal oxides used to produce color in glasses, glazes or enamels are CuO, Ti02, Cr203, CoO, Fe203, Mn02, NiO and ZnO. Other heavy metal ions like Pb, Cd and Sr are also used extensively. PbO is added in as much as 30 weight percent, to provide high index of refraction glasses (commonly referred to as crystal glasses). Basically, the IRC process is a standard ceramic/glass production technique that uses combinations of silica with additives to form a silicate structure that results in a polycrystalline ceramic, an amorphous structure, or a combination of the two. In a standard flat glass (window glass) process, quartz (Si02) is mixed with a flux, usually some form of sodium oxide (Na20) to lower the melting temperature, possibly calcium oxide (CaO) or Aluminum oxide (AI203) to increase chemical resistance and transition and a heavy metal ion to give a specific color or to increase the hardness. (Figure 5) However, the coloring agent is usually added in the part per million range because the color desired is a translucent tint and not an opaque solid. Also, hardness is not a property that is of concern in standard glasses. The rather unique deviation from the standard glass process used by IRC is that we are using larger amounts of heavy metal ions to obtain opaque glass materials (2-5 weight percent) to produce products that have potential marketability. More important, IRC uses different additives to accomplish this, based on the composition of the waste materials being processed, in order to adjust the chemistry of the product. Fortunately, silicate glasses are able to accept relatively large amounts of metal ions into the Si02 Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 5 ] network structure. When the glass cannot accept additional metal ions, the metal precipitates out of the glass and forms oxides that are insoluble or nearly insoluble in water and acids ARKANSAS BLACK GLASS ANNEALED SPECIMEN #1 MICROHARDNESS TESTING DATA Vickers Indentor (200 gf Load) 400Z Magnification PHASE I 882.5 922.5 806.0 PHASE 2 646.5 686.1 652.0 PHASE 3 908.9 1083.6 970.3 Fig. 5 400X magnification of Vickers hardness test in the various areas Environmentally Sound The Inorganic Recycling process has been fully evaluated and determined to be a legitimate recycling activity by the U.S. Environmental Protection Agency and every state regulatory agency with jurisdiction over Inorganic existing full scale or pilot operations. As a recycler, Inorganic is authorized to process any inorganic wastes at its facilities upon completion of the testing Protocols outlined in the initial U.S. Environmental Protection Agency authorization letter of April, 1990. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 6 ] As an established recycler with approved standard testing protocols, Inorganic offers owners and/or generators of hazardous waste a demonstrated, environmentally beneficial means of ma!1aging hazardous waste, and reduces the liabilities associated with hazardous waste management to an absolute minimum. By analyzing the typical flow of hazardous waste from “Cradle to Grave” the advantages of utilizing the Inorganic Process becomes readily apparent ( Fig 6 ) By consistently demonstrating that any waste that passes the testing protocols established by U.S. EPA can be effectively managed through the Inorganic process, the agencies were assured that neither the initial characterization of those wastes nor the means by which they were generated are material considerations. Whether such wastes are cast off from chemical manufacturing, industrial processing, commercial use, incinerator ash, spills arising from transportation or processing accidents, or residues in pits, ponds or lagoons, all inorganic hazardous wastes can be legally recycled. Inorganic has commercially demonstrated the environmentally sound re-cyclability of various plating sludge, Incinerator ashes and residues in un-permitted pits, ponds and lagoons. Recycling of these wastes by Inorganic results in environmentally non-hazardous commercial products sold into commerce. Commercial contracts are in place for sale of IRC material primarily into blast media and asphalt shingles. The prime attribute of the Inorganic product, over and beyond its unique color and hardness characteristics, is the fact that the product itself, even at the molecular level, is non hazardous based on U.S. EPA's toxicity characteristic leaching procedure test ("TCLP"). As illustrated in Figure 6, based on U.S. EPA's recycling regulations, wastes lose their "hazardous" label at or before the time they are placed in Inorganic receiving hoppers at its fully enclosed recycling facilities. If the recycling facility is located on the site of the generator of the hazardous waste, those wastes lose their "hazardous" title and become hazardous raw materials immediately upon movement into the recycling process, whether from the generator's initial collection unit or upon excavation and transport to the Inorganic facility. Because Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 7 ] of this shift in legal characterization of these materials, Inorganic is willing to take title to the materials early in the recycling process. Once within the Inorganic facility, these once "hazardous wastes" are managed as hazardous raw materials. Upon entering the Inorganic thermal processing unit, the materials lose their hazardous characteristics through the crystal and chemical bonding that occurs with additives chosen specifically for the incoming material's chemistry. Through further refinement of these additives, Inorganic is able to "tailor" its product to meet the unique chemical specifications of Inorganic's customers. Throughout the whole process, records are kept on the results of initial testing protocols, the quantity and chemistry of the incoming materials and the quantity and chemistry of the outgoing products to assure that the transformation of the "wastes" into nonhazardous commercial products has been successfully completed. Any spills or off specification products produced can be reintroduced into the mixing vessels within the Inorganic facility. Under U.S. EPA's recycling guideline, any "hazardous waste" that is recycled and incorporated into a commercial product, losses its original label as a "hazardous waste" as a matter of law, and is therefore no longer regulated as a waste. Having severed the legal and chemical "liability trail" normally associated with hazardous waste operations, both Inorganic and the original generator of the wastes are thoroughly and completely isolated from future hazardous wastes liability associated with commercial products shipped. Once in commerce, the Inorganic products are regulated merely as a function of normal industry guidelines, including compliance with manufacture safety date sheet specifications. Generators doing business with Inorganic are invited to periodically inspect the Inorganic operations and records maintained to confirm the complete recycling of the original wastes into the products and assure themselves of the legal and chemical sufficiency of the recycling process. Any dusts generated in the course of hazardous material processing are collected in approved air pollution control devices and introduced back into the recycling process with the initial hazardous materials. Any product that does not completely satisfy the customer's specifications could be simply reprocessed back through the kiln. Inorganic Recycling has been active in the true recycling of inorganic materials since 1988. Chrome plating waste was the first material approved by the EPA for this method of recycling. The first EAF dust recycling unit was started in 1992 in Arkansas and it is also approved by the Federal and State EPA as true recycling. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 8 ] ROOFING Face granule 12/30 mesh Backing angular coIor unimportant angular to spherical 500,000 tons per year Fig. 7 Schematic showing various aspects of a typical roofing shingle. The IRC recycling process has now been proven in full scale commercial operation. It has demonstrated the ability to recycle a continuous flow of EAF dust into salable products since May, 1995. For over eighteen months, with the exception of a few planned outages, IRC has recycled EAF dust every day, and has sold all products as originally produced. Every pound has been "right" the first time. EAF dust and other feedstock materials, custom engineered to produce' products meeting customer standards, are mixed and fed into the recycling kin and molten material is tapped out, continuously. The molten glass ceramic products is routinely sized to customer requirements and shipped. Due to proximity to the Mississippi River, barge shipment provides low cost transportation. Shipments are made approximately once every six weeks. All dust sent to the IRC facility is recycled and sold. No materials are buried. No materials are returned to the mill. Currently, virtually all IRC products are used as roofing granule materials and provide home owners with a consistent, more UV resistant product. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 9 ] All products, without exception, produced by IRC have passed the EPA's TCLP test and of equal importance, have met more rigorous customer specifications. We have no reason to doubt that record will continue well into the future. No other on-site EAF dust recycling system can match the IRC record as a proven process. Except for the few well established dust disposal alternatives, no other dust handling system can match the IRC record as a proven process. One reason for this success is that the IRC process simply adds special know-how to well understood glass-ceramic processing methods. Basic methods are highly flexible and well able to meet the challenge of different sources and dust composition, normally encountered. Custom engineered feed stocks are added to EAF dust in a manner designed to assure that all product specifications are met. The melting process is designed to accommodate dark glass and to accept changes while continuing to meet specifications. Both dry and wet scrubbing systems are in place to address any off gases from the kiln that may contain sulfur, chlorides and fluorides. The current unit processes dust at a rate of 12,000 TPY. A new unit (one kiln) is designed for 20,000 TPY dust and will come on stream in late 1997. The new unit will incorporate both oxyfuel and electrical resistant heating. The new unit will also' incorporate various methods of forming the end product that will allow such steps as beading, forming, fiber forming, coating, annealing, shapes, etc. both Alternatively and/or simultaneously. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 10 ] Most Economical Solution Inorganic Recycling Corporation (IRC) is positioned to offer the best economical environmental solution to the EAF dust problem over the next several years. This is possible due to four major factors: - Shipping Cost - The practical size of an IRC VIT processing unit is suited for on site application where the dust is generated. A typical unit can process 10,000 TPY, 20,000 TPY or multiples of these. Shipping, even by rail, can typically add $20/ton to $30/ton to the bottom line cost of processing. Markets for the end products are distributed evenly across the United States and shipping costs are absorbed into the cost of sales. - Raw Material Costs - Frequently, raw materials are conveniently located right at the generators site in various forms of silica, alumina, calcium, sodium, spent refractory and slag. Potential Raw Materials (Fig. 9) Spent Refractory and Grog Slag Si02 50 to 65% CaO 47% A1203 39 to 25% Si02 23% Fe203 1.5 to 2.5% Fe203 20% CaO 0.8 to 0.6% MnO 4.5% MgO 0.3 to 0.7% MgO 3.5% Ti02 1.0 to 1.5% Cr203 .5% lkalies 2 to 3% A103 1.0% Cullet or Ground Glass (Fig. 10) Soda Lime Glass Plate Flint Amber Emerald Si02 73.25 73.21 72.45 72.26 Na20 13.45 13.45 13.01 13.11 CaO 8.58 10.332 10.48 10.47 MgO 3.77 1.04 0.68 0.78 Fe203 0.356 0.081 0.31 0.205 A1203 0.28 1.34 1.95 2.05 S03 0.19 0.16 0.03 0.08 K20 0.11 0.40 0.44 0.93 PbO 0.0037 . Cr203 0.0023 0.0026 - 0.12 Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 11 ] These materials provide an excellent lowcost source of feedstock, often solving other disposal problems. - Energy Costs - Energy costs can be kept to an absolute minimum by using evolving technology of oxy-fuel burners combined with electrical melting to allow optimum melt bath depths. Computer technology and modeling allow precise sizing and placement of both these technologies. Use of excess heat from the VIT exhaust will also be used for pre-heating and annealing. - Value Added Product - Inorganic Recycling is more than a Recycler of EAF dust. We are a manufacturer of end products that will continue to be of value well into the future. The potential market for IRC's glass ceramic products is very large compared to the amount of products that can be produced from EAF dust. Dust generation in the U.S. is about 0.8 million TPY. If IRC recycled all of that dust into products, about 1.2 million TPY of product would be manufactured. The glass-ceramic market in the U.S. today is 800 million TPY. A broad market for large quantities if IRC products has already been identified. Long term commitments, for the sale of all current production, are in place. Additional demand exists for more products in the current applications. The new applications include abrasive grains for metal cleaning and conditioning which are superior to current available materials. Other products are being investigated through IRC's Product Development Program. (Figure 13) That program is targeting higher value uses for IRC products that will bring benefits to customers, steel mills and IRC alike. Promising developments are already being realized. Products can be altered either chemically and/or by varying post Forming treatment such as annealing. (Figure 11 and 12) A significant increase in the value of IRC products is expected over the next decade. Benefits from the sale of higher value products are available to steel mills since IRC will share those benefits as they are realized. It is expected that recycling fees for dust generators will decline as a result of benefit sharing. Conversely, fees for land filling can be reduced only if, and to the extent that costs can be not only contained, but reduced, despite inflationary pressures. The same is true of metals reclaiming processes since the market price of zinc and other reclaimable metals is projected to be relatively fixed compared to the value of IRC products. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.1/ 12 ] Developmental Glass Melting System Fig. 13 Concept sketch of IRC's Developmental Kiln with oxy/fuel and electrical heating. Summary Inorganic Recycling has now Commercially demonstrated an economical, reliable vitrification system for processing EAF dust. Further refinement of the end product using our own developmental unit and full scale commercial units will further position the IRC process to be the most environmentally sound and the most economical process available for the next several years. References 1. Introduction to Ceramics, 1960. 2. J. Wiley and Sons W.D. Kingery M.LT. 3. American Ceramic Society Ceramic Bulletins 1994 thru 1996 4. Ceramic Industry, July 1996 Business News Publishing Co. This Paper is Printed with Permission from: Pacific Sterling Technologies, Inc. USA For Plant Set up, please contact: Mr. Shankar Chowdhury, President BD & Proj. Zoom Developers P Ltd. Poonam Building, 3rd Floor ; 5/2 Russel Street ; Kolkata - 700 071, Phone : +91 33 22263669/70 ; Fax : +91 33 22263668 Director (Projects & Business Development), Steel Mobile : +91 9831899469 ; E mail : firstname.lastname@example.org Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 1 ] RECOVERY AND USE OF STEELMILL IN-PLANT WASTES (Taken over by Pacific Sterling Inc.) Paper printed with Permission from Pacific Sterling T.C.INC 26363 S. TUCKER RD., ESTACADA, OR 97023 PHONE: 503-630-6759 FAX: 503-630-6759 EMAIL: email@example.com (originally written and published in Europe in 2005 as a processing technology for Waste Recovery and for Direct Steel Making Modified and rewritten for publication for (Indian Institution of Plant Engineers and SAIL (Steel Authority of India) International Seminar on Waste Management In The Steel Industry May 9/10, 2008 Abstract: In 2005, 2006 and 2007, over 1 billion tons of steel were produced each year worldwide, an increase from 800 million due to developing markets in China, India and a few others. This increase in steel production, and resultant use of raw materials, iron ore and coking coal, has spurred a major shortage in the raw materials and more than doubled the price for the entire world. New strategies are being developed to secure raw materials for the future, investments in mines, investments in scrap steel and exports, opening of new mines or re-opening of old ones and so on and so on. All the while, during the processing of iron ore from the mine to the rolling mill, 10% of the iron ore used to make this billion tons of steel is thrown away as waste. That seems to be a figure of over 100 million tons of iron bearing materials is mostly thrown away. According to the steel mill operators, this waste is too difficult to handle, it will upset the normal operations, there’s more where that came from, let the accountants deal with it. If you look at the invested cost in producing the waste, perhaps the accountants should deal with it. What is the cost of steel, for example, in the rolling mill? On average, mill scale accounts for 10% of the waste, is the highest quality iron oxide you can find and has an invested cost to the steel maker of over $400 a ton. In the US, the normal practice of getting rid of mill scale is to sell it to cement plants for $10 per ton, or less, while striving to purchase other iron units and repeat the practice. This same philosophy of handling waste iron units from ore screenings and dust, mill scale and spillage, hazardous waste handling, landfill costs and fees has to be reviewed with a strict analysis on cost, environmental effect, wasted energy and replacement of raw materials. Restricting progress in overcoming the environmental, energy and waste issues has been the inability to treat fine materials. Some methods that have tried to recover wastes or to use fines contribute to further use of energy and pollution. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 2 ] The iron and steel industry in the U.S. has issued criterion for a Direct Iron and Steel making process, for the future, that should be developed over the next 20 years. The process criterion, uses coal directly, eliminates wastes, reduces emissions, reduces costs and energy and uses iron ore fines. A new process that meets all the criterion has been developed which provides for an agglomeration of iron bearing materials fines, premixed with coal or other carbon sources and fed directly to a smelter, eliminating the need for coke, pre-processing of feed materials, sintering and pelletizing and eliminating air pollutants and energy consumption from those processes, while also recovering iron bearing wastes and utilizing other wastes from iron and steel making processes. The technology, called the RBI Process, for which T.C.Inc. has been issued a U.S. Patent, includes the agglomeration of feed materials, mixed with a carbonaceous fuel, to produce a self reducing feed to a smelter. The selected agglomeration technique is a hydraulic ram briquette machine, which will produce feed material to withstand any handling, maintain strength and integrity during processing, penetrate any slag barrier and maintain strength during the reduction. The ram briquette machine was also selected to reduce or eliminate use of binders due to its inherent ability to make an agglomerate of high density. The research phase of the RBI Process was completed in the 80’s. Technology and designs now developed include the methods to make hot metal from the waste and ore fines, use of coal instead of coke, operating a steel mill 100% waste free, reducing capital costs, reducing or eliminating in some cases, greenhouse gases, reducing energy and building an iron making or steel making plant from 50,000 TPY and up on a competitive scale with large capacities. While the selection of a smelter for Direct Iron Making will follow the route of an oxygen furnace, the technology will utilize any existing melter/smelter for the recovery of waste, since most wastes recycling has to be site specific. Additional technology is also being developed to utilize this processing method for the non-ferrous and ferrous –alloy industries, such as directly making stainless from as mined materials, such as nickel laterites, and using any waste carbon sources such as wood from forest fires and other sources of wastes. Review Of Technology In the 1980’s in the US, it became apparent that iron and steel plant wastes, emissions and effluents were a cause of concern due to, ground water contamination from stockpiling or land filling, air born particulates were contaminating soils in surrounding plant areas and there was concern of the greenhouse effect from gas emissions. As a result, restrictions were put on land filling and stockpiling of wastes and air born emissions from plants and a new era of monitoring and control was Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 3 ] established. The added cost to iron and steel making then dictated that new technologies be developed for collecting the emissions and effluents and treating the collected materials to reduce leaching into groundwater and potential health hazards. The iron and steel industry, since, has incorporated new technology in reducing particulate emissions from air born sources and in collecting wastes. Some methods have also been incorporated to recycle, through existing processes, the sinter plant for example, wastes that have no ill effect on production capacity or quality from contaminants. Greenhouse gas emissions have also been reduced with increased plant efficiencies. However, no technology had been implemented, en-masse, to recover and use waste materials. Iron and steel plant wastes are normally categorized into iron bearing materials, refractories and carbonaceous materials. Methods to recover any or all of the wastes needed to be developed. Waste materials from iron and steel making plants were studied. This included mining and beneficiation and pelletizing operations, material shipping , sinter plants, coke oven plants, integrated iron and steel plants and EAF and DRI operations. The physical characteristics of the wastes revealed that, with the exception of slag, most iron bearing materials were in the form of minus ¼ inch, most refractories were in the form of brick or large particles, carbonaceous materials were liquid, dust or breeze or in the form of graphite rods. The chemical or elemental form of wastes, especially the iron bearing materials from various iron and steel plants each had compositions specific to those iron and steel plant operations and products. The refractory waste and carbon graphite needed to be separately reviewed due to size and potential reuse. The major emphasis was put into finding a means to handle iron bearing wastes of all the various operations for a case by case and site specific scenario. Handling the fines and dust and collecting them was not the issue, as technology and equipment was readily available to do this. Making the iron bearing wastes a reusable product or in some cases a non-hazardous product became the objective. To do so various technologies were reviewed: a. Pelletizing and induration and cold bonded pelletizing. These required the materials to be ground to normal pelletizing grade feed, required the addition of unwanted binders, and added an element of handling in induration or curing. The product pellet still generated dust and fines and added to chemical constituents undesirable in further processing. The cost associated with any site specific case could not be justified. Shipping materials to a central location for a more economically sound project only added to the cost in handling the materials and the materials would then be mixed and unacceptable to any specific site for reuse. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 4 ] b. Roll type briquetting or brick making This technology provided that any materials of less than ¼ inch could be used without grinding. However, binders were required far in excess of pelletizing adding to the unwanted chemical constituents in further processing. The briquettes also had to be cured to increase the strength, but, handling and shipping still caused generation of fines and dust. Again, the cost of briquette operations and high maintenance costs of machines eliminated the justification for commercial use. In both type technologies, pelletizing and briquetting, or brick making only integrated iron and steel plants could reuse the materials for recycling. EAF operations waste iron bearing materials contained hazardous materials not suitable for recycling and the EAF operations are not an iron making or iron reduction facility. c. Pre-reduction studies were then made in order to provide a feed material that was of more value to the iron and steel maker. Processes were developed to use the technology of pelletizing or roll briquetting for a cold bonded feed to rotary kilns, rotary hearths and shaft furnaces with carbon added to the pellet or briquette. The technology was adapted in some operations and subsequently shutdown due to high operating costs, high capital costs with few benefits to the iron and steel maker. The technologies also required carbon sources of the highest quality, coke, and added the same chemical constituents from binders, defeating any benefits to steel making. d. Pre-reduction and smelting, as a combined process was also studied, not only for recovery of in-plant wastes but to directly make iron from fines. This technology also requires the highest quality feed and carbon sources, pelletizing and major capital investments. Operating costs can only be justified with large scale plants, therefore contributing to added iron and steel overcapacity. The only recognized benefit is the use of coal instead of coke. Later developments abandoned the recycling of wastes. e. Direct steelmaking has been considered, to use fines and coals, not of coke quality, and smelt/reduce materials directly. This had been considered as the most viable technology under development, which could use recycled iron units, dust and fines, directly, however, no studies are being conducted to use waste materials. The technology also is limited to only large scale operations to justify operating and capital costs and is not viable for site specific cases in recycling wastes. Material losses from fume exhaust also reduce efficiency and carbon additions are far in excess of the requirements of stoichiometric reduction. Fines and dust feed do not penetrate slag barriers without injection systems. Process Development The requirements to handle the iron bearing wastes and fines had the following criterion: Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 5 ] • Carbon wastes products or non-coking coals should be used. • Site specific • As-available iron bearing wastes, with the exception of slag, had to be considered. • Product must have the integrity to withstand the reduction phase during reduction/smelting. • Product must withstand any handling or shipping with minimal losses. • Product must be heavy enough to penetrate any slag barriers. • The addition of a carbon source should be limited to carbon required for reduction of oxides and the carbon equilibrium in the hot metal. • Product should be able to be fed to any melter/smelter. • Minimal energy use. • Minimum additions of materials, such as binders. Maximum use of other in-plant waste, such as refractories • Iron fines of less than ¼ inch had to be used. Hydraulic ram briquetting was then reviewed and it met all the criterion listed. Historically, the ram briquette machine had been used commercially since the 1930’s for the “punch pressing” of machine shop turnings and borings for feed to a foundry. This practice has been continued through today. Tests were then conducted on various iron and steel mill wastes, singularly without binders. Both iron bearing wastes and carbon sources were tested, then in combinations, simulating typical site specific cases. In some instances refractory material was crushed and added. If dust collection material was used, only, the product briquette was somewhat weaker. This was compensated for by the addition of a tar or pitch or coal and in some cases ground refractory. By mixing dissimilar sized particles, no binders were required. However, by adding a carbon source of some waste materials or coal, it was found that the material had an inherent binder. It was also found that oxides would be self reducing upon feed to a smelter. Since the ram briquetter is a known technology, can produce an agglomerated product from fines with mixtures desirable to the iron and steel maker, can utilize and agglomerate any iron and steel wastes and can provide a self reducing feed material, it was expected that the technology meets the criterion for direct iron and steel making, ahead of its time. The technology is viable, in that it can be utilized at any site specific plant, in any size to meet the requirements of capacities. The only inputs required, other than feed equipment apparatus are cooling water for hydraulic cooling and power, making it also environmental friendly, as compared to any other process which may require induration, pelletizing or pre-reduction and therefore use of hydrocarbon fuels with resultant gaseous emissions. This process can claim total use or recovery of all iron and steel wastes. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 6 ] The process also will utilize direct feed of as mined iron oxide feed, not ground to meet pelletizing or concentrated feed to sinter plants. The material feed will be mixed with coal fines or waste carbon sources and ram briquetted to provide a smelter with a feed material that is self reducing. This will eliminate the need for pelletizing or sintering and the use of coke making plants. As compared to pelletizing, sintering and coke plants, no fuels are used, no gaseous emissions are experienced, there are no losses of materials, capital expenditures and operating costs are reduced. Other benefits are derived from using the ram briquetted technology, in that imports of feed materials can be reduced and curtailed, or an area of low need for iron or steel goods can build a micro plant, suitable for its local needs and using low quality ore and carbon sources. The potential application to the iron and steel industry is the recovery and use of all iron bearing wastes, the potential application to replace sinter and pellet plants, the potential of replacing coke ovens and using coal directly. The research objective addressed the specific need for improvements in the iron and steel industry to; increase efficiency through recovery of iron and steel wastes and through the use of iron oxide fines in making iron, decrease the dependence on coke by using coal directly, decrease the gaseous emissions in pre-processing, sintering, pelletizing of iron oxides and coke making plants and decrease the energy consumption in pre-processing, sintering, pelletizing, coke making and energy losses due to waste materials. In 2005, over 1000 trillion Btu’s were invested in energy to produce waste iron bearing materials and over 1500 trillion Btu’s were used to pre-process, pelletize and sinter iron oxide fines. The goal is to recover the energy invested in wastes by utilizing the waste and to reduce the energy consumption in pre-processing, pelletizing and sintering. The objective is to use coal directly, eliminating the need for coke making. Additionally, it is the objective to eliminate the gaseous emissions by eliminating some steps in pre-processing and to eliminate sintering, pelletizing and coke making. These goals will be accomplished by using an alternate method of agglomeration, iron oxide mixed with a carbon for direct feed to a smelter and feeding any type smelter that hot metal can be produced. It will not be necessary to develop a new machine for agglomeration as the process technology uses a well know hydraulic ram briquetting machine. Technical Feasability To make iron and subsequently steel, carbon is used, under heat, to chemically extract the oxygen from the natural oxides of iron. Most processes convert some sort of carbon source or hydrocarbon source into a reductant CO and/or H2 to be introduced as a gas, externally to the iron oxide and extract the oxygen from the iron, by forcing the gas through the iron oxide particle, producing somewhat of a pure iron, then the iron is Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 7 ] melted. The process is more complex as there are also other elements combined with the iron and carbon sources that are dealt with separately and there are major considerations as to how to get the gas into the iron oxide material. However, simplistically, this is what occurs. In order to make this processing as efficient as possible, iron oxides have been meticulously beneficiated, such that, a maximum value of other materials is reduced, but, the iron oxide is then in a form that can’t be used unless it is agglomerated, normally by sintering or pelletizing. Shaft furnaces, namely the blast furnace also has been designed for the purpose of accepting iron oxides in the form of sinter and pellets. In order to have a carbon source for reduction in the blast furnace, efficiency dictated that coal could be used but it had to be beneficiated by removing the volatiles and other matter that would interfere with quality of hot metal and the coal had to be more permeable to achieve efficiency, resulting in the processing of coal to coke. It is the intent of using a ram briquetted mixture of iron oxide particles and coal particles, tightly bound through compression as feed to a smelter. At elevated temperatures in a smelter the carbon will oxidize by the extraction of oxygen from the iron in the particle next to it. Gas flow and bed permeability is, therefore not a concern, only heat. The ram briquette becomes a self reducing material and in the smelter, within minutes is reduced of oxides and melted into hot metal. Since the reduction takes place inside the ram briquette, it is anticipated that close to stoichiometric carbon, plus carbon equilibrium, can be achieved Reducing current energy usage, recovering iron and steel making wastes and eliminating steps in pre-processing, sintering, pelletizing and coke making, using coal directly and reducing gaseous emissions were the achievements desired. Selecting the type smelter to achieve the desired hot metal results will be a goal as well as type of heat input. It will be a goal to review the potential of heat recovery in off gases for cogeneration of power based on various types of carbon input. Another goal, and considered in the developmental phase, is to apply the technology to the non-ferrous and stainless industries, such as nickel laterites and aluminum bauxites and others. Benefits The energy consumption for the RBI process to recover the world’s 100 million tons of iron bearing wastes is 30 trillion Btu’s/yr, as compared to 1000 trillion Btu’s used to make the waste. The per unit energy consumption is calculated at 40 kWh per ton electrical power input. (per unit installed process is an engineering calculation of a ram briquetting facility, including all materials handling, mixing, feeding mechanisms and the machine requirements of a hydraulic system.) There is no comparable or competing technology that is used to recover and use iron and steel plant wastes. Some captive sinter plants are feeding some acceptable wastes into the process, however, sinter plant energy use is about 1.6 million Btu’s per ton of combined energy consumption. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 8 ] Therefore if wastes were recycled through sinter plants the energy required would be about 160 trillion Btu’s. Processes that use iron oxide agglomeration and pre-reduction, such as rotary hearth technologies or other techniques before feed to a smelter will consume a minimum of 15 million combined Btu’s per ton. In recovering the iron bearing wastes the energy consumption is 1500 trillion Btu’s. As compared to ram briquetting the energy savings with RBI is 98%. To replace coke ovens, sinter and pellet plants, the blast furnace would also have to be modified or replaced with an alternate smelting/steel making technology, for example an oxygen furnace. Overall benefits to the iron and steel industry are in the preparation of materials, the development of a site-specific technology, reduction of effluents and total recovery of wastes. The technology is designed to recover iron and steel plant wastes in the form of iron bearing materials, carbon products and other wastes, such as refractories or lime dust. Through this technique, about 10% of total steel production can be recovered and reused, improving the productivity and cost of making steel. The proposed technology also has the potential of replacing processing steps in iron and steelmaking in materials preparation for smelting. It is anticipated that by using the patented process of ram briquetting, hot metal can be produced at a significant savings over conventional methods through energy savings alone. If capital costs, operating costs and maintenance costs of conventional equipment were included, it is anticipated the savings in costs per ton of prepared materials would be in excess of one half. Environmental Benefits There are no wastes associated with using ram briquetting technology as a feed preparation for materials to the iron and steel sector. 100 million tons per year of iron bearing wastes associated with the iron and steel sector are already being produced which can be recovered with ram briquetting. With existing technologies, sintering or pelletizing of iron oxides and coke making,, CO2 emissions would be eliminated by using ram briquetting technology. Currently the amount of CO2 emissions are calculated from sintering (assuming pelletizing uses the same relative amounts of fuel) and pelletizing at 69 pounds/ton of steel and coke making at 102 pounds/ton of steel. . Wastes and by-products of coke making are also eliminated, but, with new smelting technologies, effluents now that exist will be changed and have to be studied. It is suspected that the selection of the smelting furnace with the ram briquette will greatly enhance the use of all carbon and hydrocarbon products in coal and reduction of NOX with the use of enriched air. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 9 ] How To Get Started A. To recover iron bearing materials at the mine or the beneification plant, pellet plant, sinter plant, DR plant or steel mill do a complete mass balance of all materials. At each step put a value and physical and chemical analysis next to the waste, iron bearing materials, carbon, lime, etc. B. To make steel or a ferrous alloy from as mined materials do a sourcing analysis of local ores and carbon sources, putting a value and analysis of the materials as-is C. For a mixture of the materials to be self reducing in a smelter 1 carbon is added for each oxygen attached to the iron, plus a bit of carbon to make sure the atmosphere and equilibrium is reducing. Therefore, this mixture will give a feed capacity on an annual basis. Ram briquette machines can be purchased with annual capacities from a few thousand tons per years to 25,000 tons per year for a single machine. Any smelter can be used to make hot metal or even cast iron in any capacity and depending on local fuels, power availability. It is not necessary to build an oxygen smelter but over the long term it will be the cheapest to operate. D. Make an analysis of the products you wish to make and then select the downstream facilities you need to make them, whether it is casting or making hand pumps or rebar or just providing hot metal for the steel mill next door. (you can also just make feed materials for the smelter customer with a stable known feed material for his operation.) E. RBI product does not have to be stored with any particular restriction, outside is fine and in stacks. The density of RBI briquettes is about 5 g/ml so there is no need for any protection from absorbsion of moisture. . F. Capital costs to make RBI briquettes can be calculated on total local supply of conveyors, mixers, bins, weigh feeders. The ram briquette machine is the only part needing to be imported at the present time as the alloys for the ram and dye have to be carefully made to handle iron ore roughness. The smelter, if an oxygen furnace is used can also be made to almost any size and can be made locally. Supply of oxygen can be supplied from any commercial gas supplier and heat recovery for co-generation of power to be self sufficient with a sustainable operation also can be supplied from any technology. After you have reviewed the total cost of putting in ram briquetting equipment, make a comparative cost of installing a DR plant, a pellet plant with all the beneficiation or a sinter plant, and add a coke plant. In smelting of iron ore pellets and coke and/or sinter add a blast furnace. In the DR route, in addition, add a pellet plant, then an EAF or induction furnace. If the ram briquetting or RBI process is selected, just add a BOF shop of the size needed. We think the capital cost will be obviously low at about ½ or less for RBI. Operating costs are equally low using ore fines and coal Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 10 ] instead of pellets, sinter or sized lump and using coal instead of coke. The only water for RBI is cooling water for the hydraulics. Manpower costs are at a minimum since there is no special training involved and no IT degree required nor expansive instrumentation. Care can also be given to total recycling therefore no landfill, 100% free of waste, and most importantly reduce your materials purchases by 10%. G. Care can also be given to total use of all in-plant waste materials or use of fines and local coals, a steel mill 100% free of waste. A total sustainable operation. Elimination of material preparation high cost operations and green house gas emissions. References cited 1. Energy and Environmental Profile of the U.S. Iron and Steel Industry, August 2000, by Energetics, Inc., prepared for the U.S. DOE, OIT. 2. Steel Industry Technology Roadmap, December 2001, published by the AISI in cooperation with the U.S. DOE. 3. Theoretical Minimum Energies to Produce Steel, March 2000, Carnegie Mellon University, Published for the U.S. DOE 4. Energy Use in the U.S. Steel Industry, September 2000, John Stubbles, Published for the U.S. DOE 5. U.S. Patent # 4,917,723, issued to applicant, Thomas J. Coyne, jr., assigned to T.C.Inc., April, 1990. T.C.Inc. is an international project development and consulting firm dealing in iron and iron bearing materials in the fields of agglomeration, beneficiation, pelletizing and reduction. The makeup of T.C.Inc. includes associates and associated companies with expertise in iron and steel making technologies, gas reforming and burner systems and syngas technology. T.C.Inc. provides services in technology development and evaluation, project evaluation, process evaluation and application, project, construction and operations management, plant commissioning and training and operations optimization. T.C.Inc. also offers patented technology in Direct Reduction of Iron Oxides with any fuels, Increase in Capacities with a Shaft Furnace DRI Technologies of 20%, DRI and the Rotary Hearth and Rotary Kiln and the patented RBI Process for Direct Iron and Steel Making and Waste Recovery. Thomas J. Coyne, Jr., the author has published papers in iron and steel making technology that cover such areas as raw materials for iron making and direct reduction, direct reduction plant operations, shipping and reoxidation of direct reduced iron, pelletizing of magnetite, gas flows and pressure considerations in shaft furnaces, shaft furnace balances and assumptions, raw material plants mass balances, international project development and management. He has also been involved in technology transfer of these technologies to developing nations for the past 40 years in the iron and Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 11 ] steel industries from mining to finished products and has developed a free email advisory service for these areas, specifically for deserving third world nations coming into their own. This paper is a product of T.C.Inc., copywrited by T.C.Inc. and the technology displayed may not be used or copied without the express approval of T.C.Inc. and follows applicable law of the US Patent offices and US Dept. of Commerce. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.2 / 12 ] Business Opportunities in Waste Reuse in Iron & Steel Industry [4.3 / 1 ] USE OF PLASTIC WASTE IN IRON AND STEEL INDUSTRIES – AN APPROACH FOR ENERGY REDUCTION R.B. Gupta, G.C Pattnaik Sail, Rsp, Rourkela – 769011 E-mail : firstname.lastname@example.org Abstract: The major Iron and steel producers in the world, as their voluntary energy saving action plan, proposed a more than 10% energy reduction by 2010 with 1990 as the basis. Further, some steel major has put forward an additional more than 1.5% energy by the use of waste plastics as a metallurgical raw material. Coke – making process and Blast furnace process of Iron making are considered to be promising area to which the thermal decomposition of waste plastics is applicable because the process involves coal Carbonization in a light temperature, reducing atmosphere. Some plants in Japan has started using waste plastics in coke oven and in Blast Furnace injection. In coke oven 1% addition of waste politics in raw coal did not deteriorate the coke strength. In Blast Furnace addition of plastics in injection process improves the thermal regim of the furnace and results in coke rate, reduction in slag volume also. In India there is too much scope of recycling waste plastics in steel Industries as the plastic waste generation is more than 6 million tones and this can solve some extend the shortage of coking coal problem for Iron and steel Industries particularly for Blast furnace process of Iron making. This paper outlines technology of recycling businesses that make the best use the iron and steel making process of the steel works. Introduction As the advent of the 21st Century, mankind is facing global environmental problem, causing the industrial sector to take initiatives in establishing recycling for the efficient utilization of our natural resources. By effectively utilizing the synergistic effects of Iron and steel making technology and engineering technology built up through its long history. In the world due to energy crises, major steel makers tackling issues related to conserving energy and resources as well as protecting the environment throughout the world. The plastic is most commonly used in many plants of world for sample India during 2003 about 4 million tones of plastic waste were discharged and in Japan this figure was as high as 9-8 million tones (1999) in USA. This was many times than Japan and India. Out of the world total plastic waste only 33% is effectively used and balance were disposed of by land filling. See Table No.1, plastic waste generation in India. The Business Opportunities in Waste Reuse in Iron & Steel Industry [4.3 / 2 ] growth of plastic industry is more than 17% against the population of about 1 billion and this growth is further expected to rise due to mineral water bottles. Table No. – 1 : Plastic Waste generation in India (2007) 1995-96 2001-02 2006-07 Total polymers 1889 4374 8054 Process waste 38 87 161 (2%) Post Consumption Waste 870 (46%) 1966 (45%) 3624 (45%) The trend of plastic use in India has been shown in Table No. – 2 Table No. – 2 Plastic uses in India (2007) Polymer 1995-96 2001-02 2006-07 Polyethylene (PE) 823 1835 > 3500 Polypropylene (PP) 340 885 > 1800 Polyvinyl Chloride 489 867 > 1400 (PVC) Polyethylenetero 34 140 > 300 phthalate (PET) Others 203 647 > 1500 Total 1889 4374 > 8054 Plastics packaging 976 2272 4037 % of packaging 52% 52% > 50% PET – bottle production 840 million 2000 6 million 2006 In many parts of the world 50% plastic waste collected as general waste is recycled today. Recycle waste is used as or for raw material around (4%), chemical resources (3%), solid fuel (1%), waste power generator (35%) and heat source (7%), However, the remaining half is disposed of at landfill causing environmental hazards. Basic question how to put plastics in a recycle net, So that like steel recycling, plastics also can be recycled in 100% productive use without affecting the economy and the environment for this purpose. Iron and steel Industries has shown the ways to use recycle plastic as partial substitute of coke in Blast Furnace and in coke oven also. Recycling of waste plastics in Iron and steel Industries Business Opportunities in Waste Reuse in Iron & Steel Industry [4.3 / 3 ] Recycling as Blast Furnace feed material Case Study (I) Chemical Recycling In an iron making blast furnace, coke is gasified into, CO, and used for reducing Iron ore into iron. Waste plastics can be used as the reducing agent in the blast furnace in place of coke. The process of waste plastic utilization is very simple, waste plastics are pulverized and granulated, and then injected into the blast furnace (Similar like coal dust injection.) through the tuyeres. The injected plastics are decomposed into Carbon mono oxide and Hydrogen, both of which act as reducing agents for converting iron ore into iron. As H2 is used in the reducing reaction in addition to CO, approximately 30% less CO2 is generated than when the blast furnace is operated slowly by coke. Normally 60% of the plastics injected into the furnace are consumed for reduction of Iron ore. The gas generated by the remaining 40% of the plastics is used as fuel gas. Plastics such as PVC (Polyvinyl chloride) can not be used in the blast furnace without de-chlorination. Solid plastics such as plastics bottles are pulverized into designated sizes by the pulverizer and directly injected into the blast furnace. The film plastics are pulverized and granulated into designated sizes by the granulator before being injected into the blast furnace. Means all kind of waste plastics like electrical appliances, communication equipment, auto markers, machine components plastic waste of chemical companion, domestic appliances. In India there is now waste of mineral water bottles – which will some as principle plastic waste for such purpose. In Japan – Ohgishima and Fukuyama plants has tie up with municipal corporations of major metropolitan country for supply of waste plastics. In this recycling system, consumers are required to selectively discard waste plastic containers and packaging which are then collected separately, stored in accordance with designated sorting criteria and sorted by municipalities. Each municipal – has got contracts with above two plants. Process In Blast Furnace The process of converting domestic waste plastics to blast furnace fled material has been shown in fig No 1. The Bales of waste plastics are fist taken to ballistic separator for separating into solid plastics and film plastics. Solid plastics such as plastic bottles are then placed on the manual sorting line for removing impurities, and pulverized into designated sizes by the pulverizer, and injected into the blast furnace as the reducing agent film plastics are pulverized into designated sizes by the pulverizer, and charged into the specific gravity separator for PVC removal by using the difference in specific gravity. After PVC removal, the pulverized film plastics are granulated into designated sizes by the granulator before being fed into the blast furnace. The amount of plastic injected into the blast furnace will replace 11/2 times of the coke requirement, which means by great extend blast furnace coke shortage problem can be over come. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.3 / 4 ] Specially in the developing countries like India, when not sufficient presence of coking coal is existing. Fig. No.-1, Schematic flow for converting domestic waste plastics to Blast Furnace Material Recycling of waste PET bottles Several companies in the world have started the business of recycling waste PET bottles since 1990 PET bottles are widely used as contains for soft drinks, soy sauce, mineral water, eatable Oil, other for example domestic consumption of PET bottles in Japan is increasing each year and reached almost 70,0000 tons in 2005, of which about 270000 tons were collected by municipalities. The process flow treating waste PET bottle has been shown in fig no. 2, Based on keihin works. This plant processes transparent waste PET bottles into PET resin flaken. Waste PET bottles collected by municipalities contain coloured bottles, caps and label. The most important issue in this operation is how to remove these foreign objects efficiently and accurately. For sorting purpose, combination of mechanical sorting, manual sorting, automatic bottle sorting and label and cap separation equipment are used. After removal of foreign object, the waste plastic is processed as per chart and part of this as per pre-design action injected in the blast furnace as substitution of coke. Similar pattern recycling and utilization of used electrical appliances is also done as per fig No 3. The major features of used electrical appliances recycling is that most of recovered materials can effectively used in Iron and steel industries as being done in Japan’s keihin works. Its unique advantage is that the recovered plastics, which account for nearly 30% of home electrical appliances, are directly used in the blast furnace waste plastic feeling operation. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.3 / 5 ] Waste Plastics Recycling Process Using Coke Ovens The most suited process of recycling plastic waste of the blast furnace is coke oven, In coke ovens waste plastics can be converted into chemical raw material. The process has been shown in figure No 4. In coke ovens, coal charged into coke oven chambers is carbonized at a temperature of about 1,1000 C in a reducing atmosphere and is converted into products, namely coke, tar, light oil and coke oven gas etc. At the exit from ascension pipes at the top of the ovens, ammonia liquor is used for flushing high temperature gas generated in the chambers through the carbonization, and the gas is cooled quickly to about 800c or less. Then the gas is cooled in a primary gas cooler to about 350 c, where conversation liquid is separated into tar and ammonia liquor at a tar decanter. The carbonization condition in the coke ovens are considered suitable for the recycling of waste plastics because charged plastics decompose easily at high temperature in a reducing atmosphere. Fig. No.-2, Schematic flow of the recycling for waste PET bottles. Fig. No.-3, Schematic flow of recycling used home electrical appliances. Business Opportunities in Waste Reuse in Iron & Steel Industry [4.3 / 6 ] Waste Plastics Recycling Process Using Coke Ovens The Najoja and Kimitsu works of Japan commercially using waste plastic in coke – ovens since 2000.In above plants a test of processing general waste of plastic container and packages (The analysis results of which are shown in table 3 & 4) using commercial coke ovens. The yields from the carbonization of the general waste plastics at the test were 20% of coke, 40% of tar and light oil and 40% of gases, approximately. (See fig. no. – 3) Table No. 3 : Ultimate analysis and Ash content of waste plastics. Ultimate analysis (mass % day) Ash (mass % ) C H N S 72.6 9.2 0.3 0.04 - 5.0 Table No. – 4 : Component of waste plastics Component (mass %) PE PS PP PVC PVDC PET Others 21.4 24.8 13.7 52 0.4 15.5 19.0 Influence of waste plastics Addition on coke quality Fig. No.-4, Coke making process Fig. No.-5 Fig. No.-6 Business Opportunities in Waste Reuse in Iron & Steel Industry [4.3 / 7 ] To evaluate the performance of waste plastic addition in coke oven, on coke quality, some test in commercial coke oven. The coke strength in the case that general waste plastics after a volume reduction treatment is added to coal by 1 mass%. The coke strength was evaluated in terms of drum index (DI), which indicates, the coke strength at the room temperature and CSR which indicates the coke strength after high temperature reactions. The result with 1 mass% waste plastics addition, coke strength remains unchanged. This has been shown in fig. 5 & 6. Fig No.7 Conversation rate of waste plastics For example the annual consumption of coking coal of the Japanese steel industry is about 50mt. If waste plastics are to be added to the coal charge by 1 mass%, the waste plastics consumption will be about 5 lakhs t/y in coke oven along and this will be a energy saving. Process : Fig No. 8 shown the process flow of the waste plastic recycling by the coke oven from waste plastics to chemical raw materials method. After waste plastic containers and packaging are pre treated for crushing, removal of foreign matters and briquetting, they are mixed with blended coal, charged into coke ovens, and decomposed at 12000C at the maximum without oxygen supply to yield 20% of coke, 40% of tar and light oil and 40% COG (a Hydrogen – rich gas), approximately. The collected material is used as a chemical raw material. The recovered coke is used to reduce the iron ore in a Blast furnace, the tar and light oil are used as raw materials for Business Opportunities in Waste Reuse in Iron & Steel Industry [4.3 / 8 ] plastics etc. and the COG gas is used at power plant etc. as a clean energy source. The waste plastics recycling by the coke oven from waste plastics to chemical raw material method is most popular in Japan and many steel plants has adopted. These methods of plastic recycling to reduce the energy consumption in Iron and steel plants. Conclusion Many parts of the world business development and R&D activities on resource recycling were outlined many steel plants. Recycling business are making the best use of the advantage of etc steel works located in the urban area, where huge accounts of industrial and municipal wastes are generated. Thus providely the steel works with new social value. Existing facilities are being effectively used to turn waste into Iron and steel making material. The future shortage of coking coal effectively can be solve by use of waste plastics in blast furnace and in coke oven.
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