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RAW MATERIALS AND SOLID WASTES ENGINEERING A. Bonoli, F. Ciancabilla Foreward The current research areas under this topic, that will be briefly discussed below, are: (i) raw materials processing, (ii) work safety and environmental protection, (iii) life cycle analysis, (iv) environmental management system for MSW landfill and landfill management modelling, (v) sustainability in water utilisation. Raw materials processing A few steps are usually adopted in these analyses and targeted investigations have been performed. Particle size analysis. Size analysis of the various granular products is a basic part of laboratory testing procedures as it allows to determine the quality of grinding and to establish the degree of liberation of valuable substances from the gangue. Particle size analysis is conduced by screening for sizes greater than 100 µm or by a laser method for smaller particles; it is finalised to determine the feed optimum size for process maximum efficiency. Comminution, crushing and grinding mills. These processes are intended for ore particle size reduction. Crushing, which is the first mechanical stage in the process, is generally conducted as a dry operation and is performed in two or three stages, with small reduction ratios. While the last stage in the comminution process is grinding, which is performed generally in tumbling mills where the particles are reduced in size by a combination of impact and abrasion – either in dry or wet conditions. These investigations are meant to define the comminution parameters, wear and energy consumption by a laboratory tube mill. There is also closed grinding circuit control. Industrial screening and classification. Industrial screening in mineral processing is intended to prevent the ingress of undersize material into the crushing machines, to prevent oversize material from passing to the next stage in closed circuit crushing, to prepare a closely sized feed for gravity concentration processes, to produce a narrow sized end product. Factors affecting screen performance are screen types, capacity and efficiency. Classification is applied as a method for mixture separation, based on the velocity with which the grains fall through a fluid medium (water). As for the industrial classifiers, performance and efficiency are evaluated. Tests of indirect classification are performed to determine the sedimentation velocity – in particular for very small particles of different shapes. An analysis has been carried out to define the main parameters governing the motion law – namely liquid density and viscosity, particle size and shape. Gravity concentration with Heavy Medium Separation (HMS). A new research line has been started up recently to help defining a better method for industrial applications (HMS or flotation) of Coal Water Fuel (CWF) slurries. The goal is to use CWF as a “green” fuel with low emissions; chemical, mineralogical and technical characterization of various types of coal have, therefore, been performed to find the optimum characteristics of coal for CWF technologies. Dewatering and tailing disposal. Most mineral separation processes involve the use of large quantities of water and the final concentrate has to be separated from a pulp in which the water/solids ratio may be high. Studies of the main dewatering methods (sedimentation, filtration and thermal drying) are, therefore, performed. Environmental problem and methods of tailings disposal are considered, like tailing discharging for the quarry environmental remediation or solid fraction recycling to other processes (as ceramic or brick production). Tests have been performed in order to check if ceramic materials can be reutilised as additives in the grinding charge. Work safety and environmental protection Case studies regarding industrial plants have been carried out, in relation with the following subjects. Risk assessment in mineral processing plants. Studies are developed in relation to the main environmental impact factors as dust inhalation, mechanical risks, noise exposure, mobility, chemical compounds, waterborne emissions, airborne emissions and waste management in mineral processing plants. Solid wastes processing: reuse and recycling opportunities for waste materials. Studies in this field deal with the recovery possibility of separated materials, separation and processing of solid waste components, transformation processes to separate the waste and to recover useful products. Particular attention is paid to the energy recovery systems (waste thermovalorisation, energy production from biological conversion products, etc.). An investigation is in progress to assess the possibility to use coal ashes in mixture with cement. Waste size reduction, materials separation and materials recovery from municipal solid waste (MSW). The following steps are developed in this field: optimisation of equipment for size separation (vibrating screens, trommel screens, disc screens) and of unit operations used for the reduction of both MSW and recovered materials. An analysis is in progress about density separation of shredded MSW into a light fraction (paper, plastics, organics), a heavy fraction (containing metals, wood and other inorganic materials) and plastic and homogeneous materials. Another study regards MSW mechanical selection that consists of the following phases: waste handling and storing, waste comminution in hammer-mill shredder, magnetic separation of the ferrous fraction, density separation of the waste into a light fraction for landfill and a heavy fraction (organic) for composting. Construction and demolition (C&D) waste recycling. This research regards the technical characterization of t construction and demolition materials in view of their recycling, based in particular on size analysis and crushing, grinding and screening laboratory tests. Waste electronic and electric equipment separation and recycling. This research line regards the optimisation of manual and mechanical selection as well as grinding, magnetic and electrostatic separation of TV, PCs and other equipment and batteries. Technical and cost effectiveness analysis of these processes is performed, taking into consideration the characteristics of the recovered substances (metals, plastics, ceramics, glass, etc.). Life Cycle Analysis A number of applications of Life Cycle Assessment (LCA) methodology to different sectors have been carried out, namely the ceramic sector, brick works and separated waste collection. Ceramic sector. Cases have been analysed in ceramic productive processes using the SimaPro code and the EcoIndicator’99 method. Data have been collected, then the LCA methodology has been applied and the results have been evaluated; environmental performance indicators were defined and criteria for the most significant environmental aspects were set forward. Comparison between the environmental management system adopted in the ceramic sector and the LCA results was made. Brick works. Energy consumption and the environmental aspects of bricks production have been studied and assessed using LCA simplified tools for small and medium size enterprises; data have been collected for life cycle inventory and elaborated with LCA simplified tools. Separated waste collection. This line consists of: data collection for life cycle inventory and LCA methodology application to recycling processes of the materials deriving from Municipal Solid Waste (MSW) collection, as paper and cardboard, plastics, organics, glass. Environmental management system for MSW landfill and landfill management modelling Studies have been carried out in relation with MSW management. They include: data collection; definition of criteria for environmental significant aspects; environmental policy; environmental objective and targets; environmental planning; Environmental Management System according to ISO 14001 standard and to the EMAS European Regulation. A black-box multivariable identification procedure was also adopted, where it was supposed that the response times of landfill and surrounding ground water bodies to rainfall were long enough so monthly cumulative data retrieved from meteorological stations in the area could be used for the model. The investigation regards the identification method and the results of the dynamic identification of water quality data for some Italian landfills. The model for the case study was provided by ARPA-ER (Environmental Protection Agency of the Emilia Romagna Region). Sustainability in water utilisation Studies have been carried out about the characterisation of ground water and thermal water. In particular, the minimisation of water consumption and water management have been considered. Selected Publications A. Bonoli, S. Goldoni, F. Tilomelli, A. Dal Rio, “Il riciclaggio dei rifiuti C&D: caratterizzazione tecnica e valutazioni economiche degli inerti riciclati. Il caso studio della C.A.R. S.r.l. di Imola”, Atti Ecomondo, (Rimini, 22-25 Oct.), 2003. A. Bonoli, L. Galletti, “Uso sostenibile delle acque e sviluppo di tecnologie pulite per il risparmio idrico”, Ambiente e Sicurezza, n.9, Il Sole 24 ore, ed. Pirola, 18 maggio 2004. F. Ciancabilla, A. Bonoli, S. Goldoni. “A case study on particulate material derived from comminution process in a plant for inert material production: a technical characterisation for recycling”, 10th Int. Mineral Processing Symp., (Cesme, Turkey Oct. 5-7), 2004. A. Bonoli, S. Goldoni, G. Guerra. “Analysis of WEEE treatment methodologies within the meaning of directive 2002/96/EC of the European parliament”, Proc. Global Symp. on Recycling, Waste Treatment and Clean Technology, (Madrid, Spain, Sept. 26-29), 2004. A. Bonoli, S. Goldoni, “Weee treatment and recycling processes: a case study about mobile telephones batteries recycling project”, Proc. Int. Conf. of Restoration, Recycling and Rejuvenation Technology for Engineering and Architecture Application, (Cesena, Italy, 7-11 June), 2004. A. Bonoli, “La valorizzazione degli inerti da costruzione e demolizione (C&D)”, Recycling, ed. PEI, settembre 2004. pp.41-58, S. Goldoni, F. Ferrari, A. Bonoli. “Analisi dei dati storici di monitoraggio e prospettive future nella valutazione dell’inquinamento generato da una discarica per rifiuti non pericolosi da selezione meccanica. Caso studio: la discarica di Novellara”, Atti Ecomondo, (Rimini, 3-6 Nov.), 2004. A. Bonoli, S. Fabbri, S. Goldoni, “The recycling of inert waste from construction, demolition and industrial activity: technical characterization and possibilities of reuse of the recycled inert waste”, Proc. Restoration, Recycling and Rejuvenation Technology for Engineering and Architecture - RRRTEA’04, pp. 297-304, Cesena, june 2004 A. Pistocchi, F. Ciancabilla, G. Gottardi, S. Simani, “Ex-post hydrological evaluation of landfill using hydrological analysis and system identification techniques”. Intern. Symp. on Sanitary and Environmental Engineering, (Trento, 18-23 September), Vol. 3, pp.161-172, 2000. S. Goldoni, A. Bonoli, P. Buttol. “LCA simplified tools for SMES. Comparison between the software VERDEE and the software EVERDEE through the case study of a brick works”, 12th SETAC Europe LCA Case Studies Symposium, 2004/2005 European Meeting of the Int. Society for Industrial Ecology, (Bologna, 10-11 Jan.) 2005. S. Goldoni, A. Bonoli, P. Neri, “A case study about LCA of ceramic sector. Application of life cycle analysis results to the environmental management system adopted by the enterprise”, 12th SETAC Europe LCA Case Studies Symp., 2004/2005 European Meeting of the Int. Soc. for Industrial Ecology, (Bologna, 10- 11 Jan.), 2005.
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