COPPER METALLURGY:
PAST, PRESENT, AND FUTURE
Fathi Habashi
Department of Mining, Metallurgical, and Materials Engineering
Laval University, Quebec City, Canada Fathi.Habashi@arul.ulaval.ca
Bishop François de Laval
(1623-1708) 1663 Seminary 1852 University
Quebec City
COPPER
While gold was the first metal used by man, copper was the first metal chemically extracted from its ores Copper Age was very short The Bronze Age emerged when it was found that bronze was easier to handle than copper
Copper Age
One of the most ancient copper articles is the statue of the ancient Egyptian Pharaoh Pepi
cyprium
In Roman times, most copper ore was mined in Spain (Rio Tinto) and Cyprus The word “copper” is derived from the island: aes With the fall of the Roman Empire, mining in Europe came to a virtual halt
Middle Ages
• Saxony • Incas
Inca knife
Second Bronze Age
Gunpowder
Seventeenth Century
Falun mine Sweden the world's greatest copper producer
1850, Chile became the most important producer of copper ores Towards the end of the twentieth century the United States had taken the world lead in mining copper ores and in production of refined copper Copper matte from Chuquicamata and Butte, Montana was shipped to Wales for refining
Haford Copper Works in Swansea, Wales - - largest in the world, 1880s
The Steel Converter, 1856
Replaced the “Puddling process” In 1880, Pierre Manhès in France adapted Bessemer’s steelmaking process to the copper industry
Henry Bessemer (1813-1898) in Wales
1950s, Flash smelting
displaced reverberatory furnace
1980s, Flash converting
1990s
2008, Ausmelt furnace,
fluoroboric acid leaching, electrowinning in diaphragm cell
Hydrometallurgy and Electrowinning
Saltpeter deposits at the Atacama Desert the major source of nitrates, owned by the Guggenheim family Smith improved the leaching technology and applied it to the low grade copper deposits of Chuquicamata Elias Anton Cappelen- Smith
(1873-1949)
Vat leaching
Peirce – Smith converter
The Norwegian-born engineer who together with William H. Peirce developed what became later known as the Peirce – Smith converter The community's name was given by Smith in honour of his wife Mary Helen (1877– 1927), or “María Elena" when she passed away at the young age of 50
Porphyry Copper Ores
The term "porphyry" is from Greek and means "purple“ The "Imperial Porphyry" was a purple igneous rock with large crystals of plagioclase. This rock was prized for various monuments and buildings in Imperial Rome The rock had been discovered in the Eastern Desert of Egypt and was transported from the quarry westward to Roman Maximianopolis (Qena) on the Nile, loaded on barges to Alexandria, and then to Rome
Imperial Porphyry
Imperial Porphyry
Porphyry copper ores
contain molybdenite which contains rhenium
Chalcopyrite ore Crushing and grinding Tailings SO 2 Purification, e.g., leaching Cu2 + MoS2 Roasting
Bulk flotation Steaming
Selective flotation Chalcopyrite concentrate
D ust collector Re2O 7
MoO 3
Porphyry copper ores
Recovery of Uranium
Copper oxide ore H2SO4 Leaching
Filtration Iron Cementation
Gangue
Air Solution
Filtration
Oxidation pond
Copper
Fe(OH)3
To uranium recovery
Bingham Canyon in Utah, 1903
0.4 - 1 % Cu
Daniel C. Jackling (1869-1956)
Bacterial leaching of chalcopyrite concentrates
In 1998 by BacTech at Mt. Lyell in Tasmania In 2001 Peñoles in Monterrey in Mexico In 2002, Alliance Copper at Chuquicamata
Peñoles
Bacterial Leaching
Six large reactors, mechanically agitated, and lined with acid-resisting brick Reaction is slow - - it is complete in 4 – 5 days Add nutrients to the microorganisms High oxygen consumption:
CuFeS2 + 4 O2 → CuSO4 + FeSO4
Disposal Problem
FeSO4 + Ca(OH)2 + 2 H2O → Fe(OH)2 + CaSO4.2H2O
takes place in slightly acidic medium
Bacterial Leaching
2Fe2+ + 2H+ + ½O2 → 2Fe3+ + H2O Fe3+ + 3H2O → Fe(OH)3 + 3H+
Outokumpu process, 2000
PRESSURE LEACHING, 1960s CuFeS2 +1½ O2 + 2H+ → Cu2+ + FeOOH + 2S + H2O
• •
The oxidizing agent does not need regeneration. The iron component of chalcopyrite is obtained as a residue during leaching. • Selenium and tellurium will be associated with the elemental sulfur while arsenic precipitates as ferric arsenate • The precious metals in the concentrate could be recovered from the residue • Reaction complete in 2- 4 hours
• The process is self-sufficient with respect to the acid used when the copper-containing solution is electrolyzed:
Cu2+ + H2O → Cu + 2H+ + ½O2
H2SO4 Sulfide
concentrate
O2
Leaching Filtration Purification Spent electrolyte Metal Electrolysis Gangue, S, PbSO4, FeOOH
Pressure leaching plant
Piston Pump
Autoclave
Flash Tank
Pre-heater
Recent Development
A new plant designed for chalcopyrite concentrates to operate at 150oC to get elemental sulfur is now under construction at Morenci, Arizona by Freeport-McMoran [formerly Phelps Dodge]
CONCLUSIONS
Copper, an ancient metal, its recovery from ores has undergone many technological changes when finally pressure leaching in acid medium followed by electrolysis in conventional sulfuric acid medium has been accepted This simple technology solves the sulfur problem It has been applied earlier for zinc sulfide concentrates in1980s and recently adopted to nickel sulfides at INCO’s Voisey Bay plant in Canada
Looking back …. and looking to the future …..
Pressure leaching is the technology of the future
Thank you