Solvent extraction and electrowinning (SX/EW) is a two-stage hydrometallurgical process that first extracts and upgrades copper ions from low-grade leach solutions into a solvent containing a chemical that selectively reacts with and binds the copper in the solvent. The copper is extracted from the solvent with strong aqueous acid which then deposits pure copper onto cathodes using an electrolytic procedure (electrowinning).
SX/EW processing is best known for its use by the copper industry, where it accounts for 20% of worldwide production, but the technology is also successfully applied to a wide range of other metals including cobalt, nickel, zinc and uranium.
Extractive metallurgy is a branch of metallurgical engineering wherein process and methods of extraction of metals from their natural mineral deposits are studied. The field is a materials science, covering all aspects of the types of ore, washing, concentration, separation, chemical processes and extraction of pure metal and their alloying to suit various applications, sometimes for direct use as a finished product, but more often in a form that requires further working to achieve the given properties to suit the applications.
Chalcopyrite ( KAL-kə-PY-ryte, -koh-) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green-tinged black.
The Chino Mine, also known as the Santa Rita mine or Santa Rita del Cobre, is an American open-pit porphyry copper mine located in the town of Santa Rita, New Mexico 15 miles (24 km) east of Silver City. The mine was started as the Chino Copper Company in 1909 by mining engineer John M. Sully and Spencer Penrose, and is currently owned and operated by Freeport-McMoRan Inc. subsidiaries. The area where the mine is located is at an average elevation of 5,699 feet (1,737 m).
Copper extraction refers to the methods used to obtain copper from its ores. The conversion of copper ores consists of a series of physical, chemical and electrochemical processes. Methods have evolved and vary with country depending on the ore source, local environmental regulations, and other factors.
Hydrometallurgy is a technique within the field of extractive metallurgy, the obtaining of metals from their ores. Hydrometallurgy involve the use of aqueous solutions for the recovery of metals from ores, concentrates, and recycled or residual materials. Processing techniques that complement hydrometallurgy are pyrometallurgy, vapour metallurgy, and molten salt electrometallurgy. Hydrometallurgy is typically divided into three general areas:
Carbon in pulp (CIP) is an extraction technique for recovery of gold which has been liberated into a cyanide solution as part of the gold cyanidation process.
Pregnant leach solution or pregnant liquor solution (PLS) is acidic metal-laden water generated from stockpile leaching and heap leaching. Pregnant leach solution is used in the solvent extraction and electrowinning (SX/EW) process.
Electrowinning, also called electroextraction, is the electrodeposition of metals from their ores that have been put in solution via a process commonly referred to as leaching. Electrorefining uses a similar process to remove impurities from a metal. Both processes use electroplating on a large scale and are important techniques for the economical and straightforward purification of non-ferrous metals. The resulting metals are said to be electrowon.
Liquid–liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds or metal complexes, based on their relative solubilities in two different immiscible liquids, usually water (polar) and an organic solvent (non-polar). There is a net transfer of one or more species from one liquid into another liquid phase, generally from aqueous to organic. The transfer is driven by chemical potential, i.e. once the transfer is complete, the overall system of chemical components that make up the solutes and the solvents are in a more stable configuration. The solvent that is enriched in solute(s) is called extract. The feed solution that is depleted in solute(s) is called the raffinate. Liquid–liquid extraction is a basic technique in chemical laboratories, where it is performed using a variety of apparatus, from separatory funnels to countercurrent distribution equipment called as mixer settlers. This type of process is commonly performed after a chemical reaction as part of the work-up, often including an acidic work-up.
Skorpion Zinc is a zinc mine in the ǁKaras Region of southern Namibia, producing Special High Grade (SHG) zinc. The mine is situated near Rosh Pinah. It was established at a cost of US$450 million by Anglo American in 2003. It is the tenth-largest zinc mine in the world, and the largest employer in Rosh Pinah, providing 1,900 jobs.
In-situ leaching (ISL), also called in-situ recovery (ISR) or solution mining, is a mining process used to recover minerals such as copper and uranium through boreholes drilled into a deposit, in situ. In-situ leach works by artificially dissolving minerals occurring naturally in the solid state.
The Whim Creek Copper Mine is a copper oxide mine, located in the City of Karratha in the Pilbara region of Western Australia.
The Toquepala mine is a large porphyry copper mine in the Tacna Province, Tacna Department, Peru. The mine is an open-pit mine producing copper, molybdenum, rhenium and silver with minor gold and zinc.
Bwana Mkubwa is a settlement and a mine in Copperbelt Province, Zambia. It is the oldest mine in Zambia's Copperbelt region. As a settlement with no municipal status, it became a locale due to the abundant copper deposits found in the area. Today, it is part of Ndola.
The Ruashi Mine is an open-pit copper and cobalt mine operated by Metorex that is located about 10 kilometres (6.2 mi) from Lubumbashi in Katanga Province, Democratic Republic of the Congo. The project includes a plant to concentrate the ore from the Ruashi and Etoile mines, and a modern solvent extraction electrowinning (SX-EW) processing plant. As of 2008, annual capacity was estimated to be 10,000 tonnes of copper and 1,000 tonnes of Cobalt.
The Etoile Mine is an open-pit copper mine on the outskirts of Lubumbashi in Katanga Province of the Democratic Republic of the Congo (DRC). Chemaf owns the license. Chemaf is 95% owned by Shalina Resources and 5% by the DRC government.
Escondida is a copper mine at 3,100 metres (10,200 ft) elevation in the Atacama Desert in Antofagasta Region, Chile.
The Jameson Cell is a high-intensity froth flotation cell that was invented by Laureate Professor Graeme Jameson of the University of Newcastle (Australia) and developed in conjunction with Mount Isa Mines Limited.
The IsaKidd Technology is a copper electrorefining and electrowinning technology that was developed independently by Copper Refineries Proprietary Limited (“CRL”), a Townsville, Queensland, subsidiary of MIM Holdings Limited, and at the Falconbridge Limited (“Falconbridge”) now-dismantled Kidd Creek refinery that was at Timmins, Ontario. It is based around the use of reusable cathode starter sheets for copper electrorefining and the automated stripping of the deposited “cathode copper” from them.
Mineral processing and extraction of metals are very energy-intensive processes, which are not exempted of producing large volumes of solid residues and wastewater, which also require energy to be further treated and disposed. Moreover, as the demand for metals increases, the metallurgical industry must rely on sources of materials with lower metal contents both from a primary and/or secondary raw materials. Consequently, mining activities and waste recycling must evolve towards the development of more selective, efficient and environmentally friendly mineral and metal processing routes.