The Chino open-pit copper mine in New Mexico.

Chalcopyrite

Currently, the most common source of copper ore is the mineral chalcopyrite (CuFeS₂), which accounts for about 50% of copper production. The focus of this article is on the process of copper extraction from chalcopyrite ore into pure metal. Processes for other minerals are mentioned. The Chino open-pit copper mine located just out of Silver City, New Mexico. ... The Chino open-pit copper mine located just out of Silver City, New Mexico. ... Chalcopyrite. ... Chalcopyrite. ... Copper has played a significant part in the history of mankind, which has used the easily accessible uncompounded metal for nearly 10,000 years. ... Iron ore (Banded iron formation) Manganese ore Lead ore Gold ore An ore is a volume of rock containing components or minerals in a mode of occurrence which renders it valuable for mining. ... Chalcopyrite (sometimes called peacock pyrite) is a copper iron sulfide mineral that crystallizes in the tetragonal system. ...

For economic and environmental reasons, many of the byproducts of extraction are reclaimed. Sulfur dioxide gas, for example, is captured and turned into sulfuric acid — which is then used in the extraction process. Sulfur dioxide (or Sulphur dioxide) has the chemical formula SO2. ... R-phrases S-phrases , , , Flash point Non-flammable Related Compounds Related strong acids Selenic acid Hydrochloric acid Nitric acid Related compounds Hydrogen sulfide Sulfurous acid Peroxymonosulfuric acid Sulfur trioxide Oleum Supplementary data page Structure and properties n, εr, etc. ...

Hydrometallurgical extraction

Name	Formula	% Copper when pure
Chalcopyrite	CuFeS2	34.5
Chalcocite	Cu2S	79.8
Covellite	CuS	66.5
Bornite	2Cu2S•CuS•FeS	63.3
Tetrahedrite	Cu3SbS3 + x(Fe,Zn)6Sb2S9	32-45
Malachite	CuCO3•Cu(OH)2	57.3
Azurite	2CuCO3•Cu(OH)2	55.1
Cuprite	Cu2O	88.8
Chrysocolla	CuO•SiO2•2H2O	37.9
Principal Copper-bearing Minerals[1] Image File history File links Metadata Size of this preview: 800 × 599 pixelsFull resolution (1920 × 1437 pixel, file size: 703 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ... Chalcopyrite (sometimes called peacock pyrite) is a copper iron sulfide mineral that crystallizes in the tetragonal system. ... Chalcocite (Copper Sulfide) [1] File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Chalcocite, copper(I) sulfide (Cu2S), is an important copper mineral ore. ... Copper sulfides occur in a number of different forms and are minerals often used as copper ore. ... Image File history File links Metadata Size of this preview: 782 × 600 pixelsFull resolution (1565 × 1200 pixel, file size: 779 KB, MIME type: image/jpeg) Image of Covellite from the U.S. Geological Survey Photographic Library U.S. Geological Survey Photographic Library http://libraryphoto. ... Covellite (also know as covelline) is a crystalline form of copper(II) sulfide (CuS). ... Copper sulfides occur in a number of different forms and are minerals often used as copper ore. ... Image File history File links Bornite Source File links The following pages link to this file: Bornite ... Bornite (Copper Iron Sulfide) Tarnish of Bornite Bornite is a sulfide mineral with chemical composition Cu5FeS4 that crystallizes in the cubic system. ... Image File history File links Metadata No higher resolution available. ... Tetrahedrite is a rare copper antimony sulfosalt mineral with formula: Cu12Sb4S13. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2272 × 1704 pixel, file size: 1,011 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ... This article is about the mineral. ... Image File history File links Metadata Size of this preview: 800 × 532 pixelsFull resolution (3008 × 2000 pixel, file size: 3. ... // Fresh, unweathered stalactitic azurite crystals showing the exceptionally deep blue of unaltered azurite. ... Cuprite. ... Cuprite Cuprite is a mineral composed of copper(I) oxide Cu2O, and is a minor ore of copper. ... Commons:Image:Chrysocolla USA.jpg File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Chrysocolla from Nevada, USA. Chrysocolla (hydrated copper silicate) is a mineral, CuSiO3·nH2O. It is of secondary origin and forms in the oxidation zones of copper ore bodies. ...

Oxide ores

Oxide ores are readily leached by sulfuric acid, usually using a heap leach or dump leach process in combination with solvent extraction and electrowinning technology (SX-EW). Commonly sulfuric acid is used as a leach for copper oxide, although it is possible to use water. There have been examples where froth flotation was used to concentrate malachite. In general froth flotation is not used to concentrate copper oxide ores, as the cost of leaching is cheap when compared to the cost of grinding and flotation. The implication of this is that copper oxides are more economic to process than copper sulfides. Leaching is the process of extracting a substance from a solid by dissolving it in a liquid. ... R-phrases S-phrases , , , Flash point Non-flammable Related Compounds Related strong acids Selenic acid Hydrochloric acid Nitric acid Related compounds Hydrogen sulfide Sulfurous acid Peroxymonosulfuric acid Sulfur trioxide Oleum Supplementary data page Structure and properties n, εr, etc. ... Heap leaching is an industrial mining process to extract precious metals and copper compounds from ore. ... Dump leaching is an industrial process to extract precious metals and copper from ores. ... In chemistry, liquid-liquid extraction (or more briefly, solvent extraction) is a useful method to separate components (compounds) of a mixture. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Solution extraction/electrowinning (SX/EW) is a two-stage process that first extracts and upgrades copper ions from low-grade leach solutions into a concentrated electrolyte, and then deposits pure copper onto cathodes using an electrolytic procedure. ... Froth Flotation is a selective process for separating minerals from gangue by using surfactants and wetting agents. ... This article is about the mineral. ... In materials processing a grinder is a machine for producing fine particle size reduction through attrition and compressive forces at the grain size level. ... Froth Flotation is a selective process for separating minerals from gangue by using surfactants and wetting agents. ...

Secondary ores

Secondary sulfides - those formed in supergene secondary enrichment - are resistant (refractory) to sulfuric leaching. High grade secondary sulfides may be concentrated using froth flotation, and subsequently smelted to recover the copper, or else they can be leached using a bacterial oxidation process to oxidize the sulfides to sulfuric acid, which also allows for simultaneous leaching with sulfuric acid. As with oxide ores, solvent extraction and electrowinning technologies are used to recover the copper from the pregnant leach solution. In ore deposit geology, supergene processes or enrichment occur relatively near the surface. ... The term refractory can refer to multiple things: A refractory clergyman is one who refused to swear an oath to the French Revolution-era French state under the Civil Constitution of the Clergy. ... Smelting rhymes with melting Electric phosphate smelting furnace in a TVA chemical plant (1942) Chemical reduction, or smelting, is a form of extractive metallurgy. ... Bacterial oxidation is a bio-hydrometallurgical process developed for pre-cyanidation treatment of refractory gold ores or concentrates. ... Pregnant Leach Solution (PLS) is acidic copper-laden water generated from stockpile leaching and heap leaching. ...

Pyrometallurgical extraction

The following is a process of copper extraction from chalcopyrite ore into pure metal. While oxide ores can be processed using pyrometallurgical techniques, hydrometallurgical methods are more cost effective. Pyrometallurgy is a branch of extractive metallurgy. ... Hydrometallurgy is the field of extractive metallurgy involving the use of aqueous chemistry for the recovery of metals from ores, concentrates, and recycled or residual materials. ...

The copper ore is crushed and ground before it is concentrated to between 20 and 40% copper in a flotation process. The next major step in production uses pyrometallurgical processes to convert the copper concentrate to 99% pure copper suitable for electrochemical refining. These high temperature processes first roast the concentrate, then smelt it in a furnace, oxidise and reduce the molten products to progressively remove sulfur, iron, silicon and oxygen to leave behind relatively pure copper.

Concentration

Most high grade copper sulfide ores are concentrated using the froth flotation process. Ground ore is mixed with xanthate reagents (or other reagents of the thiol class), which react with the copper sulfide mineral to make it hydrophobic on its surface. (Besides xanthates, dithiophosphates and thionocarbamates are commonly used.) Froth Flotation is a selective process for separating minerals from gangue by using surfactants and wetting agents. ... Xanthates are the salts of xanthic acid, C2H5OCS2H. Many xanthates have a yellow colour, which gives the compound its name (Greek xanthos means yellow). ... A reagent is any substance used in a chemical reaction. ... For other uses, see Mineral (disambiguation). ... In chemistry, hydrophobic or lipophilic species, or hydrophobes, tend to be electrically neutral and nonpolar, and thus prefer other neutral and nonpolar solvents or molecular environments. ... An open surface with X-, Y-, and Z-contours shown. ...

The sulfide ore is crushed and ground to increase the surface area of the ore for subsequent processing. The powdered ore is mixed with chemicals (the 'collector chemical') and introduced to a water bath (aeration tank) containing surfactant. Air is constantly forced through the slurry and the hydrophobic copper sulfides particles latches onto and rides the air bubbles to the surface, where it forms a froth and is skimmed off. These skimmings are generally re-processed (cleaned) to reach a high purity copper concentrate. The remainder is discarded as tailings, or processed to extract other elements. Surfactants, also known as tensides, are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids. ... Tailings (also known as slickens[1]) are the waste left over[2] after removing the gangue from ore. ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ...

• An example collector chemical is potassium amyl xanthate.
• An example frother chemical is methylisobutyl carbinol or, for short, MIBC, an alcohol.

To improve the process efficiency, limestone is used to raise the pH of the water bath, causing the collector to ionize more and to preferentially bond to chalcopyrite (CuFeS₂) and avoid the pyrite (FeS₂) - iron exists in both primary zone minerals. For other uses, see Limestone (disambiguation). ... For other uses, see PH (disambiguation). ... Chalcopyrite (sometimes called peacock pyrite) is a copper iron sulfide mineral that crystallizes in the tetragonal system. ... Copper has played a significant part in the history of mankind, which has used the easily accessible uncompounded metal for nearly 10,000 years. ... For other uses, see Iron (disambiguation). ... This article is about the chemical element. ... The mineral pyrite, or iron pyrite, is iron sulfide, FeS2. ...

The product from this froth flotation process is known as copper concentrate. When the froth (which is between 20 and 40% copper) is dried it is known as copper concentrate. Copper concentrate may be treated by either hydrometallurgical methods or sintered before pyrometallurgical methods are used to produce copper metal. Copper concentrate is sometimes traded either via spot contracts or under long term contracts as an intermediate product in its own right. Froth Flotation is a selective process for separating minerals from gangue by using surfactants and wetting agents. ... Copper concentrate is the first stage of refining copper ore and contains 25%-30% copper with various other elements. ... Sintering is a method for making objects from powder, increasing the adhesion between particles as they are heated. ... Pyrometallurgical refers to a type of chemical metallurgy used to change metals, for example: roasting or smelting. ...

Smelting

The calcine is then mixed with silica and limestone and smelted at 1200°C (in an exothermic reaction) to form a liquid called copper matte. This temperature allows reactions to proceed rapidly, and allow the matte and slag to melt, so they can be tapped out of the furnace. In copper recycling, this is the point where scrap copper is introduced. The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... For other uses, see Limestone (disambiguation). ... In thermodynamics, the word exothermic describes a process or reaction that releases energy in the form of heat. ...

Several reactions occur.

For example iron oxides and sulfides are converted to slag which is floated off the matte. The reactions for this are:

FeO_(s) + SiO_{2 (s)} → FeO.SiO_{2 (l)}

In a parallel reaction the iron sulfide is converted to slag:

2FeS_(l) + 3O₂ + 2SiO_{2 (l)} → 2FeO.SiO_2(l) + 2SO_2(g)

The slag is discarded or reprocessed to recover any remaining copper. A reaction is the following: In physics, a reaction (physics) is defined by Newtons third law: For every action there is an equal and opposite reaction. The idea that any given force has a pair or opposite force. ... Slag is also an early play by David Hare. ...

Conversion to blister

The matte, which is produced in the smelter, contains around 70% copper primarily as copper sulfide as well as iron sulfide. The sulfur is removed at high temperature as sulfur dioxide by blowing air through molten matte:

2Cu₂S + 3O₂ → 2Cu₂O + 2SO₂

Cu₂S + 2Cu₂O → 6Cu + SO₂

In a parallel reaction the iron sulfide is converted to slag:

2FeS + 3O₂ → 2FeO + 2SO₂

2FeO + 2SiO₂ → 2FeSiO₃

The end product is (about) 98% pure copper known as blister because of the broken surface created by the escape of sulfur dioxide gas as the copper ingots are cast. By-products generated in the process are sulfur dioxide and slag.

Reduction

The blistered copper is put into an anode furnace (a furnace that makes anodes) to get rid of most of the remaining oxygen. This is done by blowing natural gas through the molten copper oxide. When this flame burns green, indicating the copper oxidation spectrum, the oxygen has mostly been burned off. This creates copper at about 99% pure. The anodes produced from this are fed to the electrorefinery. Diagram of a zinc anode in a galvanic cell. ... This article is about the fossil fuel. ...

Electrorefining

Apparatus for electrolytic refining of copper

The copper is refined by electrolysis. The anodes cast from processed blister copper are placed into an aqueous solution of 3-4% copper sulfate and 10-16% sulfuric acid. Cathodes are thin rolled sheets of highly pure copper. A potential of only 0.2-0.4 volts is required for the process to commence. At the anode, copper and less noble metals dissolve. More noble metals such as silver and gold as well as selenium and tellurium settle to the bottom of the cell as anode mud, which forms a saleable byproduct. Copper(II) ions migrate through the electrolyte to the cathode. At the cathode, copper metal plates out but less noble constituents such as arsenic and zinc remain in solution.^[1] The reactions are: Image File history File links Size of this preview: 800 × 458 pixelsFull resolution (926 × 530 pixel, file size: 113 KB, MIME type: image/png) Subject: Diagram of electrolytic copper refining apparatus. ... Image File history File links Size of this preview: 800 × 458 pixelsFull resolution (926 × 530 pixel, file size: 113 KB, MIME type: image/png) Subject: Diagram of electrolytic copper refining apparatus. ... This article is about the chemical process. ... Drinking water This article focuses on water as we experience it every day. ... Copper (II) sulfate (CuSO4) is the most common copper salt, made by the action of sulfuric acid on the base copper oxide. ... R-phrases S-phrases , , , Flash point Non-flammable Related Compounds Related strong acids Selenic acid Hydrochloric acid Nitric acid Related compounds Hydrogen sulfide Sulfurous acid Peroxymonosulfuric acid Sulfur trioxide Oleum Supplementary data page Structure and properties n, εr, etc. ... For other uses, see Selenium (disambiguation). ... General Name, Symbol, Number tellurium, Te, 52 Chemical series metalloids Group, Period, Block 16, 5, p Appearance silvery lustrous gray Standard atomic weight 127. ... General Name, Symbol, Number arsenic, As, 33 Chemical series metalloids Group, Period, Block 15, 4, p Appearance metallic gray Standard atomic weight 74. ... General Name, symbol, number zinc, Zn, 30 Chemical series transition metals Group, period, block 12, 4, d Appearance bluish pale gray Standard atomic weight 65. ...

At the anode: Cu_(s) → Cu²⁺_(aq) + 2e^– Diagram of a zinc anode in a galvanic cell. ...

At the cathode: Cu²⁺_(aq) + 2e^– → Cu_(s) Diagram of a copper cathode in a Daniells cell. ...

Copper cathode is 99.99% copper in sheets of dimensions: 96 cm x 95 cm x 1 cm, with a mass of about 100 kg. It is a true commodity, deliverable to the metal exchanges in New York, London and Shanghai. The chemical specification for electrolytic grade copper is ASTM B 115-00 (a standard that specifies the purity and maximum electrical resistivity of the product). Diagram of a copper cathode in a galvanic cell. ... This article does not cite any references or sources. ... This article is about the state. ... This article is about the capital of England and the United Kingdom. ... For other uses, see Shanghai (disambiguation). ... An electrolyte is a substance containing free ions that behaves as an electrically conductive medium. ...

See also

• Copper mining in the United States
• Metallurgy
• Extractive metallurgy
• Smelting
• Category:Copper minerals
• In-situ leach

Copper mining in the United States has been a major industry since the rise of the northern Michigan copper district in the 1840s. ... Georg Agricola, author of De re metallica, an important early book on metal extraction Metallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their compounds, which are called alloys. ... Extractive metallurgy is the practice of extracting metal from ore, purifying it, and recycling it. ... Smelting rhymes with melting Electric phosphate smelting furnace in a TVA chemical plant (1942) Chemical reduction, or smelting, is a form of extractive metallurgy. ... In-situ leaching (ISL), also called in-situ recovery (ISR) or solution mining, is a process of recovering minerals such as copper and uranium through boreholes drilled into the deposit. ...

External links

• The Copper Development Association's copper production page.
• CCU-1c Copper Concentrate
• Copper Processing
• National Pollutant Inventory - Copper and copper compounds fact sheet
• University of Pittsburgh School of Engineering Chemical and Petroleum Engineering Department, Froth Flotation Lab notes.

Notes

1. ^ ^{a b} Samans, Carl H. Engineering Metals and their Alloys MacMillan 1949