Typical Copper Extraction Process Flow Chart (Copper Oxide):

Multotec specialises in process equipment used in copper beneficiation, with over 50 years of global experience. Our team of metallurgists and engineers will help devise the optimum solutions for your plant.

Typical Copper Extraction Process Flow Chart (Copper Sulphide):

Different Copper Extraction Methods:

The physical removal process of copper is dependent on the type of ore (either oxide or sulphide ores). These kinds of ores have different extraction processes, as explained in detail below.

Extraction of Copper from Oxide ores:

When working with oxide ores, a hydrometallurgical leaching process is typically utilised. This process makes use of aqueous (water-based) solutions to extract and purify copper from copper oxide ores at normal temperatures. This process could include three steps: heap leaching, solvent extraction, and electrowinning.

Heap Leaching

Crushed ore is loaded into a heap on top of an impermeable layer, at a slight angle. A leaching reagent (dilute sulfuric acid) is sprayed onto the bed and trickles down through the heap, where it dissolves the copper from the ore.

The resulting “pregnant” leach solution of sulphuric acid and copper sulphate is collected in a small pool below the heap. This copper sulphate holds copper concentrations of between 60-70%.

Solvent Extraction

The next step is solvent extraction, in which two immiscible liquids are mixed vigourously together and then allowed to separate based on solubility. This way, the copper moves from one liquid to the other.

The copper that was in the leach solution moves into the solvent, leaving impurities behind. The leftover leach solution is recycled by adding additional acid and using it again in the heap leaching process.

Electrowinning

The last step is a type of electrolysis, whereby an electrical current passes through an inert anode (positive electrode) and through the copper solution from the previous step, which acts as an electrolyte.

Positively-charged copper ions (called cations) come out of solution and are plated onto a cathode (negative electrode) as almost pure copper.

Extraction of Copper from Sulphide ores:

Sulphide ores, both secondary (supergene) and primary (hypogene), make use of froth flotation to physically separate ore from gangue.

Sulphide ores are generally processed using mineral processing, hydrometallurgy and pyrometallurgy (involves the application of heat). Using a series of physical steps and high temperatures, copper is extracted and purified.

Froth flotation:

Following mining, transporting, and crushing to the required size, the crushed ore is further processed through a mill and then secondary milling and classification. Water is added into the milling circuit to create a slurry.

The slurry is transported to a flotation circuit where the copper mineral is separated from gangue. Chemical reagents (termed “collectors”) are added to the slurry to connect with copper minerals, making them hydrophobic (water repellent). Air is introduced into the flotation cell allowing the formation of bubbles, which then rise to the surface, allowing a froth mineral-rich layer to form.

The froth of copper-rich bubbles found at the top of the tank is then further processed. The gangue is systematically removed out of the system and then disposed of as mine tailings.

Thickening

The froth is transported into large tanks (thickeners), where the bubbles break and solids from the froth solution settle to the bottom of the tank. Solids are filtered to remove excess water, which can be reused in the circuit. The solid copper concentrate is then sent to the smelter.

Smelting

High temperatures further purify the ore in a series of smelting steps. The copper concentrate is first placed in the smelting furnace to be heated up to 1260 °C and converted into molten liquid.

The heated liquid is poured into a slag-settling furnace. During this step a combination of matte, a mixture of copper, sulfur and iron, and slag, a dense, glassy material made of iron, silica, and other impurities, is produced. The copper matte contains 58-60% copper at this point.

The molten matte is then taken to another furnace (a converter) to have the remaining iron and sulfur removed. The product created is referred to as blister copper, which contains 98% copper. Next, this is taken to the anode smelter, where the oxygen in the copper is burned off and changes from a yellow colour to a blue-green color. The resulting product is a molten anode copper, which is poured into molds called anode-casting wheels.

Electrolysis

The copper anode slabs are then refined in a final step called electrolysis. Here, anode slabs are hung in a large tank that is full of an electrolyte solution of copper sulphate and sulfuric acid.

Thin sheets of pure copper, which are called cathodes, are hung in between the anodes. This is the final refinement where the copper is purified into copper cathodes. An electric current is supplied, and positively-charged copper ions (cations) leave the anode (positive electrode) and move in solution through the electrolyte solution to be plated on the cathode (negative electrode).

Other metals and impurities move from the anode to drop to the bottom of the tank or stay in the electrolytic solution. These are collected and may be refined to recover other metals such as silver and gold.

The cathodes are taken out of the tank and rinsed with water to prevent further reaction. The final copper cathodes can then be made into wires, plates, tubes, and other copper products.

Did you know?

• Copper processing begins with mining copper ore, which contains less than 1% of copper, and ends with sheets of 99.99% pure copper (cathodes).
• Copper mining generally takes place through open-pit mining, in which a series of stepped benches are dug deeper into the earth. Yet, it can also be mined underground, through horizontal tunnels.
• To remove the ore from the earth, boring machines are used to drill holes into the hard rock, and then explosives are inserted into the drill holes to blast and break the rock.

What is the most common ore of copper?

There are two specific types of ore deposits, copper oxide and copper sulphide, which are both processed differently on account of their different chemical structures.

Yet, the most common source of copper ore is the sulphide ore mineral chalcopyrite, which accounts for around 50% of copper production in the world.

Types of Copper Ore

Chalcopyrite

Chalcocite

Covellite

Bornite

Tetrahedrite

Digenite

Malachite

Azurite

Cuprite

Chrysocolla

Tennantite

Dioptase

Enargite

Field Service Maintenance

Multotec’s entire range of copper processing equipment is backed by extensive field service and maintenance agreements, ensuring longevity and superior product performance.

• Regular field service & maintenance site visits
• Preventative maintenance
• Lifecycle management
• Condition monitoring

Proper maintenance can extend the lifespan of your copper processing equipment. Using our range of condition monitoring products ensures your plant continuously operates at optimum efficiency.

With over 50 years of application experience, maintenance management, and a mobile workforce of field technicians based around the world, our skilled field services teams have a full understanding of global mineral processing challenges.

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Your Copper Beneficiation partner:

Multotec supplies a complete range of processing equipment, designed for copper extraction, with full maintenance contracts.

With a well-established and strategically located distribution network, we can supply your mineral processing equipment anywhere in the world.

We’ve supplied copper beneficiation solutions to some of the world’s leading mining houses and engineering companies:

Mining Houses: African Rainbow Minerals | Chemaf S.P.R.L. | Eurasian Natural Resources Corp | First Quantum Minerals | Freeport McMoRan Copper & Gold | Glencore International plc | Katanga Mining | Metorex | Rio Tinto | Vale | Vendanta Resources | Anglo American | GFI Mining| Xstrata | Quadra FNX

Design Houses: Sente | DRA | Lycopodium | New Concept Projects | Fluor | METC Engineering | ProProcess | Hatch | Baldmin Projects | Proserve

Innovation driven by R&D:

Multotec is a specialist in copper mineral processing equipment, with over 50 years of experience in mineral processing across the world.

Our Research and Development (R&D) department responds to our customers’ unique processing challenges, creating innovative solutions through new beneficiation technologies.

We aim for more efficient customer processes by providing equipment that requires reduced maintenance. A prominent advancement made on this front is our Hawkeye™ condition monitoring technology.

The Hawkeye™ predictive software tool delivers accurate data on your products lifecycles and replacement rates, creating an accurate prediction of service intervals and scheduled downtimes. Hawkeye can be used in screen panel maintenance schedules and mill liner maintenance programs.

Multotec is committed to your copper extraction process, consistently aiming to lower your cost per ton.