The different processes to make copper are described below:
1. Mining
Mining of copper ores is usually done in large open pit mines which are open holes in the ground that are dug deeper gradually. Explosives are used to blast the rock, and the resulting boulders are transported for crushing into smaller pieces for processing.
2. Extraction
There are two main purification processes for the two common types of copper ore. A hydrometallurgical process is used for oxide ores. The crushed ore is heaped and an acid-leaching solution is percolated through the heap. This creates a pregnant leach solution. A pyrometallurgical process is used for sulfide ores. The extraction of the ore is done by froth flotation and thickening according to the density of the particles.
3. Purification
For oxide ores, the pregnant leach solution is sent to a solvent extraction process to concentrate the copper in the solution in a process called “hydrometallurgy.” The solution is then sent to electrowinning, where electricity is used to deposit the solid copper. For sulfide ores, pyrometallurgy is used, which means that a smelter is used to create the raw copper. This is then purified in the electrorefining process.
4. Alloying
Copper alloys are made by first melting the alloying material, then melting the copper to add to it. The molten mixture is then cast and allowed to cool and solidify.
5. Electrorefining
Electrorefining of copper involves electrolytically dissolving impure copper material into solution. Pure copper is electrochemically deposited on an electrode by applying an electrical current through the solution to remove impurities from the metal. The process is quite expensive and has a very high electrical demand.
