The element copper sits on the periodic table between nickel and zinc and has an atomic number of 29. This orange-red, non-ferrous metal is one of the most widely used and easily recyclable metals on the face of the earth. In fact, it is estimated that nearly 80% of all copper that has ever been mined is still in use in some form or another, today.
For over 10,000 years, copper has been a popular metal and has been used for everything from jewelry to pipes and electrical wiring. Around 3000 B.C., copper deposits were discovered in Cyprus. The Romans, after conquering the people of this island, gave this metal its Latin name: aes cyprium. From the shortened form, cyprium, a corrupted form cuprum was born. It is this name that gives the element its periodic table abbreviation of Cu and ultimately where the English word “Copper” is rooted.
Copper is generally found in nature mixed with other chemicals, which form copper ore. This ore is mined from open pits that are generally created through drilling and blasting with explosives. After the ore is uncovered, it is scooped up and hauled to a refining plant.
The refining process begins by concentrating the copper ore. A series of conical crushers is used to concentrate the copper and eliminate large quantities of dirt. As the ore is ground into smaller particles it is mixed with water to form slurry. This slurry is then placed into a rod mill, which breaks the ore into even smaller pieces. Once this process is finished, the slurry is run through a ball mill. The ball mill produces finely ground ore that consists of particles that have a diameter of roughly 0.25mm.
After the initial breakdown of the ore is complete, chemical reagents are mixed with the slurry. These chemicals coat the copper particles and concentrate the copper even further. By the end of this process, the resulting mixture consists of about 25-35% copper. The copper is treated again with more chemical agents and heat. This is called the smelting process and provides the means to physically remove waste materials. The result is molten metal called blister copper, which is 99% pure copper.
After the smelting process, copper is refined even further. Despite the fact that the molten result of smelting is 99% copper, the 1% of impurities such as sulfur, oxygen and iron are still present and must be removed. The blister copper is refined by heating it in a refining furnace. This process involves air being blown into the molten blister, which oxidizes the impurities and makes them easier to remove. Samples are drawn and the furnace operator determines whether or not the level of impurities is acceptable. At this point, the copper is about 99.5% pure and is molded into electrical anodes, which are used in the electro-refining process. Once the electro-refining process is complete, the resulting copper is 99.95 to 99.99% pure.
The final form of the pure copper is determined by its use. Ingots are cast if the copper is going to be alloyed to make brass or bronze. Cakes are cast if the copper is going to be used to make plates, sheets, foil or strips. Billets, which are cylindrical in shape, are used to manufacture drawn copper products such as tubing and pipe. Finally, rods are cast and coiled and are used to make wire.
During the entire process, many precious metals such as gold and silver are refined from the copper and are recovered. These byproducts are obviously a good source of income for the refinery. Unfortunately, precious metals aren’t the only forms of ‘waste’ associated with the production of copper. Different chemical pollutants are released through the furnace exhausts. For this reason alone it’s a very good idea to recycle copper. Recycling copper creates far less pollution than the mining and refining process.
Copper is one of the leading recycled materials on our planet. Pure copper can be extracted from scrap copper at a rate of 90%. This makes copper a very valuable recyclable material. For the future of the earth and for future economic purposes, it makes a lot of sense to recycle our used scrap copper.