How Copper is Made

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.