Copper extraction from the earth has been taking place for over ten thousand years. Known for its reddish hue and multiple uses, copper (Cu) has been known throughout the centuries as a reliable metal with multiple usages. It has thousands of years of history, particularly due to its usage in both ancient and modern times for coins, jewelry, cookware and more recently, industrial applications. It even has a biological role, as it is a trace element in many plants and animals and minimal amounts of copper in the human diet are vital for health and well-being, not unlike iron. In industry, copper is utilized mainly for building as well as electrical equipment, but copper still has a huge demand as it has multiple uses in numerous fields, ranging from healthcare and car maintenance to computer sciences.
Its atomic number of 29 puts copper in Group 11 in the periodic table with valuable elements such as gold and silver. The elements in this group are often found together at mining sites and share many similar properties. Like gold and silver, copper is a strong conductor of electricity and heat, which makes it incredibly popular for use in electronic equipment such as wiring in building structures and computer parts. It also has antimicrobial properties, which also makes it useful for medical purposes such as cathodes, devices and diagnostic instrumentation.
However, not unlike gold and silver, in its purest form copper is a very soft metal. As a result, it’s often combined with other elements such as zinc, tin and nickel in order to change its strength and flexibility. These combinations create copper alloys such as brass and bronze. Although these are popular in many different markets and have their own uses, pure copper is still a vital part of multiple industries including but not limited to markets that require electrical wiring. Contact us to discuss your copper verification needs!
Copper is mined throughout the world in a variety of geological settings. Over 50 countries are mining for copper, ranging from Albania to Zimbabwe. Chile is the world’s largest producer and exporter of this metal, with its Escondida Mine being one of the biggest in the world. Other high-ranking copper producers include Peru, China, Indonesia and the United States, although there are also large deposits in Canada, Russia and parts of Africa that are still being tapped. The largest mine in the United States for copper is found in Bingham Canyon in Utah, followed by the high-producing states of Arizona, Michigan, New Mexico and Montana.
Since there are two types of copper ore: sulfide ores and oxide ores, different techniques are used for copper extraction. Each of these ores have both a different extraction and processing technique. Sulfide ores typically are extracted through open pit mining, which uses drilling and explosive blasting to obtain the copper. It is then extracted through smelting or hydro-metallurgical processes, depending on the percent of concentration of the copper to other elements. Examples of sulfide ores include bornite and chalcopyrite, which accounts for approximately 50 percent of all copper ore production. Sulfide ores are typically more desirable than oxide ores due to their higher grade status once the extraction process is complete.
Oxide ores need to be leached out by sulfuric acid, which creates a copper sulfate solution. The pure copper is then stripped out through solvent extraction and electrowinning, or SX/EW. A handheld XRF instrument also called a Copper Extraction Analyzer can assist with the SX/EW process. In fact, it can assist in practically every stage of mining. In SX/EW, the analyzer can be used to quantify the chemical composition of the electrolyte solutions that are responsible for leaching out precious metals such as copper during the SX/EW process. In this fashion, one can make determinations using the real-time results which can save valuable time during the process and help maximize the output, as you’re able to adjust the solutions being used accordingly making the process more efficient as you go. This process is almost 20 years old and neutralizes the waste from the process, which makes it an environmentally-friendly way to help extract ore and takes less time and energy overall than smelting. It is also used in 30 percent of the copper ore production in the United States. At first blush, oxide ores typically appear to be the less desirable ore with which to perform copper extraction due to the final product’s lower grade status; however, it is also more economical to extract this type of ore, so more industries are willing to tap these resources that go through the more expensive process of obtaining the more pure sulfide ore. Common examples of oxide ores of copper include malachite and azurite.
These types of ore can yield between 20 and 40 percent pure copper, which can then be used in a variety of industries, from ammunition for guns to car radiators. Although most of the market is looking for copper to combine with other metals rather than in its pure form, there is still a huge market for pure copper since it doesn’t oxidize as fast as its alloys, which can sometimes turn green when exposed to oxygen for extended periods of time. The best example of this process is the Statue of Liberty, which is made of iron coated in a thin layer of copper. After being exposed to oxygen, water and other pollutants over time, the statue has gone from its once-copper color to its current trademark shade of green.