From Ore to Finished Product

Copper is a major metal and an essential element used by man.

It is found in ore deposits around the world. It is also the oldest metal known to man and was first discovered and used about 10,000 years ago. And as alloyed in bronze (copper-tin alloy) about 3000 BC, was the first engineering material known to man.

Today, copper's uses have expanded to include heating, cooling and refrigeration, electrical wiring, electronics, power generation and transmission, automotive applications, antimicrobial uses and many more.

1. Exploration and Discovery

The element Copper is found in a variety of minerals in the earth's crust. Its uses are many. On the periodic chart of elements it is identified by the symbol "Cu".

2. Mining Methods

In each of these mining methods, various earth-moving equipment including shovels, dozers, hauling trucks, and loaders are used to remove and transport the ore. However, the first step is to loosen the rock in the ore body so that it can be moved and processed. Blasting and grinding equipment are used to accomplish this task.

Open pit mining is a technique used to extract copper ore near the earth's surface. Open pit mining is the most widely used technique of mining copper today. It is accomplished by creating and using benches or terraces to gradually reach deeper under the earth's surface.

A split illustration showing an open-pit mine with excavators on the left and an underground mining operation with a conveyor belt and elevator shaft on the right, set against a mountain backdrop.

Left: Open Pit Mining. Right: Underground Mining.

3. Processing of Copper Ore

The process varies slightly depending on the type of ore that is being mined. Sulfide ores are first put through a jaw or gyratory crusher to reduce the rocks to about 7 - 8 inches. This material is then fed to a secondary grinder that further reduces the size to about 1 - 2 inches. The next step is to feed the crushed ore into a wet grinding process in tumbling mills. These mills contain the ore, water and steel balls and further reduce the particles to the optimum size for the flotation process which follows. About 80% of copper from ore is generated using flotation, smelting and refining.

Oxide ores are generally just crushed prior to further processing since leaching does not require the same small particle size as floatation.

Two illustrations show a process involving trucks unloading soil into a machine, which then processes and transports it via a conveyor. In the second image, trucks drive away filled with processed material.

Top: Sulfide ore processing. Bottom: Oxide ore processing.

4. Beneficiation of Copper Ore

Sulfide ores are mixed with water and special chemicals creating a slurry. The slurry, when agitated causes the copper sulfide minerals to float at which point they are skimmed off the surface and eventually dried. The dried material called concentrate is then sent to the smelter.

Oxide ores (and certain sulfide ores) are placed onto a leach pad and saturated with weak acid solutions that dissolve the copper mineral content. The resulting copper-bearing solution is collected and pumped to a solvent extraction plant.

Illustration showing two water management systems: the top has tanks, pipes, and a drum connecting to a grassy mound; the bottom shows a tank connected by pipes to a landscaped area with plants growing on top.

Top: Slurry tanks for sulfide ore. Bottom: Leach field for removing copper from oxide ore.

5. Smelting and Extraction

Sulfide Ore: The dried copper concentrates are sent to the smelting operation where it is reduced and melted in several operations. At the end of this melting process the copper is about 99% pure. While this may sound high, it is still not pure enough for electrical applications, so further processing is required.

Oxide Ore: The copper-bearing solution is collected and pumped to the extraction plant where it is purified. It progresses through a number of steps that combine an organic solvent or sulfuric acid to the solution until the copper concentration is high enough for effective electro-plating.

A split image: Top shows manure being loaded into a digester next to a house; bottom shows tanks connected by pipes, representing a biogas or wastewater treatment system.

Top: Dried concentrate delivered to smelter. Bottom: Solvent extraction tanks for copper solution leached oxide ore.

6. Refining

Sulfide Ores: After smelting, the 99% copper rich material is poured into molds as "anodes" using a casting wheel and transported to the plating house. In this form, they are ready for the next step, which involves dissolving and re-plating the copper to increase its purity level.

Oxide Ores: The copper-bearing solution, from the solvent extraction operations, is plated into pure copper cathodes using a process called electrowinning. Stainless steel blanks are added to the plating tanks to act as cathodes and copper is plated onto them by electro-chemical deposition. It takes about a week before the cathode is ready to be removed from the tank so the copper can be stripped off the blank. The cathodes are now 99.99% pure copper and ready to be made into wire, tube or any number of useful products.

Two illustrated panels: The top shows a round building with parts being loaded onto yellow trucks. The bottom shows the trucks delivering those parts to a rectangular structure under construction in a green landscape.

Top: Copper from smelter is cast as anodes. Bottom: Electrowinning produces copper cathodes ready for shipment.

7. Sulfide Ore Refining

The anodes of 99% pure copper are sent to the electrolytic refinery for purification into very pure copper cathodes. They are immersed into a tank of electrolyte. The electrolyte is an aqueous solution of sulfuric acid and copper sulfate. The copper dissolves off the anode and is plated on the stainless steel, while all impurities remain in the electrolyte. After 7 - 14 days, the transfer to the cathode is complete and it is removed from the tank. The copper is stripped from the stainless steel sheet, washed and shipped to customers. It is now ready to be made into products we all recognize.

A cartoon shows cows inside a factory, being transformed into packaged meat on an assembly line. The meat is loaded onto a truck outside, set in a green field under a blue sky with clouds.

Copper from smelter is cast as anodes

8. Copper Products & Uses

The cathodes are shipped to various production plants to be made into rod, wire, cable, tube, special tubular shapes, sheet, strip and plate. During production of shaped copper materials, various other metals are added to give copper additional properties. These alloying elements add strength, ductility, durability, corrosion protection and other properties. There are over 800 copper alloys registered in the United States. All of these product forms of copper and copper alloys are used to make products we use every day. Copper is an important material for improving our quality of life.

A split image shows a cozy, modern living room with electronics and guitars on the top half, and a yellow car driving down a road bordered by grass and a fence on the bottom half.

Copper transports electricity to and in our homes for appliances and electronics. It is used in roofing, door hardware, railings and in automobiles.

9. Uses of Copper

The Statue of Liberty and other art objects are often made of copper materials because of their durability. Bronze has been used for statuary and artwork for thousands of years.

Copper is one of the world's most important natural resources. Not only for its intrinsic value but for the many uses it can be put to everyday. Copper and copper alloys are used to transport electricity to and in our homes and businesses. Copper is the primary electrical conductor for appliances and electronics. It is used in durable and decorative applications such as copper roofing, door hardware, railings and decorative trim. It is used in our cars and airplanes and in our plumbing systems.

Illustrated view of the Statue of Liberty on its island, surrounded by blue water, with the New York City skyline and a few boats visible in the background under a partly cloudy sky.

Statue of Liberty - one of the world's most famous statues made from copper

10. Marine & Other Applications

Ships and offshore structures often use copper alloys in seawater applications for their corrosion resistance and durability. Tanks, piping, propellers and platform supports are often made from copper alloys.

Musical instruments use copper alloys for sound clarity and long life. In addition to a pleasing appearance and sound, copper alloys can be used to make very intricate shapes and components.

Coinage is made from copper and copper alloys in the United States and many countries worldwide.

We do not always see the copper alloys in use but they are there working for us.

A large gray ship with the number 83 sails on calm blue water under a partly cloudy sky. On the right, illustrations of a medal, a trumpet, a coin, and a ship propeller are stacked vertically.

Copper and its alloys are widely used where strength and durability are required.

11. Recycling and Reuse

Copper materials are recycled without changing the physical properties of the metal. This means it does not have to go into a "cheaper" product, it can be used again and again in the same application. Many copper mills utilize copper scrap materials in the production of new alloy products. The history of copper mining and recycling goes back to the time copper was first used, about 10,000 years ago. The copper industry is committed to contributing to the local economies, providing a safe workplace, and protecting the environment and reclaiming the land.

A city dump with bins labeled Metal Scraps Only containing items like a bicycle, washing machine, and lawnmower. On the right, a crane lifts metal at a scrapyard labeled Scrap Metals Inc. behind a fence.

Copper is easily recycled which is good for the environment.