What is a Copper Cathode?

C.B. Fox

Copper cathode is a form of copper that has a purity of 99.95%. In order to remove impurities from copper ore, it undergoes two processes, smelting and electrorefining. The resulting, nearly pure copper is an excellent conductor and is often used in electrical wiring.

Copper sulfate, which is used in electrorefining copper.
Copper sulfate, which is used in electrorefining copper.

When it is in the ground, copper does not exist in its pure form. Rather it is part of a compound. One of the most common types of copper ore is a mixture of copper, iron and sulfur. This ore is called chalcopyrite. After the ore is mined, it is heated in a furnace to 2,012° F (1,100° C). At this temperature, oxygen reacts with the iron in the ore, turning the ore into three substances, iron oxide, sulfur dioxide and copper sulfite.

In order to remove impurities from copper ore, it undergoes two processes, smelting and electrorefining.
In order to remove impurities from copper ore, it undergoes two processes, smelting and electrorefining.

After most of the iron is removed from the copper ore, the copper sulfite, which is also known as copper matte, is exposed to high levels of oxygen. The copper matte is still in a molten state, and the oxygen sent into the furnace is able to bond with the remaining sulfur, creating more sulfur dioxide and 99% pure copper.

At this point, the refined copper can be used for goods that do not require a high degree of conductivity, but the copper can be refined further into copper cathode through the electrorefining process. Many of the remaining impurities in the copper are traces of other minerals, including nickel, silver, and gold. These trace minerals are collected during electrorefining.

In electrorefining, the 99% pure copper is placed in a solution of sulfuric acid and copper sulfate. The sheets of impure copper are lined up next to materials that pure copper will deposit on. Electricity is sent into the tanks through the impure copper slabs, called anodes, and leaves through the pure copper that is formed, also called the copper cathode. Impurities in the copper either sink to the bottom of the tanks or rise to the surface as ions of pure copper travel through the solution to the cathodes.

As an excellent conductor of electricity and heat, copper cathode is often used to make copper wire. The pliable nature of copper makes it an excellent choice for electrical and audio wires, which must be thin and flexible. Aside from wire, copper cathode is also used to make copper cake, which ranges in thickness from thin foils to thick plates. Ingots of electrorefined copper may also be used to make alloys, such as bronze.

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Discussion Comments


Dear Domido, Why do you think that anything that is extracted while purifying the cooper, is not used? Who doesn't like silver or gold? What brought you to the point to write your comment?


The price of copper is usually as dear as it is because of the process that it must go through to become purified. Doing all of that takes time and resources, which basically equals money to suppliers.

That is why many people are turning to recycled copper. They often come with better prices attached but the same exact benefits.

The only problem with recycled copper usually stems more from the fact that many folks sale their excess copper to these recycling centers for a pretty penny. The suppliers can often actually buy the copper cheaper than they can mine it.

This has led to a huge outbreak of robberies of copper from homes that are being renovated or built. Many of the burglars responsible for these kinds of crimes strip the homes of their pipes and wiring, plus any other copper they can get their hands on while no one lives in them.


After copper cathode has been made into its purest form, I know that the copper itself is very useful. But what becomes of all of the other elements that were naturally a part of the compound?

It seems like that it would be more productive and just plain wise to find ways to use these valuable bi-products as well.

I know sometimes iron and sulfur are part of what comes away from the copper through the process of purification. Wouldn't it be greener if we utilized these as well?

I mean if you’re going to go through all of the trouble of extracting it from the copper, why not find a good use for it too? It seems like this could even help copper suppliers keep costs down.

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