On regular basis, the metals produced by ore fusion, need to be refined to rise their purity, and to separate the precious metals that may content. In this article we will see some of the chemical operations involved in this process in the case of copper production, these operations are:
In the oxidation process, air is blown into the molten copper to selectively remove impurities such as Iron, Zinc, Aluminum, Magnesium, and some others such as Sulfur and Lead are partially volatilized, other elements such as Arsenic and Antimony, can only be eliminated with the use of fluxes, such as calcium oxide and sodium oxide.
The most used way to add these fluxes is by means of pneumatic injection, where with spears the flux comes into direct contact with the metal, this prevents from decomposing and being dragged in a powder form together with the exit gases.
After the oxidation process, the reduction take place, since a part of the oxygen is dissolved inside the metal and not as gas, when the temperature drops this oxygen produces cuprous oxide, the excess of copper oxide causes the content of copper in the electrolyte in the tanks of the ectrorefining.
The principal objective of the reduction process, is to remove the excess of copper oxide in the anode, since it dissolves easily in the tanks of the electrorefining, and forms copper sulfate, and also increases the copper content in the electrolyte. In this operation, reducing agents are used to supply carbon monoxide, dihydrogen and carbon.
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