Electrolytic purification of copper: blister copper (99% copper) is pre-made into a thick plate as the anode, pure copper is made into a thin sheet as the cathode, and a mixture of sulfuric acid (H2SO4) and copper sulfate (CuSO4) is used as the electrolyte. After energization, copper dissolves into copper ions (Cu) from the anode and moves to the cathode. After reaching the cathode, electrons are obtained and pure copper (also known as electrolytic copper) is precipitated at the cathode. Impurities in blister copper, such as iron and zinc, which are more active than copper, will dissolve into ions (Zn and Fe) along with copper.

Copper Electrolysis Machine

Since these ions are less likely to be precipitated than copper ions, the precipitation of these ions on the anode can be avoided by appropriately adjusting the potential difference during electrolysis. Impurities that are less active than copper, such as gold and silver, are deposited at the bottom of the electrolytic cell.

The copper plates produced in this way, called "electrolytic copper", are of extremely high quality and can be used to make electrical products. The deposit at the bottom of the electrolytic cell is called "anode mud", which is rich in gold and silver, which is very valuable, and it has extremely high economic value when it is taken out and processed.