Electrolytic refining uses pure copper sheets as cathodes. The cathode and anode are placed in an electrolytic cell, and the electrolyte is an aqueous solution of sulfuric acid and copper sulfate. Under the influence of direct current, the copper on the anode dissolves and enters the solution, while the copper in the solution precipitates on the cathode.
During this process, metals with a more negative potential than the copper on the anode enter the solution but cannot precipitate on the cathode; instead, they remain in the electrolyte and are removed during electrolyte purification. Because precious metals and certain other metals have a higher potential than the dissolution potential of copper, they are insoluble in water and precipitate at the bottom of the electrolytic cell, forming anode precipitate. Therefore, the metallic copper precipitated on the cathode is of high purity and is called cathode copper or electrolytic copper. Since its first application in 1896, the copper electrolytic refining process has been used in industrial production for over 140 years. During this time, while the basic principles have remained unchanged, significant progress has been made in technology, equipment, production scale, copper quality, and energy consumption reduction. Electrolytic workshops typically have hundreds or thousands of electrolytic cells, depending on the scale of production. These electrolytic cells are arranged in parallel within the workshop. Within each cell, an anode and a cathode are connected in parallel. The cell and cathode are connected in series via direct current. Both the cathodes and anodes throughout the electrolysis workshop are energized, but because the voltage within the cells is very low (0.3 volts), it will not cause harm to humans.
The electrolyte within the cells circulates continuously, approximately once every 2 to 3 hours. Heating devices are installed during the electrolyte circulation process to ensure a constant electrolyte temperature.
