Overview of the electrolytic copper foil production process

The electrolytic copper foil has been used in the electronics industry since its production began in the late 1930s. With the development of the electronics industry, the quality of electrolytic copper foil is constantly improving and its manufacturing technology is also developing rapidly. The key technologies for the production of electrolytic copper foil vary widely, but no matter how different the key technologies and their specific processes are, the process of electrolytic copper foil manufacturing broadly includes electrolyte preparation, original foil manufacturing, surface treatment, slitting processing, and related inspection and control, ancillary equipment and other processes.

Electrolyte preparation is the first step in the production of copper foil. It is the process of dissolving copper into a sulfuric acid solution and purifying it through a series of filters to produce electrolytes with qualified composition and high purity. The quality of electrolyte directly affects the quality of copper foil products, not only the internal quality of copper foil but also the appearance quality of the copper foil. Therefore, it is necessary to strictly control the raw materials and auxiliary materials used in the process of copper dissolution and liquid making, as well as the production equipment and operation process of electrolyte preparation. As
The raw materials used in the electrolyte preparation process are electrolytic copper, bare copper wire, copper dollar rod, copper rice, etc. It is required that the purity of raw materials containing copper must reach 99.95% or more, and various impurities in copper materials such as Pb, Fe, Ni, As, Sb, AI, and S, and organic impurities must meet the requirements of national standards. Sulfuric acid, as an important material, is essential in the production process, and its quality must also meet the technical requirements of the national standard chemical purity level.
The different grade requirements for the production of copper foil are all different in the way the electrolyte is prepared and circulated. Although the electrolyte circulation methods are different, the mechanism is the same, and all contain the role and purpose of copper material dissolution, organic matter removal, solid particle filtration, temperature adjustment, electrolyte composition adjustment, etc.
Firstly, cleaned copper and sulfuric acid, deionized water is added to the dissolved copper tank with dissolution capacity, compressed air is drummed into the tank, and under the condition of heating (generally 50-90t), copper oxidation occurs, and the generated copper oxide reacts with sulfuric acid to produce aqueous copper sulfate solution, which enters the original liquid tank (or after filtration) when dissolved to a certain cu2+ concentration (generally 120-150gIL). Then, after a series of activated carbon filtration, mechanical filtration, temperature adjustment, and other equipment and processes, the electrolyte that meets the process requirements is sent to the barrel-making machine (or electrolysis unit) for original box production and manufacturing. In the actual production process, the electrolyte is recycled, constantly producing the original Jane from the cycle-making machine, consuming the copper in the electrolyte, while the copper is constantly dissolved by the copper dissolution tank, and then sent to the barrel-making machine after a series of filtration, temperature adjustment, and composition word adjustment. In this process, activated carbon is used to adsorb organic materials (including organic additives) from the electrolyte, and mechanical filtration filters out (retains) the solid particles in the electrolyte.
The process of electrolysis not only requires continuous circulation of electrolytes but also timely adjustment and control of electrolyte composition (copper and acid concentration), electrolyte temperature, circulation volume matching, and other technical indicators.

The auxiliary conditions for electrolyte preparation include copper material treatment, compressed air supply, steam supply, sulfuric acid, and pure water supply, etc.

1. Copper material treatment As mentioned earlier, the raw material used in the production of the electrolytic copper boxes is copper material, which includes electrolytic copper, bare copper wire, copper dollar rod, and copper rice. Its intrinsic quality must meet the national standards, purity, and impurity technical requirements. The appearance requires clean and oil-free, no organic matter, no dirt, no other metal incidental, and other kinds of harmful substances. The thinner and higher the grade of the electrolytic copper cylinder produced, the higher the quality of the copper material required, the lower the content of impurities the better, the higher the purity of copper the better, and the less the organic matter attached the better. The copper material, especially electrolytic copper, should be cut into strips or blocks before loading into the copper dissolution tank and should be city-washed, acid-washed, and water-washed to remove the surface oil, dust, and other debris.
2.  Sulfuric acid supply sparse acid is a consumable material in the production process of the electrolytic copper box, and its quality will have a great impact on the appearance and internal quality of the copper cylinder.
3.  compressed air supply to the copper dissolution reel supply of compressed air, the main role of two: one is to supply oxygen to promote the dissolution of the copper tank with sufficient oxygen, copper oxidation, to achieve the purpose of copper dissolution: the second is to provide stirring effect, to promote the flow of copper solution in the copper dissolution tank to improve the speed of copper dissolution.
4. pure water supply in the electrolytic copper wrong production of the whole process to use pure water, as the electrolyte preparation using pure water, mainly for the initial liquid and production of liquid volume consumption of the supplement. At present, there are many ways to produce pure water, such as electrodialysis, reverse osmosis, ion exchange, etc.
5. As the electrolyte preparation also needs to have a steam supply capacity for heating the electrolyte in the copper dissolution tank, and in addition must have a draft-inducing device to discharge the acid mist generated in the copper dissolution equipment.