Copper dissolution methods
The two common copper dissolution methods used in the production of electrolytic copper foils are immersion dissolution and spray dissolution.
Immersion Dissolution: In immersion dissolution, the raw copper sheets or wires are cut into small pieces or cast into wires and then immersed into a copper dissolution tank. Copper sulfate water solution and compressed air enter from the bottom of the tank. After being heated by a tubular heat exchanger, they flow slowly from the gaps between the copper pieces in a “Y,” “Z,” or “S” pattern, moving upward. During this process, a chemical reaction occurs on the copper surface, causing the raw copper sheets or wires to dissolve into copper sulfate water solution. Immersion dissolution is suitable for a wide range of applications and is not affected by regional or climatic conditions. The copper dissolution tank is always filled with the solution, and the raw copper is soaked in the solution. The heat loss inside the dissolution tank is relatively small, saving energy. The temperature is usually controlled above 70°C.
Spray Dissolution: In spray dissolution, the raw copper wires are placed into a bottomless copper dissolution tower. The copper wires are exposed to the air, while the copper sulfate water solution is sprayed onto the wires from the top of the tower using pumps. The solution reacts with the copper oxide on the wire surface, generating copper sulfate and entering the solution. The key to spray dissolution is to ensure that the solution is evenly sprayed on the surface of the raw copper to allow complete dissolution. Fresh air is continuously drawn into the tower to supply sufficient oxygen for the copper dissolution reaction. Spray dissolution is suitable for regions with higher temperatures.
Each of these copper dissolution methods has its advantages and disadvantages. The choice of the appropriate method depends on specific production conditions and requirements. Different factories will select the most suitable copper dissolution method based on their individual circumstances for the production of electrolytic copper foils.
Comparison
Let’s compare their advantages and disadvantages:
- Immersion Copper Dissolution: Advantages:
- Wide applicability and adaptability to various geographical and climatic conditions.
- The copper material remains submerged in the solution, maintaining a stable temperature and reaction environment.
- Lower heat loss in the immersion tank, leading to energy savings.
- Copper dissolution can be carried out at relatively lower temperatures, reducing energy consumption and production costs.
Disadvantages:
- Relatively slower copper dissolution rate, resulting in longer production cycles.
- Requires larger amounts of solution and air supply, which may lead to resource wastage.
- Additional control and insulation measures are needed in cold climatic conditions for solution and air supply.
- Spray Copper Dissolution: Advantages:
- Faster copper dissolution rate, leading to shorter production cycles and improved production efficiency.
- Uniform heating and oxygen supply due to the spray method, facilitate efficient copper dissolution reactions.
- Suitable for regions with higher temperatures, providing production stability in such climates.
Disadvantages:
- Limited applicability in colder regions, unsuitable for use in cold climates.
- Requires larger air supply and exhaust volumes, resulting in increased heat loss and resource consumption.
- Adequate fresh air supply is essential; otherwise, it may impact copper dissolution efficiency.
The selection of the appropriate copper dissolution method depends on specific production conditions, resource availability, and process requirements. Different factories may choose the most suitable copper dissolution method to maximize production efficiency and cost-effectiveness.