In the production process of electrophoretic paint planting parts, it is necessary to rinse the surface of the plated parts with water first, and then rinse with pure water. When washing the plated parts with water and pure water, wastewater containing electrophoretic paint is produced. Electrophoretic paint wastewater mainly contains harmful chemicals such as epoxy resin, paint, vegetable oil, carboxylic acid, butanol and pigments.
When electrophoretic paint is electroplated, the conductivity between electrodes does not change after electrodeposition. While the organic coating has insulating properties, so dot-like deposition will appear at the beginning of electrodeposition, and gradually connect into flakes. As the electrodeposition continues, the electrodeposition is partially insulated. When the resistance rises to a certain level, the electrodeposition gradually moves to the uncoated part with the formation of paint film until the surface is coated.
As the electrophoresis process goes on, the content of water, cosolvent and inorganic ions in the electrophoresis solution in the metal tank increases, which affects the quality of the paint. The use of Ultrafiltration Membrane technology can retain polymer coatings and pigments, remove excess water and other impurities in the electrophoresis solution, extend the use time of the coating solution, and improve the quality of the paint.
When the painted part is taken out from the electrocoating tank, it needs water to wash off the residual coating liquid on the surface, thus producing electrophoretic paint wastewater. The electrical coating in the wastewater is 30% of the paint used. Adopting ultrafiltration membrane device will form a closed circulation route, which can realize the reuse of paint and water. Ultrafiltration Membrane technology has the following advantages in electrophoretic paint wastewater treatment:
1. Good retention effect, clean and transparent filtrate after treatment.
2. Automatic system control, simple and easy to use, safety in operation.
3. The equipment has a rigorous structure, low energy consumption and space saving.
4. Large water output, suitable for recovery of cathode and anode electrophoretic paint.
5. Has good anti-pollution ability, long-term operation will not affect the water production.
At present, UF ultrafiltration membrane technology has played a major role in the metal electrophoretic painting process of automobiles, luggage accessories, electrical appliances and other industries. The recovery rate of electrophoretic paint is significantly increased, and the processing cost is reduced by 30% compared with before using this technology, which effectively improves the quality of electrophoretic planting parts.