Cathode plate anticorrosive coating for zinc electrowinning and preparation method of cathode plate anticorrosive coating

Abstract

The invention provides a cathode plate anticorrosive coating for zinc electrowinning and a preparation method of the cathode plate anticorrosive coating. The method comprises the step of coating anticorrosive paints on a part between a liquid level line which is easy to corrode of the cathode plate and a conductive beam by means of spraying or blade coating, wherein the anticorrosive paints consist of a base layer, an intermediate layer and a surface layer, the base layer is epoxy modified paint with excellent binding force with base material of the cathode plate, the intermediate layer is anticorrosive paint which is used for connecting the base coat with the finishing coat and has excellent corrosion resistance performance, and the surface layer is anticorrosive and wearable finishing coat. By using the anticorrosive coating, the service life of the cathode plate can be obviously prolonged by 1 / 3-1 / 2, and the replacing frequency of aluminum plates is reduced, so that the production cost of electrowinning zinc is reduced, and the production benefit is improved.

Description

technical field [0001] The invention relates to a cathode plate anticorrosion coating for zinc electrowinning and a preparation method thereof, belonging to the technical fields of hydrometallurgy technology and surface treatment. technical background [0002] The cathode plate for zinc electrowinning refers to the pure aluminum rolled plate. The principle of zinc electrolytic deposition is: use pure zinc sulfate solution as the electrolyte, lead-silver alloy as the anode plate, and pure aluminum rolling plate as the cathode plate. Under the action of direct current, the positively charged zinc ions in the solution move to the cathode. , and deposited at the cathode discharge, the reaction is: [0003] Zn 2+ +2e→Zn↓ (cathode reaction) [0004] The negatively charged ions in the solution move to the anode and are deposited by discharge at the anode. The reaction is: [0005] 2OH - -2e→H 2 O+1 / 2O 2 ↑ (anode reaction) [0006] The overall reaction formula of zinc sulfat...

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Problems solved by technology

[0008] In the wet zinc smelting process, most of the cathode plate and the anode plate are immersed in the zinc solution during zinc electrolysis, but the parts above the liquid level line are exposed outside the solution, and they have been working with a high acid concentration for a long time. The environment and the existence of some impurities in the zinc solution cause serious corrosion on the exposed part of the cathode plate. Even when the plate surface is basically intact, the exposed part has been severely corroded, causing the plate to be unusable and reducing the service life of the plate. Among them, chloride and fluorine ions have the greatest impact on the corrosion of aluminum plates. Due to the diversification of electrolytic zinc raw materials in recent years, the chlorine / fluorine ions in the solution have exceeded the standard, resulting in aggravated corrosion of the aluminum cathode plate. Therefore, how to improve the aluminum cathode plate, especially It is the corrosion resistance of the parts exposed above the liquid level line and increasing the service life of the aluminum plate has become an urgent problem to be solved.

[0009] Chinese patent [CN2887892Y] proposes a method of coating a layer of anti-corrosion coating on the surface of the neck of the cathode plate and anode plate used in wet electrolytic zinc to prolong the corrosion resistance of the electrolytic zinc anode and cathode plate, but only one layer of ring is coated. Oxygen resin or temperature-resistant and anti-corrosion materials, the extended life is relatively short, and can be extended by an average of 60 days

Aluminum is a relatively active metal and is easily corroded, especially the part of the electrolytic zinc cathode plate exposed outside the liquid level line. The anti-corrosion methods mentioned above are not clear enough, and the operation process is relatively complicated.

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