An environmentally friendly process to replace hydrochloric acid for derusting

Abstract

The invention provides a rust removing agent replacing hydrochloric acid to remove rust. The rust removing agent for removing the rust is prepared from the raw materials in parts by weight: 20-30 parts of composite organic acid, 5-10 parts of polymethylacrylic acid, 6-12 parts of chromium trioxide, 10-20 parts of a surface active agent, 3-6 parts of sodium gluconate, 1-3 parts of triethanolamine,1-3 parts of polyacrylamide, 1-2 parts of 1,4-butynediol, 0.01-0.1 part of sodium chloride, 0.5-2 parts of a functional additive and 70-90 parts of water; the pH value of the rust removing agent is about 6.0, and the density is 0.9-1.2 g / cm<3>; according to the rust removing agent, the hydrochloric acid is not used, that is, generation of acid mist is reduced from the source, matter which harms human body is not used in the rust removing agent, the environment cannot be polluted, and the rust removing agent is an environment-friendly rust removing agent; and the rust removing agent has a superior rust removing property, the rust removing time is short, meanwhile, the rust removing efficiency is high, the gloss on the surface of metal substrate effectively recovers, and the rust removing agent has good application prospects.

Description

technical field [0001] The invention belongs to the technical field of metal rust removal and rust prevention, and in particular relates to an environmentally friendly process for replacing hydrochloric acid rust removal. Background technique [0002] Rust removal treatment is the basic process before steel surface painting. Rust removal methods can be roughly divided into two categories: mechanical methods and chemical methods, each of which has its own characteristics and is suitable for different occasions. Among them, the chemical method has a series of advantages such as good effect, high efficiency, simple process operation, and low cost, so it has been widely used in industry. A common method in chemical rust removal is to use a rust removal solution, such as acid, to clean the steel surface. Different acids have different prices, and sulfuric acid and hydrochloric acid with lower prices are commonly used. Sulfuric acid is very dangerous, and it is not easy to wash...

AI Technical Summary

Problems solved by technology

However, there are three environmental pollution problems in the hydrochloric acid pickling of steel parts: more acid mist, a large amount of acid rinse water and waste acid with a concentration of more than 7% are produced, which not only causes certain pollution to the environment, but also because of the harsh environment of the pickling workshop, In recent years, it has become extremely difficult to hire pickling operators. Therefore, in order to solve the problem of environmental pollution in hydrochloric acid derusting, many methods have been invented.

Chinese patent CN1039850 discloses a low acid concentration rust remover formula: acid concentration 8-12%, 15-200g / L iron (III) ions, in the practical application of this kind of rust remover because the formula is too simple, there is steel matrix Excessively corroded, requiring vigorous flushing to remove loose rust layers, thus generating large amounts of rinse water

[0005] To sum up, at present, for the pre-treatment rust removal of steel parts electroplating and hot-dip plating process, there is either acid mist or a large amount of rinsing water. The process of using hydrochloric acid for rust removal can no longer meet the existing development requirements for rust removal.