Study on the method of filter rust removal

It is understood that the chemical derusting method of filter generally includes acid cleaning and alkali cleaning (alkali electrolysis, alkali reduction, alkali boiling, etc.), among which the acid cleaning method is widely used As for the definition of acid pickling method, generally speaking, it is a method that metal products are immersed in various acid solutions, and the acid and metal corrosion products react chemically, so that the insoluble corrosion products become soluble substances and dissolve into water solution without metal surface Acid used in pickling filter mainly includes sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, hydrofluoric acid, etc Through research, the rust removal ability of hydrochloric acid solution is strong, the mechanical effect of hydrogen generated by sulfuric acid is large, the price is cheap, and it is widely used in steel rust removal Nitric acid and hydrofluoric acid can be used for rust removal of non-ferrous metals such as aluminum products Compared with hydrochloric acid sulfuric acid, phosphoric acid has poor rust removal ability, but weak rust resistance It can react with the surface of copper and iron to form an insoluble film of ferric phosphate After washing, it has a temporary rust prevention effect in the air If the acid washing method is compared with the general physical mechanical method, its main advantages are not to cause metal material deformation, the treated surface is not rough, the operation is simple, and the efficiency is high The rust can be removed from all corners of metal products, which is suitable for the removal of a large number of small products without special equipment, and the cost is low Of course, as a chemical rust removal method commonly used by relevant enterprises, acid pickling method has obvious corrosion effect on metals, which is easy to cause "hydrogen embrittlement" and affect the surface finish Therefore, many related scholars have been studying and developed a kind of alkaline cleaning method in recent years, which is carried out in the solution containing caustic soda, carboxyacetic acid, complexing agent and foaming agent Therefore, in the process of filter derusting, alkali washing method will not rust the base metal, and will not produce "hydrogen embrittlement" The metal surface can maintain a relatively complete finish, which is more practical by comparison.