Waste acid purification method and system for pickling treatment of metal surface of iron part

Abstract

The invention relates to a waste acid purification system and treatment method for pickling treatment of a metal surface of an iron part, and is characterized in that the waste acid treatment system comprises an acid purification system, an iron ion recovery system and an ammonium chloride recovery system, purified acid can be recycled, and resource recovery of iron ions is realized.

Description

technical field [0001] The invention relates to a waste acid purification method and system for pickling metal surface of iron pieces. Background technique [0002] At present, before the metal surface treatment of electroplating, steel rolling and other industries, acid is usually used to remove the surface oxide scale before processing, so as to better realize the advanced treatment requirements such as anti-corrosion or aesthetics of the metal surface coating of iron parts. In the traditional pickling process, when the iron ion content in the pickling tank reaches a certain concentration of about 11%, the pickling effect will be significantly reduced. The usual practice is to replace the new pickling solution and transfer the previous pickling solution to the sewage station for sewage treatment. For example, electroplating industry wastewater is known as one of the three major industrial wastewaters that are difficult to treat. The main reason for its difficulty in treat...

AI Technical Summary

Problems solved by technology

[0003] At present, there are two commonly used treatment methods for the treatment of electroplating and steel rolling pickling rust wastewater. One is to treat pickling rust wastewater with a pH greater than 2 through reverse osmosis. However, the current pickling process usually uses high-concentration pickling solution in order to achieve the effect of rust removal on the metal surface of iron parts in a short time. For example, the pickling tank in the electroplating industry usually uses 14-17% hydrochloric acid solution As a cleaning solution, this makes the reverse osmosis system very limited in the treatment of pickling wastewater; the other is to use alkali to neutralize the acid in the pickling solution, and iron and other iron ions are combined with hydroxide to produce Precipitation, although this treatment method can treat wastewater with high acid content, it needs to consume a large amount of alkali to neutralize the acid in pickling rust wastewater, resulting in waste of alkali and acid, and there is a problem of high production costs

[0004] At present, there is no effective and low-cost method for treating the waste acid produced by pickling rust with high acid content and pH below 1, and the method requires reducing the waste of acid and the consumption of alkali

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