Disposal method for iron and steel pickling waste water containing hydrochloric acids

Abstract

The invention discloses a disposal method for iron and steel pickling waste water containing hydrochloric acids. Through the adoption of the method disclosed by the invention, not only can the hydrochloric acids be recovered for cyclic utilization, so that the optimal allocation of sources is realized, but also the problem of environmental pollution is solved, the discharge of pollutants is reduced, and the method has the advantages of low production cost, simple technology and the like. The method comprises the following steps: spent acid solutions after purification and impurity removal and pickling cleaning water flow through the internal part of an anion exchange membrane diffusion dialyzator at the same time, so that the spent acid solutions flowing out of the internal part of the anion exchange membrane diffusion dialyzator are changed into raffinate containing iron with a low content of hydrochloric acids, and the cleaning water flowing out of the internal part of the anion exchange membrane diffusion dialyzator is changed into recovered acids containing a large quantity of hydrochloric acids, an extremely small quantity of iron ions and an extremely small quantity of ferrous ions; then the recovered acids are returned to an iron and steel pickling workshop section for cyclic utilization, and are continuously used for pickling; the raffinate containing the iron is led to a waste water collecting pond for neutralizing treatment and pressure filtration treatment, and iron mud and filtrate which reaches a discharge standard are obtained.

Description

technical field [0001] The invention relates to the technical field of waste liquid treatment, in particular to a treatment method for steel pickling wastewater containing hydrochloric acid. Background technique [0002] Pickling in the steel industry such as stainless steel and steel cord will produce a large amount of acid liquid waste containing hydrochloric acid, and the concentration of free hydrochloric acid in the pickling waste liquid is about 5% to 20%. At present, the methods for treating this kind of waste liquid are mainly acid-base neutralization, evaporation, concentration, cooling and crystallization, etc., which not only have high treatment costs, but also cause waste of hydrochloric acid, and also have a great impact on the environment. Contents of the invention [0003] In view of the above problems, the present invention provides a treatment method for steel pickling wastewater containing hydrochloric acid, which can not only recover hydrochloric acid fo...

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Problems solved by technology

[0003] In view of the above problems, the present invention provides a treatment method for steel pickling wastewater containing hydrochloric acid, which can not only recover hydrochloric acid for recycling, realize the optimal allocation of resources, but also solve the problem of environmental pollution and reduce the discharge of pollutants. And has the advantages of low production cost, simple process, etc.

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