Cold-rolled acid wastewater resource and zero-emission method

Abstract

The invention relates to a cold-rolled acid wastewater resource and zero-emission method, which specifically comprises: (1) filtration pre-treatment: filtering cold-rolled acid washing wastewater as pre-treatment to filter out particles having a particle size of more than 5-30 [mu]m so as to obtain filtered acid washing wastewater; (2) membrane concentration: concentrating the filtered acid washing wastewater by using an efficient membrane concentration technology to obtain concentrated acid and pure water; and (3) acid regeneration: carrying out acid regeneration on the main components such as the acid and the Fe<2+> in the concentrated acid after the concentration with the membrane concentration process, the acid washing waste liquid and the like, wherein the acid generated during the acid regeneration process re-enters the acid washing system so as to be recycled, and the Fe<2+> finally form iron oxide red as the product for sale. According to the present invention, through the wastewater filtration, the membrane concentration and the acid regeneration, the resource recovery and utilizations of the acid and the water in the acid wastewater are respectively achieved, no sludge is generated, and the zero emission of the solid and the liquid is achieved.

Description

[0001] 【Technical field】 [0002] The invention relates to the technical field of wastewater treatment, in particular to a method for recycling acidic wastewater from cold rolling and zero discharge. [0003] 【Background technique】 [0004] Pickling is one of the indispensable processes in cold rolling mills. During the production process, the cold-rolled steel needs to be pickled to remove the oxide scale on the steel surface, and after pickling, the steel surface needs to be rinsed with pure water to clean the residual acid on the steel surface. Therefore, acid pickling waste liquid and acid rinse water are produced. Usually, most of the waste acid in the pickling process is returned to the acid regeneration system for regeneration and reuse. The rinse water cannot be regenerated because the acid concentration is too low, so it can only be discharged. [0005] The patent application number is 200310120052.4, which relates to a neutralizer for treating cold-rolled acid wastew...

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Problems solved by technology

[0008] The main problem of the lime neutralization process is that the treated wastewater has high conductivity and high calcium ion content, which is not conducive to subsequent desalination and reuse. The concentrated brine produced by desalination and reuse has no good outlet and can only be used for slag flushing Other occasions that do not require high water quality, but the impact on the subsequent use of slag needs further research; in addition, a large amount of sludge will be generated during the neutralization and sedimentation process of wastewater, which cannot be used as a resource and can only be landfilled or used for other purposes. treatment, and the cost of sludge disposal is increasing year by year

At present, there are no reports on the recycling and zero discharge of cold rolling acid wastewater

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