Recycling process of waste sulfuric acid from corrosion of electrode foil

Abstract

The invention discloses a recycling process of waste sulfuric acid from corrosion of an electrode foil, and the specific steps are as follows: preheating, evaporating, cooling, condensing and crystallizing, performing centrifugal separation and drying. According to the recycling process disclosed by the invention, steam-saving three-effect evaporation is adopted for concentrating the waste sulfuric acid, basic conditions for enabling aluminum sulfate in the waste acid to form a colloid are created, and sulfuric acid-containing steam which is evaporated out is condensed and recovered; and the aluminum sulfate in the concentrated sulfuric acid is further crystallized at certain temperature for facilitating centrifugal separation of the concentrated sulfuric acid and an aluminum sulfate polymer, the effective recovery of the sulfuric acid and the aluminum sulfate is realized, the purpose of reducing the emission is achieved, and the cost of a corrosion process of the electrode foil is further effectively reduced, thereby greatly assisting in upgrading of market competitiveness of an electrode foil product.

Description

technical field [0001] The invention relates to a recovery and treatment process for electrode foil corrosion waste sulfuric acid. Background technique [0002] At present, there is a lot of waste acid output in the corrosion hole expansion process of electrode foil production, of which: sulfuric acid is 28%, Al 3+ 0.8%, hydrochloric acid and nitric acid are 1%, density is 1140 kg / m 3 , normal temperature, colorless. The recovery and treatment process of electrode foil corrosion waste sulfuric acid is: waste acid—ion exchange resin—adding lime to adjust pH—precipitation—discharge, such as figure 1 shown. Although this process can absorb part of sulfuric acid through the resin, the concentration of sulfuric acid after washing with water is less than 20%, which is lower than the concentration of sulfuric acid required by the corrosion process, and the concentration of aluminum ions in it exceeds the standard. Considering the impact of aluminum ion concentration on the corr...

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Problems solved by technology

Although this process can absorb part of sulfuric acid through the resin, the concentration of sulfuric acid after washing with water is less than 20%, which is lower than the concentration of sulfuric acid required by the corrosion process, and the concentration of aluminum ions in it exceeds the standard. Considering the impact of aluminum ion concentration on the corrosion process, part of the recovered acid cannot be reused; on the other hand, the lime precipitation process produces a large amount of gypsum solid waste, which must be sent to the solid waste treatment center for treatment. The cost is high, and it still needs to be discharged every day A lot of w

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