A recovery and treatment process of electrode foil corrosion waste sulfuric acid

Abstract

The invention discloses a recovery and treatment process of electrode foil corrosion waste sulfuric acid. The specific steps are as follows: preheating; evaporation; cooling; condensation and crystallization; centrifugal separation; drying. The present invention uses steam-saving three-effect evaporation to concentrate waste sulfuric acid, creates the basic conditions for aluminum sulfate in waste acid to form a colloid, and condenses and recovers the evaporated sulfuric acid steam; then crystallizes the aluminum sulfate in the concentrated acid at a certain temperature, It is convenient to centrifuge and concentrate sulfuric acid and aluminum sulfate polymers to realize the effective recovery of sulfuric acid and aluminum sulfate, which not only achieves the purpose of emission reduction, but also effectively reduces the cost of electrode foil corrosion process, which is very helpful for improving the market competitiveness of electrode foil products. big help.

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 1140kg / 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 corro...

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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 waste water, waste of resources

[0003] Patent CN102079512A discloses the process of recovering sulfuric acid and sulfate from the waste acid of titanium dioxide prepared by sulfuric acid method. By adopting three times of evaporation and three times of condensation, the heat energy of steam evaporated each time is not utilized, and the energy consumption is large; Filtration, because the aluminum sulfate colloid has formed a dense filter layer during the press filtration process, which affects the filtration speed, and it is not easy to carry out continuous operation, and no other substances are recovered from the waste materials

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