Treatment device and method for waste acid containing heavy metals, fluorides and chlorides

Abstract

The invention discloses a treatment device and method for waste acid containing heavy metals, fluorides and chlorides, which are applied to the technical field of environmental protection. According to the technical scheme, the method is characterized by comprising the process flows of an oxidant preparation system, a heavy metal reaction system, a membrane filtration impurity system, a salt evaporation crystallization system, an acid evaporation rectification separation system, a tail gas absorption system and the like, wherein dilute sulfuric acid containing heavy metals enters an oxidationreactor together with a prepared oxidant via an oxidant feeding pump through a waste acid feeding pump. The treatment method has the advantages that the investment and device space arrangement is decreased, the oxidation reaction and tail gas treatment of waste acid heavy metals are safe, the reaction effect is good, the process is simplified, and the treatment cost is low.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a waste acid treatment device and method containing heavy metals, fluorides and chlorides. Background technique [0002] A large amount of sulfuric acid is consumed in the process of non-ferrous smelting, phosphoric acid industry and rare earth roasting in industrial production. Rare earth concentrates contain heavy metals such as lead, zinc, copper, arsenic, iron, fluorine, manganese and other substances, which will be produced in the roasting flue gas purification system Sulfuric acid and fluoride-containing waste acid (water) has a large output, strong corrosiveness, high toxicity, and direct discharge will cause great environmental pollution to the receiving water body. According to the analysis data of pyrite waste acid, the sulfuric acid is 20-30g / L, the arsenic content is 2-5g / L, the iron content is 0.9g / L, the chloride content is 2g / L, and the fluoride co...

AI Technical Summary

Problems solved by technology

Limestone neutralization method has high cost and poor effect, and there are difficulties in handling the neutralized slurry during operation and the waste water contains a large amount of salts and other substances

The concentration of arsenic after treatment often fails to meet the emission standards, and a large amount of arsenic-containing solid waste is difficult to handle, and long-term accumulation is likely to cause secondary pollution

The vulcanization method uses the preparation of hydrogen sulfide to react with heavy metal substances, and the sulfate precipitates as a substrate. During the preparation of hydrogen sulfide, it is easy to produce highly toxic hydrogen sulfide gas and overflow, which has great potential safety hazards.

The expansion dialysis membrane method uses the acid concentration difference to intercept heavy metal ions. This method has high investment and maintenance costs, cannot remove fluoride and chloride, and the heavy metal waste liquid produced needs to be treated again, which cannot meet the discharge standards.

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