Method for purifying and recycling high arsenic polluted acid wastewater

Abstract

The invention provides a method for purifying and recycling high arsenic polluted acid wastewater. A main technique process comprises steps: filtering polluted acid, performing acid concentrating by membrane distillation and recycling condensed water, performing reduction on the concentrated acid, and then cooling to separate out arsenic trioxide, then sulfidizing to perform deep arsenic and heavy metal removing, and finally, removing fluorine and chlorine by ion exchange to obtain acid with low impurity and recycling for a system. The processing method effectively combines a traditional distillation technology and a membrane technology and can realize high quality recycle of purified water without affecting a smoke washing effect. The concentrated acid subjected to membrane distillation is subjected to efficient sulfidizing and then subjected to fluorine and chloride removing by ion exchange, thus providing guarantee for recycle of the concentrated acid. Enriching and concentrating of arsenic can be realized, the arsenic is reduced by a reducing agent, liquid is cooled and crystallized after reducing, 60 percent to 70 percent of arsenic is finally removed in a form of As2O3 from the polluted acid, the effective opening of the arsenic in a smelting system is realized, dosage of a subsequent sulfidizing or neutralizing agent can be greatly reduced, operation cost is reduced, an arsenic filter cake and waste residue are reduced, and secondary pollution risk to the environment is reduced.

Description

technical field [0001] The invention relates to a method for purifying waste water with high arsenic pollution by flue gas washing, and belongs to the field of metallurgy, chemical industry and environmental protection. In particular, it relates to a method for purifying and recycling waste acid waste water from flue gas washing in a sulfuric acid system for non-ferrous smelting. Background technique [0002] my country is a major producer of non-ferrous metals, and its output of non-ferrous metals has ranked first in the world for 11 consecutive years. The smelting process of non-ferrous metals produces a large amount of SO mixed with heavy metal fumes such as lead, arsenic, and mercury. 2 Flue gas, during the process of making sulfuric acid, the use of wet method to remove impurities in flue gas will produce a large amount of acidic wastewater, which is the dirty acid wastewater from non-ferrous heavy metal smelting flue gas washing. Among the polluted acid wastewater pr...

AI Technical Summary

Problems solved by technology

The patent (201310501529.7) method and device for resource recycling of heavy metal polluted acid wastewater discloses a method for recovering waste acid using electrodialysis and heavy metal vulcanization equipment. The main problems are that the recovered acidity is low, and the recovered acid contains fluorine and chloride ions, which limits the reuse of the acid, etc. Problem: Patent (201410786969.6) discloses a method for purification of smelting dirty acid by using diffusion dialysis, ion exchange, and multi-effect evaporation to purify dirty acid. Water, which increases the treatment capacity of dirty acid, low-acid waste water containing fluorine, chlorine and heavy metals still needs to be neutralized, which is not conducive to reuse

Images