Comprehensive utilization method for arsenic and acid wastewater

Abstract

The invention discloses a comprehensive utilization method for arsenic and acid wastewater, Arsenic and acid wastewater generated by nonferrous metallurgy and sulfuric acid industries is used as a process object, prereduction, evaporation and concentration are conducted, after concentrated liquid is cooled, trivalent arsenic is crystallized in the form of arsenic trioxide, through filtration separation and drying, arsenic trioxide is obtained, the evaporating liquid is condensed and reused, filtered concentrated acid and arsenic-containing soot are mixed for briquetting, sulfatizing roasting is conducted, arsenic trioxide in soot is recovered and used as a crude white product or further reduced for preparing metal arsenic with the crystallized arsenic trioxide, generated roasting sand is subjected to wet leaching, and valuable metal is extracted. Waste acid does not need to be neutralized, arsenic-containing waste slag is not generated, waste is controlled through waste, comprehensiverecycling of all elements of valuable components is achieved, meanwhile, the process is short, operation is simple, the treatment cost is low, the economic benefits are considerable, and the problem of acid wastewater treatment in the industry can be solved.

Description

technical field [0001] The invention belongs to the technical field of heavy metal polluted acid wastewater treatment, specifically a method for comprehensive utilization of arsenic-containing polluted acid wastewater, which can solve the traditional problem of neutralizing arsenic to produce a large amount of arsenic-containing hazardous waste, and realize the transformation of arsenic elements from waste to treasure At the same time, the concentrated sulfuric acid produced can be comprehensively utilized to further realize the dearsenization of arsenic-containing materials and recover valuable metals. Background technique [0002] Arsenic and its compounds seriously damage human health, and have been identified as the first class of carcinogens by the US Centers for Disease Control and National Cancer Research Institute, mainly endangering human health through drinking water. Therefore, China, the United States, Western Europe, Japan and many other countries have listed ar...

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Problems solved by technology

[0004] At present, domestic treatment of arsenic-containing wastewater mainly includes lime neutralization precipitation method, sulfide precipitation method, iron salt oxidation to remove arsenic, extraction method, ion exchange method, adsorption method, etc. Extraction method, ion exchange method, and adsorption method are mainly used to treat low concentration. Arsenic-containing wastewater, but the process is complicated, the treatment cost is high, and there are few industrial applications

Lime neutralization precipitation method, sulfide precipitation method, and iron salt oxidation arsenic removal method are currently more commonly used methods for treating arsenic-containing sewage acid wastewater. The amount of slag is large, and it is easy to cause secondary pollution. The sulfuric acid in the polluted acid wastewater is wasted due to neutralization. At the same time, valuable elements and arsenic enter the waste slag and cannot be used. Discharge will pay environmental protection tax in the future; at present, the most commonly used method in the treatment of arsenic-containing sewage acid wastewater in China, but it produces a large amount of waste residue, which is easy to cause secondary pollution, and the discharge of arsenic-containing residue will pay environmental protection tax in the future, which brings great benefits to enterprises and society. to enormous economic and environmental pressure

[0005] Arsenic-containing soot generally contains valuable metals such as zinc, lead, antimony, indium, germanium, etc., and wet acid leaching is generally used to extract valuable metals, but there are two main problems in the direct leaching of arsenic-containing soot with sulfuric acid: (1) the soot The content of arsenic is high. As the main forms of arsenic are arsenate, arsenite and arsenic sulfide, arsenic is easily leached into the solution together with zinc during the leaching process. It is difficult to purify and remove arsenic from the leaching solution and produce arsenic. (2) The metal part in the soot exists in the form of sulfide, and the leaching of this part of sulfide requires oxidation conditions, and the direct leaching of sulfuric acid is more difficult

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