Method for resource utilization of waste sulfuric acid wastewater produced in copper smelting and acquisition of arsenic-containing products

Abstract

The invention belongs to the technical field of industrial sewage treatment, and particularly discloses a method for resource utilization of waste sulfuric acid wastewater produced in copper smeltingand acquisition of arsenic-containing products. The method comprises the following steps: 1, oxidization of trivalent arsenic: oxidizing the waste sulfuric acid wastewater by air and hydrogen peroxidein sequence; 2, separation of arsenic from fluorine and chlorine: carrying out negative pressure evaporation after oxidation to obtain a condensate A containing fluorine and chlorine, a concentratedsolution B and arsenic pentoxide crystals; 3, separation of fluorine and chlorine: absorbing the condensate A with magnesium oxide to obtain a magnesium fluoride product and diluted hydrochloric acid;4, recovery of valuable metal: adding a sodium sulfide solution into the concentrated solution B to obtain a valuable metal precipitate and arsenic-containing waste liquid C, and returning the valuable metal precipitate to a furnace for refining; and 5, crystallization: adding caustic soda flakes or recycled concentrated alkali liquor E into the arsenic-containing waste liquor C, adjusting a pH value to 13.5-14.0 to obtain a sodium arsenate product and a crystallized filtrate D, filtering the crystallized filtrate D, and conducting concentrating to obtain a sodium sulfate product and the concentrated alkali liquor E. According to the method, waste sulfuric acid wastewater is subjected to resource recycling, and arsenic pentoxide and sodium arsenate products are obtained.

Description

technical field [0001] The invention relates to the technical field of industrial sewage treatment, in particular to a method for utilizing copper smelting sulfuric acid waste water resources and obtaining arsenic-containing products. The method of the invention is suitable for the treatment of waste water with high acidity, fluorine, chlorine, arsenic and valuable metals. Background technique [0002] Sulfuric acid polluted acid widely exists in the copper smelting industry. It has the characteristics of high acidity, arsenic, fluorine, chlorine and other valuable metal elements. It is the most difficult wastewater in the copper smelting industry to treat. The traditional techniques for treating this waste water are sulfidation method and lime iron salt method, although they can all make sulfuric acid polluted acid wastewater meet the national discharge standard. However, as environmental protection laws and regulations become more and more stringent, standard discharge can...

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Problems solved by technology

The technical difficulties of the former are as follows: ① Due to the relatively low concentration of valuable metal elements in sewage acid, the boundary point of arsenic sulfide and other valuable metal sulfides cannot be effectively distinguished, resulting in the failure of recycling of valuable metals; ② Acid concentration Finally, the arsenic content in the concentrated solution exceeds the national standard, and further sulfuration is required to remove arsenic before it can be reused; ③The efficiency of hot air blowing off fluorine and chlorine is low, and the amount of hot air consumed is relatively large

The technical difficulties of the latter are: ① The cost of sulfidation treatment is relatively high, and the generated arsenic sulfide slag is extremely difficult to handle

②At the same time of negative pressure evaporation, arsenic and fluorine and chlorine enter the condensate together, and the proportion of arsenic escaping into the condensate can reach up to 20%, which makes the condensate unable to be reused and can only be treated by adding calcium, resulting in more (Shen Dianbang. Research on the treatment technology of dirty acid produced by flue gas acid production in non-ferrous smelting [C] 2011.) and (Liu Xiaolai. Experimental research on removal of fluorine, chlorine and arsenic by evaporation and concentration of dirty acid in copper smelting [D ].2014.)

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