| Arsenic is usually rich in toxicity.If we do not deal with various arsenic containing materials scientifically and properly,a series of arsenic pollution incidents will occur.Because of its stable properties and light weight,it is one of the most typical arsenic precipitate.In this study,tin anode slime was pretreated by acid leaching to leach arsenic from the slime.Then,arsenic was precipitated by ferric sulfate precipitation method to prepare scorodite with high arsenic content,stable crystal state,low leaching toxicity and safe disposal.In addition,the technological conditions of arsenic removal from anode slime of sulfuric acid leaching tin were optimized,and the properties and leaching toxicity of alligator were analyzed and studied.It is of great practical significance to reduce the emission of toxic substances.The acid leaching process of tin anode mud was studied in depth,and the optimum experimental conditions were determined: under the acid leaching system,the system temperature was 80?,the liquid-solid ratio of tin anode mud to sulfuric acid was 15:1,the leaching time was 4 h,the stirring speed was 600 r/min,the arsenic leaching rate in tin anode mud could reach 93%,the leaching rate of tin is 1.2%.The effects of the initial acidity,system temperature,iron-arsenic molar ratio and initial arsenic concentration on the formation of stinking scallion crystals were studied.Then,the leaching toxicity of scorodite sediment under different experimental conditions was tested.The results showed that the best technological conditions for preparing scorodite crystal by precipitation of ferric sulfate in the acid leaching tin anode slime washing solution were as follows: the acidity of the acid system was p H= 2,the initial arsenic concentration was 10 g / L,under the condition of controlling the molar ratio of iron and arsenic to 1,the reaction temperature was 90 ?.the scorodite with high arsenic fixation rate,low leaching toxicity and relatively stable structure could be obtained. |
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