Research And Application Of Key Technologies For Reducing Arsenic Content In Ammonium Sulfate From Smelting Flue Gas

Environmental pollution has presently become one of the main problems affecting the comprehensive development of our country.With the development of science and technology,the traditional metallurgical industry gradually introduces advanced science and technology and production equipment,which improves production efficiency and reduces it to a certain extent.In recent years,the recycling of industrial waste has become more efficient environmental protection method.,which can conducive to the construction of environmentally friendly metallurgical enterprises and improve the comprehensive benefits of metallurgical enterprises to a certain extent.Ammonium sulfate,a smelting by-product obtained from the treatment of zinc system waste residues from the fuming furnace,is mainly used as fertilizer,suitable for various soils and crops,and can also be used for textiles,leather,medicine,etc.Through investigation,it was found that when a certain company's fuming furnace was processing zinc system waste slag,the smelting flue gas was cooled and dedusted through two stages of cooling tower and foam washing tower,and the bottom was washed and sent to the sewage treatment station for treatment;the mother liquor(ammonium sulfite and ammonium bisulfite)was absorbed)Decompose with excessive concentrated sulfuric acid,and then desorb the decomposition liquid.The high concentration SO2 gas produced is sent to the acid system to produce acid;the decomposition liquid is neutralized with ammonia,and the arsenic removal treatment is carried out,and finally the ammonium sulfate solution is sent to solid sulfur The ammonium section produces solid ammonium sulfate fertilizer.Due to the complex composition of the flue gas,ammonium sulfate fertilizer contains a certain amount of heavy metals,The heavy metals uncork into the environment when ammonium sulfate is used,thus removing these heavy metals is necessary.Arsenic,which is the main impurity in ammonium sulfate production,is considered as one of the cancerogen.Therefore,based on the actual problem of the existence of As impurity in ammonium sulfate,the influence of parameters on the purity of ammonium sulfate was studied,and the purpose of reducing the arsenic content in ammonium sulfate products and improving the quality of ammonium sulfate products was achieved through experimental comparison and analysis.This subject conducts experiments on various dearsenic agents to finally determine the best dearsenic agent and gradually expand it to industrial production to verify the actual dearsenic effect,mainly including the following aspects:(1)The existing dearsenic agent have been adopted to carry out a small laboratory test.Sodium sulfide precipitation(first and second),ferrous precipitation(first and second),and ferrous + sodium sulfide precipitation(second and third),the arsenic removal experiment of secondary evaporation crystallization,quickly and accurately find the effective precipitant,precipitation method and dosage of the agent.On the basis of the small test,the pilot test and the expanded chemical industrial test are carried out,and the dearsenic agent with the technical conditions of industrial production is obtained.(2)A new type of active iron-based dearsenic agent has been introduced,and compare with the existing dearsenic agent in the previous experiment,it is determined to adopt the first-level new-type active iron-based dearsenic method or the first-level ferrous sulfate dearsenic method,and add it to the neutralization solution The arsenic removal agent reacts to open-circuit the arsenic in the neutralization solution to reduce the arsenic in the neutralization solution.The final determination of the arsenic removal process with ammonium sulfate is the "first-level nano-iron removal of arsenic and hydrogen peroxide removal" process,so as to achieve sulfuric acid removal.The purpose of reducing As in ammonium fertilizers to below 0.001%.(3)The determined process for removing arsenic from ammonium sulfate was promoted to production for implementation,and two-stage industrial tests were carried out.The first-stage industrial test explored the process control conditions,and compiled the "Operation Guide for Arsenic Removal from Ammonium Sulfate Solution".In the second stage of industrial experiments,the amount of arsenic removal agent added was continuously optimized to reduce costs and maximize economic benefits.