Study On The Removal Experiment And Mechanism Of Arsenic And Chlorine In Zinc Smelting Pollution

In the non-ferrous smelting enterprises,the comprehensive treatment and resource utilization of the flue gas generated by flue gas washing is an urgent problem to be solved.This paper is aimed at the large amount of waste slag present in the treatment of foul acid in a certain enterprise in Yunnan,and needs to adjust the pH frequently.For the existing problems,the purpose of purifying and treating the impurity elements arsenic and chlorine in the contaminated acid is to use the process of adding metal powder and copper sulfate.The removal mechanism is mainly through the added metal.The powder reacts with impurity ions in the contaminated acid to form precipitates such as As₂S₃ and CuCl,thereby removing As and Cl impurities in the contaminated acid.The paper carried out experimental research on the addition of metal powder and copper sulfate in the sulphuric acid to find out the influence of different influencing factors on the removal of impurity elements,and then obtain the best experimental parameters to return to the zinc smelting system after the removal of impurities.The results showed that the concentration of arsenic in the sulphuric acid decreased from525 mg/L to 71.9 mg under the experimental conditions of zinc-arsenic ratio of 4,copper sulfate addition of 0.05 g/L,reaction temperature of 35°C and reaction time of30 min./L,which is lower than the limit of 100mg/L of arsenic in the enterprise;in the experimental conditions of 92.7g/L of copper sulfate,6.4 of copper to chlorine ratio,35°C reaction temperature and 30min reaction time,The chloride ion content in the acid was reduced from the initial 1300 mg/L to 88 mg/L,which was lower than the chlorine reuse limit of 180 mg/L in the sulphuric acid.In addition,the kinetics study of the arsenic removal and dechlorination processes was carried out,and the kinetic control model of the above reaction was determined.The XRD and SEM analysis of the filter residue showed that the main components in the slag were As₂S₃,Cu₃As,PbSO₄ and ZnS.And CuCl,etc.,and determined the reaction mechanism of the above process.