Abstract: The arsenic content is high in the acidic wastewater generated in the fume purification process in a gold smeltery.Therefore,coagulation and sedimentation processes were selected to treat the arsenic with ferrous sulfate heptahydrate as the coagulant,and the reaction conditions were optimized.The results show that the optimum arsenic removal conditions were for coagulation and sedimentation process with ferrous sulfate heptahydrate as follows:the ferrous sulfate heptahydrate dosage of 10.0 kg/m3,the reaction time of 40 min,initial pH value of 9.0,the PAM flocculant dosage of 10 g/m3,and the precipitation time of 30 min.After the treatment,in the wastewater,the arsenic mass concentration is reduced to 0.45 mg/L,which meets the requirements of the arsenic discharge limit in the GB 8978-1996 Comprehensive Sewage Discharge Standard.