Taking the second layer salt from the ship of Jilantai south line as the raw material,the ammonia alkali waste liquid and fresh water were mixed and then the solution extraction reaction was used to remove sulfate radical and produce liquid salt for soda ash.Pilot scale research was used to optimize the process conditions.On the basis of the optimum process conditions of pilot test,the influence of polyacrylamide on the sedimentation effect of calcium sulfate dihydrate was determined.The results of pilot study showed that the volume ratio of ammonia alkali waste liquid to fresh water in the slag washing process was 1∶9,the residence time of slag washing was 2.5 h,the residence time of brine making was 3 h,the optimal n（sulfate）∶n（calcium ion） for the secondary desulfurization of the reaction tank was 1∶0.75,and the residence time of the secondary desulfurization of the reaction tank was 5 min.When the amount of polyacrylamide added in the secondary sedimentation process was 62.5 mg/L,the sedimentation effect of calcium sulfate dihydrate was better,and the light transmittance of liquid salt was≥80%.Under the optimized process conditions,the liquid salt standard for enterprise soda production could be reached,in which the mass concentration of calcium ion was ≤2 g/L,the mass concentration of sulfate radical was≤5 g/L,and the mass concentration of sodium chloride was≥305 g/L.at the same time,the comprehensive utilization of resources could be realized by using this process.