Abstract: Size mixing experiments were carried out by using clarified tail liquid and saturated brine to mix with band machine filtrate respectively in flotation process.Results showed that in sylvite flotation process,the accumulation of MgCl₂ in solution will be raised with the increasing of cycle numbers of flotation medium,i.e.saturated high-Mg solution.When the content of MgCl₂ exceeds a certain value,the solution viscosity will be too high to deteriorate the flotation process.The flotaion indices decline,which is not good for prduction,will be caused when saturated brine was used for size mixing,because phenomenon of brine salting will appear as it to be used.Therefore,it′d better try to let the Mg²⁺ concentration of mother liquor near or lower than Mg²⁺ concentration of decomposing liquid while meeting the process control conditions,and whenever possible,use the clarified tail liquid to replace the band machine filtrate to make size mixing,so that the Mg²⁺ concentration of mother liquor could be improved,the flotation indices could be optimized and the yield of KCl could be raised to more than 23% in flotation process. 

Key words: potassium chloride, saturated brine；flotation, mother liquor