Abstract: Using industrial by-product fluorosilicic acid as raw material for preparing potassium fluoride，phosphate，and sul- fate will accumulate in the product therefore affecting the quality of products.The use of potassium hydroxide solution is diffi- cult in the process of quantity control，slightly excessive will dissolve silica，thus affecting the quality of potassium fluoride. This process mainly studied the preparation of high purity potassium fluoride and silica with industrial by-product fluorosili- cic acid，solved the impurity accumulation，and deep analysis was also made from the experimental principle，experimental methods，key points of control，product quality，and cost etc..The process had the characteristics of low production cost，good product quality，reasonable technology，and little environmental pollution.It is in line with the China′s environmental protec- tion policy of energy conservation，emission reduction，and comprehensive utilization of resources.

Key words: fluorosilicic acid, potassium fluoride, silica, product quality