Abstract: Taking the advantage of the exhausted fluorine-contained gas in the production of phosphorous fertilizer as the raw material,after it absorbed by water,the obtained fluorosilicic acid solution can react with ammonia under the appropriate conditions to produce ammonium fluoride and silica.Through washing and drying,silica can be processed into white carbon black product;ammonium fluoride can be changed into ammonium bifluoride after concentration and high-temperature decomposition.The obtained ammonium bifluoride and white carbon black met the standards of HG/T 3586—1999 (superior grade) and GB 10571—1989,respectively.The production cost of the new process is lower than that of the traditional process and it has good social,economic,and environmental benefits.<BR>