Abstract: A technology，using sodium fluorosilicate to react with sodium carbonate at a certain temperature to produce sodium fluoride and silica（by-product） was introduced.Taking a 3 000 t/a sodium fluoride and 450 t/a silica project as an example，the process technology and production operation points were introduced in detail.The raw material，sodium fluorosilicate is external purchase.The actual running of the project showed all the techno-economic indexes met the design requirements，sodium fluoride product′s quality satisfied all the requirements of the standard of Sodium Fluoride，YS/T 517—2009，and silica product′s quality reached the requirements of Rubber Compounding Ingredients-Silica，Precipitated，Hydrated， HG/T 3061—2009.If this project could be built with a phosphorus fertilizer enterprise together，the by-product，sodium fluorosilicate of the enterprise could be effectively utilized to produce a high valued added sodium fluoride product.At the same time， by-produced silica could also prolong the industry chain of phosphorus fertilizer enterprise.

Key words: sodium fluoride, silica, sodium fluorosilicate, phosphorus chemical industry