Abstract: To reduce production cost and energy consumption,sodium monofluorophosphate was prepared by fusing assistant method with industrial grade sodium hexametaphosphate and sodium fluoride as raw materials.According to physical nature of fluxing agents,sodium fluorosilicate was chosen as the best fluxing agent.Influences of drying temperature,drying time,synthesis temperature,synthesis time,and n(Na₂SiF₆)∶n\[(NaPO₃)₆+NaF\] on the synthetic reaction were investigated by single factor experiment,and the optimal process conditions were confirmed by selective preference of orthogonal test as follows:drying temperature was 470 ℃,drying time was 24 min,synthesis temperature was 620 ℃,synthesis time was 22 min,and n(Na₂SiF₆)∶n\[(NaPO₃)₆+NaF\]=0.1.The purity of the product reached 97.59%,the yield was 94.88%,and mass fraction of free fluorine was below 0.7% under the optimal conditions.Therefore,sodium fluorosilicate being used as fusing assistant for preparing sodium monofluorophosphate is feasible.

Key words: sodium monofluorophosphate, sodium fluorosilicate, fusing assistant