The invention discloses a method for reducing 
ammonium fluorosilicate in 
ammonium bifluoride. The method comprises the steps as follows: 
fluorosilicic acid is subjected to an ammoniation reaction anda 
silicon dioxide-containing 
ammonium fluoride mixed solution is obtained, wherein the 
mass concentration of 
ammonium fluoride is 20%-35%, the 
mass concentration of 
silicon dioxide is 2%-15%, and thePH value is 8.0-10; the 
ammonium fluoride mixed solution in step (1) is filtered by a 
filter press, most 
silicon dioxide is removed, a filtrate enters a filtrate tank and left to stand and clarified for 1-3 h, most 
silicon dioxide settles to the bottom, and the upper layer is a clear 
ammonium fluoride liquid; the upper clear ammonium 
fluoride liquid in step (2) is finely filtered again by micropores with the 
diameter being 3-10 micron, and a wet 
filter cake returns to a feeding chute of the 
filter press; a refined filtrate enters a concentrated 
raw material chute to be left to stand and clarified for 1-3 h, an upper clear ammonium 
fluoride liquid enters a concentration 
system, conventional concentration, acid addition, 
crystallization and 
centrifugal separation are performed later, and anammonium 
bifluoride product is obtained. The method can effectively reduce 
ammonium fluorosilicate in 
ammonium bifluoride, has low 
energy consumption, introduces no other impurities and avoids waste emission.