Cryolite is sodium fluoroaluminate, with molecular formula of Na3AlF6. Cryolite has excellent performance. It is not only an indispensable cosolvent in aluminum smelting industry, but also widely used in other industries, such as opal agent in enamel industry, wear-resistant filler in rubber and grinding wheel industry, shading agent in glass industry, etc.

There are many methods to prepare cryolite. According to different sources of fluorine, it can be divided into fluorite method, phosphate fertilizer by-product method, fluorine-containing waste method and so on. Cryolite was prepared by neutralization and impurity removal, synthetic reaction, washing and drying with smelting fluorine-containing non-acid as raw material. Under the optimal conditions of neutralization and impurity removal pH value of 7.5, reaction pH value of 8.0, feed ratio of Na: Al: F of 4:1:6, reaction temperature of 80 ℃ and reaction time of 60min, the recovery rate of fluorine can reach 98.9% and the concentration of residual fluorine ion can be reduced to 200mg · L-1; The quality of the prepared cryolite product meets the requirements of GB / t4291-2007. The amount ratio of sodium to aluminum is 2.5, which belongs to medium molecular ratio cryolite.

The process has the advantages of simple operation, low cost and 1m? About 30kg of cryolite product can be obtained by smelting fluorine-containing waste acid. The difficulty of smelting waste acid is reduced, and the difficulty of waste acid treatment is reduced.