The production of cryolite at home and abroad mainly has the following processes:
Hydrofluoric acid method: separable dry method and wet method The dry method is to react gaseous hydrofluoric acid at 400-700 ° C with aluminum hydroxide to form fluoroaluminate (H3AlF6), which is then reacted with soda ash at a high temperature. The wet method is prepared by reacting 40 to 60% of hydrofluoric acid with aluminum hydroxide and then adding soda ash.
Fluorosilicic acid method: The ammonium fluoride intermediate product method and the sodium fluorosilicate intermediate product method, and the former is formed by reacting fluorosilicic acid with ammonia water and then reacting with sodium aluminate. The latter is obtained by recovering fluorine-containing waste gas in the production of phosphate fertilizer by recovering sodium fluorosilicate and then performing ammoniacal synthesis.
Carbonation method: cryolite can also be obtained by using carbon dioxide in sodium aluminate and sodium fluoride solution.
Aluminum industry recycling method: Dilute hydrofluoric acid recovered from the waste gas produced by aluminum production can react with sodium aluminate to recover cryolite.
Alkali method: Soda ash, fluorite, silica sand are calcined, pulverized, leached and reacted with aluminum sulfate, which is rarely used in industry.
High Purity Synthetic Cryolite/ for Glass
High Purity Synthetic Cryolite/ for Aluminum
High Purity Synthetic Cryolite/ for abrasive, cut wheels