PROCESS OF PRODUCTION OF CRYOLITE FROM ALUMINUM-CONTAINING CRUDE ORE Russian patent published in 2008 - IPC C01F7/54 C01F3/02 

FIELD: mining industry.

SUBSTANCE: invention relates to chemical and metallurgical processing of crude ore to produce technical-destination aluminum compounds, in particular cryolite (Na₃AlF₆). Cryolite is produced, in particular, from beryl concentrate. Charge consisting of beryl concentrate, soda ash, and limestone is melted and subjected to wet granulation, Granulate is ground and sulfatized with sulfuric acid. Sulfatized granulate is subjected to water leaching to extract aluminum and beryllium sulfates into solution. Resulting sulfate solution is neutralized with aqueous ammonia to jointly precipitate aluminum and beryllium hydroxides. Mixture of the two hydroxides is separated from mother liquor, dissolved in concentrated sodium hydroxide solution, and diluted in water to precipitate beryllium hydroxide, which is separated from sodium aluminate solution. Then, cryolite is precipitated via treatment with 40% hydrofluoric acid, used in amount 2.0-2.5 ml acid per 1 g sodium in solution, and with freshly precipitated aluminum hydroxide until weight ratio Na/Al = 2.5-3.0 is attained in cryolite pulp.

EFFECT: optimized process flowsheet.

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