Patent ID: 8399710

Claim:
A process for producing an alkali metal fluoride dispersion consisting essentially of an alkali metal fluoride and an aprotic organic solvent obtained by conducting the following (A), subsequently conducting the following (B) at least once, and then conducting the following (C): (A): separating a liquid phase from a residue of an alkali metal fluoride dispersion comprising at least one alcohol solvent selected from the group consisting of methanol, ethanol and isopropanol and an alkali metal fluoride, and mixing the separated liquid phase with an aprotic organic solvent having a boiling point of 85° C. or higher at normal pressure to obtain a mixture containing the alkali metal fluoride, wherein the liquid phase comprises the alkali metal fluoride and the alcohol solvent, and wherein the amount of the alcohol solvent used in (A) is less than 5 parts by weight per 1 part by weight of the alkali metal fluoride; (B): obtaining a mixture containing the alkali metal fluoride comprising by applying at least the following (31) to (b3); (b1): concentrating the mixture containing the alkali metal fluoride, which is obtained in (A) or (b3), to obtain a concentrated fraction and a concentrated residue; (b2): mixing a residue of the alkali metal fluoride dispersion obtained by the separating the liquid phase in (A) or a residue of the mixture obtained by separating a liquid phase in (b3) with the concentrated fraction obtained in (b1), to obtain a mixture containing an alkali metal fluoride; and (b3): separating a liquid phase from the mixture containing an alkali metal fluoride, which is obtained in (b2), and mixing the separated liquid phase with the concentrated residue obtained in (b1), to obtain a mixture containing an alkali metal fluoride; and (C): removing the alcohol solvent from the mixture containing the alkali metal fluoride, which is obtained in (B), to obtain the alkali metal fluoride dispersion essentially consisting of the alkali metal fluoride and the aprotic organic solvent.