Stella Chemifa Corporation

Naoki Yahata

Tetsuo Nishida

Shuichi Minamigawa

Provided is a method for purifying a difluorophosphate, in which a difluorophosphate is purified to a high purity. The method includes a method for purifying a difluorophosphate, comprising bringing hydrogen fluoride into contact with a difluorophosphate containing an impurity and subsequently heating and drying the difluorophosphate, or bringing the hydrogen fluoride into contact with the difluorophosphate containing the impurity while heating and drying the difluorophosphate containing the impurity, thereby removing the impurity.

Method for purifying difluorophosphate

Provided is a method for producing a difluorophosphate, which can easily and industrially advantageously produce a high-purity difluorophosphate. The method includes a step of producing a difluorophosphate in the fluorophosphoric acid solution by reacting hydrofluoric acid anhydride containing no solvent with an oxoacid and/or the like of phosphorous to produce a fluorophosphoric acid solution; a step of adding a hexafluorophosphate to the fluorophosphoric acid solution in the absence of respective halides, carbonates, borates, phosphates, hydroxides, and oxides of an alkali metal and the like; and a step of heating and drying the fluorophosphoric acid solution containing the difluorophosphate to distill away a fluorophosphoric acid, or a step of depositing the difluorophosphate in the fluorophosphoric acid solution by crystallization, subsequently separating the difluorophosphate by solid-liquid separation, and distilling away a fluorophosphoric acid contained in the difluorophosphate after the solid-liquid separation.

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Osaka, Japan

Naoki Yahata