Kanto Denka Kogyo Co., Ltd.

Hiroyuki Uehara

Osamu Omae

Katsuhiro Saito

Hiroki Takizawa

Wataru Kashikura

Shinsuke Katayama

Takuro Abe

Mitsuhara Shimoda

Shinji Mita

Kazuhide Yoshiyama

Hiromi Oya

Yasuyuki Fujiwara

Keisuke Kude

Ichiro Morimoto

Norihisa Kimura

Disclosed is a method for purifying a difluorophosphate, the method including mixing a difluorophosphate containing an impurity with at least one treatment agent selected from the group consisting of carbonates, hydroxides, and halides of alkali metals or alkali earth metals and amines to isolate the impurity. It is preferable that the method further include filtering off, by filtration, a salt or a complex that has been formed by allowing the impurity to be mixed with the treatment agent. Preferably, a carbonate, a hydroxide, or a halide of an alkali metal is used as the treatment agent, and more preferably a carbonate, a hydroxide, or a halide of lithium is used as the treatment agent.

Method for purifying difluorophosphate

A method for obtaining high-purity phosphorus pentafluoride (PF), which is industrially useful in the fields of semiconductors and batteries, from PFcontaining a gas mixture of HCl, HF, and so on. Specifically, provided is a process for purifying phosphorus pentafluoride including () an immobilization step in which phosphorus pentafluoride containing a mixture is brought into contact with a metal fluoride (MF; M is an n-valent metal) having a specific surface area of 1.0 m/g or more at 40&#xb0; to 150&#xb0; C. to immobilize phosphorus pentafluoride in the form of a hexafluorophosphate (M(PF)), () a separation step in which the mixture remaining in the gas phase is expelled out of the reaction system to separate the mixture from the hexafluorophosphate, and () a heat-decomposition step in which the hexafluorophosphate freed of the mixture is heated at 150&#xb0; to 400&#xb0; C. under a pressure of &#x2212;0.1 to 0.1 MPa&#xb7;G to give phosphorus pentafluoride.

Process for purifying phosphorus pentafluoride

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Gunma, Japan

Hiroyuki Uehara