Stella Chemifa Kabushiki Kaisha

Hirofumi Yazaki

Hirohisa Kikuyama

Masahide Waki

Shinji Hashiguchi

Hiroto Izumi

Kenji Aoki

Toshirou Fukudome

Masatsugu Kawawaki

Yuko Murakami

Tomohiko Satonaga

An object of the present invention is to provide a method for purifying a highly pure niobium compound and/or tantalum compound, the method enabling the purification of a highly pure niobium compound and tantalum compound in a simplified manner at a low cost. The object is met by providing a method comprising adding an organic solvent to an aqueous solution containing a niobium compound and/or tantalum compound together with impurities, and then performing extraction via the solution. A niobium compound and/or tantalum compound dissolved in a solution is allowed to precipitate, and said aqueous solution is obtained by dissolving the precipitate in water.

Purification method for producing high purity niobium compound and/or tantalum compound

The present invention provides a method enabling the high purification of a niobium compound and/or tantalum compound in a simplified manner at a low cost. This is accomplished by providing a method enabling the high purification of a niobium compound and/or tantalum compound comprising the steps of preparing a solution containing niobium and/or tantalum, allowing a precipitate comprising niobium and/or tantalum to develop, separating the precipitate by filtration from the filtrate, converting the precipitate to a liquid melt or taking the filtrate, and separating a niobium compound from a tantalum compound or vice versa by utilizing the difference in solubility to the solvent between the niobium compound and the tantalum compound.

A method for reducing oxygen and carbon components in high-purity fluoride such as calcium fluoride and barium fluoride (a high-purity fluoride that is not limited to calcium fluoride and barium fluoride), or in rare-earth fluorides such as ytterbium fluoride and cerium fluoride used for an optical fiber, a coating material, and so on. The oxygen and carbon components contained in the high-purity fluoride are reduced by a fluorine gas treatment.

Method for reducing oxygen component and carbon component in fluoride

A method of purifying lithium hexafluorophosphate that allows to purify lithium hexafluorophosphate, useful as lithium secondary cell electrolyte, organic synthesis medium or the like, to an extremely high purity is provided. Lithium hexafluorophosphate containing harmful impurities such as oxyfluoride, lithium fluoride is purified by adding phosphoric chloride. The purification is performed in the presence of phosphoric chloride and hydrogen fluoride of the quantity equal or superior to the equivalent amount for reacting them, and then by converting lithium fluoride lithium hexafluorophosphate with generated phosphor pentafluoride.

Method of purifying lithium hexafluorophosphate

A method of purifying lithium hexafluorosphate that allows to purify lithium hexafluorophosphate, useful as lithium secondary cell electrolyte, organic synthesis medium or the like, to an extremely high purity is provided. Lithium hexafluorophosphate containing harmful impurities such as oxyfluoride, lithium fluoride is purified by adding phosphoric chloride. The purification is performed in the presence of phosphoric chloride and hydrogen fluoride of the quantity equal or superior to the equivalent amount for reacting them, and then by converting lithium fluoride to lithium hexafluorophosphate with generated phosphor pentafluoride.

Growing community of inventors

Izumiootsu, Japan

Hirofumi Yazaki