The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 10, 1999
Filed:
Jun. 03, 1998
Elf Atochem, S.A., , FR;
Abstract
The process of the present invention consists in bringing into contact, on the one hand, (A) gaseous phosphorus pentafluoride or a gaseous mixture comprising phosphorus pentafluoride and hydrochloric acid, and, on the other hand, (B) a solution of lithium fluoride in hydrofluoric acid, in a column (10) having a sufficient number of transfer units to carry out the reaction of PF.sub.5 with LiF under the chosen conditions of temperature, of pressure and of molar ratio of the two contrasting reactants and with complete or substantially complete absorption of the PF.sub.5 in the column. This process makes it possible to solve the problems of blockage by preventing recrystallizations of salts; to discharge the heat given off by the reaction by the evaporation of a portion of the HF; and to separate the HCl which may be contained in the starting PF.sub.5, without loss of PF.sub.5, thus allowing subsequent recovery/value enhancement of this HCl. Moreover, this process is very simple, with a very small number of stages, which makes it possible to avoid any entry of air or moisture capable of contaminating the final LiPF.sub.6.