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:
Oct. 08, 1991
Filed:
Jul. 27, 1987
Laurent Seigneurin, Salindres, FR;
Aluminum Pechiney, , FR;
Abstract
Process for the production of anhydrous calcium fluosilicate from anhydrous calcium chloride and impure fluosilicic acid solution, a by-product of the acid treatment of phosphorus ores containing fluorine, characterized in that a calcium fluosilicate dihydrate is precipitated at low temperature and quantitatively by suitable adjustment of the fluosilicic acid concentration and the molar ratio CaCl.sub.2 /H.sub.2 SiF.sub.6 and that after filtration, washing and drying of the precipitate, an anhydrous calcium fluosilicate which can be easily decomposed by heat treatment is obtained to restore calcium fluoride and silicon tetrafluoride suitable for the manufacture of pure hydrofluoric acid and fluosilicic acid. For gravimetric concentrations of H.sub.2 SiF.sub.6 >25% and molar concentration ratios CaCl.sub.2 /H.sub.2 SiF.sub.6 between 2 and 5, the yields of the anhydrous calcium fluosilicate obtained are greater than 94%.