Patent · US Active

Process for preparing calcium fluoride from fluosilicic acid

US11873229B2 · kind B2 · utility

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Inventors

Key dates

Filing dateApr 22, 2016
Grant dateJan 16, 2024
Priority date—
Expiry dateApr 22, 2036

Classification

  • Technology area (CPC C)Chemistry; Metallurgy
  • CPC primaryC01P2006/80
  • WIPO fieldMaterials, metallurgy
  • WIPO sectorChemistry

Abstract

A process for preparing synthetic calcium fluoride (CaF2) (min 90% CaF2 by weight) from fluosilicic acid is provided. The processes comprises the steps of (a) reacting fluosilicic acid (H2SiF6) with ammonium hydroxide or ammonia in a first reactor so as to obtain a first slurry and filtering the first slurry so as to obtain a filtrate containing a solution of ammonium fluoride (b) precipitating the solution of ammonium fluoride with calcium in a second reactor so as to produce a second slurry containing calcium fluoride and (c) evolving the major part of ammonia from the second reactor and then scrubbing and returning said ammonia to the first reactor.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.