Process for preparing calcium fluoride from fluosilicic acid

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 fir...

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Bibliographische Detailangaben
Hauptverfasser:	Kossir, Abdelaali, Samrane, Kamal
Format:	Patent
Sprache:	eng
Schlagworte:	AMMONIA CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY CHEMISTRY COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM,CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THERARE-EARTH METALS COMPOUNDS THEREOF CYANOGEN INORGANIC CHEMISTRY METALLURGY NON-METALLIC ELEMENTS PERFORMING OPERATIONS PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL THEIR RELEVANT APPARATUS TRANSPORTING
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Beschreibung
Zusammenfassung:	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.