Chemistry of inorganic compounds – Silicon or compound thereof – Oxygen containing
Patent
1996-08-28
1998-12-29
Marcantoni, Paul
Chemistry of inorganic compounds
Silicon or compound thereof
Oxygen containing
423340, 423342, 423343, C01B 3312
Patent
active
058536850
ABSTRACT:
High purity silica is obtained by the reaction of impure by-product waste silica with hydrogen fluoride preferably in the presence of water or sulfuric acid, producing silicon tetrafluoride gas and a mother liquor. The silicon tetrafluoride is separated from the mother liquor, which retains the impurities originally contained within the impure silica. The silicon tetrafluoride gas is contacted with high-purity water, in a clean environment, to form a slurry of high purity silica and high-purity hydrofluosilicic acid (FSA). A portion of the silica is filtered from the slurry and washed producing a high purity silica product. The rest of the silica-FSA slurry is preferably reacted with ammonia to form a slurry of ammonium fluoride and silica. The silica is separated from the ammonium fluoride and preferably washed and calcined to remove any remaining ammonium fluoride, leaving additional high purity silica product. The separated ammonium fluoride may be reacted with lime to produce additional products for recycling back into the process. The process can be repeated for further purification of the silica. The process may be used to produce substantially spherical silica particles about 1.0 to about 25.0 microns in diameter.
REFERENCES:
patent: 2306021 (1942-12-01), Knowles et al.
patent: 2785953 (1957-03-01), Fitch
patent: 3498746 (1970-03-01), Smaltz et al.
patent: 3615195 (1971-10-01), Bierman, Jr. et al.
patent: 3645678 (1972-02-01), Parish et al.
patent: 3645679 (1972-02-01), Parish et al.
patent: 3645680 (1972-02-01), Parish et al.
patent: 3764658 (1973-10-01), Darwin et al.
patent: 4144158 (1979-03-01), Nagasubramanian et al.
patent: 4539187 (1985-09-01), Russ et al.
patent: 4557918 (1985-12-01), Lagerstrom et al.
patent: 4613494 (1986-09-01), Barber
patent: 4915705 (1990-04-01), Mollere et al.
patent: 4981664 (1991-01-01), Chieng
patent: 5165907 (1992-11-01), Chieng
patent: 5180569 (1993-01-01), Erickson et al.
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