Method of production of high purity fusible silica
AssigneeInternational Minerals & Chemical Corp.
InventorsPaul C. Chieng, Vikram P. Mehrotra, Chin-Liang Chou
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Abstract
A method of producing a high purity silica powder which can be fused to form transparent, bubble-free particles. An ammonium fluosilicate solution is purified preliminarily by removing colloidal-sized silica onto which impurities in the solution have been adsorbed. The high purity powder is produced by ammoniation of an unsaturated aqueous solution of ammonium fluosilicate. Silica powder produced is filtered, washed, and dried before fusion. Additional pre-fusion treatments such as washing, hydrothermal leaching, calcination, and a combination thereof, may be utilized to ensure that the concentration of volatile material is low.
Claims27
A method of producing high purity silica powder which can be fused to form transparent, bubble-free particles from an aqueous solution of ammonium fluosilicate comprising:
- (a) removing colloidal material from said aqueous ammonium fluosilicate solution;
- (b) ensuring that the colloid-free ammonium fluosilicate solution of step (a) is unsaturated with respect to ammonium fluosilicate;
- (c) ammoniating said unsaturated solution to produce silica precipitate;
- and
- (d) recovering said silica precipitate.
A batch method of producing high purity silica powder which can be fused to form transparent, bubble-free particles from an aqueous solution of ammonium fluosilicate comprising:
- (a) removing colloidal material from said aqueous ammonium fluosilicate solution;
- (b) ensuring that the colloid-free ammonium fluosilicate solution of step (a) is unsaturated with respect to ammonium fluosilicate;
- (c) ammoniating said unsaturated solution to produce silica precipitate;
- and
- (d) recovering said silica precipitate.
Dependencies are inferred from the claim text.