Process for production of silica from olivine
AssigneeSilMag DA
InventorGudmundur Gunnarsson
Life of this patent
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Abstract
A process for producing from olivine precipitated silica with controlled specific surface area and high degree of purity. The process comprises adding olivine in a controlled manner to a heated mineral acid solution; after separating undissolved olivine and filtering the silica is slurried in aqueous solution to obtain a low viscosity high solid content silica slurry that can be efficiently degritted and dried with a relatively low energy consumption. The obtained silica can be in powder, bead or granule form and preferably has a specific surface area of at least about 100 m2/g.
Claims15
A process for producing silica in a powder form with controlled specific surface area, said process comprising:
- (a) providing olivine particles of a suitable grain size;
- (b) mixing the olivine and a mineral acid solution which is at a temperature in the range of about 50-110° C., and reacting for a period in the range of about 10-600 minutes to obtain silica with a controlled BET specific surface area in the range of about 50-500 m2/g;
- (c) optionally separating at least a part of undissolved olivine and other minerals from the resulting silica slurry;
- (d) filtering said silica slurry to separate dissolved metals salts from the silica and washing the silica filter cake;
- (e) slurrying said silica filter cake in an aqueous solution and subjecting the slurry to a dispersion step to obtain a low viscosity slurry with a solid content in the range of about of 10-30%;
- (f) separating mineral impurities from said silica slurry;
- (g) optionally adjusting the pH of said silica slurry to a desired pH value;
- (h) drying the silica slurry;
- to obtain high purity silica in powder form with controlled specific surface area.
Dependencies are inferred from the claim text.