Process for making non-porous micron-sized high purity silica
AssigneeCabot Corporation
InventorsJameel Menashi, Kenneth C. Koehlert
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Abstract
A process for making non-porous, dense, silica partices having a diameter of about 3 to 1000 microns, a nitrogen B.E.T. surface area less than about 1 m.sup.2 /g, a total impurity content of less than about 50 ppm and a metal impurity content content of less than about 15 ppm from an aqueous dispersion of fumed silica. The particles are converted into porous particles and sintered in an atmosphere having a water partial pressure of from about 0.2 to about 0.8 atmosphere for temperatures below about 1200.degree. C.
Claims11
A process for producing nonporous, dense, silica particles having a diameter of about 3 to 1000 microns, and nitrogen B.E.T. surface area less than about 1 m.sup.2 /g, a total impurity content of less than about 50 ppm and a metal impurity content of less than about 15 ppm, comprising:
- a) Forming an aqueous dispersion of fumed silica containing from about 5 to about 55 weight percent solids;
- b) Converting the aqueous dispersion of step (a) into porous particles;
- and
- c) Sintering the porous particles of step (b) in an atmosphere having a water partial pressure ranging from 0.2 to 0.8 atmosphere at temperatures below about 1200.degree. C.
Dependencies are inferred from the claim text.