Process for the preparation of silica spheres
Patent 4640807 Issued on February 3, 1987. Estimated Expiration Date: 
July 24, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
July 24, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.InventorsAssigneeApplicationNo. 06/758623 filed on 07/24/1985US Classes:264/13, By extrusion spraying or gravity fall through orifice264/5, FORMATION OF SOLID PARTICULATE MATERIAL DIRECTLY FROM MOLTEN OR LIQUID MASS (E.G., LIQUID COMMINUTING)264/621, Utilizing sol or gel423/338, By gelling423/339By precipitatingExaminersPrimary: Silbaugh, Jan H.Assistant: Fertig, Mary Lynn International ClassesB01J 21/00 (20060101)B01J 21/08 (20060101) C01B 33/154 (20060101) C01B 33/00 (20060101) Foreign Application Priority Data1984-08-02 GBAbstractSilica spheres are prepared in a process comprising:(a) preparing a silica hydrosol by mixing an aqueous solution of an alkali metal silicate with an aqueous solution of an acid;(b) converting the hydrosol into droplet form;(c) aging the droplets in a fluid to produce hydrogel particles;(d) partially drying the hydrogel particles at 10° to 60° C. in air having a relative humidity in the range of from 45 to 95%, to a water content in the range of from 0.3 to 1.3 kg/kg solids;(e) decreasing the cation content of the hydrogel particles by ion-exchange in an aqueous medium to less than 10% w, calculated on dry material; and(f) finally drying the hydrogel particles to obtain silica spheres.Other References
Field of SearchBy extrusion spraying or gravity fall through orifice |
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