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US 4,615,875 AGranted
Process for preparing high purity alpha-alumina
AssigneeAllied Corporation
InventorsStephen T. Gonczy, Roy T. Mitsche
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Abstract
High purity alumina with a low sodium content and with a friable, easily ball milled structure is produced in this invention through a modified sol-gel procedure which includes digestion of the contaminant containing aluminum metal with hydrochloric acid in the presence of excess aluminum, removal of the contaminants, seeding the resulting sol with high purity alumina, drying to a solid, and then calcining said seeded sol solids to produce said high purity alpha alumina.
Claims10
A method for the preparation of high purity, fine particulate, friable alpha alumina from an alumina sol comprising the steps of
- (a) digesting aluminum metal containing contaminants in an excess of aluminum metal with hydrochloric acid and water at digestion conditions to produce an alumina sol containing solid contaminants and excess aluminum metal;
- (b) purifying said sol;
- (c) seeding said purified sol with fine particulate alpha alumina;
- (d) drying said seeded sol to produce an alpha alumina precursor;
- (e) calcining said dried precursor at calcination conditions to produce a high purity, friable alpha alumina;
- and,
- (f) recovering said alpha alumina.
4 more elements
Dependencies are inferred from the claim text.