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Abstract

An alumina particle and a method of its manufacture. The alumina particle comprises a spheroidal alumina particle of about 1/16 inch in diameter and a crush strength of from about 13 to about 16 pounds. The method comprises preparing a mixture of an acidic alumina hydrosol and an ammonia percursor at below gelation temperature, dispersing the mixture as droplets in a water-immiscible liquid at a temperature and for a time to effect at least partial gelation of the hydrosol to form hydrogel particles, contacting the hydrogel particles with a liquid having a pH no greater than about 7 and an osmotic pressure sufficient to prevent disintegration of the hydrogel particles, aging the hydrogel particles in an aqueous solution having a pH greater than 7, and thereafter drying and calcining the hydrogel particles.

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First Claim