Patent ID: 7615172

Claim:
A method for producing sintered particles comprising: preparing a slurry having a solids content of from about 40 to about 60% by weight, and comprising water, a binder, a mullite growth promoter and a raw material having an alumina content in a range of from about 55 to about 80% by weight; atomizing the slurry into droplets; coating seeds comprising alumina with the droplets to form green particles; and sintering at least a portion of the green particles at a temperature of from about 1000° C. to about 1600° C. for about 5 minutes to about 90 minutes, to form sintered particles having an alumina content of greater than about 55% by weight, an iron oxide content in a range of from about 2 to about 10% by weight, a specific gravity in a range of from about 2.70 g/cm 3 to about 3.50 g/cm 3 , and a bulk density in a range of from about 1.55 g/cm 3 to about 1.95 g/cm 3 .