Slip for porcelain prodn - contg. calcined bentonite and reduced amt. of low-grade kaolin

Porcelain crockery, technical articles, sanitary ware, etc., are produced from 10-42% calcined bentonite, 33-64% kaolin (contg. about 1% Fe2O3), 11-35% feldspar and 14-26% of dressed quartz sand. Calcined bentonite can be incorporated into the porcelain mix. in an amt. larger than in convenctional compsns., because it does not affect the flowability of the slip to such an extend as raw bentonite. As a result, the kaolin content is thus reduced and low-grade kaolin (1% Fe2O3) can be used without purification. A whiteness degree of 66-80% is achieved. The firing temp. is 30-50 degrees C lower compared with conventional compsns.