Patent ID: 8524191
Filing Date: 2013-09-03
Classification: C01F,C01P,C04B

Abstract:
1. A process for preparing aluminum oxide with a low calcium content, in which (1) crude alpha- and/or gamma-aluminum oxide with a total calcium content in the range from 50 to 2000 ppm, based on the crude alpha- and/or gamma-aluminum oxide, is mixed with an aqueous solution or suspension comprising an inorganic acid, an organic acid, a complexing agent, or mixtures thereof, (2) the mixture from step (1) is admixed with a first flocculating aid, (3) in the mixture of step (2), solids are separated from liquid, (4) the solids separated are mixed with water in the presence or in the absence of a second flocculating aid, (5) in the mixture of step (4), solids are separated from liquid, and (6) optionally, steps (4) and (5) are repeated once or more than once.