Patent ID: 11964878
Assignee: nan
Field: Materials, metallurgy (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A method to produce an alpha alumina comprising at least the steps of:
i) providing a boehmite slurry comprising boehmite; wherein a crystallite size of the boehmite is in the range of between 3.0 and 6.5 nm along a (120) axis thereof and 3.0 and 6.0 nm along a (020) axis thereof;
ii) aging the boehmite slurry to obtain an aged boehmite slurry comprising boehmite particles with a modified crystallite size, wherein the aging is carried out at a temperature of between 30 and 240° C. for a period of between 0.5 and 170 hours until the boehmite particles of the aged boehmite slurry:
a) either have a difference between the crystallite size along the (120) axis and the crystallite size along the (020) axis bigger than 0 and smaller than 1 nm, or
b) have the crystallite size along the (120) axis being larger than 30 nm, or
c) have both conditions of a) and b) applying thereto;

iii) drying the aged boehmite slurry to form a dried boehmite, and
iv) calcining the dried boehmite at a temperature of between 1300 to 1400° C. for a time of calcination of between 1 and 5 hours to produce the alpha alumina.