Alpha alumina with high purity and high relative density, a method for its production and its use

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.