MANUFACTURE OF CALCINED ALUMINA WITH CRYSTALLITE SIZE ADJUSTED ON REQUEST WITH LOW DISPERSION

摘要

The invention concerns a method for manufacturing alumina for ceramics by calcination of alumina trihydrate in the presence of a mineralising agent such as a halogenated compound and/or a boron compound, said calcined alumina being constituted of friable conglomerates of elemental particles or alpha alumina crystallite the size of which is adjusted on request with a confined unimodal distribution of the crystallite size. The invention is characterised in that the calcination in industrial furnace, in renewed oxidising atmosphere, of the alumina trihydrate filler at a temperature between 800 °C and 1300 °C for half an hour to four hours is carried out simultaneously in the presence of a halogenated compound acting as mineralising agent and a recrystallisation modifier of alumina, with a silica base, evenly and closely distributed in the alumina trihydrate filler.