FINE-CRYSTALLINE ALPHA-ALUMINA PRODUCTION PROCESS Russian patent published in 2005 - IPC

FIELD: industrial inorganic synthesis.

SUBSTANCE: invention relates to manufacture of ceramic powders, namely to production of optical purity-grade α-alumina. Process comprises autoclave heating of water and aluminum oxide or hydroxide, taken at weight ratio 1:(0.7-1.2), respectively, to synthesis temperature 250-400°C at elevated pressure followed by aging for 20 h at the same temperature and pressure 300-600 atm. After aging, heat treatment is carried out either by way of cooling the mixture to ambient temperature for 24 h at the same pressure or by reducing pressure with rate 20-50 atm/h to atmospheric value at synthesis temperature followed by stopping heating in autoclave.

EFFECT: enabled formation of high-purity microcrystalline alumina.

3 cl, 1 tbl, 2 ex