PROCESS FOR PRODUCTION OF REACTIVE ALPHA ALUMINA Russian patent published in 2023 - IPC C01F7/441 C01F7/23 B22F9/04 C04B35/10 C04B35/626 

FIELD: chemical technology for producing reactive alpha-alumina.

SUBSTANCE: invention relates to a chemical technology for producing reactive alpha-alumina oxide (α-Al₂O₃), which is used as a highly dispersed component in the production of biocompatible, structural and technical corundum ceramics, as a component of matrix systems in the technology of low-cement refractory casting masses, as well as a catalyst, adsorbent, abrasive material. The method includes dry grinding of alumina in a ball mill using cylindrical grinding media with a volume of 6.3 cm³ each and a volume loading of the drum with grinding media of 35%. Metallurgical alumina oxide with a median D₅₀ particle size of 9–22 mcm is used as initial material containing crystalline phases γ-Al₂O₃ and θ-Al₂O₃, into which an additive-mineralizer - ammonium dichromate - is introduced in an amount of 0.005–0.5 mol.% in terms of chromium, then water is added to the resulting mixture until a pasty state is obtained, briquettes are prepared by laying in molds and dried to constant mass at a temperature of 110±15°C, after which the briquettes are calcined at a temperature of 1350–1550°C for 3 hours, then the calcination products are crushed, 0.05% polyethylene glycol is added to the calcined alumina in excess of the mass, and then crushed in a ball mill using cylindrical grinding bodies with a volume of 6.3 cm ³ each and a volumetric loading of the drum with grinding bodies of 35% for 2–8 hours.

EFFECT: as a result of dry grinding, reactive alpha-alumina powders are obtained with an average primary crystal size of 0.5-1 mcm and a specific surface area of more than 27,000 cm²/g; the invention also provides a low viscosity of suspensions based on submicron reactive alpha-alumina oxide at a minimum operating humidity and an improvement in the grindability of alumina calcination products due to a decrease in the sintering of finely dispersed solid-phase particles.

1 cl, 5 dwg, 1 tbl, 3 ex