METHOD OF OBTAINING ALUMINIUM OXIDE APPLICABLE FOR MANUFACTURING ARTIFICIAL CORUNDUM CRYSTALS Russian patent published in 2012 - IPC C01F7/42 C25B1/00 

FIELD: chemistry.

SUBSTANCE: in order to obtain aluminium oxide applicable for manufacturing artificial corundum crystals, aluminium of 99.95-99.999% purity is dissolved in solution of chlorides of ammonium, sodium or their mixture, which contains 5-150 g/l of chloride-ions, at temperature 20-95°C with reverse supply of constant current at current density 0.045-0.12 A/cm². Electrode surface is washed with rate 60-1400 l/(m²·h) with electrolyte, circulating in outer contour. Formation of dense aluminium hydroxide sediment is performed in collection expansion tank with expansion coefficient 25-400. Aluminium hydroxide is separated from electrolyte by centrifugation with rotation rate 20-60 rev/s. Sediment is washed in specially prepared water with specific resistance 0.4-18 megaohm·cm. Washed sediment is dried in flow of hot air with temperature 100-400°C and annealed in electric furnace until aluminium oxide is obtained.

EFFECT: invention makes it possible to increase product output and electrolyser productivity, improve quality of obtained aluminium oxide.

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