RU2003119050A - METHOD FOR PRODUCING SCANDIUM OXIDE FROM RED Sludge - Google Patents

Claims (2)

1. A method of producing scandium oxide from red mud, waste from alumina production, including multiple sequential leaching of red mud from a mixture of sodium carbonate and sodium bicarbonate solutions, washing and separating the precipitate, introducing zinc oxide dissolved in sodium hydroxide into the resulting solution, holding the solution at elevated temperature and stirring, separating the precipitate and treating it with sodium hydroxide solution at boiling point, separating, washing and drying the resulting product, followed by extraction scandium oxide by known methods, characterized in that a gas-air mixture containing 10-17% CO ₂ (by volume) is passed through a mixture of solutions of sodium carbonate and sodium bicarbonate first, and the leaching step is repeated until a solution with a concentration of at least 50 g of scandium oxide is obtained / m, and then introduced into a solid sodium hydroxide solution to a concentration of 2-3.5 kg / m ³ to Na ₂ O _caustic and maintained at a temperature not higher than 80 ° C, followed by introduction of flocculant, exposure and separation of the precipitate, then the resulting solution under Yergali electrolyzed with solid electrodes at a cathodic density of 2-4 A / dm ² and a temperature of 50-75 ° C for 1-2 hours, followed by the addition of zinc oxide in a solution of sodium hydroxide to Zn0 relation: Sc ₂ O ₃ = (10- 25): 1, the flocculant is introduced and kept at 100-102 ° C for 4-8 hours, the precipitate is separated, which is then treated with a 5-12% sodium hydroxide solution at the boiling point, the flocculant is again introduced, the sediment is kept and the precipitate is separated. 2. The method according to claim 1, characterized in that as a flocculant use a flocculant brand "Nalko" in an amount of 2-3 g / m ³ .