METHOD OF EXTRACTION OF SCANDIUM IN PROCESSING BAUXITES FOR ALUMINA Russian patent published in 2003 - IPC

FIELD: non-ferrous metallurgy; extraction of scandium component from intermediate products of processing bauxites for alumina: sintering dust of electric filters or red mud. SUBSTANCE: method includes leaching starting product, extraction and concentration of scandium from solution followed by separation of solution from sediment, introduction of solution containing hydroxide of amphoteric metal-collector into solution thus obtained and filtration, flushing, drying and calcination of sediment. Leaching is performed with water and/or 5-12-% solution of sodium carbonate or hydrocarbonate (baking soda) or their mixture at least thrice at temperature not higher than 50 C for at least three hours at solid-to- liquid ratio = 1:2.5-5.0 at addition of new amounts of product of processing bauxites as starting material. Used as solution containing hydroxide of amphoteric metal-collector is solution of aluminum or zinc oxide in sodium hydroxide; after introduction of aluminum or zinc oxide solution in sodium hydroxide, solution is kept for at least two hours at temperature not below 80 C. Sediment is separated, washed and treated with 10-25-% solution of sodium hydroxide at simultaneous heating to boiling; then, sediment is filtered and washed with 1-5-% solution of sodium hydroxide and dissolved in 1-5-% solution of hydrochloric acid and is again filtered; filtrate is treated with 10-25-% solution of ammonia or 2-10-% hydrofluoric acid at 1-3-% excess of stoichiometry. EFFECT: simplification of method; increased percentage of extraction of scandium. 3 cl