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AssigneeUnited Company RUSAL Engineering and Technology Centre LLC
InventorsSuss Aleksandr GENNADIEVICH, Kozyrev Aleksandr BORISOVICH, Panov Andrej VLADIMIROVICH
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The invention relates to a method for producing a scandium-containing concentrate from the wastes of alumina production and extracting high-purity scandium oxide from the same. Provided is a method for producing a scandium-containing concentrate from a red mud, wherein the Sc2O3 content therein is least of 15 wt. % (in terms of dry matter), the TiO2 content not more than 3 wt. % (in terms of dry matter), the ZrO2 content not more than 15 wt. % (in terms of dry matter), and wherein scandium in the concentrate is in form of a mixture of Sc(OH)3 hydroxide with ScOHCO3×4H2O. Also provided is a method for producing high-purity scandium oxide, with a purity of approximately 99 wt. %.
A method for producing a scandium-containing concentrate from a red mud, said method comprising filtrating the red mud from a liquid phase, repulping a red mud cake with a sodium bicarbonate recirculated solution, gassing the solution with carbon dioxide until a pH of ≤9 is reached, leaching the red mud with a soda-bicarbonate solution, filtrating and washing the red mud cake with water on a filter, sorbing scandium from the filtrate on a phosphate ion exchanger following which the recirculated solution is recycled for repulping the red mud cake, desorbing scandium from the phosphate ion exchanger with a strong soda solution at a high temperature to obtain a strippant rich in scandium, and at least one strippant hydrolysis stage to obtain a scandium-containing concentrate at the second stage, characterized in that the carbonization leaching of the red mud is carried out at least in a single stage using a solution with a mixture of sodium carbonate and bicarbonate, scandium is sorbed from the obtained scandium-containing solution on a phosphorous-containing ion exchanger, scandium is desorbed from an ion exchanger organic phase using a sodium carbonate solution to obtain commercial regenerated scandium from which a scandium concentrate is precipitated, wherein the Sc2O3 content therein is least of 15 wt. % (in terms of dry matter), the TiO2 content not more than 3 wt. % (in terms of dry matter), the ZrO2 content not more than 15 wt. % (in terms of dry matter), and wherein scandium in the concentrate is in form of a mixture of Sc(OH)3 hydroxide with ScOHCO3×4H2O basic salt.
A scandium-containing concentrate produced by a carbonate sorption hydrolysis process, comprising a mixture of scandium, titanium, zirconium, iron, sodium oxides, hydroxides and carbonates, characterized in that the of Sc2O3 content therein is at least 15 wt. % (in terms of dry matter), the TiO2 content not more than 3 wt. % (in terms of dry matter), the ZrO2 content not more than 15 wt. % (in terms of dry matter), wherein scandium is present in the concentrate in the form of a mixture of Sc(OH)3 hydroxide with ScOHCO3×4H2O basic salt.
A method for producing a high-purity scandium oxide, said method comprising dissolving a scandium-containing concentrate in sulfuric acid, removing an acid-insoluble precipitate, precipitating scandium, filtrating, washing, drying and calcining to obtain a precipitate of scandium oxide, characterized in that the Sc2O3 content in the scandium-containing concentrate is least of 15 wt. % (in terms of dry matter), the TiO2 content not more than 3 wt. % (in terms of dry matter), the ZrO2 content not more than 15 wt. % (in terms of dry matter), and scandium in the concentrate is in form of a mixture of Sc(OH)3 hydroxide with ScOHCO3×4H2O basic salt, wherein, once the acid-insoluble precipitate is removed, scandium from the filtrate is precipitated with sodium sulfate in the form of a double salt of sodium and scandium sulfate, filtered out, the obtained precipitate is washed with a sodium sulfate solution, the double salt is dissolved in water and scandium hydroxide is precipitated with caustic soda, then the cake is filtered, washed and added to a solution of oxalic acid to turn scandium into scandium oxalate using oxalic acid, scandium oxalate is filtered out, washed with water, and calcined to produce scandium oxide with a purity of approximately 99 wt. %.
Dependencies are inferred from the claim text.