Biosorption of scandium and yttrium from solutions

The usage of biosorbents allows separation of scandium and yttrium from each other and from Fe, Al, Ti, Si, and Ca in hydrometallurgical processing of ores and wastes. It was shown that sorption of scandium and yttrium increased with the increase of pH of solution. Initial rate of scandium sorption depended on the biomass type; however 85-98% of scandium was sorbed within 10-30 min with most biomass types tested. The presence of aluminium, iron (III), and titanium in the solution inhibited sorption of scandium and particularly yttrium. After four cycles of sorption, 98.8% of scandium and 87% of yttrium was extracted from red mud leach solution by the biomass of Saccharomyces cerevisiae and Aspergillus terreus, respectively. Selectively of the process of scandium and yttrium recovery could be achieved during sorption and also desorption, when solubilization of sorbed associated elements was inhibited by high pH values. (Author)