LAUSR

Abstract A study was carried out for recovery of scandium from KOH sub-molten salt (SMS) leaching cake of fergusonite. Major metals in the cake were rare earths (RE), K, Th, U and Ca, and minor metals were Pb, Nb, Ta, Ti, Fe, Si, Sn, Al, Bi and Mn. Scandium content was about 0.94% in the cake. Experiments for the recovery of scandium involved washing of the cake with water for potassium removal, leaching of scandium from the cake with HCl, solvent extraction with tri-butyl phosphate (TBP) and precipitation of scandium with oxalic acid. Effects of liquid-to-solid ratio and leaching temperature on leaching of scandium as well as impurities such as uranium, thorium and other rare earths such as yttrium and lanthanides were investigated, with the aim of both increasing scandium leaching and selectively pre-separating the impurities. And also, the separation characteristics of scandium and the impurities were evaluated in the solvent extraction with TBP. Finally, we proposed a process for recovery of scandium from the KOH SMS leaching cake of fergusonite.