Selective Extraction of Yttrium from Zr-Y-Nb-Th-Rich Microgranite Dike Leach Solution Using Cyanex 921

Abstract

ABSTRACT The Yttrium (Y)-rich sample was collected from the microgranite dikes in the Ras Abdah area, Northern Eastern Desert of Egypt. The mineralogical studies on the Y-rich microgranite dike (RMGD) revealed the presence of REEs-bearing minerals with 8480 mg/kg Y content. In this study, a novel method was used to selectively recover the Y(III) content (8480 mg/kg) from other rare earth elements (REEs) in the digested concentrate solution. Solvent extraction using Cyanex 921(Cy-921) was applied for the first time to achieve this secondary recovery process. Different factors affecting Y extraction were studied. Using the slope analysis technique, we may infer that Cy-921 has extracted Y as a complex with a 3:1 (Cy-921: Y) molar ratio. Extraction efficiencies of around 99% were achieved for Y(III), employing a concentration of 1 mole. L-1 of Cy-921/ Kerosene. The organic to aqueous ratio was 1:1, the aqueous pH was 0.3, and the contact period was 15 minutes. Thermodynamic calculations showed that Cy-921/Y extraction is characterized by an exothermic nature. The stripping process of Y (99.8%) was achieved using 2.5 mole. L-1 H2SO4. A highly refined Y precipitate was obtained from the stripped solution by an oxalic acid precipitation method and then subjected to calcination, resulting in the production of Y2O3 with a purity of 99.8%.