Selective separation and purification of cerium (III) from concentrate liquor associated with monazite processing by cationic exchange resin as adsorbent

Abstract The present study is directed to find the optimal conditions required for efficient separation and purification of Ce 3+ as an analog for lanthanides from Fe 3+ , Th 4+ , and Zr 4+ (interfering ions) using Amberlite IR120H (AIR120H) resin as a strongly cationic exchange adsorbent. The main factors affecting the separation processes had been investigated and optimized. Ce 3+ (Ln 3+ ) as an admixture with Fe 3+ , Th 4+ , and Zr 4+ was successfully separated by batch and column techniques. The sorption efficiency ( S , %) from different acidic media was in this order: HCl > HNO 3 > H 2 SO 4 . In a quaternary mixture with Fe 3+ and Th 4+ , the maximum separation factor between Ce 3+ and Zr 4+ was ~ 13 after 90 min of equilibration, and the sorption capacity of AIR120H resin for Ce 3+ was 8.2 mg/g. The rate of adsorption was found to follow a pseudo-second-order kinetic model. Separation of the absorbed ions was achieved by desorption processes. Firstly, 98 ± 2% of loaded Ce 3+ is fully desorbed by 1 M sodium acetate solution without interfering ions. Moreover, ~ 95% of Zr 4+ is desorbed by 1 M citric acid solution. Finally, 85% of loaded Fe 3+ and Th 4+ ions are desorbed with 8 M HCl solution. The batch technique was applied to separate and purify Ln 3+ -concentrate in chloride liquor (LnCl 3 ), coming from the caustic digestion of Egyptian high-grade monazite. However, the enhanced radioactivity in LnCl 3 due to radium -isotopes ( 228 Ra 2+ , 226 Ra 2+ , 224 Ra 2+ , 223 Ra 2+ ) and radio-lead ( 210 Pb 2+ ) is initially reduced by a factor of 92% (i.e., safe limit) by pH-adjustment. As result, it can be recommended that the sorption process by AIR120H resin is efficient and promising for exploring pure lanthanides from its minerals.