LAUSR

Abstract The present study aims to investigate the optimum parameter in producing high-purity thorium dioxide (ThO2) using Di-2-ethylhexyl phosphoric acid (D2EHPA) and Aliquat-336 as solvent materials. The extraction and purification process was performed using [Th-RE](OH)4 compound which was selectively precipitated from the monazite leach solution. Several parameters such as types of acid (HCl, HNO3 and H2(SO4)), acid molarity (1M–6M), and solvent ratio (10%–30%) were investigated. The findings indicate that different solvents require a distinctive aqueous medium to extract thorium. The optimum concentrations of D2EHPA and Aliquat-336 in extracting thorium were identified to be at 1M H2(SO4) and 4M HNO3 with 30% and 20% ratio, respectively. The multi-stage extraction process was successfully extracted and purified thorium at a purity of 96.8% (D2EHPA) and 98.0% (Aliquat-336). Subsequent conversion to ThO2 yielded a high-purity thorium dioxide at 99.1%. In general, the study elucidates that both solvents have the potential to be utilized as thorium extracting agents in preference to the conventional tri-butyl phosphate (TBP).