Purification of rare earth chloride liquor associated with high-grade monazite exploitation

Removal of the non-desired impurities (radionuclides, Th(IV) and Fe(III)) with Ln(III) in high-grade monazite was developed. The chromate solution and pH are the factors controlling removal of the non-desired impurities. At pH 3, removal of radionuclides and Fe(III) was 30 and 60%, respectively, whereas Th(IV) interfered with Ln(III) liquor. When liquor was treated by 0.23 M chromate solution at pH 3, ~ 98% of Th(IV) and Fe(III) was removed and ~ 70% of radionuclides was removed from Ln(III) liquor with loss ≤ 20% is low compared with a previous study. Thus, exploitation of valuable Ln(III) can be done safely using the optimized chromate solution.