Rational Technology for Separation of Rare Earth Elements Isolated from Monazite

The behavior of actinium-227 and actinium-228 in the life cycle of monazite processing is considered. The recommended system for separation of actinium-227 and actinium-228 is 90–100% TBP–300–350 g/dm³ of Ln(NO₃)₃–0.1–0.5 mol/dm³ of HNO₃. The process is combined: actinium-227 and actinium-228 are removed simultaneously with purification from rare earth impurities, iron, aluminum, calcium, and phosphate ions occurs. If monazite does not contain uranium, it is recommended to hold the rare earth concentrate (solution or carbonates) after separation of thorium for 1–2 days. A process flow chart for separation of the sum of REEs isolated from monazite is proposed, with production of didymium, lanthanum–cerium concentrate, and yttrium REE concentrate.