a REE in 8 M Hal solution.A mixture of 50% HF and 10% NH4F solutions,together with a La.3+ carrier solution (8 mg/cm3), was then added to precipitate the rare earth fluorides. The fluorides were separated by centrifugation, and dissolved with a HN03 solution (1:1, 5 cm3) and a H3BO3 saturated solution (5 cm3).The fluoride precipitation step was then repeated without the addition of La3+ carrier. The fluorides are finally dissolves as described.