Precipitation of crystal hydrates of acetylacetonates as the technique of REE purification (neodymium being taken as example) from calcium

It is suggested that precipitation of rare earth-calcium crystal hydrates of acetylacetonates should be used for the element mixture separation, since solubility and stability constants of calcium and neodymium acetylacetonates, for instance, differ considerably. Using neodymium-calcium systems by way of example, the optimal conditions of quantitative isolation of cerium subgroup rare earths from calcium were found. By adding equimolecular amount of acetylacetone, neutralized by aqueous NH3, to aqueous solution of neodymium-calcium mixture (mole ratio was varied from 9:1 to 1:9) at pH 8 crystal precipitates of NdA3·3H2O with calcium content of 0.01-0.02 mol% were prepared