Separation of cerium earths from large quantities of mixtures with yttrium earths by fractional crystallization of magnesium double nitrates

The fractional crystallization of magnesium double nitrates was used to separate cerium earths from 112 kg yttrium earth mixtures; they were recovered in three different fractions. By using excess magnesium nitrate the crystallisation could be extended at least to gadolinium without using HNO3 as solvent. In the resulting solutions (69 kg oxide) there remained yttrium and nearly all erbium and heavy yttrium earths. (author)