Reindarstellung von Lanthan- und Praseodym-Ammoniumdoppelnitraten durch fraktionierte Kristallisation in großem Maßstab

Summary Lanthanum ammonium nitrate of purity 97%, containing 34.1 kgRE ₂O₃, was crystallized fractionally and yielded 32.5 kg oxide of purity better than 99.9% (the larger part was 99.99% pure). Out of mixtures with 66% Pr there resulted praseodymium ammonium nitrate containing 13.45 kg oxide of purity better than 99.5%. The effective separation factors are discussed, showing a better efficiency of the ammonium than of the magnesium double nitrates for the separation of praseodymium and lanthanum.