The Ames Laboratory has been actively involved in the preparation of very pure rare earth metals since the early 1940s, when Dr. Frank H. Spedding and his group of pioneers developed the ion-exchange process. Their technique separates the "fraternal fifteen" plus yttrium and scandium. As a result of this process and subsequent work, high-purity oxides are available from which high-purity rare earth metals can be prepared. In most cases, the rare earth oxides are first converted to their respective fluorides and then reduced metallothermically on a kilogram scale, using pure calcium metal specially sublimed for this purpose. The resulting metals are very pure. Nonetheless, many are further refined at the Materials Preparation Center (MPC) by one of the following processes:
- vacuum casting
- zone refining
- electro-transport processing
Quantities of high-purity rare earth metals and alloys in single and polycrystalline forms are available to scientists outside of Ames Laboratory. Complete chemical analyses, obtained by laser mass spectrometry, inert gas fusion, and combustion analysis, accompany these materials. Special preparations of high-purity alloys and compounds are also available in small quantities.