Abstract: A phase change crucible that includes an inner chamber comprising an inner chamber wall extending from an inner chamber floor to an inner chamber upper end, an outer chamber comprising an outer chamber wall extending from an outer chamber floor to an outer chamber upper end, wherein the inner chamber upper end terminates beyond the outer chamber upper end and the outer chamber wall encircles the inner chamber wall, an inner collection region formed by the inner chamber wall and the inner chamber floor, and an outer collection region formed by the outer chamber wall, the inner chamber wall, and the outer chamber floor.

Abstract: A method including sublimating or distilling an ytterbium composition from an initial solid composition comprising ytterbium and lutetium in an inert or reduced pressure environment and at a first average temperature for a first sublimation/distillation period to leave a lutetium composition comprising a higher weight percentage of lutetium than was present in the initial solid composition, collecting the ytterbium composition; retaining the ytterbium composition for a waiting period to form a decayed ytterbium composition, wherein the waiting period is longer than the first sublimation/distillation period; and subsequent to the waiting period, sublimating or distilling a refined ytterbium composition from the decayed ytterbium composition in an inert or reduced pressure environment and at a second average temperature for a second sublimation/distillation period to leave a waste composition.

Abstract: A method for purifying lutetium includes providing a solid composition comprising ytterbium and lutetium and subliming or distilling ytterbium from the solid composition at a temperature of about 1196° C. to about 3000° C. to leave a lutetium composition comprising a higher weight percentage of lutetium than was present in the solid composition.