Rare Earth Materials Purity Definition
Purities of Rare Earth Metals and Oxides:
In rare earth industry, chemical purities of rare earth metals are often presented on rare earth metal or oxides basis (REM/REO basis), content of a specific rare earth material in comparison to total rare earth metals(TREM) or oxides (TREO) present: REM/TREM and REO/TREO.
The statement of "Sc > 99.9%" often means Sc/TREM > 99.9%. And Sc2O3 > 99.99% (REO) means Sc2O3/TREO > 99.99%.
To obtain its absolute purity of a specific metal, you can use formula: REM/TREM X Percentage of TREM in the material.
Purity examples (same purity for below three):
Sc > 99.9%
Sc > 99.9%(REM)
TREM>99%, Sc/TREM > 99.9%
Link to this article: https://www.albmaterials.com/knowledge/rare-earth-materials-purity-definition.html