1.IntroductionRare earth resources in China are the most abundant with more than twenty factories pro-ducing rare earths in the country,the production capabilit
Vanadium-bearing stone coal is a new resource of vanadium. V in stone coal mainly exists in three oxidation states: 7.84%V(Ⅲ), 72.08% Ⅴ(Ⅳ) and 20.08% Ⅴ(Ⅴ). The c