V-bearing stone coal is a new kind of vanadium resource.The oxidation states of vanadium in the Yangjiapu stone coal were analyzed by means of electro-analysis and mineral separation.Sample analysis gave:93.8% V(Ⅲ）and 6.2%V(Ⅳ）Neither V(Ⅱ）nor V（Ⅴ）was present in the stone coal.Valency analysis showed that vanadium was present in the form of VO^2+n vanadium porphyrin.The distribution of oxidation states of vanadium shows that in the presence of organic matter and pyrite only a small amount of V（Ⅲ）can be oxidized into V(Ⅳ）when the stone coal is roated.At 450℃ pyrite was oxidized into α Fe2O3 and 95% of the arganic matter were oxidized,Under such conditions 85% of V(Ⅲ） were oxidized into V(Ⅳ） At about 520℃ V(Ⅲ） was completely oxidized into V（Ⅳ） At 800°-1000℃ 91% of vanadium in the stone coal were oxidized into V(Ⅴ）.Over the range of high temperatures no more vanadium was oxized into V(Ⅴ）that is to say,an equilibrium was established.Salt roasting may play a very important role in extracting vanadium from the stone coal.From the results of our experiments it is considered that sodium chloride cannot only promote the oxidation of vanadium,but also react with vanadium to form soluble vanadate.It is evident that 800℃ is the optimum temperature at which vanadium is extracted from stone coal.
