On the Oxidation States of Vanadium in Chong Yang Stone Coal

V-bearing stone coal is a new kind of vanadium resource.The oxids tion states of vanadium in the Chong Yang stone coal were analyzed by means of electroanalysis and mineral separation, the result shows that it contains 98.77% of V (Ⅲ) and 1.23% of V (Ⅳ).neither V (Ⅱ) nor V (Ⅴ).The distribution of oxidation states of V shows that both organic matter and pyrite could prevent V (Ⅲ) from oxidizing to V (Ⅳ),below 400℃,the oxidation states of V are mainly dependent upon reducing minerals, but over 400℃, the temperature is the most important factor. At about 520℃, V (Ⅲ) is completely oxidized into V(Ⅳ):at 700-1000℃ 82% of V in the stone coal are oxidized into V(Ⅴ), over the range of high temperature no more V is oxidized into V(Ⅴ), an equilibrium, between V (Ⅳ) and V (Ⅴ) is established.Salt roasting may play very important role in extracting V from the stone coal,from the results of our experiment it is considered that NaC1 can not only promote the oxidation of V, but also react with V to form soluble vanadate.The best conditions for roasting are temperature 775℃ for 15 minutes and mineral:salt=100:10 by weight, η reaches 81%.