Abstract: Among a vanadium-bearing stone coal from Hubei province，more than 85% vanadium exists in mica minerals.V3+ and V4+ account for 70.83% and 29.17% of total vanadium respectively，in which V3+ replaces Al3+ as isomorphism in mica lattice which make vanadium hard to be released by direct acid leaching at atmosphere pressure.In order to find a high efficiency，low consumption，environmental friendly vanadium extracting process and parameters，by compared with atmosphere pressure acid leaching results，the oxygen pressure acid leaching process conditions were examined.The research results indicate that increasing leaching temperature，sulfuric volume concentration and oxygen partial pressure can significantly improve vanadium leaching efficiency，and introduction of pressure field can substantially raise vanadium leaching efficiency，shorten leaching time and reduce acid consumption.Vanadium leaching efficiency by oxygen pressure acid leaching reach 75.98% with sulfuric volume concentration of 20%，leaching for 5 h，leaching temperature at 160 ℃，oxygen partial pressure of 0.5 MPa，which is 45.12% higher than that of atmosphere pressure leaching at sulfuric volume concentration of 20%，leaching for 5 h and leaching temperature at 98 ℃.

Key words: Mica-type vanadium bearing stone coal, Vanadium extracting, Atmosphere pressure acid leaching, Oxygen-pressure acid leaching, Vanadium leaching efficiency