Abstract:Effects of different calcareous additives on roasting effect of stone coal were studied with mica-type vanadium-bearing coal as raw material from Hubei Province. CaO and CaF2 were selected as composite additives. The effects of ratio of compound additives, roasting temperature, and roasting time on vanadium leaching rate were investigated. The roasted stone coal was analyzed by XRD, SEM, and thermodynamics. The results show that the roasted clinker can be obtained by adding 6% CaO 4% CaF2, roasted at 850 ℃ for 90 min. The leaching rate of vanadium is 91.73% under the conditions including temperature of 95 ℃, volume fraction of sulfuric acid of 20%, leaching time of 2 h, and L/S of 3︰1(mL/g). The results of thermodynamics analysis and XRD show that CaF2 is involved in chemical reaction, and mica structure is effectively destroyed during roasting process, which is basic for vanadium dissociation. CaO has a good affinity to V2O5. Roasting can promote generation of calcium carbonate and is in favor of leaching of vanadium.