Experimental and Thermodynamic Study on Reduction of Carbon-containing Pellet of Vanadium Tailings Smelted by Electric Arc Furnace

The thermodynamics of carbothermal reduction of vanadium and chromium oxides in vanadium tailings was calculated and analyzed. It is shown that the reduction sequence of vanadium oxide is V₂O₅ →VO₂→V₂O₃→VO→VC→[V],and the reduction sequence of chromium oxide is CrO₃→CrO₂→Cr₂O₃→Cr₄C →[Cr]. Using electric arc furnace (50 k VA) for the carbothermal reduction of carbon-containing pellet of vanadium tailings,the effects of carbon ratio and alkalinity on the distribution ratio of V and Cr between slag and metal phase,the recovery rate of Fe,V and Cr,were investigated. The results indicate that with increase in carbon ratio,distribution ratio of V and Cr between slag and metal phase increases and the recovery rate of Fe,V and Cr decreases. With increase in alkalinity,distribution ratio of V and Cr between slag and metal phase decreases in association with increase in recovery rate of Fe,V and Cr. The optimum process parameters are proposed as follows: 12%~14% of carbon ratio and 1.0~1.1 of alkalinity,under which the recovery rate of Fe,V and Cr can exceed 90%.