Influence of Mixing-milling Technique on Sodium Roasting of Vanadium Slag

Vanadium slag and sodium carbonate were mixed and milled by an omni-directional ball mill.The particle size distribution,morphology and uniformity of the materials after mixing and milling were analyzed and compared with those of the materials of vanadium slag and sodium carbonate by direct mixing.The difference in leaching rate of the roasted vanadium slag respectively by the direct mixing and mixing-milling processes were investigated at variable alkali ratios,and the effects of mixing-milling time and roasting temperature on the leaching rate of the roasted vanadium slag were also studied.The results show that compared with direct mixing the mixing-milling process can increase the leaching rate of the roasted vanadium slag significantly at the same alkali ratio.A leaching rate of 92.67% can be obtained for the roasted vanadium slag by mixing-milling process at 22% of alkali ratio,while the leaching rate of 92.34% can be obtained for the roasted vanadium slag by direct mixing at 26% of alkali ratio.The mixing-milling process can decrease the sodium carbonate dosage at the same leaching rate requirement in comparison with the direct mixing.When the mixing-milling time exceeds 20 min,the leaching rate of the roasted vanadium slag changes slightly.The favorable roasting temperature is determined at 770～790 ℃.The research has a practical guidance on enhancement of vanadium recovery and decrease of sodium salt consumption during sodium roasting of vanadium slag.