实验研究了不同条件下钒渣焙烧与NaOH溶液水热浸出对钒浸出率的影响,并分析了过程机理.结果表明,焙烧温度达700℃以上可实现钒铁尖晶石的氧化分解,850℃焙烧2 h是钒渣空白焙烧的最佳条件,浸出的最佳条件是反应温度180℃、钒渣粒度小于74μm、反应时间2 h、液固比5 L/g、碱浓度30%(ω)、搅拌速度500 r/min.该条件下钒浸出率达95%以上,无有害气体产生.
The effects of vanadium slag roasting and NaOH solution of hydrothermal leaching on the leaching rate of vanadium were studied, the optimum parameters of the process were obtained, and the mechanism was analyzed. The results showed that when the roasting temperature reached over 700℃, the oxidative decomposition of vanadium iron spinel could be achieved, the optimum conditions for roasting process were roasting at 850 ℃ for 2 h. The optimum leaching conditions were obtained as leaching temperature of 180 ℃, vanadium slag particle size lass than 74 μm, leaching time 2 h, ratio of liquid to solid 5 L/g, concentration of NaOH 30%(ω) and stirring speed 500 r/min. Under these conditions, the leaching rate of vanadium could reached 95%. No harmful gases were produced in the roasting and hydrothermal leaching of NaOH.