Roasting With Low Ratio Of Chloride And Leaching At High-temperature For Extraction Of Vanadium From Stone Coal

Stone coal is an important vanadium-bearing resource, which is widely distributed in many provinces of China. The process of vanadium extracting has received more and more attention in recent years due to the increasing demand of vanadium products. Although there has been developed a lot of vanadium extraction process, but most of these processes have the characteristic of high cost, poor universal applicability and low resource utilization. This artical focus on the problem of traditional vanadium extracting process which has serious environmental pollution and low resource utilization, and come up with the process which use low chlorine additive and high-temperature leaching to extracting vanadium, which effectively reduce the emission of toxic gas and improve the gross recovery of vanadium from stone coal, is turning into a effective technique to break this limitation.In the course of extracting vanadium from stone coal, the influences of roasting with low chloride and high-temperature leaching on the vanadium recovery rate were studied. The experiment with low chlorine compound additives take sodium chloride and sodium carbonate as the baking additives, and the boiling temperature、 granularity、roasting temperature and roasting time are the important factors which effect extracting rate of stone coal. The optimized technological parameter was the boiling temperature of200℃, the roasting time of3h, the roasting temperature of820℃. According to the experiment results, the vanadium recovery rate could reach up to70%under this condition.The leaching rate of vanadium tends to decrease as secondary reactions would happen when the calcine cools slowly during the vanadium leaching extraction process. So a new leaching technology of extracting vanadium by dipping the high-heat calcine directly into water was proposed in this research through singular factor and orthogonal experiments. The optimized leaching condition was the tapping temperature of650℃, the leaching time of9h and the liquid-solid ratio of2:1mL/g, respectively and the leaching rate could reach up to89%under that condition according to the experiment results. The peak leach rate in this research was19percent higher than that of control experiment in which leaching extraction process was conducted after cooling of the calcine. This method could not only improve the leaching rate of the vanadium by reducing the generation of insoluble vanadium bronze, but also speed up the leaching process by effectively utilize the heat from the high-heat calcine.