钙化提钒尾渣碳酸氢铵脱硫及酸浸提钒工艺研究

Study on desulfurization using ammonium bicarbonate and vanadium extraction by acid leaching from calcified vanadium tailings

针对钙化提钒尾渣难以实现有效提钒利用的现状,提出采用碳酸氢铵脱硫-酸性浸出的工艺对钙化提钒尾渣进行处理。研究了脱硫过程中反应温度、碳酸氢铵加入量、液固比对脱硫效果的影响;酸浸过程中温度、pH、液固比对提钒效果的影响,并采用曲面响应的研究手段进行了条件优化,获得了最佳反应参数。结果表明:在脱硫反应温度为30℃,碳酸氢铵用量与脱硫理论值之比为1.4∶1,脱硫液固比(L∶S)=5∶1时,脱硫率为94.58%;在酸浸温度30℃,酸浸液固比L∶S=6∶1,酸浸pH=1.0的条件下,尾渣钒的浸出率为56.79%。通过曲面响应试验得到了最佳工艺参数:浸出pH为0.977,浸出温度为39.36℃,液固比4.455∶1。在该条件下,钒的浸出率的预测值为56.80%,验证性试验浸出率为56.77%,比预测值仅低0.03个百分点。研究结果表明该工艺操作简单,脱硫率高,提钒效果较好,有利于钙化提钒尾渣的有效利用,具有良好的发展前景。

In view of the current situation that it is difficult to achieve effective utilization of vanadium from calcified vanadium extraction tailings,a process of desulfurization using ammonium bicarbonate followed by acid leaching was proposed.The effects of reaction temperature,adding amount of ammonium bicarbonate and liquid-solid ratio on desulfurization were studied.In the subsequent process of acid leaching,the effects of leaching temperature,pH value and liquid-solid ratio on the vanadium extraction were also studied.The surface response method was used to optimize the conditions and the best reaction parameters was obtained.The results show that the desulfurization rate reaches 94.58%when the reaction temperature is 30℃,the ratio of ammonium bicarbonate to the theoretical value of desulfurization is 1.4∶1 and the ratio of liquid to solid(L∶S)is 5∶1.Under the conditions of acid leaching temperature of 30℃,liquid-solid ratio(L∶S)of 6∶1 and pH value of 1.0,the vanadium leaching rate of tailing slag is 56.79%.According to the surface response test results,the optimal process parameters were obtained containing leaching pH value of 0.977,leaching temperature of 39.36℃and liquid-solid ratio of 4.455∶1.Under these conditions,the predicted value of vanadium leaching rate is 56.80%,and the confirmatory experiment shows that the leaching rate is 56.77%,which is only 0.03%lower than the former.This process has the advantages of simple operation,high desulfurization rate and good vanadium extraction effect,which is conducive to the effective utilization of calcified vanadium extraction tailings and has a good development prospect.