除钒尾渣短流程工艺制备高纯NH_(4)VO_(3)

High-purity NH_(4)VO_(3) Preparation with Short Process Using Vanadium-removal Slag

粗TiCl_(4)除钒尾渣含钒2%~5%,具有较高的回收利用价值。为实现除钒尾渣中钒资源的低成本回收,提出了除钒尾渣直接焙烧—铵盐浸出—沉钒制备偏钒酸铵的新工艺,并开展了相关条件试验,重点考察了焙烧温度、NH_(4)HCO_(3)用量、浸出温度、浸出时间对提钒效果的影响。结果表明:①除钒尾渣在650℃下焙烧150 min,获得的焙烧样中主要物相有金红石型TiO_(2)、锐钛型TiO_(2)、Al_(2)O_(3)、V_(2)O_(5)和SiO_(2),钒氧化率达78.12%,可采用铵盐浸出实现钒的低成本提取。②条件试验确定焙烧样适宜的浸出条件为:NH_(4)HCO_(3)用量n(NH_(4)+)/n(V)=2,液固比5 mL/g,浸出温度80℃,浸出时间30 min。在上述条件下,钒浸出率可达76.65%,浸出液V浓度为5.71 g/L。浸出液经4次循环浸出后,V浓度提高至19.66 g/L。该较高浓度的浸出液直接沉钒,获得了纯度>99%的偏钒酸铵产品,满足标准一级品(YS/T 1022—2015)的要求,XRD分析进一步证实其具有较高的纯度。研究结果可为除钒尾渣中钒资源的短流程回收提供技术支撑。

Vanadium-removal slags of crude TiCl_(4) contain vanadium of 2%to 5%,indicating high recycling value.In order to realize the low cost recovery of vanadium resources from vanadium-removal slag,a new process of direct roasting,ammonium salt leaching,precipitation of vanadium to prepare NH_(4)VO_(3)from vanadium-removal slag was proposed.And the related conditions tests were carried out focusing on the effects of roasting temperature,NH_(4)HCO_(3) dosage,leaching temperature and leaching time on vanadium extraction.The results showed that:①After roasting at 650℃for 150 min,the main phases of the roasting samples are rutile TiO_(2),anatase TiO_(2),Al_(2)O_(3),V_(2)O_(5) and SiO_(2),and the vanadium oxidation rate reaches 78.12%.The low-cost extraction of vanadium could be realized by ammonium salt leaching.②The optimum leaching conditions of roasted samples were determined as follows:dosage of NH_(4)HCO_(3) of n(NH_(4)+)/n(V)=2,ratio of liquid to solid of 5 mL/g,leaching temperature of 80℃,leaching time of 30 min.Under the above conditions,the leaching rate of vanadium could reach 76.65%,and the concentration of vanadium of leaching solution is 5.71 g/L.After circulating leaching for four times,the concentration of vanadium increased to 19.66 g/L.The high concentration leaching solution could directly precipitates vanadium to obtain NH_(4)VO_(3)product with purity above 99%,which meets the requirements of standard Grade I product(YS/T 1022—2015).XRD analysis further confirms that it has high purity.The research results can provide technical support for the short process recovery of vanadium resources from vanadium-removal slag.