盐酸磷酸络合浸出白钨矿的试验研究

Coordination Leaching of Scheelite Ore by HCl-H_3PO_4

采用盐酸和磷酸络合浸出白钨矿,用原子吸收分光光度法（AAS）测定溶液中钨的含量,研究了盐酸初始浓度、W/PO2-4重量比、反应温度对浸出动力学的影响,并通过二次回归的方法处理这些结果,建立了宏观的动力学方程。另外,考察了粒度、盐酸初始浓度、温度、W/PO2-4重量比、液固比和浸出时间对白钨矿浸出率的影响,分析了实验结果并利用单因素法对影响反应体系的各个影响因子进行优化。结果表明,白钨矿络合浸出反应属液-固相非催化收缩核模型,整个反应过程属于界面化学反应控制,计算得出该络合反应的表观活化能为59.8kJ·mol-1,其反应动力学方程为：K=4.85×108C0.585HClC0.504PO3-4exp（-59910/RT）;最佳工艺参数为：温度90℃、搅拌速度900 r·min-1、粒度48～58μm、盐酸初始浓度2 mol·L-1、W/PO3-4质量比mw/mPO3-4=3∶1、液固比8∶1和浸出时间2.5 h。在此工艺参数下,白钨矿的浸出率为99.6%。

The coordination leaching kinetics of scheelite ore with HCl-H3 PO4 was studied in the following factors ： initial concentration of HC1, W/PO4^3- weight ratio, temperature. The concentration of WO3 was analyzed by atomic absorption spectrophotometry （AAS） after leaching. The kinetic equation for tungsten leaching with HCl-H3PO4 was established after dealing with the data by quad- ratic regression. Besides, the effecting factors, such as particle size, initial concentration of HCl, temperature, W/PO1^3- weight ratio, liquid-solid ratio and leaching time, on scheelite leaching rate were observed. Then, the results were analyzed and the affecting factors in reac- tion system were optimized in single-factor test. The results showed that, an unreacted shrinking core model was used to describe the leaching process and it was controlled by the interfacial chemical reaction. The apparent activation energy was calculated to be 59. 8 kJ·mol^-1 and the 8 .585 .504 dynamic equation could be described as： K = 4.85 × 10 CHCl^0.585 C^0.504PO4^3- exp （-59910/RT） ; the optimum conditions obtained were that temperature was 90 ℃, stirring speed was 900 r·min^-1 , particle size was 48 ～58 μm, initial concentration of HCl was 2 mol·L^-1 , W/PO4^3- mass ratio was 3： 1, liquid-solid ratio was 8： 1, and leaching time was 2.5 h. Under these conditions, the leaching rate of scheelite was 99.6%.