镍钼矿酸浸液中磷钼存在形态的热力学计算

Thermodynamic analysis for species of molybdenum and phosphorus in Ni-Mo ore acidic leaching solution

通过热力学计算25℃时H_+-MoO_4^(2-)-HPO_4^(2-)体系在水溶液中的离子形态并绘制其随p H、磷浓度变化的关系图。为了模拟镍钼矿硫酸浸出液的液相环境,控制模拟料液中钼的浓度在0.1mol/L左右,分析磷钼摩尔比(n(P):n(Mo))为1:1、1:9、1:12、1:50时其热力学平衡图的变化规律。结果表面:随着p H值的降低,钼的存在形态分别是钼酸根离子、磷钼杂多酸根离子和同多钼酸根离子。当氢离子浓度在0.1mol/L左右,随着溶液中磷浓度的降低,钼的存在形态由Dawson结构的Mo_(18)P_2O_(62)^(-6)转变成Keggin结构的Mo_(12)PO_(40)^(3-)。

The thermodynamic diagrams of the ionic species were plotted at different pH values and phosphorus concentration in H＋-MoO4^2-HPO4^2- system at 25℃. To simulate the liquid phase environment of Ni-Mo ore leaching solution, the diagrams were plotted with different phosphorus-molybdenum molar ratios of 1：1, 1：9, 1：12 and 1：50 at certain molybdenum concentration of 0.1 mol/L. The results show that, as the pH value decreases, the species of molybdenum are molybdate anion, molybdophosphate anion and isopolymolybdate ion. As the phosphorus concentration decreases, the species of molybdenum is converted into Keggin-type Mo18P2O62^8 from Dawson-type Mo12PO^40^3- at certain hydrogen ion concentration 1mol/L.