用浓度比较法自动绘制Cu-NH_3-H_2O系电势E-pH图

Automatic generation of potential-pH diagrams for the Cu-NH_3-H_2O system using concentration comparison

报道了利用浓度比较法自动绘制Cu -NH3-H2 O系的综合平衡电势E -pH图 ,以及平面内每个溶液态物质分布的优势区域图 综合平衡电势E -pH图中各固相物质 :Cu2 O3(s) ,CuO(s) ,Cu2 O(s)及Cu(s)和溶液相物质的稳定区域大小与体系的总氨T(NH3)浓度和所有溶液态物质的总铜T(Cu)浓度有关 ,而溶液态物质的优势区域图只与总氨浓度有关 ,与T(Cu)无关 与简单的Cu-H2 O系比较发现 ,配位体NH3的存在使Cu2 O(s)或CuO(s)的稳定区变小甚至消失 ;而优势区域图中 ,Cu+优势区的大部分被Cu(NH3) +l(l=1,2 )所取代 ,HCuO- 2 的优势区被Cu(NH3) 2 +l (l=1,2 ,3,4 )所取代 所提出的绘制E -pH图的方法简单 ,运行时间短 ,Cu -NH3-H2 O系中各溶液态物质的优势区域图为首次报道 对相应体系的湿法冶金过程进行了实例分析 ,表明理论计算结果具有一定的指导作用 图 3,参

Potential-pH diagrams for the Cu-NH 3-H 2O system, including both general Pourbaix diagrams (also called overall equilibrium potential-pH diagrams) consisting of stable regions of all solid species and the stable region of all aqueous species as a whole, and predominance diagrams of total dissolved species on pH-potential(E) plane, have been first generated using concentration comparison in this paper. The stable regions of Cu 2O 3(s), CuO(s), Cu 2O(s), Cu(s) and solution phase are dependent upon both total ammonia concentrations T(NH 3) and total copper concentrations T(Cu) of all dissolved species in the system. However, predominance diagrams of the aqueous species are free from T(Cu). Compared with simple Cu-H 2O system, stable regions of Cu 2O(s) or CuO(s) decrease, even disappear in presence of the ligand NH 3, and in the predominance diagrams stable regions of Cu + are mostly replaced by Cu(NH 3) + l (l=1,2) and those of HCuO - 2 are replaced by Cu(NH 3) 2+ l (l=1,2,3,4). Although the computation is simple, it can automatically handle the situation where a solid phase becomes unstable with respect to the aqueous phase. Quantitative information on real hydrometallurgical processes can be obtained from these diagrams.3figs.,7refs.