Pourbaix diagram and predominance area diagram are important thermodynamic stability diagrams. Computer programs have been developed to plot such diagrams. However, their application of E-pH Diagram are somewhat limited due to the differences between real conditions and those theoretically assumed. In this paper, a new algorithm is proposed on E-pH predominance diagrams. The equilibrium constant approach and activity term method are used to plot E-pH diagrams for Metal-H20 and Metal-Ligand-H20 systems based on the thermochemical database developed. A new approach, arithmetic-geometric method, is used to solve nonlinear equations group, which proves to be efficient and easily convergent. The mathematical and computer algorithms are described, with the Pb-H20, Cu-NH3-H20 and Cu-C1-H20 systems as examples. More information on real hydrometallurgical processes can be obtained from these diagrams compared to conventional E-pH predominance diagrams.

By a mathematical model of distribution behaviors of Ni, Co, Sn, Pb, Zn, As, Sb, Bi, Au and Ag in copper smelting process, accessory-element behavior was studied for two types of slag, fayalite and ferrite, and two levels of oxidation. The model can predict any set of controllable process parameters, such as feed composition, smelting temperature, degree of oxygen enrichment and volume of oxygen enriched air, in copper flash smelting, Mitsubishi and Noranda processes. The predictions by the present computer model were compared with the known commercial data from Guixi Smelter in China, Horne Smelter in Canada and Naoshima Smelter in Japan. The agreement between the computer predictions and the commercial data was excellent, therefore the present computer model can be used to monitor and optimize the actual industrial operations of copper smelting. The effects of oxygen enrichment, matte grade, smelting temperature and types of slag, on accessory-element behavior were elucidated.

In a former report4) the authors have proposed a new method to prepare strong briquettes for the vertical retort zinc smelting process by mixing zinc sulfide concentrate with pulverized coal and calcium oxide followed by preheating, briquetting, and coking. In the present study, calcium carbonate has been substituted for calcium oxide because the latter quickly reacts with moisture in the ambient atmosphere and causes the briquette to collapse in a day or two. The coked briquette with calcium carbonate is as strong as the one with calcium oxide, does not collapse after being left in the laboratory for weeks, and is faster for zinc sulfide to be reduced. Fixation of sulfur during the reduction of zinc sulfide is excellent and substantially all the sulfur is fixed in the form of CaS. Although the specific resistance at room temperature, 29.2Ω·cm, of the coked briquette in this study in abtut six times as large as that of the former on with calcium oxide, it easily decreased to about 23Ω·cm when when heated to about 100℃, which suggests the possibility of feeding the briquette into not only a vertical retort but also an electrothermic furnace without additional coke.

A computer model has been developed to simulate the distribution behaviors of Ni, Co, Sn, Pb, Zn, As, Sb, Bi, Au and Ag in copper smelting process. The model assumes that the copper smelting furnace is in thermodynamic equilibrium. As many as 21 elements (Cu, S, Fe, Ni, Co, Sn, As, Sb, Bi, Pb, Zn, Au, Ag, O, N, C, H, Ca, Mg, A1, and Si) and 73 compounds are considered. This model accounts for physical entrainment in the melts. The predictions by the present computer model are compared with the known commercial data from Guixi Smelter in China, Horne Smelter in Canada and Naoshima Smelter in Japan. The agreements between the computer predictions and the commercial data are excellent, so that the present computer model can be used to monitor and optimize the actual industrial operations of copper smelting. It is applicable to simulation of almost all copper pyrometallurgical processes.

Aqueous E-pH Diagram is an essential tool for analyzing hydrometallurgical and corrosion processes. Due to the requirements for environmental protection and energy saving in recent years, waste water processing and hydrometallurgical process of concentrate have been greatly developed. The construction of E-pH diagrams has turned to multi-component systems. However, there are some limits in plotting such diagrams. There is only one diagram for one multi-component system, which can not reflect the truth of the aqueous reaction. In the paper, a new computation method is proposed to construct E-pH diagrams. Component activity term is used to determine the boundary of stable areas. For the multi-component systems, different atom ratios of elements have been taken into account. M-S-H2O system is chosen to study since it is of importance in metallurgical solution. Compared with conventional methods, the algorithm is simple and conforms to real conditions.