By newly-developed computer model[1, 2] of the distribution behaviors of minor elements As, Sb, Bi and accessory elements Pb, Zn in copper flash smelting, copper flash smelting process of Guixi Smelter was simulated. Results showed that the predictions by the computer model were in agreement with the known commercial data from Guixi Smelter. Using Nagamorips physical suspension index equation[3], the apparent percentages of Cu and S in the slag were calculated, and the main form of mechanically entrained copper particles in the slag was determined to be sulfide. Furthermore, the effects of smelting temperature upon the fractional pressures, activity coefficients of As, Sb, Bi, Pb, Zn, etc. and their distributions in matte, slag and gaseous phase were analyzed. According to the simulations, when smelting temperature rises, the volatilizations of As, Sb, Bi, Pb and Zn in gaseous phase increase, while their distributions in matte decrease. The increase of smelting temperature is helpful to improve the total elimination rate of above-mentioned elements in gaseous and slag phases.

The main obstacle in directly reducing zinc sulfide concentrate in a commercial vertical retort is the difficulty to produce strong briquettes. The authors have successfully applied a new method to the preparation of strong briquettes which have satisfactory strength even after almost all the zinc sulfide in the concentrate has been reduced to zinc vapor. The method consists of mixing zinc sulfide concentrate with pulverized coal and calcium oxide, preheating and briquetting the mixture into a cylindrical briquette of 1.3cm in diameter, and then coking the briquette. Effects of mixing ratio, preheating temperature and time, particle sizes of concentrate, coal and calcium oxide on the strength of the briquette have been axamined. Sinze almost no sulfur has been observe to come out of the briquettes and also since they have considerably low specific resistance of 5.1Ω·cm, it has been suggested that the briquettes may be fed not only into a vertical retort but also into an electrothermic furnace without additional coke.

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.

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.