Vapor Pressure Measurements of Zinc and Lead Chlorides from Slag System

摘要

Vapor pressure is a key thermodynamic parameter to control vaporization behaviors of heavy metals during high temperature process. In this study, the vapor pressures of ZnCl_2 and PbCl_x (representing the total vapor pressure of PbCl_2 and PbCl) were measured by using of transpiration method in the cases of zinc and lead singly-existed and coexisted in Fe_t0-CaO-SiO_2-Al_2O_3 system. The effects of influencing factors such as temperature, slag compositions, and Cl content were studied. The results suggested that the vapor pressure of ZnCl_2 is a stronger function of temperature, slag compositions and Cl content, while that of PbCl_x showed less dependency on these. The morphology analysis by using of SEM implied a stronger affinity between zinc and slag matrix. With an increase in Cl content the vapor pressure of ZnCl_2 greatly increases while that of PbCl_x raises with the increasing molar ratio of ZnO:PbO:CaCl_2 up to 1:1:2 and then tends to remain constant. Further, the activity information of zinc/lead in slag matrix and their possible interaction mechanism were discussed.