Abstract:In order to effectively control the vaporization behaviors of heavy metals, such as zinc and lead in smelting process, it is necessary to obtain the basic knowledge, such as the saturated vapor pressure and activities of heavy metals in complex system. The transpiration method was used to measure the saturated vapor pressures of zinc and lead chlorides in FeO-CaO-SiO₂-Al₂O₃ system and the effect of influencing factors, such as temperature, slag compositions and so on, was discussed. The results show that the saturated vapor pressures of zinc and lead chlorides increase with the increase of temperature, and the logarithmic value of pressure has a good linear relationship with the reciprocal of the temperature. Additionally, the slag compositions, such as basicity and FeO content, give great influence on the saturated vapor pressure. The low basicity and high FeO content tend to enhance the saturated vapor pressure of ZnCl₂ and lead chlorides, while the vapor pressure of ZnCl₂ shows a stronger function of temperature and slag composition compared with that of the lead chlorides. The data acquired in this study are able to supply important theoretical foundation for effectively controlling the vaporization of heavy metals in the melting process.

Key words: zinc chlorides; lead chlorides; transpiration method; saturated vapor pressure; influence factors