金属鉛とＰｂＯ−ＦｅＯｘ−ＣａＯ−ＳｉＯ２系ないしはＰｂＯ−ＦｅＯｘ−ＣａＯ−ＳｉＯ２−ＺｎＯ系スラグ間のｌ，４２３Ｋにおける相乎衡

Abstract

In order to clarify the behavior of the metallurgical phases in the oxidation zone of the QSL lead smelting process, the phase equilibrium between the metallic lead and the PbO-FeOx-CaO-SiO2or PbO-FeOx-CaO-SiO2-ZnO slag was investigated at 1, 423 K. The EMF method using a solid electrolyte with calcia-stabilized zirconia was applied to measure the oxygen partial pressure in the system. The oxygen pressure increases with increasing PbO content in the slag. The PbO activity and activity coefficient estimated from the oxygen pressure increase with the addition of CaO into the slag. However, the PbO activity is slightly affected by the FeOxcontent at constant PbO concentration in the experimental region. Itwas clarified that ZnO gives a small effect to the activity coefficient of PbO in the PbO-FeOx-CaO-SiO2-ZnO slag. The partial pressure of the PbO component in the gas phasecalculated by using the PbO activity coefficient in the slag isconsiderably small compared with that of metallic lead.