Composition Region of Homogeneous Liquid Phase in Lead-Containing Slags Related to QSL Process

摘要

As a fundamental study to control compositions ofthe slag in the oxidation zone of a QSL lead smelting furnace,phase equilibrium between the metallic lead and the PbO-FeOx-CaO-SiO2 or PbO-FeOx-CaO-SiO2-ZnO slag was investigated at1,323~1,523K and a composition region of the homogeneousliquid slag phase and the composition and chemical formula ofsolid phases in the slag coexisting with the liquid phase weredetermined. The PbO-FeOx-CaO-SiO2 slag with Q(=mass %CaO/(mass% CaO+mass% SiO2 )) of 0.4 is completely fusible at1,423K when the mole fraction ratio of FeOx, R, defined asR=NFeOx/(NFeOxNCaO+NSiO2), is around 0.4, and departure fromthis value gives rise to a solid-liquid two phase region in therange of the low PbO content.