Review and modeling of viscosity of silicate melts: Part II. viscosity of melts containing iron oxide in the CaO-MgO-MnO
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I.
INTRODUCTION
A good understanding of the viscosity of iron oxide– containing slags has practical importance in both ferrous and nonferrous pyrometallurgical processes. As such, a considerable number of experimental investigations have been carried out in the past.[4–22] There have also been general reviews which collated and evaluated the available experimental viscosity data.[3,23–25] In particular, the reviews by Mills and Keene[23] and Utigard and Warczok[3] provide detailed discussions on the general behavior of viscosity and the applicability of some models. Mills and Keene’s review[23] was on the viscosity of BOS-type slags, (basic oxygen steelmaking) which include systems from binary to quaternary synthetic slags and multicomponent industrial slags. The experimental data obtained through different studies were compared and presented in graphic form. The values calculated using the Riboud model[26] and the Urbain model[2] were also compared with the experimental values. The main features, according to their review, can be summarized as follows. (1) Viscosity data for BOS-type slags are limited and disparate, especially for Fe-containing melts, because of the difficulties encountered in experimental studies. These are mainly chemical attack of the containing materials by slags and difficulty in controlling the oxidation states of Fe in melts. (2) The behavior of BOS slags appears to be similar to that for the CaO-FexO-SiO2 system. (3) The models tested (i.e., the Riboud and Urbain models) give a reasonable estimation of the viscosity of BOS LING ZHANG, Senior Research Scientist, and SHARIF JAHANSHAHI, Senior Principal Research Scientist and Research Manager, Base Metals Pyrometallurgy, are with the G.K. Williams Cooperative Research Centre for Extractive Metallurgy, CSIRO–Division of Minerals, Clayton South, Victoria 3169, Australia. Manuscript submitted March 4, 1997. METALLURGICAL AND MATERIALS TRANSACTIONS B
slags and synthetic slags. However, the models cannot reproduce the isoviscosity contours observed in some systems. Utigard and Warczok[3] reviewed the viscosity of copper/nickel smelting and converting slags, which included viscosity of the FexO-SiO2 binary system and some industrial slags. A correlation for the calculation of viscosity for these type of slags was proposed based on a regression analysis of the existing experimental data. In their study, different measurements on viscosity in the FeO-SiO2 system have been assessed, particularly in the composition range around fayalite (Fe2SiO4). In the vicinity of this composition, a peak in viscosity was found and large scatters of experimental data were common. It was found that the experimentally measured viscosity of liquid fayalite at and above 1523 K has a small error bar, and it decreases linearly with increasing temperature. However, the reported viscosity at 1473 K has a large scatter, and the maximum measured value is approximately 5 times higher than the minimum value reported. They have stated that the scatter is most likely due to unc
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