Sponsored by: EPD Pyrometallurgy Committee
Program Organizer: Jerome P. Downey, Hazen Research, Inc., Golden, CO 80403; Ed Mounsey, Ausmelt Limited, 2/13 Kitchen Road, Dandenong, Victoria 3175 Australia
Wednesday, PM Room: A16-17
February 7, 1996 Location: Anaheim Convention Center
Session Chairmen: J. M. Toguri, Professor, Department of Metallurgy and Materials Science, University of Toronto, 184 College Street, Toronto, Ontario, Canada M5S 1A4; Ed Mounsey, Marketing Manager, Ausmelt Limited, 2/13 Kitchen Road, Dandenong, Victoria 3175, Australia
2:00 pm
INTERFACIAL PHENOMENA BETWEEN ALUMINA, QUARTZ AND FAYALITE SLAG: J. R. Donald, H. Fukuyama, J. M. Toguri, Department of Metallurgy and Materials Science, University of Toronto, 184 College Street, Toronto, Ontario, Canada M5S 1A4
Traditionally in the nonferrous industry, refractory expenses were considered to be fixed costs because they constitute a relatively small portion of the total production expenditures and the product value is inherently high. However, in the current global economy, in order to remain competitive, all costs must be minimized. Hence, the extension of refractory life in the nonferrous sector has become an important issue. Surface and interfacial phenomena play a significant role in refractory performance. For example, the wettability of the refractory material with slag, matte, and metal influences infiltration and interfacial reactions. Yet, very little fundamental information regarding the surface properties of refractory materials and slag is available. Thus, in the present work, the sessile drop technique incorporating a high temperature furnace equip with x-ray fluorescence was employed to investigate the surface and interfacial phenomena of fayalite slag on solid alumina and quartz (SiO2). Contact angles, interfacial tensions and surface tension of the fayalite slag are reported. In addition, electron microprobe analysis (EPMA) was utilized to determine the products of the interfacial reactions as well to investigate the diffusion of elements into and out of the refractory material.
2:25 pm
PHYSICAL MODELLING OF THREE-PHASE MIXING IN A COUNTERCURRENT REACTION LAUNDER (CCRL) PROCESS FOR METAL REFINING: K. Narayana Swamy, David G. C. Robertson, Kent D. Peaslee, Center for Pyrometallurgy, Department of Metallurgical Engineering, University of Missouri-Rolla, 215 Fulton Hall, Rolla, MO 65401-0249
Experimental results of three-phase mixing in a physical model of a CCRL for metals refining, at high levels of bottom gas injection (up to a Q/A = 25 cm/min), are presented. The experimental results at low levels of bottom gas injection through a line of central, single tuyeres (up to a Q/A = 7.5 cm/min) have already been discussed in a previous paper. A thermal tracer technique was used to elucidate both longitudinal mixing and interphase heat transfer. The results indicate that even under conditions of significant bottom gas injection, it should be possible to maintain acceptably low longitudinal mixing (Ds < 20 cm2/s and Ds/uL < 0.1) in the CCRL. Interphase mass-transfer coefficients of the order of 0.02 cm/s and higher are predicted from the measured interphase heat transfer coefficients using the mass and heat transfer analogy. Adequate rates of refining are predicted for an industrial CCRL operated under such conditions.
2:50 pm
INTERFACIAL PHENOMENA IN THE COPPER-CALCIUM FERRITE SYSTEM: T. Sakai, S. W. Ip, J. M. Toguri, Department of Metallurgy and Materials Science, University of Toronto, 184 College Street, Toronto, Ontario, Canada M5S 1A4
The Mitsubishi process is an innovative pyrometallurgical operation for the processing of copper-containing sulphide ores. In the converting stage, a calcium ferrite slag is used to absorb the iron oxide generated during converting. To better understand the operation variables in the furnace, the surface and interfacial tensions of the copper and calcium ferrite slag were studied at 1,300[[ring]]C using a high temperature x-ray apparatus. The results indicated that dissolution of copper increases with oxygen potential. The surface tension of the slag decreased with decreasing calcium oxide content. However, the effect of calcium oxide on the interfacial tension between copper and slag is negligible. Increasing oxygen pressure has a negative effect on the interfacial tension. Using these results, the entrainment behavior of copper by gas bubble attachment in the calcium ferrite slag was determined. The results indicate that copper entrainment is unavoidable.
3:15 pm BREAK
3:45 pm
OXIDATION OF SYNTHETIC NICKEL MATTES UNDER SIMULATED FLASH SMELTING CONDITIONS: Satu Jyrkönen, M. Nopanen, E. Peuraniemi, S. Strömberg, A. Jokilaakso, Department of Materials Science and Rock Engineering, Helsinki University of Technology, FIN-02150 Espoo, Finland
A single-particle laminar-flow technique was used to study oxidation of four synthetic nickel mattes, which were screened into three size fractions. Experimental conditions were: reaction gas from N2 + 21 to 75 vol% O2, gas preheating temperatures ranging from 500 to 1,100C. The four mattes were synthesized so that Ni/Cu ratios of 1 and 10 were obtained with high and low iron contents. Chemical analysis of the particles was used to determine the oxidation degree of the materials, and optical and scanning electron microscopy were used to detect their morphology, internal composition and structure. The best sulfur removal from the synthetic nickel mattes was achieved under the most oxidizing conditions with the finest size fraction. The matte with Ni/Cu = 1 and high iron content was found to be most reactive. The least reactive matte was with Ni/Cu = 10 and low iron content; the coarse fraction particles did not react at all under the conditions studied.
4:10 pm
MINIMIZATION OF DUST GENERATION IN OUTOKUMPU FLASH SMELTING: D. M. Jones, Magma Metals Company, P. O. Box M, San Manuel, AZ 85631; W. G. Davenport, University of Arizona, Dept. of Materials Science, Tucson, AZ 85711
Dust generation data have been obtained from 19 industrial Outokumpu flash furnaces. Statistical analyses of the data have been carried out and the most significant factors affecting dust generation evaluated. The results indicate that dust production may most effectively be minimized by 1) minimizing the distance between the molten slag and the furnace roof and 2) optimizing burner design and combustion parameters.
4:35 pm
VOLATILIZATION KINETICS OF MINOR ELEMENTS FROM MATTE: Xu Zhong and D. C. Lynch, Arizona Materials Laboratory, Dept. of Materials Science & Engineering, University of Arizona, Tucson, AZ 85721
The theoretical limit to smelting rate and possibly the size of a smelter is
dependent on the rate of heat transfer and the chemical kinetics of both sulfur
removal and minor element volatilization. The kinetics of volatilization of
minor elements such as As, Sb, Bi, and Pb from matte and white metal is being
investigated. It has been shown that the molecular form of trace elements in
matte depends on the chemical potential of sulfur and the propensity for the
minor element to form a sulfide. The impact of the variable molecular form of
the minor elements on the volatilization kinetics is unknown and is under
investigation in this study. The experimental technique is reviewed and results
are reported.
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