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Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 227-232).

The problem of determining the total number of discrete anions in both acid and basic silicate melts has been investigated in order to apply ionic theory and 'Temkin's rule' to binary and ternary silicate slags. With an examination of structure and equilibria in silicate melts, a method was developed for determining the most probable number of anions in any basic or acid slag in terms of an equilibrium constant involving singly bonded oxygen, doubly bonded oxygen, and free oxygen ions in the melt. It was found that for an appropriate value of the equilibrium constant, values of Temkin's ionic fraction of oxygen ions may be obtained that are close to, or equal to the activities of various metal oxides in binary silicate melts. This observation was consistent with the thermodynamics of the systems studied and was verified mathematically by the application of the Gibbs-Duhem relationship to ionic silicate melts. Some ionic forms of the Gibbs-Duhem equation were derived and applied successfully to the CaO-FeO-SiO₂ system containing divalent cations, and to the Cu₂O-PbO-SiO₂ system containing both divalent and monovalent cations. Some ternary activity values of Cu₂O and PbO were determined experimentally in the Cu₂O-PbO-SiO₂ system by equilibrating silica saturated melts of Cu₂O and PbO with copper-lead alloys at 1100°C. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

A viscometer was designed and built to study the rheological behavior of slags over a range of rates of shear of three orders of magnitude, up to a shear stress of [formula omitted]. The following slag compositions were studied (wt.%) 1) 42 Si02 - 20 A12O3 - 38 CaO, 2) 40.3 Si02 - 19.2 Al 2 O3 - 36.5 CaO - 4.0 CaF2, and 3) 37.8 Si02 - 18.0 Al 2 – O3 - 34.2 CaO - 10.0 CaF2, at temperatures of 1) 1390°C - 1350°C - 1332°C, 2) 1325°C - 1300°C and, 3) 1300°C respectively. Newtonian behavior was found for all compositions at the temperatures investigated. General conclusions are drawn as to the likelihood of Newtonian behavior for different compositions in these systems. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Zinc slag fuming is a kinetically controlled process based on the direct reduction of slag by entrained coal. The kinetics of the process are governed primarily by two factors: (1) the fraction of coal entrained in the slag, and (2) the rate of ferrous iron oxidation. A series of high-pressure coal injection trials have been completed at Cominco's lead smelter in Trail, British Columbia in order to facilitate increased coal entrainment. Fuming rates were increased substantially and over-all efficiencies were improved. These results are in direct contradiction to the predictions of models based on equilibrium. The kinetics based mathematical model of the zinc slag - fuming process originally developed by Richards and Brimacombe¹a has been modified to include the reduction and removal of lead from the furnace. A lead “prill” - slag reaction model has been formulated to account for the behaviour of liquid metallic lead. Analyses of the trial data with the modified model indicates that significant improvements in entrainment were achieved with high-pressure coal injection. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

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