UBC Theses and Dissertations
High-pressure coal injection in the zinc slag fuming process Cockcroft, Steven Lee
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.
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