A mathematical model that combines turbulent transport phenomena of particle-laden gas jets, chemical reactions, and thermal radiation has been developed to describe the various aspects of chalcopyrite concentrate combustion, which includes minor element behavior inside an axisymmetric reaction shaft of the flash furnace. This model has elucidated the relative importance of elimination of the four most undesirable minor elements--as, sb, bi, and pb--to the gas phase. Using a laboratory flash furnace, gas temperature, sulfur content in the particles, so2 concentration in the gas phase, particle dispersion, and average elimination of minor elements to the gas phase during flash smelting at various locations were measured for target matte grades. Numerical computations have been performed to predict the various aspects of rate processes occurring in a commercial-scale flash-smelting furnace for different feeding modes. Overall performance is greatly affected by the inlet geometry, the gas-phase turbulent field is significantly affected by the presence of particles, and the reaction of sulfide particles is almost completed in the upper zone of the furnace within about 1 m from the burner. The axial wall feeding mode of the secondary jet shows better performance than any other feeding modes considered in this study. From the computational results, the behavior of each minor element was predicted for various target matte grades.
Ph.d. Thesis, Univ. Utah, 1990, 128 PP.