| A comprehensive mathematical model that combines turbulent transport phenomena of particle-laden gas jets, chemical reaction, and thermal radiation has been developed to describe the various aspects of chalcopyrite concetrate combustion inside an axi-symmetric reaction shaft of flash-furnace. The key features include the use of the k-ε turbulence model, incorporating the effect of particles on turbulence and the four flux-model for radiative heat transfer. Numerical computations have been performed predict the various aspects of rate processes occurring in a commercial-scale flash-smelting furnace for different inlet feeding modes. Model predictions indicate that the overall performance of the flash-smelting furnace is greatly affected by the inlet geometry and the gas-phase turbulent field is significantly affected by the presence of particles. Model predictions also show that the reaction of sulfide particles is almost completed in the upper zone of the furnace within about lm from the burner, the axial wall feeding mode of the secondary jet shows better performance than any other feeding modes considered in this study. The study of the commercial scale flash-smelting operations can be summarized as follows: (1) Reactions of sulfide particles are almost completed in the upper zone of the flash-furnace shaft, within about 1m of the burner tip in most cases except the axial feeding modes of both input streams. (2) Model predictions indicate that the overall performance of the flash-smelting furnace is greatly affected by the inlet geometry. (3) The double-entry burner system with the radial feeding of the concentrate-laden distribution air shows better performance than the single-entry burner system. (4) The axial wall feeding mode of the secondary jet is one of the recommended input geometries for good performance of the flash-smelting operation with an axisymmetric furnace shaft. |
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