自熔炉内の精鉱粒子の燃焼現象に関する数値的研究

Abstract

A comprehensive mathematical model was developed to describe the combustion phenomena of the copper concentrate particles in a flash smelting furnace, and then we try to improve its accurancy by changing the number of particle diameter groups of concentrate particles. This model incorporated the fluid flow, heat and mass transfer, and chemical reactions of the copper concentrate and supplementary fuel particles. The gas flow and motion of the particles were calculated using the Eulerian and Lagrangian methods, respectively. This developed model had two remarkable characteristics that were based on our understanding of the combustion phenomena in the reaction shaft of the flash smelting furnace. One characteristic takes into consideration the reaction of the concentrate particles to produce magnetite (Fe3O4) . The other characteristic considers the effect of shielding the radiative heat transfer caused by a concentrate cloud.The copper concentrate was assumed to comprise mainly chalcopyrite (CuFeS2) . The CuFeS2 reaction was considered to occur in two steps, namely, the decomposition of CuFeS2 and the oxidation of the resulting sulfur (S) and pyrrhotite (FeS) . This model has made it possible to predict the combustion phenomena which are the trajectories and temperatures of concentrate particles, and the temperatures and mass fractions of the gas. The calculated temperatures of the concentrate particles were approximately consistent with the temperatures measured in a commercial furnace, which verified the predictive accuracy of the model.