自熔炉内の精鉱粒子の衝突を考慮した燃焼現象に関する数値的研究 Numerical Study of Combustion Phenomena in Flash Smelting Furnace Considering Collisions of Concentrate Particles

In a copper flash smelting furnace, collision of concentrate particles plays an important role in producing the desired slag and matte. Moreover, the collision of the particles and the resulting growth in the particle diameter are also very important in order to avoid the generation of a large amount of dust.The authors have developed a mathematical model incorporated the fluid flow, heat and mass transfer, chemical reactions, and collisions of the concentrate particles. Both the gas flow and particle motion were calculated using the Eulerian method. The copper concentrate was assumed to consist mainly of chalcopyrite (CuFeS2) . The concentrate reactions considered were the decomposition of CuFeS2 and the oxidation of the resulting sulfur (S) and pyrrhotite (FeS) thereby producing magnetite (Fe3O4) and sulfur dioxide (SO2) . Moreover, the oxidation-reduction reaction when concentrate particles collided was also considered. The particle collisions were assumed to occur according to a collision probability rule obtained by the model calculations. The growth in the particle diameter was described as a change in the volume fractions of the particle phases. When applied to a commercial flash smelting furnace, this model reproduced the particle diameter growth and the component transfer as observed in a pilot plant furnace.