Particle motion simulation and pulverized coal injection combustion simulation of titanomagnetite pellets in rotary kiln for reduction process with coal

The production process of direct reduced iron from titanomagnetite by coal reduction in air in rotary kiln is a key step in the extraction of titanium and iron. This process is conducive to alleviating the stocking problem of a large amount of Ti-bearing blast furnace slag. The relationships between particle movement and pulverized coal injection combustion in rotary kiln were studied by the particle motion simulation and the pulverized coal injection combustion simulation. In particle motion simulation, the repose angle of ore particles was calculated to be 28.06°, and the reaction zone was roughly determined by the reaction temperature isothermal surface and the repose angle; the axial discrete distribution of ore particles would further cause the axial energy fluctuation due to the endothermic nature of the reduction. In pulverized coal injection combustion simulation, the rebound effect of coal injection under gravity would cause local overheating in the rebound region due to the benefits of heat and mass transfer processes, while this could strengthen the reduction reaction of ore particles and cause agglomerate by melting. Two suggestions on weakening the energy fluctuation and agglomerate were proposed based on the characteristics of particle motion and external carbon reaction.