Mechanistic Analysis of the Effect of Hematite Concentrates on the Sintering Properties of Iron Ore Fines: Based on Process Mineralogy and Sintering Properties

The sintering process represents a primary source of dust, SO2, NOx, and CO2 emissions in steel mills. Utilizing high-grade concentrate with low impurity content can directly reduce slag generation at the source, thereby decreasing fuel consumption and minimizing associated emissions. This study investigated the physicochemical properties, microstructure, and elemental distribution of hematite concentrates (H2 and H3) and H1 sinter fines. Sinter pot tests were conducted to evaluate the effects of blending these two concentrates on sintering performance and key quality indices. Microstructural analysis and quantitative phase composition statistics of the sintered products were performed to elucidate the mechanisms by which these concentrates influence sintering outcomes. Results demonstrated that replacing 33% H1 sinter fines with 33% H2 or H3 concentrates reduced the tumbler index from 73.6% to 68.5% and 73.2%, respectively. The productivity coefficient decreased to 68.5% and 73.2%, while solid fuel consumption increased from 73.9 kg/t to 90.5 kg/t and 81.2 kg/t. RI declined from 80.0% to 77.9% and 78.4%, whereas RDI improved from 72.9% to 76.8% and 75.8%.