The Macroscopic Flow direction and Microscopic Distribution of Mg in Sintered Products and Its Influence

Abstract

Magnesium flux is an indispensable part of sintering materials. Its distribution and reaction behavior have an important influence on the quality of the sinter. Studying the macroscopic flow direction and microscopic distribution of MgO in sintered products is important for guiding the matching of ore for sintering and adjusting sintering technical parameters. The macroscopic flow direction situation of MgO in all sintered products was studied using X-Ray diffractometer and X-Ray fluorescence analyzer. In addition, the microscopic distribution characteristics of Mg element in the main sintered products were studied using scanning electron microscope and energy dispersive spectrometer. The results of this research are as follows. The Mg contents of sintered products are in the following increasing order: sinter ore, sinter internal return ore, and blast furnace return ore. The Mg content of the 1 to 2 mm grain size is the highest in the sinter internal return ore and blast furnace return ore, which is related to the granular distribution of magnesium flux. Moreover, the Mg content of sintered minerals are in the following decreasing order: magnetite; silico-ferrites of calcium and aluminium (SFCA); and silicate and hematite, and the Mg dissolving in the SFCA has a tendency to make the SFCA morphology coarse. The diffusion range of Mg in a large dolomite particle is much narrower, and it mainly stays at the position where the dolomite is located. In the actual sintering process, Mg increases the viscosity of the sintering liquid phase and prevents the oxidation of magnetite, which is not conducive to the improvement of the strength of the sinter.

A Quantitative and Optimization Model for Microstructure Uniformity of Sinter Based on Multiple Regression-NSGA2

“…Moreover, high-basicity sintered ores are dominated by the calcium ferrite phase, which leads to elevating the yield and quality of the ore. Xin et al [9] found that an increase in basicity and Al 2 O 3 is detrimental to the formation of glassy phases in sintered ores. Wu et al [10] investigated the effect of Mg 2+ on the properties of single minerals in sintered ores. The results showed that the solid solution of Mg 2+ in single minerals was in the order of magnetite, silico-ferrite of calcium and aluminum (SFCA), silicate, and hematite, and the solid solution of Mg 2+ prevented the oxidation of magnetite to hematite, the coarsening of the grains of SFCA, and an increase in the content of silicate.…”