Influences of MgO and Al2O3 on the mineralogical properties of calcium ferrite in iron ore sinter
HAN Xiuli, SI Tianhang, LI Mingduo, ZHOU Xiang, LIU Lei, ZHAO Kai
1. College of Mining Engineering, North China University of Science and Technology, Tangshan 063210, China
2. School of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, China
Calcium ferrite is the main binder phase mineral in high basicity sintered ore. Its mineralogical characteristics such as content, crystal form, chemical composition and crystal structure play a key role in the quality of the sintered ore. The content directly affects the formation of calcium ferrite. In this paper, we used the chemically pure reagents of Fe3O4, SiO2, CaO, MgO, and Al2O3 as raw materials and carried out micro-sintering experiments in the laboratory. Using XRD, polarizing microscope, electron microprobe and other means we performed quantitative analyses of MgO and Al2O3 in the raw material components to investigate the formation of calcium ferrite in sintered ores and its influence on mineralogical properties. The results showed that the increase of MgO content in the raw material had a certain inhibitory effect on the formation of calcium ferrite, especially when the MgO content was 2.0% to 3.0%. The calcium ferrite content in the sinter was significantly reduced, and its crystal morphology also changed from plate columnar and needle-like shape gradually transitioning to an irregular shape. The increase in Al2O3 in the raw material promoted the formation of calcium ferrite in the sinter as calcium ferrite content increased significantly with increasing Al2O3 and ferric acid contents. The morphology of calcium also changed from columnar and needle-shaped to columnar. Electronic probe composition analysis and mineral chemical formula calculation results show that calcium ferrite is a complex crystal composed of Fe2O3, CaO, SiO2, Al2O3 and MgO, and its chemical formula is Ca2.60Mg0.44Si1.07Al0.96Fe8.92O20. The changes in MgO and Al2O3 contents in the raw materials had little effect on the mole fraction ratio of Fe2O3 to CaO in the chemical composition of calcium ferrite, both were close to 3∶2. The above research results are of great guiding significance for an in-depth understanding of the chemical characteristic of calcium ferrite crystal phase under sintering process conditions and its effect on the quality of sinter.
韩秀丽，司天航，李鸣铎，周祥，刘磊，赵凯. 镁铝对烧结矿中铁酸钙的矿物学特性影响[J]. 地学前缘, 2020, 27(5): 280-290.
HAN Xiuli, SI Tianhang, LI Mingduo, ZHOU Xiang, LIU Lei, ZHAO Kai. Influences of MgO and Al2O3 on the mineralogical properties of calcium ferrite in iron ore sinter. Earth Science Frontiers, 2020, 27(5): 280-290.