Influence of basicity on solid phase reaction and mineral formation in high feed sintering of ore-rich
QIE Ya-na1, LI Yu-zhuang1, BAI Shi-hao1, WANG Jian-fang2, LIU Peng2, LIU Ran1
1. College of Metallurgy and Energy, North China University of Technology, Tangshan 063009, Hebei, China; 2. Delong Iron and Steel Group, Xingtai 054400, Hebei, China
Abstract：Ore-rich powder has the advantages of high iron grade and few impurities. However, particle size of ore-rich powder is large, and the average particle size of granulating pellets increases after its proportion increasing. It easily leads to the rapid vertical sintering speed, and is not conducive to the liquid phase generation and condensation consolidation in the sintering process, which will affect the quality and strength of sinter. Basicity and layer thickness are the key factors affecting the solid phase reaction and liquid phase formation in sintering process. The influence mechanism of binary basicity on solid phase reaction and mineral formation in high feed sitering of ore-rich was studied by thermodynamic calculation and experiment, the solid phase reaction and liquid phase formation process were analyzed, the theoretical carbon content of sintering was calculated, and the influence of basicity on sinter phase composition and metallurgical properties was analyzed. The results show that with the increase of binary basicity, the CaO in the flux is beneficial to the solid phase reaction, which increases CAF3, CAF1 and other calcium ferrite phases, and promotes the generation and development of liquid phase. It also reduces the generation temperature of Bredigite phase and increases the number of Bredigite phase, while Spinel and Melilite decrease gradually. It is favorable for bonding phase formation and consolidation. Through the mineral phase analysis of sinter after the sinter cup test with 900 mm thick material layer, it is found that when the binary basicity increases from 1.9 to 2.1, the content of calcium ferrite in sinter increases, the original and regenerated hematite decreases, and the stress generated during low temperature reduction decreases, so that the low temperature reduction degradation index is improved and the reducibility of sinter is improved. However, when the basicity continues to increase, more calcium silicate phases are formed in sinter, especially the increase of β-C2S phase reduces the strength and metallurgical properties of sinter.
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2023, Vol. 33 
