1 School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, China 2 Yangzhou Pacific Special Materials Co., Ltd., Yangzhou 225211, Jiangsu, China
Improving properties of fluxed iron ore pellets with high-silica by regulating liquid phase
1 School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, China 2 Yangzhou Pacific Special Materials Co., Ltd., Yangzhou 225211, Jiangsu, China
摘要 With rapid development of the pellet production under the background of green development, high-quality iron concentrates were gradually exhausted; thus, using high-silica iron concentrates was expected to be a promising way to relieve resource pressure for pellet production. However, increasing the proportion of high-silica acid pellets into the furnace led to worse blast furnace slag, and the metallurgical properties of high-silica pellets were imperfect. To understand the reciprocal effects of basicity (CaO/SiO2) and MgO content on the properties of the high-silica pellets, the phase compositions and microstructure were investigated using X-ray diffraction and scanning electron microscope, equipped with energy dispersive X-ray spectrometry. The results indicated that simply increasing MgO content from 0 to 2.50 wt.% could decrease the reduction swelling index, but the compressive strength rapidly declined due to the formation of magnesioferrite. However, adding CaO to 2.50 wt.% MgO pellets greatly improved the pellet qualities, which could be attributed to a substantial increase in the amount of high-melting-point silicate liquid phase.
Abstract：With rapid development of the pellet production under the background of green development, high-quality iron concentrates were gradually exhausted; thus, using high-silica iron concentrates was expected to be a promising way to relieve resource pressure for pellet production. However, increasing the proportion of high-silica acid pellets into the furnace led to worse blast furnace slag, and the metallurgical properties of high-silica pellets were imperfect. To understand the reciprocal effects of basicity (CaO/SiO2) and MgO content on the properties of the high-silica pellets, the phase compositions and microstructure were investigated using X-ray diffraction and scanning electron microscope, equipped with energy dispersive X-ray spectrometry. The results indicated that simply increasing MgO content from 0 to 2.50 wt.% could decrease the reduction swelling index, but the compressive strength rapidly declined due to the formation of magnesioferrite. However, adding CaO to 2.50 wt.% MgO pellets greatly improved the pellet qualities, which could be attributed to a substantial increase in the amount of high-melting-point silicate liquid phase.
Yuan-bo Zhang,Xi-jun Chen,Zi-jian Su, et al. Improving properties of fluxed iron ore pellets with high-silica by regulating liquid phase[J]. Journal of Iron and Steel Research International, 2022, 29(09): 1381-1392.
2022, Vol. 29 
