Mechanism analysis of effect of magnetite concentrate properties on sintering characteristics of iron ore fines
Magnetite concentrate is one of the commonly used sintering materials.Magnetite concentrates from dif-ferent origins usually have different properties,and their addition to sintered mixed ores will inevitably have an impact on the sintering process and the quality of sintered ore.Through sinter pot tests,the sintering performance of hematite-goethite-magnetite type mixed ores and the metallurgical properties of sintered products were compared between finer-grained domestic high magnesium magnetite concentrate(DM)and coarser-grained high silicon Aus-tralian magnetite concentrate(AM).Moreover,the effect of magnetite concentrate properties on the generation characteristics of calcium ferrite and the low-temperature reduction degradation performance of sinter products was analyzed from the perspectives of raw material properties and microstructure of sinter products.The results indicated that,as the proportion of AM replacing DM increased from 0 to 30%,tumble index of sinter products decreased from 59.87%to 57.35%,yield decreased from 63.69%to 60.92%,productivity decreased from 1.49 t/(m2·h)to 1.30 t/(m2·h),solid fuel consumption increased from 76.62 kg/t to 78.86 kg/t,reduction index IR decreased from 86.64%to 83.08%,and the low-temperature reduction degradation index IRD>3.15mm decreased from 68.69%to 49.40%.From the perspective of mineralogy of sinter products,as the proportion of AM replacing DM increased,the content of composite calcium ferrite in sinter products significantly decreased,and the crystallization and develop-ment situation deteriorated,transitioning from needle shaped to short columnar or plate-like.Meanwhile,the amount of silicate glass phase and irregular skeletal hematite increased.The reason for this was that DM with finer particle size has higher self-fluxing and better oxidation properties than high silicon AM with coarser particle size,which was conducive to the formation of primary melting phase,promoting the assimilation of nuclear particles,and forming a bonding phase with high bonding strength.
magnetite concentrateoxidabilitymixed oresinteringlow-temperature reduction and degradation
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