Influences of cokes'reactivity on the metallurgical properties of lump ores in the blast furnace

MA Xingye; WANG Gang; LI Chao; LIU Yang; SUI Yuesi; ZHONG Xiangyun; XU Guozhong; BAI Jinfeng

doi:10.3969/j.issn.1007-7677.2024.01.002

Abstract：The influence of cokes'reactivity on metallurgical properties(e.g.,droplet properties and dripping mate-rial quality of lump ores)was studied to discuss the actual deterioration of cokes with different reactivity in the blast furnace.It provided technical support for improving the comprehensive evaluation index system of cokes.The experimen-tal testing device was applied for the dripping performance of iron-ore load reduction.When the CO2/N2 volume fraction ratio was 30%∶ 70%,the influences of five different thermal reactivity cokes and mixed cokes on blast furnace opera-tion and dripping material quality were investigated.The results show that:when cokes'reactivity rose from 22.0%to 50.2%,the softening temperature gradually decreased and the soft melt zone thickened.When the reactivity of coke was less than 35%,as the reactivity increased,the pressure difference sharply increased and the temperature decreased,breathability was reduced,at the same time,difficult-to-reduce Fe2 SiO4 and incompletely reduced FeO gradually ap-peared in droppings,and coke powders in droppings gradually increased.When the reactivity of coke exceeded 35%,the pressure difference and temperature rose with permeability improved.Breathability was improved,difficult-to-reduce Fe2SiO4 and incompletely reduced FeO gradually decreased,and coke powders in droppings also gradually decreased.Cokes mixed in a certain proportion were superior to those with a single thermal property in reducing the thickness of the soft melt zone,improving air permeability,and reducing the concentration of coke powders in drippings.