褐铁矿在烧结工艺中的优化配置

Optimal allocation of limonite in sintering process

为了探究全进口矿条件下褐铁矿在烧结工艺中的合理配置,实现褐铁矿的高效利用以进一步提铁降本,针对S钢铁公司500 m^(2)大型烧结机实际原燃料条件,基于试验用铁矿粉的常规理化性能和高温烧结基础特性开展了不同褐铁矿配比的烧结杯试验研究,结合Factsage 7.1热力学软件,模拟计算了不同褐铁矿配比条件下的黏附粉含量和理论液相生成量及性能,并采用矿相显微镜分析了烧结矿的显微结构,探明了褐铁矿与赤铁矿和磁铁矿的优化搭配规律.研究表明:澳大利亚褐铁矿具有粒度粗、矿化能力弱,同化温度低、黏结相强度差、吸液性强的特点,当褐铁矿质量分数由45%增加至55%时,提高磁铁精矿OD矿的质量分数至15%,同时降低OC矿质量分数至10%,烧结矿转鼓强度和低温还原粉化性能等指标达到最优,这是由于一方面提高磁铁精矿配比不仅具有增加黏附粉比例、改善液相生成数量和性能的作用,而且可以均匀液相分布,消除过熔现象;另一方面,增加磁铁精矿配比可以改善烧结料球的粒度组成,减少褐铁矿吸液量,提高烧结矿强度.因此,在高褐铁矿配比条件下,增加适宜的磁铁精矿配比有利于稳定烧结矿质量,全面改善烧结矿性能.

Improvements in ore blending could be realized by an optimal match of iron ores,sinters,and fuel conditions.To further increase iron grade and reduce the cost of ore blending,in view of the actual raw material and fuel conditions of the 500 m^(2) large-scale sintering machine of S Steel company,the conventional physical and chemical properties of the iron ore powders used and their basic characteristics under high-temperature sintering were studied using sintering cup experiments in this study.The content of the adhesion powder,the theoretical liquid phase formation,and performance with different limonite ratios were simulated and calculated using the FactSage 7.1 software.The microstructures of sinters were also analyzed using a mineral phase microscope.The results show that Australian limonite exhibits coarse particle size,weak mineralization ability,low assimilation temperature,poor bonding phase strength,but strong liquid phase absorption.When the mass fraction of limonite is increased from 45%to 55%,the OD ore mass fraction of the magnetite concentrate is increased to 15%and the mass fraction of the OC ore is reduced to 10%,improving the sinter drum strength and RDI+3.15 mm.When the OD ore ratio of the magnetite concentrate is increased,not only the proportion of adhesion powder is increased,improving the amount and performance of liquid phase formation,but the liquid phase distribution also becomes uniform and overmelting is eliminated.On the other hand,increasing the ratio of the OC ore can improve the particle size composition of the sinter mixture and reduce the amount of liquid phase absorbed by the limonite,thus increasing the strength of the sinter.Therefore,a higher ratio of magnetite concentrate under a high amount of limonite is conducive to stabilizing the sinter quality and improving the overall sinter performance.