中南大学学报（自然科学版）2025，Vol.56Issue(4)：1275-1289,15.DOI:10.11817/j.issn.1672-7207.2025.04.002
还原剂有机/无机组分在高磷鲕状赤铁矿直接还原焙烧过程中的作用机制
Mechanism of reductants' organic/inorganic components in direct reduction roasting process of high-phosphorus oolitic hematite
摘要
Abstract
Direct reduction roasting-magnetic separation is an effective method for treating high-phosphorus oolitic hematite,and the difference of reductant composition affects the mechanism of reduction and dephosphorization.The reduction effects of four different reductants,namely a lignite,low-rank bituminous coal,biochar,and coke,which have significant differences in their components,were compared on high-phosphorus oolitic hematite.The influence mechanism of organic components and inorganic mineral composition of the reductant on the processes of direct reduction and phosphorus removal was elucidated through TG-DSC,SEM-EDS,and XRD analyses.The results show that when the amount of bituminous coal and biochar is 30％,the total iron grade and total iron recovery rate of direct reduced iron are both over 90％,slightly lower than that of coke,but the phosphorus content of bituminous coal is significantly reduced.The reduction effect of lignite is poor because of its high water content and low carbon content.Lignite,bituminous coal and biochar release reducing gases(H2,gaseous hydrocarbon and CO)at about 300 ℃,but biochar releases less gas and has a weak reducing atmosphere.Therefore,lignite and bituminous coal start the reduction reaction earlier than biochar due to their high volatile content.Biochar and coke show strong reactivity above 700 ℃,mainly reducing iron ore through carbon and CO.The high content of quartz in biochar and coke promotes the reduction of P and the entry of P into Fe phase,increasing P content in the directly reduced iron products.However,the CaO produced by calcite decomposition in bituminous coal inhibits the reduction of fluorapatite and reduces the P content of the product.This study provides a theoretical basis for the exploration of cost-effective and readily available alternative reductants in the development and utilization of low-quality iron ore resources,which is of great significance for the development of iron ore resources of strategic minerals.关键词
低阶煤/高磷鲕状赤铁矿/直接还原焙烧/脱磷/矿相Key words
low-rank coal/high-phosphorus oolitic hematite/direct reduction roasting/dephosphorization/mineral phases分类
矿山工程引用本文复制引用
余可馨,邹文杰,寇珏,董豪,徐宏达,孙春宝,孙体昌..还原剂有机/无机组分在高磷鲕状赤铁矿直接还原焙烧过程中的作用机制[J].中南大学学报（自然科学版）,2025,56(4):1275-1289,15.基金项目
国家重点研发计划项目(2021YFC2902404)(Project(2021YFC2902404)supported by the National Key Research and Development Program of China) （2021YFC2902404）
