氢气直接还原超细铁精矿干燥球制备超细还原铁粉研究

Research on the Preparation of Ultrafine Reduced Iron Powder by Direct Hydrogen Reduction of Ultrafine Iron Ore Concentrate Dried Pellets

摘要: 研究提出了一种氢气直接还原超细铁精矿干燥球后再磁选制备超细还原铁粉技术，系统开展了超细铁精矿干燥球氢还原特性分析及超细还原铁粉的制备与表征。结果表明：超细铁精矿干燥球的可还原性显著优于成品球，基于ROM2模型计算得出干燥球氢还原反应活化能为27.78 kJ/mol，约为成品球的1/2；超细铁精矿干燥球在850℃下氢还原150 min时，还原度达到99.92%，经磁选后制得的超细还原铁粉纯度为98.06%，粒径分布D50为18.48 μm，磁选可有效去除还原产物中的二氧化硅杂质。研究表明，氢气直接还原超细铁精矿干燥球后再磁选制备超细还原铁粉技术，具有降低超细还原铁粉生产成本的潜力，可为超细铁精矿的资源化利用提供新的技术路径。

Abstract: This study proposes a technology for producing ultrafine reduced iron powder by hydrogen direct reduction of dried ultrafine iron ore concentrate pellets followed by magnetic separation. A systematic analysis was conducted on the hydrogen reduction characteristics of the dried ultrafine iron ore concentrate pellets, as well as the preparation and characterization of the resulting ultrafine reduced iron powder. The results show that the reducibility of the dried ultrafine iron ore concentrate pellets is significantly better than that of indurated pellets. Based on the ROM2 model, the activation energy for the hydrogen reduction of the dried pellets is calculated to be 27.78 kJ/mol, which is only half that of indurated pellets. After hydrogen reduction at 850˚C for 150 min, the reduction degree of the dried ultrafine iron ore concentrate pellets reaches 99.92%. The ultrafine reduced iron powder obtained after magnetic separation has a purity of 98.06% and a median particle size (D50) of 18.48 μm. Magnetic separation effectively removes silica impurities from the reduced product. The study demonstrates that the technology of producing ultrafine reduced iron powder by hydrogen direct reduction of dried ultrafine iron ore concentrate pellets followed by magnetic separation has the potential to reduce the production cost of ultrafine reduced iron powder and provides a new technological route for the resource utilization of ultrafine iron ore concentrate.