Abstract：
Magnetic iron concentrate (MIC) and nonmagnetic tailings (NT) are obtained from magnetization roasting of iron tailings (IT). MIC containing Pb adversely affects blast furnace ironmaking, while Cu in NT poses leaching risks. This study utilizes fast pyrolysis-suspension magnetization roasting to recover iron from IT. The enrichment of Pb, Cu, and the phase transformation mechanism of Cu in the process of suspension magnetization roasting and magnetic separation were clarified. Results show 96.13 % of Cu in IT is in limonite and 47.23 % of Pb is associated with iron. At 750 °C, with 10 % dosage of biomass pyrolysis and 10 min roasting, Pb, Cu and Fe contents in MIC are 0.96, 2.14 and 3.17 times that of NT. Increasing roasting temperature enhances Cu associated with iron enrichment into the MIC, while oxidation of free copper oxide associated with iron forms magnetic copper ferrite. Increased pyrolyzed biomass leads to over-reduction of magnetite associated with Cu to FeO associated with Cu, promoting magnetic copper ferrite decomposition into FeO and free copper oxide. This research holds significant importance in controlling the quality of MIC and the storage risk of IT, and provides theoretical guidance for the regulation and recovery of valuable metals in subsequent processes.
摘要：
磁性铁精矿（MIC）和非磁性尾矿（NT）通过铁尾矿（IT）的磁化焙烧获得。含铅的MIC对高炉炼铁产生不利影响，而NT中的Cu存在浸出风险。本研究利用快速热解-悬浮磁化焙烧从IT中回收铁。Pb的富集,Cu,阐明了Cu在悬浮磁化焙烧和磁选过程中的相变机理。结果表明，IT中96.13%的Cu在褐铁矿中，47.23%的Pb与铁有关。在750°C时,10％用量的生物质热解和10分钟焙烧，Pb,MIC中Cu和Fe含量分别是NT的0.96、2.14和3.17倍。提高焙烧温度可增强与铁相关的Cu向MIC的富集，而与铁相关的游离氧化铜的氧化形成磁性铜铁氧体。热解生物质的增加导致与Cu相关的磁铁矿过度还原为与Cu相关的FeO，促进磁性铜铁氧体分解为FeO和游离氧化铜。这项研究对控制MIC的质量和IT的存储风险具有重要意义。为后续工艺有价金属的调控和回收提供理论指导。
