Abstract：
The magnetization roasting with coal as primary reductants adds cost and causes environmental pollution. Therefore, it is of great importance to investigate the biomass application as a reductant for magnetization roasting to recover iron from low-utilization iron tailings for emission mitigation and green utilization. This study systematically investigated the impact of biomass (pyrolysis gas from agricultural and forestry waste) as a reductant on the conversion of iron tailings to magnetite in magnetization roasting. Additionally, the thermal decomposition of biomass, phase transformation and microstructure evolution of iron tailings were analyzed by TG, XRD, BET, and other methods to elucidate the conversion mechanism for facilitating magnetized hematite in iron tailings with biomass-derived gas. The results showed that woody biomass was a more appropriate reductant for magnetization roasting; 650 °C was the optimal temperature for the complete transformation of hematite to magnetite by reduction roasting with biomass waste. Through magnetic separation, the concentrate with an iron grade of 62.04% and iron recovery of 95.29% was obtained, and the saturation magnetization was enhanced from 0.60 emu/g to 58.03 emu/g of iron tailings. During the magnetization roasting, CO and H2 generated from biomass reduced the hematite in tailings particles from interior to exterior, forming a loose structure with rich microfissures, facilitating the subsequent separation operations. This study offers a novel reference for applying biomass to exploit hematite minerals and shows the potential of biomass for energy savings and emission reduction in the utilization of iron tailing resources.
摘要：
以煤作为主要还原剂的磁化焙烧增加了成本并导致环境污染。因此,研究生物质作为磁化焙烧还原剂的应用，从低利用率的铁尾矿中回收铁，用于减排和绿色利用具有重要意义。这项研究系统地研究了生物质（来自农业和林业废物的热解气体）作为还原剂对磁化焙烧中铁尾矿转化为磁铁矿的影响。此外,生物质的热分解，通过TG分析铁尾矿的相变和微观结构演变，XRD,BET,和其他方法来阐明促进生物质衍生气体在铁尾矿中磁化赤铁矿的转化机理。结果表明，木质生物质是磁化焙烧更合适的还原剂；650°C是通过生物质废物还原焙烧将赤铁矿完全转化为磁铁矿的最佳温度。通过磁力分离，获得铁品位为62.04%，铁回收率为95.29%的精矿，铁尾矿的饱和磁化强度从0.60emu/g提高到58.03emu/g。在磁化焙烧过程中，生物质产生的CO和H2从内部到外部减少了尾矿颗粒中的赤铁矿，形成具有丰富微裂缝的松散结构，便于后续的分离操作。该研究为应用生物质开采赤铁矿提供了新的参考，并显示了生物质在铁尾矿资源利用中节能减排的潜力。
