Recycling of red mud (RM) has posed an enduring challenge for the alumina industry. This work offers a comprehensive investigation into the fundamental and applied research of RM blend into the iron ore sintering process. Microsintering test was employed to investigate the formation and properties of bonding phase affected by RM. It resulted in impairment of bonding phase infiltration onto the iron ore surface and a decrease in the interfacial bonding strength. The interfacial interaction mechanism showed that the excessive TiO₂ and Al₂O₃ brought by RM leads to the transformation of calcium ferrite (the target bonding phase) into perovskite and spinel with high melting points, resulting in the evolution of bonding phase from original dense strip-crystallized structure to fine-grained porous. Incorporation of CaO in conjunction with RM facilitates the formation of calcium ferrite within the bonding phase and enhances its infiltration on the iron ore surface, thereby augmenting interfacial bonding strength. Pilot-scale sintering was successfully conducted with 6% RM and 1.5% quicklime. The sinter yield of 76.68% and a tumbling index of 64.98% can be obtained, which were comparable to those achieved without RM, offering a feasible approach for large-scale recycling of RM in the steel industry.

中文翻译：

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用于铁矿石烧结矿制造的红泥综合回收：烧结过程的界面粘合调节


赤泥 （RM） 的回收对氧化铝行业构成了持久的挑战。这项工作全面研究了 RM 混合物在铁矿石烧结过程中的基础和应用研究。采用微烧结试验研究受 RM 影响的键合相的形成和性能。它导致铁矿石表面的键合相渗透受损，界面键合强度降低。界面相互作用机制表明，RM 带来的过量 TiO₂ 和 Al₂O₃ 导致铁氧体钙（靶键合相）转变为高熔点的钙钛矿和尖晶石，导致键合相从原来的致密条状结晶结构演变为细晶粒多孔。CaO 与 RM 的结合有助于在键合相中形成铁氧体钙，并增强其在铁矿石表面的渗透，从而提高界面结合强度。使用 6% RM 和 1.5% 生石灰成功进行了中试规模烧结。可以获得 76.68% 的烧结收率和 64.98% 的滚滚指数，与没有 RM 时相当，为钢铁行业大规模回收 RM 提供了一种可行的途径。