Abstract:

The waste residue of red mud produced by aluminum smelting industry is disposed in an unreasonable way, resulting in serious environmental pollution and waste of resources. The iron element rich in red mud exists in the form of Fe₂O₃, which is not conducive to the recovery of iron resources. Magnetic materials can be prepared by reduction for the removal of heavy metal ions. Based on this, a composite adsorption material was prepared by coupling red mud and lignin by carbothermal reduction method. The effects of reduction temperature, reduction time and amount of reducing agent on reduction effect were systematically explored and lead ion adsorption experiment was also carried out. The results showed that the optimum technological parameters of lignin reduction red mud were as follows: reduction temperature 625℃, reduction time 30 min and lignin to red mud mass ratio 1∶1. The analysis of co-pyrolysis gas products by GC indicated that the introduction of red mud can improved the output of hydrogen. The liquid produced by co-pyrolysis was analyzed by GC-MS. It was found that lignin/red mud co-pyrolysis could improved the yield of aromatic compounds. The adsorption experiment showed that the prepared composite can effectively remove lead ions from aqueous solution. The preparation of composite adsorption materials by coupling red mud and lignin residue can respond to the national environmental protection policies and have potential economic, energy and environmental benefits.

Key words: lignin, red mud, pyrolysis, preparation, compound material

摘要：

炼铝工业产生的赤泥废渣以不合理的方式处置，会造成严重的环境污染和资源浪费。赤泥中富含的铁元素以Fe₂O₃的形式存在，不利于铁资源回收，可通过还原方式制取磁性材料用于重金属离子的去除。基于此，本研究采用碳热还原法耦合赤泥与木质素制备一种复合吸附材料。系统探究还原温度、还原时间、还原剂用量对还原效果的影响，并开展铅离子吸附实验。研究表明，通过与烟煤还原赤泥对比得出木质素还原赤泥最佳工艺参数：还原温度625℃、还原时间30min、木质素与赤泥质量比为1∶1；GC对共热解气体产物进行分析得出赤泥的引入能够提高氢气产量；GC-MS对共热解液体产物进行分析得出木质素/赤泥共热解能够提升芳烃类化合物产量；吸附实验得出制备的复合材料能够有效去除水溶液中的铅离子。通过耦合赤泥、木质素残渣两种废弃物制备复合吸附材料，能够响应国家环保政策，具备潜在的经济、能源、环境效益。

关键词: 木质素, 赤泥, 热解, 制备, 复合材料