Müller Marius, Nobis Christian, Irmer Michael, Fischlschweiger Michael, Yagmurlu Bengi
Institute of Geotechnology and Mineral Resources, Department of Resource Processing Technologies, Clausthal University of Technology, 38678 Clausthal-Zellerfeld, Germany.
Institute of Energy Process Engineering and Fuel Technology, Clausthal University of Technology, Germany.
Waste Manag. 2025 Sep;206:115042. doi: 10.1016/j.wasman.2025.115042. Epub 2025 Aug 2.
Various approaches are being investigated to recover valuable materials from end-of-life lithium-ion batteries, particularly for lithium nickel manganese cobalt oxide (NMC) and lithium iron phosphate (LFP) cathode chemistries. Graphite recovery has gained increasing interest due to its classification as a critical raw material, with Flotation being a promising process for its recovery from black mass. A requirement for successfully realizing this process is the removal of binders from the anode and cathode surfaces, which is usually achieved through thermal treatment. This paper investigates the thermal decomposition behavior of pure and mixed NMC/LFP materials under oxidative and inert atmospheres and examines how these differences affect subsequent flotation performance. Macro thermobalance analysis, combined with differential thermal analysis (DTA) and mass spectrometry for multidimensional thermal analysis, was used to understand possible reactions and obtain thermally treated samples for flotation. The thermally pretreated samples were then subjected to flotation to assess the influence of the mixing ratio and evaluate the thermal treatment's quality. Differences between roasting and pyrolysis were identified, with roasting exhibiting higher net exothermicity, which increased with rising NMC content. Fluorine behavior also differed: in LFP, it was released as hydrogen fluoride (HF) gas, whereas in NMC, it remained in the residue and could continue to react during thermal treatment and subsequent processes. The findings demonstrate that cathode composition significantly influences behavior in thermal treatment and has to be considered to optimise pretreatment strategies for effective graphite recovery.
目前正在研究各种方法，以从报废锂离子电池中回收有价值的材料，特别是针对锂镍锰钴氧化物（NMC）和磷酸铁锂（LFP）正极材料。由于石墨被列为关键原材料，其回收受到了越来越多的关注，浮选是从黑粉中回收石墨的一种很有前景的方法。成功实现这一过程的一个要求是去除阳极和阴极表面的粘结剂，这通常通过热处理来实现。本文研究了纯NMC/LFP材料以及混合NMC/LFP材料在氧化气氛和惰性气氛下的热分解行为，并考察了这些差异如何影响后续的浮选性能。采用宏观热重分析，结合差示热分析（DTA）和质谱进行多维热分析，以了解可能发生的反应，并获得用于浮选的热处理样品。然后对经过热预处理的样品进行浮选，以评估混合比例的影响，并评价热处理的质量。确定了焙烧和热解之间的差异，焙烧表现出更高的净放热，且随着NMC含量的增加而增加。氟的行为也有所不同：在LFP中，它以氟化氢（HF）气体的形式释放，而在NMC中，它保留在残渣中，并可能在热处理及后续过程中继续发生反应。研究结果表明，阴极组成对热处理行为有显著影响，为有效回收石墨而优化预处理策略时必须考虑这一点。
