纳米气泡对锂电池电极材料浮选行为的影响

Influence of nanobubbles on flotation behavior of electrode materials from spent lithium ions batteries

  • 摘要: 废弃锂电池电极材料的组成主要为石墨和钴酸锂粉末,2 者的浮选分离是废弃锂电池二次 资源循环利用工艺中的关键一环。 由于电极材料的粒度远低于常规的浮选颗粒尺寸下限,应用常 规的浮选技术实现 2 者的高效分离较为困难。 利用原子力显微镜成像技术对界面纳米气泡进行了 表征,结合原子力显微镜胶体探针技术和激光粒度测量仪研究了界面纳米气泡对颗粒-颗粒间相 互作用的影响,设计了基于界面纳米气泡的锂电池电极材料浮选分离实验。 结果表明,冷水升温的 方法可在固-液界面产生纳米气泡,纳米气泡存在时颗粒-HOPG 基质间展现出了较大黏附力。 粒 度测量结果表明纳米气泡存在时石墨颗粒聚集体尺寸 D50 从 23 μm 增加至 29 μm。 浮选试验结果 表明冷水中浮选可燃体回收率均高于常温水浮选:在常温水中,当浮选时间从 2 min 增加到 8 min 时,可燃体回收率从约 34%增加到 66%;在冷水浮选中,可燃体的回收率从约 44%增加至 74%。 和 常温水浮选结果相比,冷水升温浮选获得了较高的可燃体回收率和较好的浮选选择性。

     

    Abstract: The electrode materials of spent lithium ions batteries mainly consist of graphite and lithium cobalt oxide,the separation of which with flotation is a key step in the recycling and utilization process of secondary re⁃ sources.The efficient separation of them with the conventional flotation technique is hard to be achieved due to the smaller size of electrode materials than that of common flotation particles.In the present study,the interface nanobub⁃ bles were imaged with the tapping mode atomic force microscope(AFM),then the influence of nanobubbles on the in⁃ ter particles interaction and the size of agglomeration of graphite were quantified with colloidal probe technique and size analyzer respectively.At last,the flotation experiment for electrode materials with nanobubbles was designed.The results show that nanobubbles can be generated with cold water by increasing temperature and the graphite probe was subjected to a weak electrostatic repulsive force during approach.Meanwhile,a high adhesion force was shown be⁃ tween graphite and substrate during retrace in the presence of nanobubbles. The D50 of graphite agglomerations increases from 23 μm to 29 μm in the presence of nanobubbles.The flotation results show that the combustible recovery increases from 34% to 66% in room temperature water while from 44% to 74% in the case of cold water as the flota⁃ tion time increases from 2 min to 8 min.The higher combustible recovery and the better flotation selectivity was ob⁃ tained in flotation with cold water compared with room temperature water.

     

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