An environmentally-friendly technology of pyrolysis-ultrasonic-assisted flotation for recovering graphite and LiCoO₂ from spent lithium-ion batteries has been evaluated in this paper. Surface properties and morphology of graphite and LiCoO₂ derived from spent lithium-ion batteries were carefully studied, and on this basis, their pyrolysis characteristics were investigated by thermogravimetry–gas chromatography–mass spectroscopy. Advanced analysis techniques, scanning electron microscopy, X-ray fluorescence spectrometry, and X-ray photoelectron spectroscopy, were utilized to analyze the effect of pyrolysis and ultrasound on the surface properties and morphology of graphite and LiCoO₂. Flotation tests were conducted to evaluate the reinforcing effect of pyrolysis–ultrasound on flotation behavior. Results show that organic binder and electrolyte are the main reasons that graphite and LiCoO₂ are hard to separate by flotation; meanwhile, pyrolysis can effectively decompose organic binders at a pyrolysis temperature of 500 °C, and ultrasonic cleaning can effectively remove residual pyrolysis products. Pyrolysis-ultrasonic-assisted flotation can make the LiCoO₂ grade improve from 67.25% to 93.89% with the recovery improving from 74.62% to 96.88%. This research work may provide an alternative process for the preparation of high purity LiCoO₂ particles for the subsequent chemical metallurgy.

中文翻译：

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热解-超声辅助浮选技术从废锂离子电池中回收石墨和LiCoO ₂

本文评价了一种热解-超声辅助浮选从废锂离子电池中回收石墨和LiCoO ₂的环保技术。仔细研究了废锂离子电池中石墨和LiCoO _2的表面性质和形貌，并在此基础上通过热重分析-气相色谱-质谱法研究了它们的热解特性。利用先进的分析技术，扫描电子显微镜，X射线荧光光谱和X射线光电子能谱分析热解和超声对石墨和LiCoO ₂的表面性质和形貌的影响。。进行浮选试验以评估热解-超声对浮选行为的增强作用。结果表明，有机粘结剂和电解质是难以通过浮选分离出石墨和LiCoO _2的主要原因。同时，热解可以在500°C的热解温度下有效分解有机粘合剂，而超声清洗可以有效去除残留的热解产物。热解-超声辅助浮选可使LiCoO ₂品位从67.25％提高到93.89％，回收率从74.62％提高到96.88％。这项研究工作可能为制备用于后续化学冶金的高纯度LiCoO ₂颗粒提供替代方法。