(中南大學 資源加工與生物工程學院，長沙 410083)
摘 要: 采用球磨-低溫熱處理兩階段流程可以將阻礙鈷酸鋰和石墨浮選分離的鋰電池電極材料表面有機物膜去除，通過TG-DSC綜合熱分析、接觸角、XPS測試進行機理研究。結果表明：機械球磨過程可以破壞石墨表面有機物膜，而鈷酸鋰表面有機物膜的去除需進行進一步處理。為去除鈷酸鋰表面有機物，同時避免石墨的損失，熱處理溫度應不高于500 ℃。在400 ℃焙燒30 min后，鈷酸鋰表面表面有機物的結構受到破壞，C—F鍵和P—F鍵打開后，F(xiàn)與活性材料中的Li、Co結合，轉化為結合能更低的Li—F鍵和Co—F鍵，從而降低鈷酸鋰接觸角，增大與疏水石墨表面的性質(zhì)差異。再經(jīng)浮選流程，鈷酸鋰回收率和品位高達90.32%和88.03%，達到了良好的分選效果。XRD、SEM、DES結果表明：浮選產(chǎn)品物相沒有受到破壞，表面有機物被去除干凈，具有直接重生再造的潛能。
關鍵字: 鋰電池電極材料；浮選回收；球磨；低溫熱處理
（School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China）
Abstract:The organic film on the surface of the lithium battery electrode material that hinders the separation of lithium cobaltate and graphite by flotation can be removed by two-stage process of ball milling-low temperature heat treatment. The mechanism study was conducted by TG-DSC thermal analysis, contact angle and XPS test. The results show that the mechanical milling process can destroy the organic film on the graphite surface, and lithium cobalt oxide needs further processing. In order to remove the lithium cobalt oxide surface organic material while avoiding the loss of graphite, the heat treatment temperature should not exceed 500 ℃. When calcined at 400 ℃ for 30 min, the structure of PVDF on the surface of lithium cobalt oxide is destroyed. After the C—F bond and P—F bond are opened, the F element is combined with Li and Co in the active material to convert to Li—F bond and Co—F bond with lower binding energy, this reduces the contact angle of lithium cobalt oxide and increases the difference in surface properties with hydrophobic graphite. After the flotation process is conducted, the recovery rate and grade of lithium cobaltate are as high as 90.32% and 88.03%, achieving a good flotation effect. XRD, SEM, and DES test results show that the flotation product phase is not damaged, the surface organics are removed, and it has the potential for direct regeneration.
Key words: lithium battery electrode materials; flotation recovery; ball milling; low temperature heat treatment
