| 英文摘要 |
With the annual amounts and percentages of recycled lithium batteries being increased significantly, how to recycle these spent lithium batteries effectively is very important and urgent. Therefore, this study aims to use the thermal treatment technology for recycling the spent lithium batteries and investigating the effects of different operation conditions on the recycle efficiency of valuable metals. The fates and distributions of different metals in solid and gas phase are also evaluated. The optimal operation conditions and the feasible treatment process for the recycling of spent lithium batteries will be proposed.
The scheduled tasks and progress of this study has been finished. The experimental results indicate that the major compositions of lithium-cobalt battery included metal foil (anode, 30-50%), graphite (cathode, 16-27%), separation film (3-5%), outer covering metal (2-7%), and packing materials (1.5-4.5%). The contents of different metals in the spent lithium-cobalt battery were lithium (4-7%), aluminum (7-10%), cobalt (40-65%), nickel (0-1.2%), and copper (20-45%). The major compositions of lithium-iron battery included metal foil (anode, 52%), graphite (cathode, 25%), separation film (8%), outer covering metal (10%), and packing materials (0.7%). The contents of different metals in the spent lithium-iron battery were lithium (5%), aluminum (15-20%), iron (38%), and copper (37-41%).
The optimal thermal treatment efficiency was obtained when the operating temperature was controlled at 600 oC. At lower temperature (400 oC), the combustible materials such as the separation film can’t be decomposed completely and the recycle efficiency of metals were decreased. The emissions of air pollutants were relatively lower when the operating temperature was controlled at 600 oC. Different feed gas compositions provided different combustion atmospheres and influenced the recycling efficiency and species compositions of metals. To comprehensively consider the recycling efficiencies of different metals and operation cost, air was the best feed gas. The recycling rates of different metals in lithium-cobalt batteries were lithium 95.38%, cobalt 93.99%, copper 96.34%, and alumina 85.28%. The recycling rates of different metals in lithium-iron batteries were lithium 90.01%, iron 85.49%, copper 83.72%, and alumina 73.75%. The concentrations of HCl and HF in the flue gas of lithium batteries treatment furnace were 2-16 ppm, the control of acid gases should be careful. The concentrations of heavy metals in the flue gas were relative low and the range was N.D.~ 0.4 mg/Nm3. More than 99.9% metals were presented and remained in the residuals (solid phase) during the thermal treatment of spent lithium batteries.
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