| Summary: | 碩士 === 朝陽科技大學 === 環境工程與管理系 === 104 === At present the battery recovery plants in Taiwan only reclaim manganese batteries and alkaline zinc-manganese dioxide batteries. The spent lithium-ion batteries are all exported outside the border. When chemical precipitation method was employed to recovery metals from the new type of NMC (LiNiO2/LiCoO2/LiMn2O4) lithium-ion batteries the three metals co-precipitated and produced a low value material. This study investigated the ultrasound assisted acid dissolution and microemulsion extraction for cathode material of NMC lithium-ion battery.
This study compared the differences of Mn and Co/Ni/Li dissolution ratios between ultrasound assistance and non-ultrasound assistance in acid solution without addition of hydrogen peroxide. Microemulsion extraction was accomplished to separate Co and Ni/Li with CTMAB (cetyltrimethylammonium bromide) as surfactant, n-pentanol as cosurfactant, n-heptance as organic phase, and NH4SCN(Ammoniutn Thiocyanate) as outer water phase.
The experiment results reveal that pre-calcination and higher acid concentrations have no obvious effect upon dissolution ratios of metals. On the hand, ultrasonic booster, ultrasonic bath and magnetic stirrer have high, middle and low improvement on metal dissolution ratios, respectively. Comparing with magnetic stirrer, ultrasonic bath can reduce 80% addition amounts of hydrogen peroxide for dissolution of metals. When using ultrasonic booster, Mn was no dissolution and the acid solution contained only Co/Ni/Li. Separation of Mn and Co/Ni/Li can be accomplished by using Ultrasonic booster
Microemulsion extraction was used to separation of Co and Ni, and extraction reached equilibrium in 30 seconds. Microemulsion extraction is an exothermic reaction. Increasing operating temperatures will not improve the extraction efficiency. The optimum operation results showed the extraction ratio of Co was 62%, and the extraction ratios of Ni and Li were all below 5%. Using two stages extraction, the extraction ratio of Co can reach 98%, and the extraction ratios of Ni and Li were all below 5%.
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