Cheng Jiehong, Lu Tao, Wu Xiao, Zhang Haojing, Zhang Chunyong, Peng Ching-An, Huang Shouqiang
School of Chemical and Environmental Engineering, Jiangsu University of Technology Changzhou China 213001
Department of Biological Engineering, University of Idaho Moscow USA 83844.
RSC Adv. 2019 Jul 23;9(39):22729-22739. doi: 10.1039/c9ra02719j. eCollection 2019 Jul 17.
Spent lithium batteries contain valuable metals such as cobalt, copper, nickel, lithium, After pretreatment and recovery of copper, only cobalt, nickel and lithium were left in the acid solution. Since the chemical properties of cobalt and nickel are similar, separation of cobalt from a solution containing nickel is technically challenging. In this study, Co(ii) was separated from Ni(ii) by chelating Co(ii) with chlorine ions, Co(ii) was then extracted from the aforementioned chelating complexes by methyltrioctylammonium chloride (MTOAC). The effects of concentrations of chlorine ions in the aqueous phase ([Cl]), MTOAC concentrations in organic phase ([MTOAC]), ratios of organic phase to aqueous phase (O/A), and the initial aqueous pH on cobalt separation were studied. The results showed that [Cl] had a significant impact on cobalt extraction efficiency with cobalt extraction efficiency increasing rapidly with the increase in [Cl]. The effect of initial pH on cobalt extraction efficiency was not significant when it varied from 1 to 6. Under the condition of [Cl] = 5.5 M, [MTOAC] = 1.3 M, O/A = 1.5, and pH = 1.0, cobalt extraction efficiency reached the maximum of 98.23%, and nickel loss rate was only 0.86%. The stripping rate of cobalt from Co(ii)-MTOAC complexes using diluted hydrochloric acid was 99.95%. By XRD and XRF analysis, the recovered cobalt was in the form of cobalt chloride with the purity of cobalt produced reaching 97.7%. The mode of cobalt extraction was verified to be limited by chemical reaction and the kinetic equation for cobalt extraction was determined to be: = 4.7 × 10[MTOAC] [Co] .
废旧锂电池含有钴、铜、镍、锂等有价金属。经过预处理回收铜后，酸溶液中仅剩下钴、镍和锂。由于钴和镍的化学性质相似，从含镍溶液中分离钴在技术上具有挑战性。在本研究中，通过用氯离子螯合Co(ii)将Co(ii)与Ni(ii)分离，然后用甲基三辛基氯化铵(MTOAC)从上述螯合络合物中萃取Co(ii)。研究了水相中氯离子浓度([Cl])、有机相中MTOAC浓度([MTOAC])、有机相与水相的比例(O/A)以及初始水相pH对钴分离的影响。结果表明，[Cl]对钴的萃取效率有显著影响，钴的萃取效率随[Cl]的增加而迅速提高。当初始pH在1至6之间变化时，对钴萃取效率的影响不显著。在[Cl]=5.5 M、[MTOAC]=1.3 M、O/A=1.5和pH=1.0的条件下，钴的萃取效率达到最大值98.23%，镍的损失率仅为0.86%。用稀盐酸从Co(ii)-MTOAC络合物中反萃钴的反萃率为99.95%。通过XRD和XRF分析，回收得到的钴为氯化钴形式，所产钴的纯度达到97.7%。验证了钴的萃取方式受化学反应限制，确定了钴萃取的动力学方程为： = 4.7×10[MTOAC][Co] 。
