|Cite this article as:|
|Hui Dang, Zhidong Chang, Hualei Zhou, Sihang Ma, Min Li, and Jialing Xiang, Extraction of lithium from simulated pyrometallurgical slag of spent lithium-ion batteries by binary eutectic molten carbonates, Int. J. Miner. Metall. Mater.,(2021). https://doi.org/10.1007/s12613-021-2366-3|
Effectively extracting lithium from the pyrometallurgical slag of spent lithium-ion batteries at a relatively low temperature remains a great challenge. Herein, potassium carbonate/sodium carbonate (K2CO3/Na2CO3) which could form eutectic molten salts at 720°C were used as the roasting agents for extracting lithium from the pyrometallurgical slag. The lithium is successfully extracted from slag by K2CO3/Na2CO3 roasting followed by water leaching. According to the theoretical calculation results, lengths of Li-O bonds increase after adsorption of K+/Na+, resulting in easily release of Li+ from the lattice of LiAlSi2O6 after roasting with K2CO3/Na2CO3. Moreover, the TG-DSC results indicate that the eutectic phenomenon of K2CO3 and Na2CO3 is observed at 720°C and the reaction of slag and eutectic molten salts happens above 720°C. The X-ray diffraction results suggest that Li+ in slag is exchanged by K+ in K2CO3 which is accompanied by the formation of KAlSiO4, while Na2CO3 is mainly employed as a fluxing agent. The lithium extraction efficiency can reach 93.87% under the following optimal conditions: roasting temperature of 740°C, roasting time of 30 min, leaching temperature of 50°C, leaching time of 40 min and water/roasted samples mass ratio of 10:1. This work provides a new system for extracting lithium from the pyrometallurgical slag of spent lithium-ion batteries.