Hui Dang,Benfeng Wang,Zhidong Chang,Xue Wu,Jingge Feng,Hualei Zhou,Wenjun Li,Changyan Sun
When the spent lithium ion battery is processed pyrometallurgically, lithium is generally fixed as slag with a high melting/boiling point which is difficult to be treated further. In this research, an innovative method to recycle lithium from pyro-slag by evaporation during chlorination roasting was proposed. Different chlorine donors, namely NaCl, AlCl3, and CaCl2 were evaluated by HSC software and experiments, among which CaCl2 possessed a stronger ability of chlorine donation in the chlorination roasting process. Experiments proved that 97.45% lithium was evaporated with the Cl/Li molar ratio of 1.8:1 when the mixture of a simulated slag and CaCl2 was roasted at 1000 °C for 90 min. XRD results demonstrated that the majority of LiAl(SiO3)2 in the slag was transformed into LiCl. All results implied that chlorination roasting should be a promising strategy for lithium recovery from the pyrometallurgical slag after pyro-treatment of the spent lithium ion battery.
Haibin Zeng,Yan Li,Ziyu Chen,Chengzong Li,Chengming Du,Zhao Zhao,Hengjun Tai,Tao Li
Selective extraction of lithium from spent lithium-ion batteries (LIBs) represents a promising solution for efficient lithium recovery. Herein, a water-aerosol-assisted roasting technology is proposed to selectively extract lithium from spent lithium transition metal oxides (LTMOs) cathodes. In an exemplary recycling of spent LiCoO 2 , the cathode material undergoes a low-temperature (350°C) chlorinating roast process to convert it into metal chlorides, followed by a higher-temperature (500°C) roasting to facilitate the selective pyrolysis of CoCl 2 . The presence of water-aerosol significantly enhances the selective pyrolysis process of CoCl 2 , reducing roasting time eightfold compared to conventional air roasting. Subsequent water-leaching effectively extracts 99.1 % of lithium as LiCl, while only 0.2 % of cobalt is extracted, ensuring selective lithium recovery. The resulting high-purity LiCl solution and Co 3 O 4 residue are directly utilizable for producing battery-grade Li 2 CO 3 and LiCoO 2 , respectively. Regenerated LiCoO 2 demonstrates excellent cycling stability, retaining 90.5 % of its capacity after 300 cycles at 1C rate. Moreover, this method is applicable to ternary cathodes (NCM) black mass, offering a sustainable, robust, and cost-effective approach for lithium extraction from spent LIBs.
Al is one of the most difficult to remove impurities from quartz. Even with HF, only a limited removal efficiency was demonstrated. This study proposes a novel and environmentally friendly strategy centered on a combined process of ball milling, Na 2 CO 3 roasting, fluorine-free acid leaching, and chlorination roasting. The core innovation lies in the strategic induction of a consecutive and reversible phase transformation cycle (α-quartz → cristobalite → α-quartz), which serves as an internal grain refiner to achieve continuous microstructure refinement, thereby constructing abundant fast pathways for impurity migration. A comprehensive XRD analysis was introduced to observe the microstructure evolution. The results indicate that Na 2 CO 3 promotes the phase transformation from α-quartz into cristobalite at a relatively low temperature, while chlorination roasting facilitates the reverse transformation back to α-quartz. It revealed that these two distinct phase transformations not only disrupt the crystal integrity but also lead to significant microstructure refinement accompanied by abundant lattice defects. Through these defects, Al impurities rapidly migrate to the quartz particle surface, where they react with the acid solution and HCl gas, enabling efficient removal. Under the optimal process, the Al removal rate reached 90.5 %, the total impurity removal rate attained 98 %, and the quartz purity increased from 99.683 wt% to 99.994 wt%. This work highlights the crucial role of reversible phase transformation-induced grain refinement as an efficient strategy for lattice impurity removal, offering a green and high-performance alternative to HF-based purification with demonstrated advantages in environmental safety, energy efficiency, and product yield.
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