The continuous development of lithium-ion batteries (LIBs) manufacturing industry calls for the mass production of Li 2 CO 3 , which serves as a pivotal raw material for LIBs. In our previous study, Li was successfully precipitated as intermediate product Li 2 SiO 3 from an alkaline solution containing Si by the hydrothermal precipitation method, realizing the preliminary separation of Li and impurities. In this research, H 2 SO 4 digestion-water leaching-Na 2 CO 3 precipitation process was proposed to manufacture Li 2 CO 3 from the intermediate product Li 2 SiO 3 . Firstly, the reaction feasibility of H 2 SO 4 digestion-water leaching and direct H 2 SO 4 leaching for Li 2 SiO 3 were comparatively evaluated through thermodynamic calculation and experimental research. Compared to direct H 2 SO 4 leaching, H 2 SO 4 digestion-water leaching process is preferred in view of its excellent filtration properties. Subsequently, systematic digestion and leaching experiments showed that up to 97.1 % of Li was extracted under the optimized conditions, and the concentration of Li in the leach liquor is as high as 29.33 g/L. After pH adjustment and Al removal, Na 2 CO 3 precipitation were adopted for Li 2 CO 3 production. The equilibrium relationship in Li 2 SO 4 -Na 2 CO 3 -H 2 O system was analyzed to predict the precipitation behavior of Li and select appropriate operation window for Li 2 CO 3 preparation. Finally, with an additional carbonation-decomposition process, a Li 2 CO 3 product with a purity of 99.51 % is produced. This process realizes efficient synthesis of battery-grade Li 2 CO 3 from the intermediate product Li 2 SiO 3 .
Yangming Xu,Lanbin Wang,Wenjie Xie,Yu Chen,Keshuo Zhang,Yaguang Du
Copper slag (CS) contains a high content of valuable iron, the stockpile of CS occupies a large amount of land and leads to a waste of secondary resources. This study proposed producing battery-grade FePO 4 ·2H 2 O from CS through selective leaching, synthesis, and purification. The combined acid leaching/evaporation method was used to leach out Fe and inhibit Si from fayalite selectively, and then FePO 4 ·2H 2 O was formed by adding Na 2 HPO 4 ·12H 2 O without extra pH adjustment. The purity of FePO 4 ·2H 2 O obtained by using a reactor heated for 5 h at 180 ℃ with an HCl concentration of 2.5 M was 99.47 %, and the impurities were all by the industry standard for battery-grade FePO 4 ·2H 2 O (HG/T 4701–2021). The LiFePO 4 /C material was further synthesized and tested for battery performance. Under the test current of 0.1C, the charging-specific capacity of the battery in the first week was 175.8 mAh/g, and the discharge-specific ability was 159.3 mAh/g, which was close to the theoretical specific capacity and effective. Life cycle assessment (LCA) indicated that for each 1 kg of iron phosphate produced, the carbon emission of this study was reduced by 4.71 kg CO 2 eq compared with the traditional technology.
The green and efficient recovery of Li + from spent LiFePO 4 (S-LFP) batteries and subsequent preparation of high-purity lithium products hold significant industrial importance. It can be applied in various fields such as electronic products, energy storage, and healthcare. A green and non-toxic potassium monopersulfate triple salt (PMTS) was used for the first time as a dual-functional reagent serving as both leaching reagent and oxidant, enabling highly in-situ selective leaching of Li + from S-LFP. Furthermore, a novel extraction system employing dibenzoylmethane (DBM) and triisobutyl phosphate (TIBP) was innovatively applied to selectively recover Li + from the leachate, ultimately yielding battery-grade lithium carbonate. Under optimized conditions, the leaching efficiency of Li + reached up to 99.40 % with nearly negligible iron dissolution (0.01 %). The DBM-TIBP system achieved selective extraction of Li + from the leachate with a single-stage extraction efficiency exceeding 94 %. A comprehensive purification process involving washing with NH 4 Cl/LiCl solution, three-stage cross-flow stripping with NH 4 HCO 3 solution, and high-temperature crystallization was implemented. This protocol achieved remarkable impurity removal efficiencies of 99.05 % for K + and 98.10 % for Na + while maintaining complete Li + retention. The stripping efficiency of Li + reached up to 99.36 %, leading to producing battery-grade lithium carbonate with 99.9 % purity. Additionally, potassium sulfate with 98.30 % purity was recovered from the residual leachate via fractional crystallization. This cost-effective and environmentally benign strategy provided a new perspective for industrial-scale green recycling of S-LFP battery cathode materials.
危险品化学品经营许可证（带存储）