Heydarian Ahmad, Vakilchap Farzane, Mousavi Seyedeh Neda, Mousavi Seyyed Mohammad
Biotechnology Group, Chemical Engineering Department, Tarbiat Modares University, Jalal Ale Ahmad Highway, Nasr, P.O. Box 14115-111, Tehran, Iran.
Modares Environmental Research Institute, Tarbiat Modares University, Tehran, Iran.
Sci Rep. 2025 May 13;15(1):16517. doi: 10.1038/s41598-025-00660-9.
Accumulating used lithium-ion battery cathodes and associated environmental concerns necessitate efficient recycling strategies. Biohydrometallurgical processes often face challenges at high pulp densities due to microbial inhibition and substrate limitations, particularly sulfur availability, which is crucial for bacterial acidic agent production. This study introduces a breakthrough spent-medium bioleaching approach optimized for high-pulp-density conditions. We systematically addressed key challenges, including bacterial inhibition, sulfuric acid optimization, and its impact on critical metal dissolution. Using response surface methodology, we optimized sulfur dosage, inoculum size, and initial pH to enhance bacterial acidic agent production by Acidithiobacillus thiooxidans, achieving a sulfate concentration of 40.3 g/l and a ΔpH of 1.87. Metal removal efficiency was assessed at pulp densities of 10-50 g/l, demonstrating high extraction rates of Li (92%), Ni (88%), and Co (78%) at 50 g/l after 7 days. Comparative analysis with chemical leaching confirmed the effectiveness of this green strategy. Furthermore, a kinetic study using the Avrami equation and shrinking core model revealed that both models yield comparable results, and diffusion through the product layer controlled the leaching rate. This study presents a comprehensive and sustainable strategy for waste recycling at high pulp densities by integrating process optimization, spent-medium bioleaching, and kinetic modeling for critical metal extraction from lithium-ion battery cathodes.
废旧锂离子电池阴极的不断积累以及相关的环境问题使得高效回收策略成为必要。生物湿法冶金工艺在高矿浆密度下常常面临挑战，这是由于微生物抑制和底物限制，特别是硫的可用性，而硫对于细菌酸性剂的生产至关重要。本研究引入了一种针对高矿浆密度条件优化的突破性废介质生物浸出方法。我们系统地解决了关键挑战，包括细菌抑制、硫酸优化及其对关键金属溶解的影响。使用响应面方法，我们优化了硫用量、接种量和初始pH值，以提高氧化硫硫杆菌产生细菌酸性剂的能力，实现了40.3 g/l的硫酸盐浓度和1.87的ΔpH值。在10 - 50 g/l的矿浆密度下评估了金属去除效率，结果表明在50 g/l的矿浆密度下7天后锂（92%）、镍（88%）和钴（78%）的提取率很高。与化学浸出的对比分析证实了这种绿色策略的有效性。此外，使用阿弗拉米方程和收缩核模型进行的动力学研究表明，这两个模型产生的结果相当，并且通过产物层的扩散控制了浸出速率。本研究通过整合工艺优化、废介质生物浸出和从锂离子电池阴极中提取关键金属的动力学建模，提出了一种在高矿浆密度下进行废物回收的全面且可持续的策略。
