2024 AIChE Annual Meeting
Recovery of Critical Minerals from Spent Lithium-Ion Batteries Via Bioleaching Methods
The sale of lithium-ion batteries (LiBs) has sky-rocketed in recent years. The International Energy Agency (IEA) estimates 145 million electric vehicles on the road by 20301. Current recycling methods for spent LiBs, such as pyrometallurgy, hydrometallurgy, are costly, inefficient, and cause pollution. Elements such as lithium, cobalt, manganese, and nickel are critical minerals (CMs) needed to manufacture LiBs. However, the domestic supply of CMs is limited, raising concerns about their shortages and price volatility. Biohydrometallurgy offers an environmentally sustainable approach to recycling CMs2, extracting them for use in the production of new LiBs through the bioleaching process. In this study, five different organic acids (i.e., lactic, succinic, citric, acetic, and gluconic acid) were examined in abiotic conditions to explore their abilities as biolixiviants on extracting critical minerals from spent LiBs. These acids were chosen because they can potentially be produced from organic waste streams via bioprocesses, which could significantly decrease the leaching cost and carbon footprint. The biolixiviants were mixed with black mass (ground up anodes and cathodes from spent LiBs) and agitated at 150 rpm. Periodical sampling was conducted to understand the kinetics of bioleaching at 40 oC. The samples were analyzed using inductively coupled plasma (ICP) to determine their elemental composition and assess the recovery rate of critical minerals from black mass. After the procedure was set with the biolixiviants, a reductant (i.e., ferrous sulfate) was added to aid in the efficiency and abundance of the recovery rate in the leachate. The results showed citric acid having a significantly higher recovery rate than any other biolixiviants in a reductant-free environment, and gluconic acid had the lowest recovery in this scenario. When a reducing agent is applied, the results show citric acid still achieved the highest recovery, while gluconic acid followed shortly behind, and the recovery for both was higher than without a reducing agent. The acetic acid leachate had the lowest recovery rate for the second experiment, with ferrous sulfate, and second to lowest in the first experiment, without ferrous sulfate. These results show that citric acid is the best leaching agent with greater than 80% recovery percent, but gluconic is viable as well when reducing agent is supplied. To continue further develop this bioleaching process, the promising biolixiviants identified in this study will be produced using specialized microbial communities from organic waste. To ensure the best results, future experiments could involve multiple microbes (producing citric and gluconic acid) and optimization of experimental conditions to maximize the recovery of critical materials from black mass. Our findings demonstrate the viability of biohydrometallurgy as a promising solution to critical mineral shortages, offering a more efficient, environmentally friendly, and cost-effective recovery method.
Reference:
[1] IEA (2021), Global EV Outlook 2021, IEA, Paris https://www.iea.org/reports/global-ev-outlook-2021, Licence: CC BY 4.0 (accessed 2024-09-17).
[2] Alipanah, M.; Reed, D.; Thompson, V.; Fujita, Y.; Jin, H. Sustainable Bioleaching of Lithium-Ion Batteries for Critical Materials Recovery. Journal of Cleaner Production 2023, 382, 135274. https://doi.org/10.1016/j.jclepro.2022.135274.