Carbon-Negative Critical Metal Recovery from E-Wastes through Responsible Design of Solvents (Co-I Escobar SOW)

1 Solvent Innovation for Critical Metal Recovery and Industrial Decarbonization Funding Opportunity: Building EPSCoR-State/National Laboratory Partnerships – DE-FOA-0003201 Key Personnel PI: Dr. Jian Shi, Associate Professor, Biosystems and Agricultural Engineering Co-PI: Dr. Rick Honaker, Professor, Mining Engineering Co-PI: Dr. Qing Shao, Assistant Professor, Chemical and Materials Engineering Co-PI: Dr. Isabel Escobar, Professor, Chemical and Materials Engineering Identified DOE National Lab/User Facility Partners Dr. Jaydeep Bardhan, Scientific Area Lead, Pacific Northwest National Laboratory (PNNL) Dr. Blake Simmons, Division Director, Lawrence Berkeley National Laboratory (LBNL) Project Description Program area of interest: L. Office of Energy Efficiency and Renewable Energy: Buildings and Industry (including Advanced Materials and Manufacturing; Buildings; and Industrial Efficiency and Decarbonization) Extracting critical metals from lean ore and from the spent lithium-ion batteries could solve the supply chain issue and address the environmental risk with the waste disposal. Current recovering process uses strong acids such as sulfuric acids to enhance the leaching of the critical metals, followed by sequential extraction with phosphine containing sulfonated kerosene to precipitate metal salts from the acidic solutions. The current process faces several challenges: (1) safety risks to the operating workers and the environment and corrosion to the equipment caused by the volatile acids; (2) high capital and energy cost to enrich the metals from very dilute stream (3) low purity in this recovery process. Thus, it is critical to develop a process that can recover critical metals more selectively using a greener solvent under milder conditions. On the other hand, there has been great investment in decarbonizing the mining and material industries through new extraction process design. Great opportunities have emerged for using deep eutectic systems (DES) as solvent, reaction medium and catalyst to enable cost effective and efficient processing technologies for broad applications. Type-V DES that is typically hydrophobic in nature can be formed from renewable hydrogen bond donors and acceptors. Leveraging the power of molecular dynamics simulation, meta-analysis and machine learning based algorithms, we can explore a large design space of type-V hydrophobic DES to enable selective and potential low-cost recovery of critical metals. Through a recent UK Igniting Research Collaborations (IRC) project, the team has developed a novel simulation-deep learning-experiment pipeline for the discovery of novel hydrophobic DES made from a range of low cost, renewable resources like plant-based phenolics, terpene, and organic acids. The team also explored the applications of those hydrophobic DES in biofuel molecule extraction, biomass fractionation, microplastic remediation and industrial decarbonization. Fig. 1 Schematic diagram of novel simulation-deep learning-experiment discovery pipeline. 2 One outcome of the machine learning-based design is the successful selection/synthesis of 19 room-temperature stable type-V hydrophobic DES from hundreds of candidate combinations. We have conducted extensive experiments to characterize the properties of these new DES such as density, viscosity, and thermostability. Additionally, various characterization techniques including FT-IR, TGA, and DSC were employed to understand the molecular structure and inter-intra hydrogen bonding in the DES system. Selected DESs were further tested for metal leaching and recovery and showed promising leaching/extraction efficiency of the critical metals (Li, Co, and Ni) from the standard active cathode materials and black mass powder under mild conditions and potential of DES recycling for reuse. This new process has several advantages compared to the existing processes relying on strong acid solutions: (a) mild reaction conditions with a “green” solvent; (b) higher selectivity and purity of the recovered critical metals, and (c) minimum waste generation due to the recyclability of the hydrophobic DESs. Up to date, we have developed 3 patents/patent applications and published several journal publications under this theme. This area is (has been) funded by one DOE IDEA grant, one USDA grant and two NSF grants. We envision that further innovations in solvent development and the surrounding process intensification strategies could help to address the following specific challenges in alignment to DOE AMMTO and IDEO foci: 1) extraction and enrichment of low REE/CM concentrations versus high impurity contents (e.g., ppm vs. %) in leach solutions; 2) improved selectivity in separating REE/CM in leach solutions; 3) lower energy consumption; 4) possibility of deep purification of REE/CM metals using combinatory solvent systems; 5) lower the carbon footprint of the processes. Leveraging our existing collaborations with Drs. Bardhan and Simmons at DOE’s national labs (funded through an NSF EPSCoR track 4 award), we will gain access to the infrastructure and expertise at DOE’s premier user facilities including the Environmental Molecular Sciences Laboratory (EMSL) at PNNL and the Molecular Foundry and National Energy Research Scientific Computing Center (NERSC) at LBNL. We hypothesize that (1) the hydrogen bond structures of DESs determine the selectivity and transport of metals, and (2) the hydrogen bonds at the DES-aqueous liquid-liquid interface determine the interfacial barrier and kinetics of extracting critical metals from DES to the aqueous solutions. Inspired by the hypotheses, this project will conduct molecular simulations and experimental research to reveal the fundamental relationship between DES composition, bulk and interfacial hydrogen bond properties, and valid the computational outcomes with experiments for the selective recovery for critical metals from low-grade ore and/or e-wastes. The revealed relationship will be used to unravel the hydrogen bond-based molecular fingerprints that could empower the machine learning (ML) models we previously developed to design DESs with improved extraction selectivity. Specific objectives include: 1) Build multiscale molecular simulations to understand effect of hydrogen bond on critical metal ion solvation in DES (via collaboration with NERSC and EMSL’s Systems Modeling and Computation experts) 2) Unravel the DES-aqueous interfacial hydrogen bond on the extraction thermodynamics and kinetics of critical metal ions (via collaboration with EMSL and LBNL’s molecule characterization facilities) 3) Explore premier ML models to search for DES for selective extraction/recovery 4) Develop process intensification strategies to lower the energy and capital cost 5) Conduct technoeconomic and life cycle analyses to understand cost factors and environment impact Fig. 2 Demonstration of selective extraction of Ni from the black mass of spent Li-ion battery: A) dissolution of black mass in DES at 120 ºC, B) the solution in DES phase, C) phase separation and precipitation of Ni salt and reuse of DES for next batch dissolution. 3 Team Background Jian Shi is an Associate Professor in the Department of Biosystems and Agricultural Engineering at University of Kentucky. He held a BS in Metallurgical and Materials Engineering, and PhD in Biological Engineering. He joined the faculty of University of Kentucky in 2015 atier worked at Sandia National Labs as a postdoc and a short stay with a biotech company (Novozymes) as a Sr. Scientist. His group have grown several signature research areas including 1) data-driven solvent innovation and enzyme engineering for renewable, circular, and low-carbon chemicals and materials; 2) waste feedstock logistics and modeling; and 3) nanotechnology and fermentation development for food and agriculture applications. Up to date, his research group has published a total of 90+ peer reviewed journal articles/book chapters and several patent applications. He is lead PI/co-PI on >$10M active grants from NSF, DOE-EERE, and USDA to develop waste treatment/valorization and DES technologies. Rick Honaker is a Professor of Mining Engineering at the University of Kentucky. His group develops, tests and commercializes innovative technologies and methodologies to advance the abilities to recover, concentrate and purify critical elements and materials including energy-relevant elements needed for renewable energy manufacturing. His substantial achievements and contributions include >$30 million in research funding received from federal and state agencies as well as private companies with over 80 funded research projects, 250+ publications as author or co-author including 140+ peer-reviewed articles, seven U.S. patents and patent applications, and over 50 substantive project reports resulting from industrial consultations. Qing Shao is an assistant professor at UK with over 10-year experience in investigating molecular thermodynamics of interfacial behavior of molecules in complex systems using molecular simulations. His group also grew into AI and machine learning based modeling of biological and chemical systems. Dr. Shao has published 60+ papers on the simulation research of complex systems. Isabel Escobar is Chellgren Chair Professor of Chemical Engineering, Director of the Chellgren Center for Undergraduate Excellence and Associate Director of the UK Center of Membrane Sciences with 20+ years of experience in membrane development. She has 100+ peer-reviewed publications with >$20M grants to design novel membrane materials for difficult applications and fouling control. Relevant Publications and Intellectual Properties 1) Method for recycling the critical metals from spent lithium-ion batteries. Provisional Patent PCT/US2023/032508 2) Method for synthesizing a hydrophobic deep eutectic solvent. U.S. Utility Patent, US20220144669A1 3) J Hunter, Q Qi, Y Zhang, Q Shao, C Crofcheck, J Shi (2023) Green solvent mediated extraction of micro- and nano-plastic particles from water. Scientific Report, 13, 10585 4) Y Zhang, Q Qiao, UL Abbas, J Liu, Y Zheng, C Jones, Q Shao, J Shi (2023) Lignin derived hydrophobic deep eutectic solvents as sustainable extractants, Journal of Cleaner Production, 388, 135808 5) MC Vin-Nnajiofor, W Li, S Debolt, YT Cheng, J Shi (2022) Fractionation and Upgrade of Endocarp Lignin to Carbon-Silicon Nanocomposites as an Anode Material in Lithium-Ion Batteries, Applied Engineering in Agriculture, 38(3): 509-516 6) UL Abbas, Q Qiao, MT Nguyen, J Shi, Q Shao (2022) Molecular Dynamics Simulations of Heterogeneous Hydrogen Bond Environment in Hydrophobic Deep Eutectic Solvents, AIChE Journal, e17382 7) UL Abbas, Q Qiao, MT Nguyen, J Shi, Q Shao (2021). Structure and Hydrogen Bonds of Hydrophobic Deep Eutectic Solvent-Aqueous Liquid-Liquid Interfaces, AIChE Journal, e17427