Improving Extraction Efficiency by Chemical and Process Design Optimization for Elemental Recovery from Waste Lithium-Ion Battery Cathodes
The modern industrial hydrometallurgical recycling process is majorly constricted by process efficiency and generalizability reflected in the limited recovery of elements like Mn and Ni in particular. Enhancement of the recovery efficiency and the solid to liquid ratio (S/L ratio) as well as optimizing the process is vital to reducing energy and chemical costs to make the recycling loop more sustainable and environmentally friendly. In this work we demonstrate two novel hydrometallurgical recycling approaches harnessing chemical and process design optimization to boost leaching efficiencies. The first utilizes ethylene glycol known as an effective alternative green cathode separation agent and demonstrates significant improvements in leaching efficiency even at very high cathode loadings. The process mitigates the use of toxic solvents and compared to state-of-the-art works is suitable for high loadings. It was then further expanded for the recovery of a mixed cathode and anode powder with equally high cathode loadings and showed no dip in leaching efficiency. In the second approach we developed a novel recycling process that takes advantage of the multi-faceted effect of an alternative heating mechanism to yield high leaching efficiencies in significantly shorter time periods. Compared to conventional heating the new process achieved high leaching efficiencies at high loadings in only a fraction of the time. The elemental extraction was also demonstrated to be unanimously efficient with a wide variety of cathode chemistries. We believe that these methods are promising for industrial scale recycling avoiding excess chemical and energy utilization.