Abstract
Aurubis AG, Europe’s largest multi-metal producer and a leading copper recycler globally, has developed and patented a hydrometallurgical process to recycle both pyrolysed and un-pyrolysed Black Mass (BM) stemming from Li-ion batteries. This purely inorganic process, comprising of leaching, precipitation, and crystallisation processes, was developed by Aurubis’ R&D Department and piloted at our Hamburg site successfully since April 2022.
Organic chemicals and associated Fluorine containing compounds that are critical components of Li-ion batteries present a unique challenge for hydrometallurgical recycling processes. Typical Li-ion batteries use a mixture organic carbonate solvents (e.g., Ethlyene Carbonate) as the electrolyte, Lithium hexafluorophosphate (LiPF6) as conducting salt and PVDF as common binder for Anode and Cathode material to adhere to current collector foils. The presence of these types of materials in BM to a greater or lesser extent, depending on pre-processing, is critical to understand in context of hydrometallurgical recycling. How these compounds react, distribute and build-up in recirculating streams has numerous impacts, including process performance and impurity deportment to products and residues.
Aurubis has investigated the presence of these type of materials in raw unpyrolized BM and their corresponding reaction products and distribution in our process. Using samples from Pilot plant and Laboratory experiments NMR-Analysis was used to identify and track Organic and Fluorine compounds through key streams. Laboratory experiments with pure LiPF6 and Ethylene carbonate were conducted to understand the influence of aqueous processing conditions (e.g., pH, temperature and background electrolyte) on their reactions and residual compound formed.