Utilization of waste leather for efficient removal of Ca2+ and Mg2+ in lithium carbonate production via nano-structural adsorption.

With the growth of electric vehicles (EVs), the demand for battery-grade lithium carbonate (Li2CO3) is increasing significantly. However, a large part of the available Li2CO3 is of industrial-grade, either ternary material or lithium iron phosphate (Li2CO3 is one of the precursors for either ternary material or lithium iron phosphate), which cannot satisfy the requirements for the preparation of cathode. Traditional production of battery-grade Li2CO3 involves converting industrial-grade lithium carbonate into LiHCO3 solution through carbonization using CO2; the insoluble impurities are then removed by filtering, followed by thermal decomposition. However, Ca2+ and Mg2+ are the most difficult impurities to be removed due to their similar characteristics as that of Li+. This study evaluates the use of a vegetable-aldehyde combination tanned leather to filter Ca2+ and Mg2+ from a LiHCO3 solution utilizing the nano structure of the leather. Results show an effective reduction in Ca2+ and Mg2+ concentrations in the LiHCO3 solution. When treated with EDTA, the leather can be reused for at least 12 cycles, indicating a cost-effective and sustainable high-quality lithium carbonate production strategy. This study highlights the tanned leather's potential as a reliable filtration medium for lithium-ion battery precursors.