Cryo-Mechanical Treatment and Hydrometallurgical Process for Recycling Li-MnO₂ Primary Batteries with the Direct Production of LiMnPO₄ Nanoparticles

In this work, an innovative hydrometallurgical recycling route for the recovery of all the materials composing Li-MnO₂ primary batteries was proposed. End-of-life batteries were mechanically treated in an innovative pilot plant where a cryogenic crushing was performed. The mechanical treatment allowed for the release of the electrodic powder contained in the batteries with the simultaneous recovery of 44 kg of steel and 18 kg of plastics from 100 kg of batteries. Electrodic powder was employed as the raw material for the synthesis of LiMnPO₄ nanoparticles. To obtain the synthesis precursors, selective sequential leaching of Li and Mn was performed. Li was extracted via water washing the electrodic powder and Li₂CO₃ and a purity of 99% was recovered. The black mass containing Mn oxides was leached using phosphoric acid, which gave a Mn-bearing precursor solution that was directly used for the hydrothermal synthesis of LiMnPO₄ nanoparticles. A preliminary materials balance of the process was presented, indicating that the proposed process should be an easy hydrometallurgical route for the recycling of primary lithium batteries. In addition, the simultaneous production of high-value-added products that could be reintroduced into the battery manufacturing chain could ensure the economic feasibility of the process.