A Contribution to a Better Understanding of Lithium-Ion Battery Recycling by Using Automated Mineralogy

Recycling is a potential solution to narrow the gap between the supply and demand of battery materials such as Co, Ni, Mn and graphite. However, increasing the efficiency of the recycling of lithium ion batteries (LIB) remains a challenge. This paper evaluates the influence of the recycling routes on the liberation of LIB components and on the joint recovery of lithium metal oxides and spheroidized graphite particles using froth flotation. The products of the two different recycling routes – mechanical, and thermomechanical – were analyzed using a particle-based method, namely scanning electron microscopy (SEM)-based automated image analysis. The mechanical process enabled the delamination of active materials from the foils. However, binder preservation hinders active materials liberation as indicated by their aggregation. In contrast, the thermo-mechanical process showed a preferential liberation of individual anode active particle thus identified as an upstream route for flotation. However, this thermal treatment led to a lack of liberation of cathode material and to the oxidation of aluminium foil resulting in its distribution in all size fractions. Among the two, the thermo-mechanical black mass showed the highest flotation selectivity due to the removal of the binder thereby producing liberated active particles.