The unexpected stability of froth structures formed with battery materials allow their characterization with x-ray computed tomography

• A first succesful 3D reconstruction of a mineral froth. • Identification of distribution of mineral species in the froth is possible. • True flotation mechanism is demonstrated for lithium cobalt oxides. • Study of bubble morphology and size in opaque froths is presented. As a result of ongoing research on direct recycling of battery active materials, it was observed that the chemical environment in flotation operations can be manipulated to produce highly stable froths. Such unexpected behavior opened the possibility to characterize this type of metastable structures using imaging techniques such as x-ray computed tomography. In this article, a first successful three-dimensional reconstruction of a live mineral froth is reported, unveiling its structural intricacies with micron-scale detail. Using this novel approach, it was possible to observe the distribution of solid species in the froth and the corresponding bubble geometries. Furthermore, the results challenge prevailing notions about the flotation mechanisms of cathode particles, emphasizing the need for more selective reagents in the flotation of end-of-life batteries.