By using proven pyrometallurgical processes, many valuable metals can be recovered from lithium-ion batteries (LIB) (e.g. Ni, Cu, Co) as alloys or metal sulphide. However, lithium dissolves in the slag, from which it cannot currently be recovered economically. A recently discussed approach is the so-called "engineering of artificial minerals", where the lithium is collected in a specially engineered phase[1]. In our previous research, it was proposed to use β-eucryptite as the lithium collection phase[2].
To achieve an economically viable process, certain properties of the collector phase must be optimised: 1) High lithium content; 2) Low levels of process-impeding impurities; 3) A microstructure suitable for liberation and sorting. The extracted crystalline slag was analysed by scanning electron microscopy (SEM), electron microprobe analysis (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to investigate these parameters.
He investigated the lithium collector phase β-eucryptite identified in slag from an industrial LIB recycler and found a lithium content of 5.54 ± 0.19 mass per cent, which is close to the stoichiometric content of 5.51 mass per cent. Furthermore, it has only small amounts of cationic impurities, mainly FeO and CaO, which can be easily removed when β-eucryptite is processed together with spodumene in a primary lithium converter. [3] In addition to the grain size distribution, the implementation of the envelope parameters for the quantitative description of the microstructure is tested. This allows a more detailed quantification of the grain shape than with conventional descriptors.
Links: Skelettförmiges Melilith und β-Eukryptit mit fein verflochtener Ca-Silikat-Phase Rechts: Schlackenprobe
