Analytical approach for the characterization of the chemical and mineralogical composition of Al$_2$O$_3$–SiO$_2$–CaO–MnO–Li$_2$O–type lithium-ion battery (LIB) slags

The process for economic recovery of Li from slags produced during the recycling of lithium-ion batteries via a combined pyro- and hydrometallurgical process route needs to be optimized. This requires a detailed knowledge of the phase composition, metal distribution, and microstructure of the produced slags. In this work, a new two-stage analytical approach is presented, which enables the geochemical, mineralogical, and structural investigation of these slags. The methodology was developed on samples of the model system Al$_2$O$_3$–SiO$_2$–CaO–MnO–Li$_2$O and is demonstrated here on an artificial Li- and Mn-rich slag sample.
Rapid analytical methods (short-wave ultraviolet radiation and micro energy-dispersive X-ray fluorescence spectroscopy) are adapted for on-site recycling process monitoring. They are validated by state-of-the-art mineralogical (X-ray diffraction with Rietveld quantitative phase analysis), bulk chemical (X-ray fluorescence, inductively coupled plasma mass spectrometry), and microanalytical (electron probe microanalysis, scanning electron microscopy-based automated mineralogy, laser ablation inductively coupled plasma-time-of-flight mass spectrometry) techniques. ... mehrApparently contradictory results of the latter techniques are discussed and reconciled.
The integration of the new routine and rapid analytical methods into the pyro- and hydrometallurgical recycling route for lithium-ion batteries will be discussed considering the key mineralogical questions to be answered in process development, industrial process control, and process route adaptation.