Recycling lithium-ion batteries is crucial for the environment and the sustainability of primary resources. In this paper, we report on the characterization of two grades of black mass from spent lithium-ion batteries (with typical lithium–nickel–manganese–cobalt oxide cathode compositions) and their behavior during heating trials. This study paves the way for optimizing lithium-ion battery recycling processes by fully characterizing black mass samples before and after heating. A gas release under pyrolytic conditions was detected using a multicomponent mass spectrometer and included dimethyl carbonate, diethyl carbonate, oxygenated hydrocarbons, hydrocarbons, and other miscellaneous gases. This can be attributed to the evaporation of volatile organic compounds, conductive salt, organic polyvinylidene fluoride binder, and an organic separator such as polypropylene. Thermal treatment led to the partial decomposition of the binder into char and newly formed fluorine cuboids. The compaction of the cathode decreased, but the remaining binder limited recycling processes. By heating the black mass samples to 900 °C, the intensity of the X-ray diffraction graphitic carbon peak decreased, and the lithium metal oxides were reduced to their corresponding metals. The graphite in the black mass samples was structurally more disordered than natural graphite but became more ordered when heated.

During a study aiming to recover strategic elements and minerals from coal fly ash and bottom ash (RAREASH and CHARPHITE projects funded, respectively, by the 2nd ERA-MIN and 3rd ERA-MIN Programs of the European Union Commission), it was found that in coal fly ash and bottom ash from Romania and Poland, several morphotypes did not fit into the general fly ash classifications, unless grouped together as “undifferentiated inorganics”. However, the combination of reflected light optical microscopy under oil immersion, scanning electron microscopy, and X-ray microanalysis (SEM/EDS) showed that many of these morphotypes not only have distinctive petrographic patterns but are also characterized by a chemical assemblage dominated by Ca, Mg, and P. In this paper, a survey of the literature is presented together with several detailed studies of samples from the RAREASH and CHARPHITE projects from which the following nomenclature are proposed: “calcispheres” for spongy Ca-rich morphotypes, “calcimagnesiaspheres” for (Ca + Mg)-rich morphotypes with visible MgO nodules and/or periclase (MgO) exsolved from Ca aluminate-silicate glass, and “magnesiaspheres” divided into “magnesiaferrospheres” for (Mg + Fe)-rich morphotypes with magnesioferrite, and “magnesiaoxyspheres” for magnesiaspheres mainly composed of (Mg + Fe)-rich amorphous material with visible MgO nodules and/or periclase.

Coal ash char concentrates from four countries (Portugal, Poland, Romania, and South Africa) were prepared, characterised, and graphitized under the scope of the Charphite project (Third ERA-MIN Joint Call (2015) on the Sustainable Supply of Raw Materials in Europe). Coal ash chars may be a secondary raw material to produce synthetic graphite and could be an alternative to natural graphite, which is a commodity with a high supply risk. The char concentrates and the graphitized material derived from the char concentrates were characterised using proximate analysis, X-ray fluorescence, X-ray diffraction (structural), Raman microspectroscopy, solid-state nuclear magnetic resonance, scanning electron microscopy, and petrographic analyses to determine if the graphitization of the char was successful, and which char properties enhanced or hindered graphitization. Char concentrates with a lower proportion of anisotropic particles and a higher proportion of mixed porous particles showed greater degrees of graphitization. It is curious to see that embedded Al₂O₃ minerals, such as glass and clay, influenced graphitization, as they most likely acted as catalysts for crystal growth in the basal direction. However, the graphitized samples, as a whole, do not compare well against a reference natural graphite sample despite some particles in select char concentrates appearing to be graphitized following graphitization.