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.

Lowering the carbon consumption and fossil CO₂ emissions is a priority in blast furnace (BF) ironmaking. Renewable biomass is one option that can play an important role in future low-carbon ironmaking particularly in the countries rich in biomass resources. In this study, full-scale trials to investigate the impact of briquettes containing torrefied sawdust on the BF efficiency and process stability have been conducted. Briquettes containing 1.8% of torrefied pelletized sawdust (TPS), 86.2% of steel mill residues, and 12% cement with sufficient mechanical strength have been produced on industrial scale. The bio-briquettes were charged at two different rates: 37% ( ~ 39 kg/tHM) and 55% ( ~ 64 kg/tHM) bio-briquettes to the SSAB BF No. 4 in Oxelösund. The gas utilization was higher during bio-briquette-charging periods without change in pressure drop up to 55% bio-briquettes, indicating sustained shaft permeability. BF dust generation or properties did not change significantly. Measurements of the top gas composition using mass spectrometry did not indicate release of hydrocarbon from TPS in connection to the charging of bio-briquettes. Evaluation of process data has been carried out using a heat and mass balance model. The evaluation of operational data in the model indicated lowering of thermal reserve zone temperature by 45 °C and reduction in carbon consumption by ~ 10 kg/tHM when charging 55% bio-briquettes compared to the reference case. The total CO₂ emission was reduced by about 33–40 kg/tHM when using 55% bio-briquettes.