The rapid growth of lithium-ion battery (LIB) applications necessitates recycling technologies that are efficient, economically viable, and environmentally sustainable. A key challenge is optimizing black mass (BM), the mixture of cathode and anode components produced during pre-treatment. This study evaluates how variations in black-mass composition along the pre-treatment route, defined as Black Mass 1 to 4 (BM1-BM4), influence thermal behavior, reaction pathways, and economic potential during pyrometallurgical processing, with the aim of identifying the most suitable feedstock. Thermodynamic simulations were conducted using FactSage 8.2 to investigate equilibrium phase assemblage over 100–2000 °C, while economic assessment was performed for materials processed at 600 °C. The results show that BM1 and BM2 generate complex solid and liquid products dominated by multi-component metallic solid solutions and intermetallics, which hinder downstream separation. In contrast, BM3 and BM4 form simpler phases that are readily compatible with hydrometallurgical purification. Gaseous phase behavior also differs significantly: BM1 releases both flammable and toxic gases, BM2 and BM3 primarily generate toxic emissions, whereas BM4 emits only oxygen, representing the safest option. Energy-demand analysis indicates that BM1 and BM2 exhibit predominantly exothermic behavior with minimal external heating requirements, while BM3 and BM4 are fully endothermic and require continuous heat input. Economically, BM1 shows the highest laboratory-grade value due to the formation of specialty compounds, whereas BM3 and BM4 perform best at the industrial grade, supported by abundant market-stable metals and oxides. Overall, BM3, and particularly BM4, emerge as the most promising feedstocks for large-scale pyrometallurgical recycling followed by hydrometallurgical refining.
Prasetyo et al. (Fri,) studied this question.