Recovery of critical metals from EV batteries via thermal treatment and leaching with sulphuric acid at ambient temperature

Journal article, 2022

In the upcoming years, todaýs e-mobility will challenge the capacity of sustainable recycling. Due to the presence of organic components (electrolyte, separator, casings, etc.), future recycling technologies will combine thermal pre-treatment followed by hydrometallurgical processing. Despite the ongoing application of such treatment, there is still a lack of information on how applied parameters affect subsequent metal recovery. In this study, both oxidative and reductive conditions in dependence on temperature and time were studied. Qualitative and quantitative characterizations of the samples after treatment were performed followed by leaching with 2 M sulphuric acid at ambient temperature to determine the leachability of valuable metals such as Co, Mn, Ni and Li. Moreover, the negative or positive effect of treatment on the leachability of the main impurities (Cu and Al) was determined. Since the presence of carbon affects the degree of active material reduction, it's content after each thermal treatment was determined as well. If all variables, temperature and time of thermal processing are taken into account, pyrolysis at 700 °C for 30 min is the optimal treatment. Under these conditions, full recovery is reached after 2 min for Li, 5 min for Mn and 10 min for both Co and Ni. In the case of the incineration, only processing at 400 and 500 °C promoted higher recovery of metals, while the treatment at 600 and 700 °C led to the formation of less leachable species.