Recycling deals with man-made material combinations, which means that an optimal process can look very different from primary metallurgy. This is especially true for battery recycling.
The metallurgical theory framework is still very useful to understand the process and the challenges specific to recycling. In lead-acid battery recycling for example, dealing with sulfates as opposed to sulfides requires heat input and reduction. Also, the specific slag systems (or mattes) used in secondary smelters are surprisingly flexible, leading to very different operational practices, some surely suboptimal. Apart from mechanical separation, hydrometallurgy (e.g. desulfurization) complements these pyro processes well. Alternative, fully hydrometallurgical processes aim at a lower environmental impact, but scale up results are needed to make a proper comparison.
The same pyro-hydro debate is also active in the quickly growing lithium battery recycling industry. The solubility of Li, as compared to Pb, makes an entirely hydrometallurgical flowsheet more viable. Nevertheless, also for Li, a case can be made for flowsheets combining the robustness of pyro and the specificity of hydro.
Presenters
Dr Sander Arnout is CEO of InsPyro and a founder of this KU Leuven spin-out established in 2009. The company aims to assist industrial customers to improve and develop metallurgical processes. It does so based on practical experience and mainly by creating insight, using scientific modelling and characterization tools. InsPyro has cooperated with many larger and smaller players in the primary and secondary lead and lithium industries. Sander holds a MSc in Materials Engineering and a PhD in the field of metallurgy.
