*Article* **Pyrometallurgical Lithium-Ion-Battery Recycling: Approach to Limiting Lithium Slagging with the InduRed Reactor Concept**

**Stefan Windisch-Kern \*, Alexandra Holzer, Christoph Ponak and Harald Raupenstrauch**

Chair of Thermal Processing Technology, Montanuniversität Leoben, Franz-Josef-Strasse 18, 8700 Leoben, Austria; alexandra.holzer@unileoben.ac.at (A.H.); christoph.ponak@unileoben.ac.at (C.P.);

harald.raupenstrauch@unileoben.ac.at (H.R.)

**\*** Correspondence: stefan.windisch-kern@unileoben.ac.at

**Abstract:** The complexity of the waste stream of spent lithium-ion batteries poses numerous challenges on the recycling industry. Pyrometallurgical recycling processes have a lot of benefits but are not able to recover lithium from the black matter since lithium is slagged due to its high oxygen affinity. The presented InduRed reactor concept might be a promising novel approach, since it does not have this disadvantage and is very flexible concerning the chemical composition of the input material. To prove its basic suitability for black matter processing, heating microscope experiments, thermogravimetric analysis and differential scanning calorimetry have been conducted to characterize the behavior of nickel rich cathode materials (LiNi0.8Co0.15Al0.05O2 and LiNi0.33Mn0.33Co0.33O2) as well as black matter from a pretreatment process under reducing conditions. Another experimental series in a lab scale InduRed reactor was further used to investigate achievable transfer coefficients for the metals of interest. The promising results show technically feasible reaction temperatures of 800 ◦C to 1000 ◦C and high recovery potentials for nickel, cobalt and manganese. Furthermore, the slagging of lithium was largely prevented and a lithium removal rate of up to 90% of its initial mass was achieved.

**Keywords:** lithium-ion-batteries; pyrometallurgical recycling; carbothermal reduction
