To guarantee future resources for Li-ion battery production, efficient recycling processes are paramount in securing critical metals. However, purity of recycled material is of essence for industry. Here, we show the influence of spinel crystallization on the distribution of Li in the five-component slag system Li-Mg-Al-Si-Ca, a model for Li-ion battery reccycling using LA-ICP-ToF-MS imaging. Our work highlights that spinel is the primary solidifying mineral phase in the investigated slag-system and that it scavenges Li from the slag melt during crystallization/cooling. Hence, future recycling protocols need to be adapted to take Li loss to spinel into account.