Abstract
Germanium is a critical element, with optical fiber production accounting for approximately 30% of its global consumption, making end-of-life fibers an important secondary resource. Microwave-assisted processing enables efficient volumetric heating compared with conventional heating and has the potential to enhance reaction kinetics while reducing operating temperatures. We aim to study microwave-assisted carbothermal reduction of waste optical fibers for germanium recovery. In this work, the influence of key process parameters governing microwave energy absorption is discussed, with particular emphasis on dielectric properties, microwave power, cavity configuration, sample volume, geometry, and position. This study aims to lay the groundwork for the development of high-temperature microwave-assisted processing for the sustainable recovery of critical metals from primary and secondary resources.