The aim of the project is to increase the material utilisation of critical materials from electronic waste. In this work, sustainable methods for purification of tantalum from tantalum capacitors are studied. Therefore, mechanical, physicochemical and electrochemical ways as well as thermal processes are used. 

The epoxy resin is separated from the tantalum anodes by mechanical processing and flotation or rather density separation. A large part of the silver contained in the capacitors is thereby also extracted from the tantalum and can be recovered. Furthermore, two methods – based on electrochemical and thermal processes – are developed for further concentration of tantalum. 

From the results, new conceptual approaches as well as technological and economic opportunities for a closed-loop circulation of critical materials can be derived.