Extraction and recycling of Tantalum – ExTRa

The ExTRa project aims to develop in France a set of innovative technological bricks to extract tantalum from electronic waste (WEEE) and recycle it into a high value-added material (superalloy used for aeronautical turbines). Ta is not currently extracted from WEEE, but an analogy is possible with primary ore extraction processes. Ta oxides being refractory, hydrometallurgy is the only way to extract and separate this metal from the ore. However, leaching is not selective and has two major drawbacks: (1) a high consumption of reagents, (2) a significant amount of waste and final effluents. These processes use concentrated hydrofluoric acid or alkaline solutions at high temperature/high pressure. After the extraction process, Ta(V) is converted into metallic Ta by different processes, all of them extremely energy consuming.
Preliminary studies of the project partners have shown that new methods can be used advantageously in the treatment of WEEE. Thus, the extraction and purification of Ta(V) is possible using a combination of alkaline treatments and precipitation that results in the production of Ta2O5 powder. A cold plasma reactor is then used to reduce the Ta2O5 to tantalum metal. This plasma reactor offers a significant energy gain compared to current energy-intensive processes because it operates from atomic hydrogen making the reduction of oxide to Ta metal simple, fast and economically interesting.
ExTra will study the various processing operations in order to improve the yield of tantalum recycling and to obtain the purest possible Ta metal. A superalloy will then be produced with the tantalum obtained, and will be the subject of mechanical and microstructural characterizations to validate its re-use in aeronautic field.