Tantalum recycling life-cycle assessment
bifa Umweltinstitut compares the environmental performance of different process strategies for recovering tantalum from printed boards
The “Development and assessment of innovative recycling paths for recovering tantalum from electronic waste” project was undertaken under the management of the Fraunhofer Research Institution for Materials Recycling and Resource Strategies, IWKS, within the scope of the "KMU Innovative resource and energy efficiency" development scheme of the Federal Ministry of Education and Research. Within the project team, the task of bifa Umweltinstitut was to evaluate different process-based approaches to solutions with regard to their life-cycle assessment.
The transition metal tantalum has manifold possible applications especially in electronics. However, the use of tantalum must be viewed critically with regard to the working conditions, the politically problematic circumstances of its mining and also the very low recycling rate. Against this background, the objective of the project was to install a recycling route for tantalum that is not only environmentally useful but also cost-effective. To this end, the following recycling paths were examined and assessed:
- Chemical transport
- Electrochemical separation
- Hydrometallurgical dissolution or leaching
The three recycling strategies have in common firstly, that printed boards with tantalum capacitors are identified and dismounted in the first process step. Secondly, the tantalum capacitors extracted in this way are treated mechanically in the second process step. The three scenarios differ in the further processing of the treated tantalum fraction through to the extraction of a tantalum concentrate. Recycling tantalum avoids all the emissions that would be produced in the conventional production of tantalum from primary raw materials. In all environmental effects of the life-cycle assessment it can be seen that all the recycling routes examined are associated with environmental relief due to these environmental credits. From a life-cycle assessment point of view, electrochemical separation produces better results overall than the two other alternatives, albeit, the environmental advantages are small compared to hydrometallurgical dissolution.
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Thorsten Pitschke
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