Rare Earth Elements Recycling from End of Life Electronics Waste: The Green Approach with Cloud Point Extraction

by Ajay Bhagwan Patil (presenting author)1, Nicole Thalmann1,2, Albert J. Schuler1, Mohamed Tarik1, Agnese Carino1, Andrea Testino1, Rudolf P.W.J. Struis1, Christian Ludwig1,3

1: Paul Scherrer Institute (PSI), Energy and Environment Research Division (ENE), Laboratory for Bioenergy and Catalysis (LBK), Chemical processes and Materials Research Group (CPM), CH-5232 Villigen PSI, Switzerland; 2: Ecological Systems Design, Institute of Environmental Engineering (IFU) ETH Zurich; 3: École Polytechnique Fédérale de Lausanne (EPFL), ENAC IIS GR-LUD

 

End-of-life electronics is one of the largest growing municipal waste stream that has to be managed and valuable resources have to be recovered to maintain a sustainable material cycle. Especially Rare Earth Elements (REEs) are gaining critical importance and should therefore be appropriately recycled as they are technologically relevant metals. The aim of this study was the development of a cloud point extraction process (CPE) suitable for the recycling of REE from NdFeB-magnets e-waste. This is a green approach , because it is environmentally benign and cost effective due to less extractant amounts requirements and no use of harsh hydrometallurgical conditions. For REEs from NdFeB-magnets, we have developed a CPE method allowing near quantitative recovery. Hereto, the magnets from end-of-life Hard Disk Drives (HDD) were dismantled, demagnetized, grinded, digested and subjected to further extraction process. The important advantage of our method is that the acid used for the digestion of the grinded waste magnet gets neutralized in the process itself. Moreover, the recycling potential of solvents and extractant makes the developed CPE method cheap, thus, particularly relevant with waste and resource management. Testing of our CPE process was done with solutions prepared from pure rare earths as well as with actual HDD waste samples. Higher extraction efficiency was found for Neodymium (Nd) and Dysprosium (Dy) compared with the transition elements co-present with the HDD magnets.

The accomplished goal is a green system that recycles REEs from HDDs and avoids the use of chemicals harmful for humans and for the environment.