In our recent study published in Scientific Reports, we present an innovative, microwave-assisted carbothermal reduction method to recover these valuable elements from end-of-life tantalum capacitors, components commonly found in smartphones, laptops, and many electronic devices.

Traditional recycling methods for tantalum often involve high energy inputs and complex processes. Our approach, however, leverages the unique benefits of microwave heating—rapid, selective, and volumetric heating—to significantly enhance recycling efficiency. Guided by Ellingham and CALPHAD-based phase diagrams, we developed a scalable three-step process, achieving tantalum recovery in the form of tantalum carbide (TaC) at an impressive 97% purity.

The process involves first reducing manganese dioxide (MnO₂) to manganese oxide (MnO), selectively forming a stable TaC sponge, and finally processing the remaining manganese compounds. Remarkably, this method consumes substantially less power than conventional thermal approaches and completes reactions rapidly due to the intrinsic self-limiting behavior of microwave heating.

Our findings highlight microwave-assisted recycling not only as a viable secondary mining strategy for critical metals but also as a sustainable alternative with significant energy and time savings. Given the increasing global generation of e-scrap, this research offers a timely solution for efficient resource recovery and contributes towards a circular economy for critical materials.

Read the full open-access article: Microwave-assisted recycling of tantalum and manganese from end-of-life tantalum capacitors (Scientific Reports, 2025)

Authors: Ansan Pokharel, Kurundu Shavinka Jayasekera, Edward M. Sabolsky, Terence Musho
West Virginia University, Department of Mechanical, Materials & Aerospace Engineering