A new technology platform for the production of electronic grade tantalum nanopowders from tantalum scrap sources

• Iodization of tantalum scrap selectively purifies tantalum as tantalum iodide.
• Hydrogen plasma reduction of tantalum iodide produces capacitor grade powders.
• The iodization concept offers economic and environmental advantages.

Conversion of tantalum alloy scrap into high-value, electronic-grade tantalum nanopowders is a significant economic and technological advancement. At present, it is only possible to recycle tantalum alloy scrap into low-value tantalum mill products; however, upgrading this metal stream into the raw materials for the capacitor industry offers economic payback and environmental savings. A new technology platform based on the iodization of tantalum alloy scrap produces volatile tantalum(V) iodides that can be condescended to form fine powders. Subsequent hydrogen reduction of the iodide powders in a plasma furnace produces high surface area tantalum metal powder precursors, which, after annealing, yield high-purity nanopowders with uniform particle size distribution, low oxygen content, and high surface area and capacitance. The hydrogen iodide produced during plasma reduction can be captured, dissociated into molecular hydrogen and molecular iodine, and recycled. The total process flow sheet is presented.