Production of Tantalum Powder by Magnesiothermic Reduction of Feed Preform

Abstract

To develop an effective process for tantalum powder production, a new preform reduction process (PRP) based on the magnesiothermic reduction of feed preform containing tantalum oxide (Ta2O5) was investigated. The feed preform was fabricated from slurry, which was made by mixing Ta2O5 powder, flux (e.g., CaCl2), and binder. Various compositions of preform in the form of plates were prepared using a conventional casting technique, and the fabricated preform was heated at 1273 K before reduction in order to remove the binder and water. The sintered solid preform, containing Ta2O5, was then placed in a stainless steel container, and reacted with magnesium vapor at a constant temperature ranging between 973 and 1273 K for 6 hours. Pure tantalum powder was recovered from the reduced preform after leaching it in acid. This process was found to be suitable for producing a fine homogeneous powder, when the composition of flux and reduction conditions are controlled.