Production of tantalum powder by external continuous supply of feed materials and reductant

Abstract

In order to produce high-quality tantalum powder of spherical shape with a uniform particle size and a high purity using a metallothermic reduction process, it is important to control the reaction temperature and reaction rate. In this study, we developed a metallothermic reduction method using a system supplying materials continuously from an external unit where the feed materials of K2TaF7 and the reductant Na were continuously supplied to control the reaction temperature and reaction rate. The characteristics of tantalum powder produced by the continuous supply system were compared with those of tantalum powder produced by a batch system in which, all of the feed materials and reductant were supplied into the reaction vessel at one time. We could obtain tantalum powder with a spherical shape and a uniform particle size with a diameter of 2∼3 μm because we used the external continuous supply system where the reaction temperature and reaction rate could be well controlled. After deoxidation, dehydration, and heat treatments, the purity of the tantalum power reached 99.5 mass% level of the reagent grade. The yield of tantalum powder increased from 80% in the batch system to 90% in the external continuous supply system. © 2005 The Japan Institute of Metals.