Bomb reduction of tantalum pentoxide by calcium metal

Abstract

Massive tantalum metal has been produced by calciothermic reduction of tantalum pentoxide in a refractory-lined steel bomb using sulphur as the thermal booster. The reaction is initiated by placing the bomb in a preheated furnace. Experimental variables such as the scale of reduction, amount of sulphur by weight of the oxide and the amount of calcium in excess of the stoichiometric requirement, have been studied at a bomb wall temperature of about 500° C. The as-reduced metal has been subjected to non-consumable arc melting and electron-beam melting to improve its physical and mechanical properties. Marked improvement in purity and workability of the electron-beam-melted metal as compared to the arc-melted one, has been observed. A cold reduction of over 96% without intermediate annealing has been possible on the metal obtained after electron-beam melting. Products like wire-rods, strips and wires could be fabricated from the electron-beam-melted metal with ease.