直流プラズマアークの高温下における五酸化ニオブの炭素還元について
プラズマアークの製錬への応用 (第1報)
1972 年 88 巻 1018 号 p. 885-890
詳細
1972 年 88 巻 1018 号 p. 885-890
In recent years, the importance of the plasma arc process has been widely recognized in the field of pyrometallurgy. In our experiment, the carbothermic reduction of refractory metal oxide was examined in high temperature zone generated by use of plasma arc generator.
A small cylindrical sample mixture of niobium pentoxide and carbon, or niobium carbide in the molar ratio of 1: 5, Placed on a water-cooled copper crucible as an anode, was rapidly heated in the hot ambience of argonhydrogen (5%) plasma gas and the surface temperature of the sample was kept at about 2, 650°C. It was observed that the reaction between molten niobium pentoxide and solid particles of carbonaceous reducing agent proceeded rapidly and niobium metal was successfully obtained with carbon monoxide and free oxygen formation. During a few minutes of the solid-liquid reaction, the niobium content in the sample reached above 90% and then gradually increased up to 99%. Better results in the purity and the recovery of niobium metal were obtained by using niobium carbide as a reducing agent. Some of the oxygen contained in the sample was removed by vaporization of niobium suboxide. The purity of the reduced metal was still more improved by electron beem melting in high vacuum and ductile niobium was obtained.
