Modeling of solid-state electrotransport for purification of gadolinium

Abstract

Modeling of solid state electrotransport (SSE) was formulated to understand the transport phenomena of the interstitial impurities in gadolinium, are of the rare earth metals. Through numerical analysis, the optimum conditions for SSE are theoretically predicted. The processing parameters such as pressure, temperature, and reaction time can be determined to attain maximum effectiveness. The concentration profiles of interstitial impurities such as oxygen, nitrogen, and carbon were calculated based on this model. The electromigration of oxygen is faster than nitrogen and carbon because of its greater diffusivity and mobility. When the reaction time was 105 seconds, the oxygen and nitrogen were refined up to 92%–95% at 10−5Pa while carbon was refined to 98% at 10−6Pa. The increase in temperature gives rise to a shorter reaction time, but extremely low pressure is required.