Calciothermic reduction of zirconium oxide in molten CaCl2

Abstract

The reduction of zirconium dioxide using liquid calcium and molten calcium chloride was investigated. The study focusing on the influence of reductant amount, reaction time, CaCl2 amount, and temperature on the reduction process. Zirconium powder with oxygen content less than 800 ppm was obtained at 1 100°C after 3 h and by using two times the theoretical amount of Ca and four times that of CaCl2. The reduction reaction of ZrO2 was found to be multi steps process through the formation of intermediate phase CaZrO3. The morphology of the obtained zirconium was observed to be highly affected by the reaction temperature. © 2007 ISIJ.