Carbothermic reduction of thorium oxide

The carbothermic reduction in vacuum of thorium oxide with graphite has been studied with the aid of a high temperature thermobalance at temperatures range of 1,300°–1,900°C. The effects of differences in the reaction temperature, molecular ratio of the reactants, and in the state of the reactants such as differences between loose powder mixture and pelleted form were examined. The reaction rate obeyed the diffusion-controlled kinetic equation, and an activation energy of 75±4 kcal/mole was obtained as a mean value of all the different cases covered. Some X-ray analyses of the product were carried out, which revealed a final product of ThC phase alone resulting from the C/ThO2 mole ratio of 3, while with ratio of 4 the product contained a mixture of ThC and ThC2. The reaction mechanism is also discussed briefly.