Production of Thorium Powder by Calcium Reduction of Thorium Oxide

A process for the preparation of high‐purity thorium powder by calcium reduction of thorium oxide has been developed, Calcined thorium oxide is reduced in an inert atmosphere at 950°C with high‐purity calcium metal in the presence of calcium chloride. The reduction vessel is fabricated of type 446 stainless steel to avoid pick up of iron and nickel impurities and permit break out of the reduction cake. The thorium powder so produced has essentially the same purity as the thorium oxide starting material. Important factors controlling yield and quality of the thorium powder are discussed.