Zirconium: Oxide Reduced with Calcium and Calcium Chloride in a Sealed Bomb at 950 °C (Kiernan, US 1,760,413)

Pure zirconium nitrate is burnt to oxide, then sealed in a steel bomb with clean calcium chips and calcium chloride and held at 950 °C. Water washes out the calcium chloride and dilute nitric acid the lime, leaving zirconium powder. Result: dark grey zirconium metal powder, passing 150 mesh. Source: J. W. Kiernan (Westinghouse), US patent 1,760,413, pp. 2-3. Picture drawn by Youblob.