Praseodymium: Anhydrous Chloride Reduced with Calcium in a Tantalum Bomb at 1050 °C, then Vacuum Cast (Daane, Ames 1950)

The same tantalum-bomb method that gave lanthanum works for praseodymium, only hotter: the dry chloride is reduced with calcium under argon at 1050 °C, the slag washed off, the spare calcium boiled away in vacuum and the metal cast. Result: praseodymium metal, 99.5 % overall yield, no other rare earths detected, 150 ppm calcium. Source: A. H. Daane, The Vapor Pressures of Lanthanum and Praseodymium (Iowa State College / Ames Laboratory, 1950), pp. 26-44. Hydrogen chloride and strong hydrochloric acid are corrosive; work at 1400 °C in vacuum. Picture drawn by Youblob.