Neodymium Metal: Oxide Reduced by Graphite in Vacuum, Distilled at 1900 °C onto Tantalum (Downing, Union Carbide, US 3,104,970)

Carbon cannot pull neodymium out of its oxide in an ordinary furnace. In a hard vacuum it can: the oxide and graphite turn into neodymium carbide, and at 1900 °C the neodymium itself boils off and condenses as metal on a cool tantalum plate. Result: neodymium metal, 99.21 % Nd and 0.83 % carbon in Union Carbide's run. Source: Downing, Gorski and Koerner, US 3,104,970 (Union Carbide, 1963), Example II. That example starts from a samarium-neodymium mixture; using it for pure neodymium oxide is ours. Picture drawn by Youblob.