[en] Pyrochemical and pyrometallurgical processes are utilized at Rocky Flats for plutonium recovery and purification. Many of these processes use molten salts and molten metals which are stirred together or equilibrated at 700 to 900⁰C, resulting in chemical reactions. In one case, an electric current is also applied. These processes include molten salt extraction (MSE) for the removal of americium from plutonium; salt cleanup (SCU) for the recovery of the americium and plutonium from the MSE spent salt; direct oxide reduction (DOR) for the conversion of plutonium oxide to plutonium metal; and two plutonium metal purification processes, electrorefining (ER) and pyroredox. The above processes also come under the heading of extractive metallurgy