UCl3 synthesis in molten LiCl–KCl and NaCl–MgCl2 via galvanically coupled uranium oxidation and FeCl2 reduction

Molten salt mixtures containing LiCl–KCl and NaCl–MgCl 2 have been infused with UCl 3 via reaction of U metal and FeCl 2 . The process starts with base salt (LiCl–KCl or NaCl–MgCl 2 ) drying/purification using hydrochlorination via bubbling anhydrous HCl. An auto-titrator running in pH-stat mode was used to determine the point at which there is no net reaction with the salt. U metal is contained in a porous stainless steel basket as it is submerged in the molten salt. The byproduct Fe metal forms dendrites on the basket walls, allowing for simple separation from the molten salt. Based on analysis of salt samples using inductively coupled plasma mass spectroscopy, UCl 3 yield of 90% was attained in both NaCl-MgCl 2 at 550 °C and in LiCl–KCl at 450 °C. Open circuit potential difference between a W rod working electrode and a Ag/AgCl reference electrode indicated a UCl 4 to UCl 3 activity ratio of 1 × 10 −5 . The iron dendrites were comprised of linked cubic structures with length scale of about 50 µm.