Given a growing interest in uranium salts for pyrochemical processing of used fuel and
uranium-fueled molten salt reactors, the synthesis of uranium trichloride in alkali-metal chloride
media was investigated in a series of four experiments. Specifically, uranium metal powder and
uranium hydride powder were prepared and separately blended with ammonium chloride and
lithium chloride – potassium chloride eutectic in two runs, while the same powders were
separately blended with ammonium chloride and sodium chloride in two additional runs. Each
of the lithium chloride – potassium chloride containing blends was slowly heated to 923 K, while
those containing sodium chloride were heated to 1123 K. During each heat up, the ammonium
chloride sublimed into gaseous ammonia and hydrogen chloride, leading to the chlorination of
uranium metal or uranium hydride and the formation of molten salt solutions of the respective
chlorides. Experimental conditions were incorporated in the runs to promote formation of
uranium trichloride over uranium tetrachloride in the respective media. Molten samples of each
run product were taken and characterized via chemical analyses, diffractometry, and microscopy.
The final products from each run were dark dense ingots of the respective salt systems with
uranium concentrations ranging from 44 to 51 wt%. Chemical analyses and diffractometry
identified the predominant presence of uranium trichloride in these systems; however, a possible
minor presence of uranium tetrachloride could not be conclusively dismissed.