Ambient pressure UCl3 synthesis starting with a mixed bed of NH4Cl and uranium hydride

Abstract

Current methods of synthesizing unblended UCl₃ have significant safety and contamination concerns due to the use of hazardous gaseous components or the potential for formation of UCl₄ or uranium oxides and oxychlorides. A new method for chlorinating uranium hydride in the solid state without hazardous gas that favors the +3 oxidation state is reported. This process forms UCl₃ via a two-step reaction using solid NH₄Cl powder and UH₃. The first step involves heating to 593 K to form an ammonium-uranium-chloride intermediate. In the second step, the intermediate is thermally decomposed by heating to 923 K under ambient pressure in an argon atmosphere to form UCl₃. Cl/U ratios of product ranged from 2.8 to 3.1.