Improvements made to the processes for the preparation of powders, in particular based on uranium

摘要

Powdered refractory uranium compounds are prepared by forming, e.g. by sintering, a compacted body of the uranium compound and a metal or alloy which metal may be the same as that in the refractory compound, and treating the compact body with at least one agent to cause disintegration of the body, e.g. by chemical reaction with or dissolution of the metal, and separating the compound in powder form, e.g. by mechanical or physical means. The compacted body of proportions in the range 60-95% refractory compound and 40-85% by weight metal or alloy, may be subjected to a grain refining heat treatment at 1000-1200 DEG C. and pressure 10-4 to 10-6 mm. Hg for 1-8 hrs. In specific Examples: (1) a compact body of uranium carbide and uranium metal having 3-4.4% C is disintegrated by H2 at 200-300 DEG C. forming uranium hydride and uranium carbide powder which is separated by classification in a liquid or by centrifuging, alternatively the hydride may be decomposed by heating at 400 DEG C. in vacuo and the mixture of uranium carbide and uranium metal separated; (2) a compact of uranium nitride and uranium is treated with N hydrochloric acid at 60 DEG C. to give uranium chloride in solution and the uranium nitride powder is filtered off, washed with water, alcohol and acetone and dried in vacuo; (3) a body of uranium silicide U3Si2 and its eutectic with uranium metal is treated with H2 or hydrochloric acid to give particles of uranium silicide which are separated physically from other reaction products.