Method of manufacture of uranium oxide his-ala-asp-gly-thr-phe-thr-ser-asp-val-ser-ser-tyr-leu-glu-gly-gln-ala-ala-lys-glu-phe-ile-ala-trp-leu-val-lys-gly-gly-nh2 of high density and of the stoichiometric composition based on ammonium uranate

摘要

Sintered stoichiometric uranium dioxide of an apparent density of at least 10,4 is prepared by calcining ammonium uranate and thereafter reducing it in dry cracked ammonia in two stages, the first at 350 DEG to 450 DEG C., serving to reduce the UO3 to UO2 and a second at 600 DEG to 700 DEG C.; the uranium dioxide powder is then pyrophoric and is reoxidized in a current of nitrogen containing oxygen thereby obtaining a uranium dioxide of approximate composition UO2,25; a moulding additive is then incorporated and the oxide is compressed in vacuo, crushed and screened and then compressed at a pressure of 2,5 to 5 tonne/cm.2 The moulding additive is removed by heating in vacuo at temperatures up to 700 DEG C. and the oxide sintered in an atmosphere of dry cracked ammonia for 5 hours at a temperature of 1250 DEG to 1400 DEG C. A suitable moulding additive is a mixture of stearic acid and camphor in a volatile solvent such as carbon tetrachloride. The function of the first moulding stage is the increase in apparent density which permits more precise moulding in the second stage.