| 摘要 |
1,172,211. Spheroidal uranium powder. UNITED STATES ATOMIC ENERGY COMMISSION. Jan. 16, 1968 [July 6, 1967], No.2253/68. Heading C7D. Spheroidal uranium powder, with a grain size of 44-840Á, is produced by mixing UO 2 powder with U powder, with a grain size less than 149Á, a stoichiometric excess of Ca powder (e. g. 18-22% excess) and iodine (e.g. 4-8% based on the weight of UO 2 ), heating the mixture to initiate the exothermic reaction in a bomb e.g. to about 800‹C. continuing the heating to raise the mixture to a maximum temperature of 1175-1225‹C. maintaining this temperature for a sufficient time to effect coalescence and spheroidization of the U metal, cooling the mixture and then recovering the powder (e.g. by crushing followed by an acetic acid leaching). The initial ratio U/UO 2 is preferably 9/10 Œ 5%. The preferred product size is 149- 420Á and any undersize product may be used as seed material in a further reduction.
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