FURTHER STUDIES ON LARGE-BATCH MELTING OF URANIUM

Investigations on the feasibility of melting uranium in open induction furaaces were conducted. One-ton heats were successfully poured in cast iron ingot molds. Rarnmed linings of MgO plus Al/sub 2/O/sub 3/ and preformed crucibles of MgO were used successfully for melting. Heats of 10 tons or more can be made in production furnaces without the use of a vacuum. One ingot weighing 1200 lb analyzed 0.01 wt.% carbon and 0.006 wt.% nitrogen. This ingot contained 0.0005 to 0.0009 wt.% hydrogen, even though it was melted in a preheated furnace without a salt cover in order to eliminate contamination by water from the furnace or salt. Thereafter, a series of tests on 170-lb ingots showed that flushing with argon or chlorine for a short time just before pouring could reduce the hydrogen content to 0.0003 to 0.0004 wt.%. The recovery of uranium in the ingot was consistently 93 to 97% of the weight of the charge when the time of melting was kept at l 1/4 hr or less. This high recovery was obtained either with or without a protective salt cover. (auth)