EXAMINATION OF FACTORS AFFECTING THE QUALITY OF VACUUM INDUCTION-MELTED URANIUM
Uranium melting was investigated to determine what reactions, variable in nature, could be detrimental to ingot purity or soundness. Experiments were conducted with 10-lb uranium charges in a vacuum induction furnace 1200 liters in volume. A special manifold allowed sampling of the furnace atmosphere for mass spectrometer analyses at appropriate times after the furnace was isolated from the vacuum system. Melts were made with a selected production grade of pure uranium. The program included (1) exploratory melts in graphite with and without MgO crucible dressings, (2) melts in graphite and zirconia crucibles under dry and wet furnace conditions, (3) replicate experiments in which known quantities of hydrogen, nitrogen, CO, oxygen, CO/sub 2/, H/sub 2/O, and argon were each admitted to the furnace to determine pressure-time relations and residual-gas compositions, and (4) a demonstration of the water-gas reaction within the furnace. The MgO crucible dressing tended to peel during initial outgassing. During the melting cycle. MgO was reduced and formed a black magnesium deposit within the furnace. Gases and, especially, water vapor adsorbed by graphite components were difficult to remove. To lower the outgas rate at 2500 deg F from 3 to 0.45 mu per min, it was necessary to heat the cricible for 5 1/2 hr at 2500 to vated temperatures produced hydrogen and CO, the products of the water- gas reaction. A secondary reaction between CO and uranium resulted in a furnace atmosphere that was mainly hydrogen. Temperature variations between surface and subsurface metal were large. Optical temperature determinations were affected by dross and varied considerably with dross thickness. The integrity of the surface dross was a controlling factor of the composition and amount of reactive gas remaining over the melt and of the ability to he melt will result in large changes in the carbon-oxygen level of the melt, and the cortribution of CO to contamination can be greater through this mechanism than by the direct CO-uranium reaction. (auth)
- Research Organization:
- Battelle Memorial Inst., Columbus, Ohio
- DOE Contract Number:
- W-7405-ENG-92
- NSA Number:
- NSA-15-018449
- OSTI ID:
- 4009588
- Report Number(s):
- BMI-1275(Del.)
- Resource Relation:
- Other Information: Decl. with deletions Jan. 14, 1960. Orig. Receipt Date: 31-DEC-61
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ADSORPTION
ARGON
CARBON
CARBON DIOXIDE
CARBON MONOXIDE
CHEMICAL REACTIONS
CRUCIBLES
DEGASSING
EFFICIENCY
FURNACES
GASES
GRAPHITE
HEATING
HYDROGEN
IMPURITIES
MAGNESIUM
MAGNESIUM OXIDES
MASS SPECTROMETERS
MELTING
NITROGEN
OPTICAL SYSTEMS
OXYGEN
PRECIPITATION
PRESSURE
QUANTITATIVE ANALYSIS
QUANTITY RATIO
REDUCTION
SAMPLING
TEMPERATURE
TESTING
URANIUM
VACUUM
VARIATIONS
WATER
ZIRCONIUM OXIDES