SOME DEVELOPMENTS IN THE EXTRACTIVE METALLURGY OF COLUMBIUM (NIOBIUM)
The program at the U.S. Bureau of Mines has involved the extraction and purification of niobium from the complex mineral euxenite, which is native to the United States, and from niobium and tantalum bearing metallurgical slags that result from the smelting of tin in the Belgian Congo. The major problem in recovering niobium involves its separation from tantalum, since these elements are very similar chemically and are almost always associated together. Solvent extraction techniques are adaptable to continuous, large-scale operation and this approach was applied to separating niobiumn and tantalum. Good separation was achieved by using a feed solution of niobium and tantalum in hydrofluoric and sulfuric acids, When this solution was contacted with methyl isobutyl ketone, both niobium and tantalum were coextracted into the organic extract leaving other metallic impurities in the aqueous raffinate. By back extracting the organic extract with a dilute acid solution, niobiumn was extracted preferentially. Niobium oxide of greater than 99.9% purity was prepared by this method using stagewise extraction. Purities of over 99.99% were achieved employing multiple extractions. Two procedures were employed to reduce niobium compounds to metal. By reacting niobium pentoxide with metallic calcium in a closed bomb, a fused mass of niobium metal was prepared directly. A method similar to the Kroll process for zirconiumn was used to prepare niobiumn sponge. It involved the controlled reaction of gaseous niobium pentachloride with molten magesium under an inert atmnosphere. Byproducts were separated from the sponge metal by volatilization in a vacuum. Metal products from both procedures contained oxygen as the major impurity and required further refining to yield ductile metal. Upon melting in a high vacuum using electron bombardment as a source of heat, soft, ductile niobium was produced. (auth)
- Research Organization:
- Bureau of Mines, Albany, Oreg.
- NSA Number:
- NSA-12-014695
- OSTI ID:
- 4214792
- Report Number(s):
- A/CONF.15/P/697
- Resource Relation:
- Other Information: Prepared for the Second U.N. International Conference on the Peaceful Uses of Atomic Energy, 1958. Orig. Receipt Date: 31-DEC-58
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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EXTRACTIVE METALLURGY OF EUXENITE
THE EXTRACTION OF TANTALUM AND COLUMBIUM
Related Subjects
ACIDITY
BUTYL RADICALS
CALCIUM
CHEMICAL REACTIONS
CONTROL
DUCTILITY
ELECTRON BEAMS
EUXENITE
EVAPORATION
GASES
HEATING
HYDROFLUORIC ACID
IMPURITIES
INERT GASES
KETONES
KROLL PROCESS
LIQUID METALS
MAGNESIUM
MELTING
METALLURGY
METHYL RADICALS
NIOBIUM
NIOBIUM CHLORIDES
NIOBIUM COMPOUNDS
NIOBIUM OXIDES
PREPARATION
PRESSURE VESSELS
RARE EARTHS
RECOVERY
REDUCTION
REFINING
SEPARATION PROCESSES
SLAGS
SOLUTIONS
SOLVENT EXTRACTION
SULFURIC ACID
TANTALUM COMPOUNDS
TANTALUM OXIDES
THORIUM OXIDES
TIN
URANIUM MINERALS
VACUUM
WATER
ZIRCONIUM