TANTALUM AND NIOBIUM Separation of Liquid-Liquid Extraction

Werning, Joseph R.; Higbie, Kenneth B.

doi:10.1021/ie50540a028

Cited by 21 publications

(4 citation statements)

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“…Methyl isobutyl ketone, MIBK, or hexone was first used to extract tantalum by Werning and coworkers (29). Their development of a tantalum-niobium separation scheme followed earlier work using diisopropyl ketone (21) and methyl ethyl ketone (9).…”

Section: Discussionmentioning

confidence: 99%

Solvent Extracting Studies of Tantalum Fluoride Complexes with N-Benzoylphenylhydroxylamine, Tri-n-octylphosphine Oxide and Methyl Isobutyl Ketone Using Computer Techniques.

Varga¹,

Wakley²,

Nicholson³

et al. 1965

Anal. Chem.

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Section: Discussionmentioning

confidence: 99%

Solvent Extracting Studies of Tantalum Fluoride Complexes with N-Benzoylphenylhydroxylamine, Tri-n-octylphosphine Oxide and Methyl Isobutyl Ketone Using Computer Techniques.

Varga¹,

Wakley²,

Nicholson³

et al. 1965

Anal. Chem.

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“…Up to this point there have been three representative theories for mass transfer from gas phase to liquid phase, namely, two‐film theory, [ 50 ] the percolation theory, [ 51 ] and the surface renewal theory. [ 52 ] The formulas of the average mass transfer coefficient of liquid phase for three different theories are respectively Equations ), (), and ().…”

Section: Model and Numerical Simulationmentioning

confidence: 99%

Numerical simulation of the mass transfer process of CO₂ absorption by different solutions in a microchannel

et al. 2020

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The flow and mass transfer characteristics of CO 2 absorption in different liquid phases in a microchannel were studied by numerical simulation. The mixture gas phase contained 5 vol% CO 2 and 95 vol% N 2 , and the different liquid phases were water, ethanol solution, 0.2 M monoethanolamine solution, and 0.2 M NaOH solution, respectively. Based on the permeation theory, the distribution of velocity and concentration in the slug flow was obtained by local simulation of flow and mass transfer coupling and was described in depth. The influence of contact time and bubble velocity on the mass transfer of the whole bubble was highlighted. The volumetric mass transfer coefficient on the bubble cap and liquid film, CO 2 absorption rate, and enhancement factor were calculated and analyzed. The results showed that the volumetric mass transfer coefficients of chemical absorption were 3 to 10 times that of physical absorption and the CO 2 was absorbed more completely in chemical absorption. The new empirical correlations for predicting the mass transfer coefficient of the liquid phase were proposed respectively in physical absorption and chemical absorption, which were compared with the empirical formulas in the literature. The volumetric mass transfer coefficients obtained by predictive correlations are in good agreement with those obtained by simulation in this paper. This work made a basic prediction for CO 2 absorption in microchannel and provides a foundation for later experimental research.

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“…Another solvent extraction scheme uses the mixed anhydrous chlorides from a chlorination process as the feed (28). The chlorides, which are mostly of niobium, tantalum, and iron, are dissolved in an organic phase and are extracted with 12 N hydrochloric acid.…”

Section: Vol 16 Niobium and Niobium Compoundsmentioning

confidence: 99%

Niobium and Niobium Compounds

Schlewitz¹

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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Niobium, discovered by Hatchett in 1801, was first named columbium. In 1844, Rosed thought he had found a new element associated with tantalum (see TANTALUM AND TANTALUM COMPOUNDS). He called the new element niobium, for Niobe, daughter of Tantalus of Greek mythology. In 1949, the Union of Pure and Applied Chemistry settled on the name niobium, but in the United States this metal is still known also as columbium. Sometimes called a rare metal, niobium is actually more abundant in the earth's crust than lead.Niobium is important as an alloy addition in steels (see STEEL). This use consumes over 90% of the niobium produced. Niobium is also vital as an alloying element in superalloys for aircraft turbine engines. Other uses, mainly in aerospace applications, take advantage of its heat resistance when alloyed singly or with groups of elements such as titanium, zirconium, hafnium, or tungsten. Niobium alloyed with titanium or with tin is also important in the superconductor industry (see HIGH TEMPERATURE ALLOYS; REFRACTORIES).1.1. Properties. Elemental niobium [7440-03-1], Nb, has a cosmic abundance of 0.9 relative to silicon 106 (1), an average value of 24 ppm in the earth's crust (2), and a comparable value on the lunar surface (3). Niobium is a monoisotopic element, although a search for residual radionuclides from the formation of the solar system has established the natural abundance of 92 Nb [13982-37-1], having a half-life, t 1/2 , of 1:7 Â 10 8 yr, to be 1:2 Â 10 À10 % (4). In addition, minute amounts of 94 Nb [14681-63-1], t 1=2 ¼ 2:03 Â 10 4 yr, and 95 Nb [13967-76-5], t 1=2 ¼ 35 d, occur in nature; the former from neutron capture by the stable isotope, and the latter as the daughter of 95 Zr in the fission products of 235 U. Niobium-93 has a nuclear spin of 9/2 and a thermal neutron-capture cross section of 1:1 AE 0:1 Â 10 À28 m 2 (1.1 barns) which makes it of much interest to the nuclear industry (see NUCLEAR REACTORS).Niobium, like vanadium, undergoes no phase transitions from room temperature to the melting point. It is a steel-gray, ductile, refractory metal having a higher melting point than molybdenum and a lower electron work function than tantalum, tungsten, or molybdenum. Niobium closely resembles tantalum in its properties; the former is only slightly more chemically reactive. The metal is resistant to most gases below 2008C, but is air oxidized at 3508C, developing an oxide film of increasing thickness which changes from pale yellow to blue to black at 4008C. Absorption of hydrogen at 2508C and nitrogen at 3008C occurs to form interstitial solid solutions which greatly affect the mechanical properties. Niobium is attacked by fluorine and gaseous hydrogen fluoride and is embrittled by nascent hydrogen at room temperature. It is unaffected by aqua regia and mineral acids at ordinary temperatures, except hydrofluoric acid in which it dissolves. Niobium is attacked by hot concentrated hydrochloric and sulfuric acids, dissolving at 1708C in concentrated sulfuric acid, and by hot alkali carbonates and ...

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TANTALUM AND NIOBIUM Separation of Liquid-Liquid Extraction

Cited by 21 publications

References 1 publication

Solvent Extracting Studies of Tantalum Fluoride Complexes with N-Benzoylphenylhydroxylamine, Tri-n-octylphosphine Oxide and Methyl Isobutyl Ketone Using Computer Techniques.

Solvent Extracting Studies of Tantalum Fluoride Complexes with N-Benzoylphenylhydroxylamine, Tri-n-octylphosphine Oxide and Methyl Isobutyl Ketone Using Computer Techniques.

Numerical simulation of the mass transfer process of CO₂ absorption by different solutions in a microchannel

Niobium and Niobium Compounds

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TANTALUM AND NIOBIUM Separation of Liquid-Liquid Extraction

Cited by 21 publications

References 1 publication

Solvent Extracting Studies of Tantalum Fluoride Complexes with N-Benzoylphenylhydroxylamine, Tri-n-octylphosphine Oxide and Methyl Isobutyl Ketone Using Computer Techniques.

Solvent Extracting Studies of Tantalum Fluoride Complexes with N-Benzoylphenylhydroxylamine, Tri-n-octylphosphine Oxide and Methyl Isobutyl Ketone Using Computer Techniques.

Numerical simulation of the mass transfer process of CO2 absorption by different solutions in a microchannel

Niobium and Niobium Compounds

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Product

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Numerical simulation of the mass transfer process of CO₂ absorption by different solutions in a microchannel