Separation of zirconium from hafnium in nitric acid solutions by solvent extraction using dibutyl butylphosphonate

Brown, A.E.P.; Healy, T.V.

doi:10.1016/0304-386x(78)90027-0

Cited by 14 publications

(8 citation statements)

References 5 publications

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“…Third phase formation was also noted when extracting with TOPO [6]. Previous studies of hafnium/zirconium separation with organophosphorus reagents involved a nitric acid medium [7,8] as used in the now largely defunct TBP/HNO 3 process. Here, as in the present work, zirconium is the selectively extracted metal.…”

Section: Introductionmentioning

confidence: 93%

Hafnium/Zirconium Separation Using Cyanex 925

Silva¹,

Ammouri²,

Distin³

2000

Canadian Metallurgical Quarterly

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The processing of zirconium ores to produce hafnium-free zirconium for nuclear applications requires a hafnium/zirconium separation step. Conventional solvent extraction technology uses methylisobutyl ketone (MIBK) to selectively extract hafnium as its thiocyanate complex from hydrochloric acid solutions of zirconium and hafnium. Use of the organophosphorus extractant Cyanex 925 has been studied as a possible alternative for hafnium/zirconium separation. Cyanex 925 selectively extracts zirconium over hafnium from hydrochloric acid solutions of these metals but without thiocyanate complexation. Advantages offered by Cyanex 925 are a lower aqueous solubility and a higher flash point relative to MIBK, while the avoidance of thiocyanate ions removes the possible formation of hydrogen sulphide, hydrogen cyanide or mercaptans. Cyanex 925 is a trialkyl phosphine oxide containing branched alkyl groups rather than the straight alkyl chains of conventional trialkyl phosphine oxide extractants.Batch contacts between Cyanex 925 in kerosene and single metal solutions of hafnium or zirconium in hydrochloric acid, at up to 6M, showed that zirconium was always loaded preferentially to hafnium. The results were consistent with extraction of both metals by solvation of a chloride complex. Subsequent tests with mixed metal solutions showed that optimum separation was at about 3.5 M. HCl, regardless of metal/extractant ratio. For example, the separation factor was 37 (61% Zr, 4% Hf extractions, O/A = 2) when using 3.6 x stoichiometric extractant addition for complete reaction with 0.10 M. Zr, 0.010 M. Hf. Résumé -Lorsqu'on veut obtenir du zirconium sans la présence de hafnium, pour applications nucléaires par exemple, le traitement de minerais de zirconium requiert une étape de séparation du hafnium et du zirconium. La technologie d'extraction conventionnelle avec solvant utilise de la cétone méthyl-isobutylique (MIBK) afin d'extraire le hafnium sélectivement, sous forme d'un complexe thiocyanate, à partir de solutions d'acide chlorhydrique de zirconium et de hafnium. On a étudié l'usage du solvant d'extraction organo-phosphore Cyanex 925 comme remplaçant possible dans la séparation de l'hafnium et du zirconium. Le Cyanex 925 extrait sélectivement le zirconium du hafnium à partir de solutions d'acide chlorhydrique de ces métaux, mais sans la formation du complexe thiocyanate. Les avantages offerts par le Cyanex 925 incluent une solubilité aqueuse plus basse et un point d'éclair plus élevé par rapport au MIBK. De plus, l'absence d'ions de thiocyanate prévient la formation d'acide hydrosulfurique, de cyanure d'hydrogène ou de mercaptans. Le Cyanex 925 est un oxyde de phosphine trialkyle contenant des groupes alkyles branchés plutôt que les chaînes droites d'alkyles des solvants d'extraction conventionnels d'oxyde de phosphine trialkyle.Les contacts par lot entre le Cyanex 925 dans le kérosène et les solutions à métal unique de hafnium ou de zirconium dans de l'acide chlorhydrique, jusqu'à 6 M, ont montré que le zirconium était toujour...

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Section: Introductionmentioning

confidence: 93%

Hafnium/Zirconium Separation Using Cyanex 925

Silva¹,

Ammouri²,

Distin³

2000

Canadian Metallurgical Quarterly

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“…Most of the reports in the literature are on the selective extraction of Zr(IV) over Hf(IV) from various kinds of source materials . In developing a selective extraction process, selective extraction of the minor element (Hf) over Zr is desirable and has such advantages as ease of multi‐stage repetition, low solvent inventory, small dimension of the equipment and economics of the process (time and power) .…”

Section: Introductionmentioning

confidence: 99%

Selective extraction of Hf(IV) over Zr(IV) from aqueous H₂SO₄ solutions by solvent extraction with acidic organophosphorous based extractants

Banda

Min

Lee

2013

J of Chemical Tech & Biotech

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“…This may be qualitatively explained in terms of hardness of occurrent anions (SO 4 22 , Cl 2 ) from which sulfate ions are stronger hard bases than chloride ones, and have greater affinity to the salt phase containing SO 4 2-anions. Less hard Cl 2 anions and their Zr (Hf) complexes prefer the PEG rich phase.…”

Section: Resultsmentioning

confidence: 98%

Extraction of Zirconium and Hafnium in Polyethylene Glycol‐Based Aqueous Biphasic System

Smolik¹,

Jakóbik‐Kolon²,

Porański³

2007

Separation Science and Technology

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The behavior of zirconium and hafnium in PEG 2000-Na 2 SO 4 -HCl aqueous biphasic system has been investigated. The dependences of HCl concentration (0.185-0.55 M), extraction temperature (298 -318 K), and extraction time (5-120 min) on distribution ratios have been determined. Extraction of this metals in PEG 2000-Na 2 SO 4 -H 2 SO 4 and PEG 2000-Na 3 Cit-HCl systems has been also studied. The sulfate and citrate complexes of Zr and Hf prefer salt-rich phase in contrast to chloride complexes which pass into PEG rich phase in about 50% (w/w) to the greatest degree in room temperature and at short extraction time. The increase of distribution ratios (D Ã Zr ¼ 3.75, D Ã Hf ¼ 4.31) was observed after addition of water soluble organic ligand -tiron (4,5-dihydroxy-m benzenedisulfonic acid disodium salt). The results obtained in studied conditions are not very useful for the separation of zirconium and hafnium.

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Separation of zirconium from hafnium in nitric acid solutions by solvent extraction using dibutyl butylphosphonate

Cited by 14 publications

References 5 publications

Hafnium/Zirconium Separation Using Cyanex 925

Hafnium/Zirconium Separation Using Cyanex 925

Selective extraction of Hf(IV) over Zr(IV) from aqueous H₂SO₄ solutions by solvent extraction with acidic organophosphorous based extractants

Extraction of Zirconium and Hafnium in Polyethylene Glycol‐Based Aqueous Biphasic System

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Separation of zirconium from hafnium in nitric acid solutions by solvent extraction using dibutyl butylphosphonate

Cited by 14 publications

References 5 publications

Hafnium/Zirconium Separation Using Cyanex 925

Hafnium/Zirconium Separation Using Cyanex 925

Selective extraction of Hf(IV) over Zr(IV) from aqueous H2SO4 solutions by solvent extraction with acidic organophosphorous based extractants

Extraction of Zirconium and Hafnium in Polyethylene Glycol‐Based Aqueous Biphasic System

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Selective extraction of Hf(IV) over Zr(IV) from aqueous H₂SO₄ solutions by solvent extraction with acidic organophosphorous based extractants