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US4737244A
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Zirconium and hafnium tetrachloride separation by extractive distillation with molten zinc chloride lead chloride solvent
Assignee: Westinghouse Electric Corp
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Filing: 1986-12-18
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Granted: 1988-04-12
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Expires: 2006-12-18
Abstract
Abstract This is a molten salt extractive distillation process for separating hafnium from zirconium. It utilizes at least principally a ZnCl 2 -PbCl 2 molten salt solvent, and preferably ZnCl 2 -PbCl 2 in a near eutectic or eutectic mixture. The extraction column is preferably run about 370°-390° C. at about one atomosphere and stripping is preferably done at 375°-400° C. utilizing an inert gas carrier.
Inventors
- 👤 David F. McLaughlin
- 👤 Richard A. Stoltz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:54
CPC Classifications
B; B01; B01D; B01D3/00; B01D3/34; B01D3/40; C; C01; C01G; C01G25/00; C01G25/04; C01G27/00; C01G27/04; C22; C22B; C22B34/00; C22B34/10; C22B34/14
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
150 words
In an extractive distillation method for separating hafnium tetrachloride from zirconium tetrachloride of the type wherein a mixture of zirconium and hafnium tetrachlorides is introduced into an extractive distillation column, which extractive distillation column has a reboiler connected at the bottom and a reflux condenser connected at the top and wherein a molten salt solvent is circulated into the reflux condenser and through the column to provide a liquid phase, and wherein molten salt solvent containing zirconium tetrachloride is taken from the reboiler and run through a stripper to remove zirconium tetrachloride product from said molten salt solvent and the stripped molten salt solvent is returned to the reflux condenser and hafnium tetrachloride enriched vapor is taken as product from the reflux condenser, the improvement comprising: said molten salt solvent having a composition of at least 30 mole percent zinc chloride and at least 10 mole percent of lead chloride.
Claim 2
Dependent Claim
150 words
In an extractive distillation method for separating hafnium tetrachloride from zirconium tetrachloride of the type wherein a mixture of zirconium and hafnium tetrachlorides is introduced into an extractive distillation column, which extractive distillation column has a reboiler connected at the bottom and a reflux condenser connected at the top and wherein a molten salt solvent is circulated into the reflux condenser and through the column to provide a liquid phase, and wherein molten salt solvent containing zirconium tetrachloride is taken from the reboiler and run through a stripper to remove zirconium tetrachloride product from said molten salt solvent and the stripped molten salt solvent is returned to the reflux condenser and hafnium tetrachloride enriched vapor is taken as product from the reflux condenser, the improvement comprising: said molten salt solvent having a composition of at least 30 mole percent zinc chloride and at least 10 mole percent of lead chloride.
Claim 3
Dependent Claim
18 words
The method of claim 1, wherein said molten salt solvent consists essentially of zinc chloride and lead chloride.
Claim 4
Dependent Claim
15 words
The method of claim 2, wherein said column is operated essentially isothermally at 360°-400° C.
Claim 5
Dependent Claim
17 words
The method of claim 3, wherein said column is operated at a pressure of about one atmosphere.
Claim 6
Dependent Claim
16 words
The method of claim 3, wherein said column is operated essentially isothermally at about 375° C.
Claim 7
Dependent Claim
25 words
The method of claim 2, wherein said molten salt solvent consists essentially of about 84 mole percent zinc chloride and 16 mole percent lead chloride.
Claim 8
Dependent Claim
16 words
The method of claim 2, wherein said stripper is operated at a temperature of 360°-450° C.
Claim 9
Dependent Claim
155 words
In an extractive distillation method for separating hafnium tetrachloride from zirconium tetrachloride of the type wherein a mixture of zirconium and hafnium tetrachlorides is introduced into an extractive distillation column, which extractive distillation column has a reboiler connected at the bottom and a reflux condenser connected at the top and wherein a molten salt solvent is circulated through the column to provide a liquid phase, and wherein molten salt solvent containing zirconium tetrachloride is taken from the reboiler and run through a stripper to remove zirconium tetrachloride product from said molten salt solvent and the stripped molten salt solvent is returned to the reflux condenser and hafnium tetrachloride enriched vapor is taken as product from the reflux condenser, the improvement comprising: said molten salt solvent having a composition consisting essentially of about 84 mole percent zinc chloride and 16 mole percent lead chloride and wherein said stripper is operated at a temperature of 360°-450° C.
Claim 10
Dependent Claim
155 words
In an extractive distillation method for separating hafnium tetrachloride from zirconium tetrachloride of the type wherein a mixture of zirconium and hafnium tetrachlorides is introduced into an extractive distillation column, which extractive distillation column has a reboiler connected at the bottom and a reflux condenser connected at the top and wherein a molten salt solvent is circulated through the column to provide a liquid phase, and wherein molten salt solvent containing zirconium tetrachloride is taken from the reboiler and run through a stripper to remove zirconium tetrachloride product from said molten salt solvent and the stripped molten salt solvent is returned to the reflux condenser and hafnium tetrachloride enriched vapor is taken as product from the reflux condenser, the improvement comprising: said molten salt solvent having a composition consisting essentially of about 84 mole percent zinc chloride and 16 mole percent lead chloride and wherein said stripper is operated at a temperature of 360°-450° C.
References Cited (Backward Citations)
US1582860A
Cited
US2741628A
Cited
US2938769A
Cited
US2744060A
Cited
US2791485A
Cited
US2816814A
Cited
US2928722A
Cited
US2852446A
Cited
US3006719A
Cited
US3671186A
Cited
US4021531A
Cited
US3966458A
Cited
US4072506A
Cited
FR2543162A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-12 | 1991-10-12 | 1992-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-12 | 1995-10-12 | 1996-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-12 | 1999-10-12 | 2000-04-12 | $7700.00 | Window Closed / Lapsed |