US3854934A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of molten aluminum and alloys
Assignee: Rio Tinto Switzerland AG
•
Filing: 1973-06-18
•
Granted: 1974-12-17
•
Expires: 1993-06-18
Abstract
Abstract A process for the removal of gaseous and solid impurities, such as occluded hydrogen and metallic oxides, from molten aluminum and aluminum alloys without excessive discharge of potentially harmful gases and fumes into the atmosphere, is carried out by passing a stream of purifying gas through the molten metal while the latter is maintained in contact with a liquefied salt cover, lower in density than the molten metal, the gas containing a small proportion of a fully fluorinated or chlorofluorinated lower hydrocarbon mixed with a relatively inactive or inert gas such as nitrogen, helium or argon.
Inventors
- 👤 J Dore
- 👤 P Sevier
- 👤 J Yarwood
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:08
CPC Classifications
C; C22; C22B; C22B9/00; C22B9/05; C22B21/00; C22B21/06; C22B21/064
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
143 words
A PROCESS FOR PURIFYUING ALUMINUM BASE ALLOYS BY REMOVING GASEOUS AND SOLID PARTCULATE IMPURITIES THEREFROM WHICH COMPRISES: PROVIDING A MOLTEN ALUMINUM BASE ALLOY CONTAINING GASEOUS AND SOLID PARTICULATE IMPURITIES THEREIN; PROVIDING OVER SAID MOLEN ALLOY A SUPERNATANT LAYER OF A MOLTEN MIXTURE OF AT LEST TWO HALIDE SALTS, WHEREIN THE CATION IS SELECTED FROM THE GROUP CONSISTING OF AN ALKALI METAL AND AN ALKALINE EARTH METAL, BUBBLING A TREATING GAS THROUGH SAID MOLTEN ALLOY, SAID GAS CONSISTING OF AN INERT CARRIER GAS AND AN EFFECTIVE AMOUNT OF FULLY HALOGENATED LOWER HYDROCARBON CONTAINING ONE TO SIX CARBON ATOMS, WHICH IS FREE OF HYDROGEN AND CONTAINS AT LEAST ONNE FLUORINE ATOM, SAID GAS CONTAINING UP TO 10 PERCENT BY VOLUME OF SAID HYDROCARBON, THEREBY TRANSFERRNG SOLID PARTICULATE IMPURITIES TO THE SUPERNATANT LAYER AND REMOVING GASEOUS IMPURITIES THEREFROM; AND SEPARATING THE SAID ALLOY IN PURIFIED CONDITION.
Claim 2
Dependent Claim
143 words
A PROCESS FOR PURIFYUING ALUMINUM BASE ALLOYS BY REMOVING GASEOUS AND SOLID PARTCULATE IMPURITIES THEREFROM WHICH COMPRISES: PROVIDING A MOLTEN ALUMINUM BASE ALLOY CONTAINING GASEOUS AND SOLID PARTICULATE IMPURITIES THEREIN; PROVIDING OVER SAID MOLEN ALLOY A SUPERNATANT LAYER OF A MOLTEN MIXTURE OF AT LEST TWO HALIDE SALTS, WHEREIN THE CATION IS SELECTED FROM THE GROUP CONSISTING OF AN ALKALI METAL AND AN ALKALINE EARTH METAL, BUBBLING A TREATING GAS THROUGH SAID MOLTEN ALLOY, SAID GAS CONSISTING OF AN INERT CARRIER GAS AND AN EFFECTIVE AMOUNT OF FULLY HALOGENATED LOWER HYDROCARBON CONTAINING ONE TO SIX CARBON ATOMS, WHICH IS FREE OF HYDROGEN AND CONTAINS AT LEAST ONNE FLUORINE ATOM, SAID GAS CONTAINING UP TO 10 PERCENT BY VOLUME OF SAID HYDROCARBON, THEREBY TRANSFERRNG SOLID PARTICULATE IMPURITIES TO THE SUPERNATANT LAYER AND REMOVING GASEOUS IMPURITIES THEREFROM; AND SEPARATING THE SAID ALLOY IN PURIFIED CONDITION.
Claim 3
Dependent Claim
14 words
A process in accordance with claim 1 wherein the said halohydrocarbon is fully fluorinated.
Claim 4
Dependent Claim
20 words
A process in accordance with claim 1 wherein the said halohydrocarbon is a mixture of at least two such compounds.
Claim 5
Dependent Claim
22 words
A process in accordance with claim 1 wherein the said halohydrocarbon constitutes 2 to 10 percent by volume of the said gas.
Claim 6
Dependent Claim
16 words
A process in accordance with claim 1 wherein the said halohydrocarbon comprises a fully chlorofluorinated hydrocarbon.
Claim 7
Dependent Claim
13 words
A process in accordance with claim 1 wherein the said halohydrocarbon comprises CCl2F2.
Claim 8
Dependent Claim
19 words
A process in accordance with claim 1 wherein the said halohydrocarbon comprises 3 to 5 percent by volume CCl2F2.
Claim 9
Dependent Claim
23 words
A process in accordance with claim 1 wherein the said inert gas is selected from the group consisting of nitrogen, helium and argon.
Claim 10
Dependent Claim
21 words
A process in accordance with claim 1 wherein the said treating gas is nitrogen containing about 3 percent by volume CCl2F2.
Claim 11
Dependent Claim
19 words
A process in accordance with claim 1 wherein the said halohydrocarbon is a mixture of CCl3F, CCl2F2, and CClF3.
Claim 12
Dependent Claim
25 words
A process in accordance with claim 1 wherein the said halohydrocarbon includes a haloethylene selected from the group consisting of CF2 CF2, and CCl2 CFCl.
Claim 13
Dependent Claim
29 words
A process in accordance with claim 1 wherein the said halohydrocarbon includes a haloethane selected from the group consisting of CCl3.CCl2F, CCl2F.CCl2F, CClF2.CClF2, CF3.CCl2F, CCl3.CF3, CCl2F.CF3, CClF2.CF3, and CF3.CF3.
Claim 14
Dependent Claim
20 words
A process in accordance with claim 1 wherein the said molten salt mixture has a melting point below 1,400* F.
Claim 15
Dependent Claim
26 words
A process in accordance with claim 1 wherein the said molten salt mixture includes a halide or an alkali metal and of an alkaline earth metal.
Claim 16
Dependent Claim
37 words
A process in accordance with claim 1 wherein the said molten salt includes about 40 - 50 percent each of an alkali chloride and of an alkaline earth chloride and up to 5 percent of a fluoride.
Claim 17
Dependent Claim
23 words
A process in accordance with claim 1 wherein the said halohydrocarbon contains one to two carbon atoms and one to four fluorine atoms.
Claim 18
Dependent Claim
24 words
A process in accordance with claim 1 wherein the said treatinG gas is nitrogen containing up to 10 percent by volume of said halohydrocarbon.
Claim 19
Dependent Claim
24 words
A process in accordance with claim 1 wherein the said treating as is nitrogen containing 3 to 5 percent by volume of said halohydrocarbon.
Claim 20
Dependent Claim
23 words
A process in accordance with claim 1 wherein the said gas is bubbled through the said molten alloy for at least 10 minutes.
Claim 21
Dependent Claim
22 words
A process in accordance with claim 1 wherein the said gas is bubbled through the said molten alloy for about 30 minutes.
Claim 22
Dependent Claim
35 words
A process in accordance with claim 1 wherein the said supernatant layer is present in a proportion of 1/8 to 2 pounds of salt mixture per square foot of surface of said molten aluminum alloy.
Claim 23
Dependent Claim
32 words
A process in accordance with claim 1 wherein the said supernatant layer is present in a proportion of about one pound per square foot of surface of the said molten aluminum alloy.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |