US3899322A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noble-type metal recovery process by use of molten salt bath
Assignee: Boeing North American Inc
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Filing: 1973-05-16
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Granted: 1975-08-12
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Expires: 1993-05-16
Abstract
Abstract Valuable metals are recovered from scrap containing metal values with substantially reduced emission of environmental pollutants by feeding the metal-value-containing scrap and a source of oxygen into a molten salt preferably at a temperature above the melting point of the metal, the molten salt containing an alkali metal carbonate and preferably also an alkali metal sulfate, to pyrolytically decompose the scrap and form recoverable metal. Organic material present in the scrap is combusted. The scrap decomposition products react with and are retained in the melt. Undesired gaseous decomposition products that are formed are suitably eliminated by being passed through the melt to a second reaction zone where oxidation of any combustible matter present is completed. Certain organic scrap materials may be completely combusted in the first reaction zone by using an excess of oxygen or air in this zone during the decomposition reaction, thereby obviating the need for a second reaction zone. Thereby the final gases vented to the atmosphere as a result of oxidative treatment in only the first zone or in both zones include only such gases as carbon dioxide, water vapor, oxygen and nitrogen.
Inventors
- 👤 Samuel J Yosim
- 👤 Leroy F Grantham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:58
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/02; C22B11/021; C22B11/025; C22B7/00; C22B7/001; C22B7/04; C22B9/00; C22B9/10; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
159 words
A PROCESS FOR THE SEPARATION AND RECOVERY OF A NOBLE-TYPE METAL SELECTED FROM THE GROUP CONSISTING OF COPPER, SILVER, GOLD, PALLADIUM, PLATINUM, AND ALUMINUM FROM SCRAP CONTAINING SUCH METAL VALUES, SAID SCRAP INCLUDING AT LEAST SOME ORGANIC COMBUSTIBLE MATERIAL, SAID PROCESS BEING PERFORMED UNDER CONDITIONS RESULTING IN SUBSTANTIALLY REDUCED EMISSION OF ENVIROMENTAL POLLUTATS, COMPRISING: FEEDING SAID NOBLE TYPE-METAL-VALUE-CONTAINING SCRAP AND A SOURCE OF UNCOMBINED GASEOUS OXYGEN INTO A POOL OF A MOLTEN SALT CONSISTING ESSENTIALLY OF SODIUM CARBONATE CONTAINING ABOUT 1 TO 25 WT.% SODIUM SULFATE AT A TEMPERATURE BETWEEN 800* AND 1,800*C AND ABOVE THE MELTING POINT OF SAID NOBLE-TYPE METAL TO THERMALLY DECOMPOSE THE SCRAP TO FORM SEPARABLE SCRAP DECOMPOSITION PRODUCTS AND SAID METAL, AND SEPARATELY RECOVERING SAID METAL IN MOLTEN FORM FREE FROM SAID SCRAP DECOMPOSITION PRODUCTS, THE PROCESS BEING SO CONTROLLED SO THAT THE FINAL GASEOUS EFFLUENT VENTED TO THE ATMOSPHERE CONSISTS ESSENTIALLY ONLY OF GASES SELECTED FROM CARBON DIOXIDE, WATER VAPOR, OXYGEN, AND NITROGEN.
Claim 2
Dependent Claim
159 words
A PROCESS FOR THE SEPARATION AND RECOVERY OF A NOBLE-TYPE METAL SELECTED FROM THE GROUP CONSISTING OF COPPER, SILVER, GOLD, PALLADIUM, PLATINUM, AND ALUMINUM FROM SCRAP CONTAINING SUCH METAL VALUES, SAID SCRAP INCLUDING AT LEAST SOME ORGANIC COMBUSTIBLE MATERIAL, SAID PROCESS BEING PERFORMED UNDER CONDITIONS RESULTING IN SUBSTANTIALLY REDUCED EMISSION OF ENVIROMENTAL POLLUTATS, COMPRISING: FEEDING SAID NOBLE TYPE-METAL-VALUE-CONTAINING SCRAP AND A SOURCE OF UNCOMBINED GASEOUS OXYGEN INTO A POOL OF A MOLTEN SALT CONSISTING ESSENTIALLY OF SODIUM CARBONATE CONTAINING ABOUT 1 TO 25 WT.% SODIUM SULFATE AT A TEMPERATURE BETWEEN 800* AND 1,800*C AND ABOVE THE MELTING POINT OF SAID NOBLE-TYPE METAL TO THERMALLY DECOMPOSE THE SCRAP TO FORM SEPARABLE SCRAP DECOMPOSITION PRODUCTS AND SAID METAL, AND SEPARATELY RECOVERING SAID METAL IN MOLTEN FORM FREE FROM SAID SCRAP DECOMPOSITION PRODUCTS, THE PROCESS BEING SO CONTROLLED SO THAT THE FINAL GASEOUS EFFLUENT VENTED TO THE ATMOSPHERE CONSISTS ESSENTIALLY ONLY OF GASES SELECTED FROM CARBON DIOXIDE, WATER VAPOR, OXYGEN, AND NITROGEN.
Claim 3
Dependent Claim
24 words
The process of claim 1 wherein molten copper is recovered, the temperature of the molten salt bath being between about 1, 100* and 1,200*C.
Claim 4
Dependent Claim
24 words
The process of claim 1 wherein molten silver is recovered, the temperature of the molten salt bath being between about 1, 000* and 1,100*C.
Claim 5
Dependent Claim
23 words
The process of claim 1 wherein molten aluminum is recovered, the temperature of the molten salt bath being between about 850* and 950*C.
Claim 6
Dependent Claim
145 words
The process of claim 1 wherein: the noble-type-metal-value-containing scrap and the source of uncombined gaseous oxygen are fed into said molten salt pool contained in a first reaction zone at a temperature above the melting point of the metal wherein said scrap is pyrolytically decomposed to form a pool of molten metal and said scrap decomposition products which include a gaseous effluent, said gasEous effluent is passed through said molten salt pool into a second reaction zone in the presence of a source of uncombined gaseous oxygen to complete oxidation of any combustible matter present in said effluent, and a final gaseous effluent product consisting essentially only of gases selected from carbon dioxide, water vapor, oxygen, and nitrogen is vented to the atmosphere from said second zone, the remaining decomposition products being retained in the molten salt melt, and the molten metal is separately recovered.
Claim 7
Dependent Claim
58 words
The process of claim 5 wherein a corrosion-resistant metal mesh in said second reaction zone provides a surface for ignition and complete oxidation of combustible matter in said second reaction zone, said metal mesh also serving to demist particles of the molten salt mixture present in the gaseous effluent prior to venting of said effluent to the atmosphere.
Claim 8
Dependent Claim
22 words
The process of claim 5 wherein molten copper is recovered, the temperature of the molten salt bath being between 1,100* and 1,200*C.
Claim 9
Dependent Claim
24 words
The process of claim 5 wherein molten silver is recovered, the temperature of the molten salt bath being between about 1, 000* and 1,100*C.
Claim 10
Dependent Claim
23 words
The process of claim 5 wherein molten aluminum is recovered, the temperature of the molten salt bath being between about 850* and 950*C.
Claim 11
Dependent Claim
164 words
A process for the separation and recovery of a noble-type metal selected from the group consisting of copper, silver, gold, palladium, platinum, and aluminum from scrap containing such metal values, said scrap including at least some organic combustible material, said process being performed under conditions resulting in substantially reduced emission of environmental pollutants, comprising: feeding said noble-type-metal-value-containing scrap and a source of uncombined gaseous oxygen into a pool of a molten salt consisting of at least one alkali metal carbonate and up to 25 wt.% of an alkali metal sulfate at a temperature between 400* and 1,800*C to thermally decompose the scrap to form separable scrap decomposition products and said metal, said metal being in a finely divided elemental state dispersed in said bath, and separately recovering said metal free from said scrap decomposition products, the process being so controlled so that the final gaseous effluent vented to the atmosphere consists essentially only of gases selected from carbon dioxide, water vapor, oxygen, and nitrogen.
Claim 12
Dependent Claim
164 words
A process for the separation and recovery of a noble-type metal selected from the group consisting of copper, silver, gold, palladium, platinum, and aluminum from scrap containing such metal values, said scrap including at least some organic combustible material, said process being performed under conditions resulting in substantially reduced emission of environmental pollutants, comprising: feeding said noble-type-metal-value-containing scrap and a source of uncombined gaseous oxygen into a pool of a molten salt consisting of at least one alkali metal carbonate and up to 25 wt.% of an alkali metal sulfate at a temperature between 400* and 1,800*C to thermally decompose the scrap to form separable scrap decomposition products and said metal, said metal being in a finely divided elemental state dispersed in said bath, and separately recovering said metal free from said scrap decomposition products, the process being so controlled so that the final gaseous effluent vented to the atmosphere consists essentially only of gases selected from carbon dioxide, water vapor, oxygen, and nitrogen.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |