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US3899308A
Expired / Lapsed
US
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Gas purification method
Assignee: Boliden AB
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Filing: 1974-04-26
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Granted: 1975-08-12
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Expires: 1994-04-26
Abstract
Abstract A process for selective purification of hot gases containing complex metallic dust in which the gases are first led to an electrostatic precipitator, whereafter the material is cooled in a first cooling step and then led to a second electrostatic precipitator and thereafter in a washing step washed with water and finally indirectly cooled in a second cooling step, the improvement being that the cooling in the first step is effected with the aid of water from the washing step and condensed water from the indirect cooling step and that water is added in the first cooling step in such a maximum quantity which can be completely vapourized.
Inventors
- 👤 Stig Arvid Petersson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:25
CPC Classifications
B; B03; B03C; B03C3/00; B03C3/01; B03C3/014
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
162 words
A PROCESS OF SELECTIVE PURIFICATION OF HOT GASES CONTAINING COMPLEX METALLIC DUST IN WHICH THE GAS IS FIRST LED TO AN ELECTROSTATIC PRECIPITATOR WHERE MATERIAL IN PARTICLE FORM IS SEPARATED AFTER WHICH THE GAS IN A FIRST COOLING STEP UNDERGOES A COOLING AND THEREAFTER IS CAUSED TO PASS A SECOND ELECTROSTATIC PRECIPITATOR AND IN A WASHING STEP IS WASHED WITH WATER AND FINALLY, IN A SECOND COOLING STEP UNDERGOES AN INDIRECT COOLING, CHARACTERIZED IN THAT THE HOT GASES IN THE FIRST COOLING OPERATION ARE COOLED BY MEANS OF VAPOURIZATION OF INJECTED WATER IN SUCH A MAXIMUM QUANTITY THAT THE HEAT PRESENT IN THE GAS IS SUFFICIENT TO VAPOURIZE COMPLETELY THE ADDED WATER AND THAT THE ADDED WATER IS DERIVED FROM THE WATER WASHING STEP AND FROM CONDENSATION IN THE SECOND COOLING STEP, SO THAT IN THE PRODUCTS CONDENSING IN THE FIRST COOLING STEP AND THOSE SEPARATED IN THE WATER WASHING STEP ARE OBTAINED IN THE SECOND ELECTROSTATIC PRECIPITATOR IN A DRY CONDITION.
Claim 2
Dependent Claim
162 words
A PROCESS OF SELECTIVE PURIFICATION OF HOT GASES CONTAINING COMPLEX METALLIC DUST IN WHICH THE GAS IS FIRST LED TO AN ELECTROSTATIC PRECIPITATOR WHERE MATERIAL IN PARTICLE FORM IS SEPARATED AFTER WHICH THE GAS IN A FIRST COOLING STEP UNDERGOES A COOLING AND THEREAFTER IS CAUSED TO PASS A SECOND ELECTROSTATIC PRECIPITATOR AND IN A WASHING STEP IS WASHED WITH WATER AND FINALLY, IN A SECOND COOLING STEP UNDERGOES AN INDIRECT COOLING, CHARACTERIZED IN THAT THE HOT GASES IN THE FIRST COOLING OPERATION ARE COOLED BY MEANS OF VAPOURIZATION OF INJECTED WATER IN SUCH A MAXIMUM QUANTITY THAT THE HEAT PRESENT IN THE GAS IS SUFFICIENT TO VAPOURIZE COMPLETELY THE ADDED WATER AND THAT THE ADDED WATER IS DERIVED FROM THE WATER WASHING STEP AND FROM CONDENSATION IN THE SECOND COOLING STEP, SO THAT IN THE PRODUCTS CONDENSING IN THE FIRST COOLING STEP AND THOSE SEPARATED IN THE WATER WASHING STEP ARE OBTAINED IN THE SECOND ELECTROSTATIC PRECIPITATOR IN A DRY CONDITION.
Claim 3
Dependent Claim
30 words
A process according to claim 1, characterized in that cooling in the first cooling step is effected by adding a part of the circulating water from the water washing step.
Claim 4
Dependent Claim
22 words
A process according to claim 1, characterized in that condensed water formed by the second cooling step is recirculated in the process.
Claim 5
Dependent Claim
22 words
A process according to claim 3, characterized in that the water is returned to the circulating water in the water washing step.
Claim 6
Dependent Claim
33 words
A process according to claim 1, characterized in that roaster gases from a pyrites roasting process are treated and that particles separated in the first electrostatic precipitator are returned to the roasting furnace.
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) | 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 |