US3917465A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of pyritic sulfur from coal using solutions containing ferric ions
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1973-10-30
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Granted: 1975-11-04
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Expires: 1993-10-30
Abstract
Abstract Finely divided coal or solid coal derivatives containing pyrite are reacted with a ferric ion solution; FeCl3 is particularly suitable. The ferric ion is reduced to ferrous ion and free sulfur is formed. The solution is then filtered from the coal which is then washed and heat dried under low pressure. Most of the free sulfur is volatized from the coal due to the heat drying; additional free sulfur can be removed by additional washing and heat drying and/or solvent extraction techniques. At least 60% of the pyrite sulfur and pyrite iron is removed using the process of this invention. If desired, the ferrous chloride can be regenerated; this permits iron oxide to be recovered as a byproduct.
Inventors
- 👤 Robert A Meyers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:16
CPC Classifications
C; C10; C10L; C10L9/00; C10L9/02
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
55 words
AN APPARATUS FOR REDUCING THE PYRITIC SULFUR CONTENT OF COAL COMPRISING IN COMBINATION: MEANS ADAPTED TO REACT COAL CONTAINING IRN PYRITE WITH A SOLUTION FOR FERRIC ION, WASHING MEANS FOR REMOVING REACTANT SOLUTION FROM THE COAL, AND MEANS FOR REMOVING FROM THE COAL, FREE SULFUR FORMED BY THE REACTION BETWEEN THE PYRITE AND FERRIC ION.
Claim 2
Independent Claim
55 words
AN APPARATUS FOR REDUCING THE PYRITIC SULFUR CONTENT OF COAL COMPRISING IN COMBINATION: MEANS ADAPTED TO REACT COAL CONTAINING IRN PYRITE WITH A SOLUTION FOR FERRIC ION, WASHING MEANS FOR REMOVING REACTANT SOLUTION FROM THE COAL, AND MEANS FOR REMOVING FROM THE COAL, FREE SULFUR FORMED BY THE REACTION BETWEEN THE PYRITE AND FERRIC ION.
References Cited (Backward Citations)
US3768988A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-03 | 1979-05-05 | 1979-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-03 | 1983-05-05 | 1983-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-03 | 1987-05-05 | 1987-11-04 | $7700.00 | Window Closed / Lapsed |