US3961031A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for removal of mercury in sulfur dioxide-containing gas
Assignee: Nippon Mining Holdings Inc
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Filing: 1974-11-11
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Granted: 1976-06-01
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Expires: 1994-11-11
Abstract
Abstract A method for the removal of mercury contained in a sulfur dioxide-containing gas which comprises contacting the sulfur dioxide-containing gas with an aqueous thiourea solution which optionally contains an acid at an acid concentration higher than one normal to selectively absorb mercury in a vapor state.
Inventors
- 👤 Hiroshi Yasui
- 👤 Iwao Kyono
- 👤 Hideo Aoki
- 👤 Haruo Manabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:23
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/64; B01D53/48; B01D53/52; B01D53/526; C; C01; C01B; C01B17/00; C01B17/48; C01B17/50; C01B17/56
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
39 words
A method for the removal of mercury vapor contained in a sulfur dioxide-containing gas containing at least 0.1% by volume sulfur dioxide which comprises contacting the sulfur dioxide-containing gas with an aqueous thiourea solution having a pH below 0.5.
Claim 2
Independent Claim
39 words
A method for the removal of mercury vapor contained in a sulfur dioxide-containing gas containing at least 0.1% by volume sulfur dioxide which comprises contacting the sulfur dioxide-containing gas with an aqueous thiourea solution having a pH below 0.5.
Claim 3
Dependent Claim
20 words
The method according to claim 1, wherein said aqueous thiourea solution has a thiourea concentration higher than 0.5% by weight.
Claim 4
Dependent Claim
16 words
The method according to claim 1, wherein said aqueous thiourea solution has a temperature below 80°C.
Claim 5
Dependent Claim
26 words
The method according to claim 1 wherein the aqueous thiourea solution also contains an acid at an acid concentration higher than one normal of said acid.
Claim 6
Dependent Claim
20 words
The method according to claim 4 wherein said aqueous thiourea solution has a thiourea concentration higher than 0.5% by weight.
Claim 7
Dependent Claim
16 words
The method according to claim 4 wherein said aqueous thiourea solution has a temperature below 80°C.
Claim 8
Dependent Claim
12 words
The mthod according to claim 4, wherein said acid is sulfuric acid.
References Cited (Backward Citations)
US3817713A
Cited
US3725530A
Cited
US3838190A
Cited
US3849537A
Cited
US3786619A
Cited
US3855387A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-01 | 1979-12-01 | 1980-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-01 | 1983-12-01 | 1984-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-01 | 1987-12-01 | 1988-06-01 | $7700.00 | Window Closed / Lapsed |