US3960585A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reducing H2 S-emission from hot cast sulfur-asphalt mixtures
Assignee: Shell USA Inc
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Filing: 1974-12-04
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Granted: 1976-06-01
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Expires: 1994-12-04
Abstract
Abstract When cast sulfur-asphalt compositions, e.g., sulfur-asphalt-aggregate pavements and construction articles, are being prepared by mixing and/or heating mixtures comprising sulfur and asphalt at elevated temperatures not exceeding 175°C, the evolution of hydrogen sulfide is substantially reduced by carrying out the mixing and/or heating step in the presence of a hydrogen sulfide suppressant selected from the class consisting of free radical inhibitors and redox (oxidation-reduction) catalysts.
Inventors
- 👤 William Gaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:11
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/02; C08K3/06; C08K3/16
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
73 words
In the process for casting sulfur-asphalt compositions by mixing and/or heating mixtures comprising sulfur and asphalt in a weight ratio of at least 1:1 sulfur to asphalt, said mixing and/or heating being carried out at elevated temperatures not exceeding 175°C, the improvement which comprises: carrying out the mixing and/or heating step in the presence of a hydrogen sulfide suppressant selected from the class consisting of free radical inhibitors, redox catalysts and mixtures thereof.
Claim 2
Dependent Claim
73 words
In the process for casting sulfur-asphalt compositions by mixing and/or heating mixtures comprising sulfur and asphalt in a weight ratio of at least 1:1 sulfur to asphalt, said mixing and/or heating being carried out at elevated temperatures not exceeding 175°C, the improvement which comprises: carrying out the mixing and/or heating step in the presence of a hydrogen sulfide suppressant selected from the class consisting of free radical inhibitors, redox catalysts and mixtures thereof.
Claim 3
Dependent Claim
15 words
The process according to claim 1, wherein the hydrogen sulfide suppressant is a redox catalyst.
Claim 4
Dependent Claim
34 words
The process according to claim 2, wherein the redox catalyst is selected from the class consisting of iodine, copper salts and coper oxides, iron salts and iron oxides and cobalt salts and cobalt oxides.
Claim 5
Dependent Claim
27 words
The process according to claim 3, wherein the redox catalyst is an iron salt selected from the class consisting of ferric chloride, ferrous chloride and their hydrates.
Claim 6
Dependent Claim
14 words
The process according to claim 4 wherein the redox catalyst is hydrated ferrous chloride.
Claim 7
Dependent Claim
16 words
The process according to claim 1, wherein the hydrogen sulfide suppresant is a free radical inhibitor.
Claim 8
Dependent Claim
26 words
The process according to claim 6, wherein the free radical inhibitor is selected from the class consisting of tetra-alkylthiuram disulfide, zinc dialkyl dithiocarbamates and diphenyl guanidide.
Claim 9
Dependent Claim
15 words
The process according to claim 1, wherein the sulfur-asphalt composition also contains a mineral aggregate.
Claim 10
Dependent Claim
23 words
The process according to claim 1, wherein the casting of the sulfur-asphalt composition is carried out at an elevated temperature not exceeding 150°C.
Claim 11
Dependent Claim
23 words
The process according to claim 1, wherein the hydrogen sulfide suppressant is added to the asphalt before it is mixed with the sulfur.
Claim 12
Dependent Claim
67 words
A castable sulfur-asphalt composition comprising sulfur and asphalt present in a weight ratio of at least 1:1 sulfur to asphalt and a hydrogen sulfide suppressant selected from the class consisting of free radical inhibitors, redox catalysts and mixtures thereof, said hydrogen sulfide suppressant being present in an amount sufficient to substantially suppress evolution of hydrogen sulfide from the composition when heated to elevated temperatures not exceeding 175°C.
Claim 13
Dependent Claim
67 words
A castable sulfur-asphalt composition comprising sulfur and asphalt present in a weight ratio of at least 1:1 sulfur to asphalt and a hydrogen sulfide suppressant selected from the class consisting of free radical inhibitors, redox catalysts and mixtures thereof, said hydrogen sulfide suppressant being present in an amount sufficient to substantially suppress evolution of hydrogen sulfide from the composition when heated to elevated temperatures not exceeding 175°C.
Claim 14
Dependent Claim
15 words
The composition according to claim 11, wherein the hydrogen sulfide suppressant is a redox catalyst.
Claim 15
Dependent Claim
34 words
The composition according to claim 12, wherein the redox catalyst is selected from the class consisting of iodine, copper salts and copper oxides, iron salts and iron oxides and cobalt salts and cobalt oxides.
Claim 16
Dependent Claim
27 words
The composition according to claim 13, wherein the redox catalyst is an iron salt selected from the class consisting of ferric chloride, ferrous chloride and their hydrates.
Claim 17
Dependent Claim
14 words
The composition according to claim 14, wherein the redox catalyst is hydrated ferrous chloride.
Claim 18
Dependent Claim
15 words
The composition accoridng to claim 11, wherein the hydrogen sulfide suppressant is a free inhibitor.
Claim 19
Dependent Claim
26 words
The composition according to claim 16, wherein the free radical inhibitor is selected from the class consisting of tetra-alkylthiuram disulfide, zinc dialkyl dithiocarbamates and diphenyl guanidide.
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) | 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 |