US3717574A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flocculation of coal slimes
Assignee: Wyeth Holdings LLC
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Filing: 1971-09-21
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Granted: 1973-02-20
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Expires: 1991-09-21
Abstract
Abstract Colloidal coal particles in aqueous alkaline medium are flocculated by the combined action of a low molecular weight water-soluble anionic polymer at least 50 mol percent composed of acrylic acid linkages and a high molecular weight anionic polymer at least 95 mol percent composed of acrylamide linkages, and adjusting the pH of the aqueous medium to a value below 7. A water-soluble anionic starch may be added as supplementary flocculant.
Inventors
- 👤 M Werneke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:58
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/52; C02F1/5263; C02F1/54
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
105 words
Process for flocculating colloidal coal particles in aqueous alkaline medium, which consists essentially in distributing through said medium an effective flocculating amount between about 2 and 20 parts per million parts by weight of said medium of a low molecular weight water-soluble anionic polymer at least 50 mol percent composed of acrylic acid linkages and having a molecular weight between about 50,000 and 500,000 and a water-soluble anionic high molecular weight polymer at least about 95 mol percent composed of acrylamide linkages and having a molecular weight in excess of about 5 million, and adjusting the pH of said medium to a value below 7.
Claim 2
Dependent Claim
105 words
Process for flocculating colloidal coal particles in aqueous alkaline medium, which consists essentially in distributing through said medium an effective flocculating amount between about 2 and 20 parts per million parts by weight of said medium of a low molecular weight water-soluble anionic polymer at least 50 mol percent composed of acrylic acid linkages and having a molecular weight between about 50,000 and 500,000 and a water-soluble anionic high molecular weight polymer at least about 95 mol percent composed of acrylamide linkages and having a molecular weight in excess of about 5 million, and adjusting the pH of said medium to a value below 7.
Claim 3
Dependent Claim
25 words
A process according to claim 1 wherein the low molecular weight polymer is composed of acrylic acid and acrylamide linkages in about 70:30 molar ratio.
Claim 4
Dependent Claim
19 words
The process according to claim 1 wherein the low molecular weight polymer has a molecular weight of about 200,000.
Claim 5
Dependent Claim
27 words
A process according to claim 1 wherein the high molecular weight polymer is composed of acrylamide and acrylic acid linkages in at least about 99:1 molar ratio.
Claim 6
Dependent Claim
21 words
A process according to claim 1 wherein the high molecular weight polymer has a molecular weight of 10 to 15 million.
Claim 7
Dependent Claim
21 words
A process according to claim 1 wherein the low molecular weight polymer is added prior to the high molecular weight polymer.
Claim 8
Dependent Claim
27 words
A process according to claim 1 wherein the PH of said medium is adjusted to a value between 6 and 7 prior to addition of said polymers.
Claim 9
Dependent Claim
19 words
A process according to claim 1 wherein the pH of said medium is adjusted by addition of sulfuric acid.
Claim 10
Dependent Claim
18 words
A process according to claim 1 wherein the pH of the medium is adjusted by addition of alum.
References Cited (Backward Citations)
US3079331A
Cited
US3493499A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |