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US4437861A
Expired / Lapsed
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Coal-deashing process
Assignee: Battelle-Institut
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Filing: 1983-02-16
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Granted: 1984-03-20
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Expires: 2003-02-16
Abstract
Abstract Natural coal containing inorganic impurities may be deashed by the selective flocculation process using a novel flocculant which is a water-soluble or water-dispersible copolymer having a molecular weight from about 100,000 to about 30,000,000 comprising a hydrophilic monomeric unit having a solubility in water greater than 15% by weight at 20 DEG C. and a hydrophobic monomeric unit having a solubility in water less than 10% by weight at 20 DEG C. in proportions of 99:1 to 20:80% by weight.
Inventors
- 👤 Tetsuo Ishizuka
- 👤 Hiroshi Hotta
- 👤 Yoshichika Nishimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:54
CPC Classifications
B; B03; B03D; B03D1/00; B03D1/001; B03D1/004; B03D1/016; B03D3/00; B03D3/06; B03D1/008; B03D1/01; B03D1/012; B03D2201/00; B03D2201/002; B03D2203/00; B03D2203/02; B03D2203/04; B03D2203/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
133 words
A process for deashing coal containing inorganic impurities which comprises the steps of: preparing an aqueous suspension of finely divided particles of coal mixed with said impurity particles; adding to said suspension an effective amount of a water-soluble or water-dispersible copolymer having a molecular weight from about 100,000 to about 30,000,000 of a hydrophilic monomeric unit having a solubility in water greater than 15% by weight at 20° C. and a hydrophobic monomeric unit having a solubility in water less than 10% by weight at 20° C., the proportions of said hydrophilic unit and said hydrophobic unit in said copolymer being a ratio from 99:1 to 20:80 parts by weight; flocculating said coal particles selectively as flocs while leaving the remainder containing said inorganic impurities suspended; and recovering said flocs from said suspension.
Claim 2
Dependent Claim
133 words
A process for deashing coal containing inorganic impurities which comprises the steps of: preparing an aqueous suspension of finely divided particles of coal mixed with said impurity particles; adding to said suspension an effective amount of a water-soluble or water-dispersible copolymer having a molecular weight from about 100,000 to about 30,000,000 of a hydrophilic monomeric unit having a solubility in water greater than 15% by weight at 20° C. and a hydrophobic monomeric unit having a solubility in water less than 10% by weight at 20° C., the proportions of said hydrophilic unit and said hydrophobic unit in said copolymer being a ratio from 99:1 to 20:80 parts by weight; flocculating said coal particles selectively as flocs while leaving the remainder containing said inorganic impurities suspended; and recovering said flocs from said suspension.
Claim 3
Dependent Claim
99 words
The process according to claim 1, wherein said hydrophilic monomeric unit is selected from an amide, a water-soluble salt or a water-soluble ester of acrylic or methacrylic acid, a water-soluble allyl compound, a polymerizable unsaturated dicarboxylic acid or a salt thereof, vinyl alcohol, vinyl sulfonic acid or a salt thereof, a styrene sulfonic acid or a salt thereof, and said hydrophobic monomeric unit is selected from an alkyl ester of acrylic or methacrylic acid, styrene or a derivative thereof, a polymerizable nitrile, a polymerizable olefin, a polymerizable halogenated olefin, a vinyl ester of aliphatic acid or a vinyl pyridine.
Claim 4
Dependent Claim
19 words
The process according to claim 1, wherein said aqueous suspension of finely divided coal particles contains a dispersing agent.
Claim 5
Dependent Claim
25 words
The process according to claim 1, wherein said aqueous suspension of finely divided coal particles has a solid content of less than 60% by weight.
Claim 6
Dependent Claim
24 words
The method according to claim 1, wherein said water-soluble or water-dispersible copolymer is added to a concentration from 0.1 ppm to 1% by weight.
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) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |