US4456528A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for removing ash from coal
Assignee: Hitachi Ltd
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Filing: 1981-11-10
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Granted: 1984-06-26
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Expires: 2001-11-10
Abstract
Abstract Mineral impurities can be effectively removed from coal by introducing oil droplets into an aqueous slurry of pulverized coal. Coal, which is lipophilic, attaches to the surface of the oil droplets and floats upwardly along with the oil droplets utilizing their buoyancy. On the other hand, mineral impurities, which are hydrophilic, are left in the aqueous slurry.
Inventors
- 👤 Hidetoshi Akimoto
- 👤 Ryuichi Kaji
- 👤 Takeo Komuro
- 👤 Yasushi Muranaka
- 👤 Hideo Kikuchi
- 👤 Yukio Hishinuma
- 👤 Fumito Nakajima
- 👤 Hiroshi Terada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:51
CPC Classifications
B; B03; B03B; B03B9/00; B03B9/005; B03B5/00; B03D; B03D1/00; B03D3/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
137 words
A process for removing ash from coal comprising: grinding ash containing coal to fine particles; dispersing the particles in water to form a slurry comprising coal particles, ash particles and water; introducing the slurry into a separating column; introducing oil and air together from a single nozzle in the form of air bubbles with all interfaces covered with oil, said bubbles formed by the mixing of air with pressurized oil, into the lower part of the separating column, said bubbles ascending to the upper part of said separating column; subjecting the slurry to no more than gentle stirring; attaching the coal particles to surfaces of the ascending bubbles to form a coal containing oil phase on the upper surface of the slurry, said ash particles remaining in the slurry; and separating the oil phase from the slurry.
Claim 2
Dependent Claim
137 words
A process for removing ash from coal comprising: grinding ash containing coal to fine particles; dispersing the particles in water to form a slurry comprising coal particles, ash particles and water; introducing the slurry into a separating column; introducing oil and air together from a single nozzle in the form of air bubbles with all interfaces covered with oil, said bubbles formed by the mixing of air with pressurized oil, into the lower part of the separating column, said bubbles ascending to the upper part of said separating column; subjecting the slurry to no more than gentle stirring; attaching the coal particles to surfaces of the ascending bubbles to form a coal containing oil phase on the upper surface of the slurry, said ash particles remaining in the slurry; and separating the oil phase from the slurry.
Claim 3
Dependent Claim
31 words
A process for removing ash from coal of claim 1, wherein coal is ground to a maximum particle size of 100μ or less and to an average particle size of 30-40μ.
Claim 4
Dependent Claim
35 words
A process for removing ash from coal of claim 1, wherein an oil, water-insoluble, having a specific gravity less than that of water is used to form said air bubbles with interfaces covered with oil.
Claim 5
Dependent Claim
24 words
A process for removing ash from coal of claim 3, wherein sizes of said air bubbles with interfaces covered with oil are 0.1-7 mm.
Claim 6
Dependent Claim
21 words
A process for removing ash from coal of claim 1, wherein said oil is heavy oil and said gas is air.
Claim 7
Dependent Claim
33 words
A process for removing ash from coal of claim 1, wherein the oil phase containing coal and oil is led to a washing vessel and washed with water to remove any attached ash.
Claim 8
Dependent Claim
33 words
A process for removing ash from coal of claim 1, wherein the oil in the separated oil phase is evaporated either by heating or under reduced pressure to recover and reuse the oil.
Claim 9
Dependent Claim
23 words
A process according to claim 1, including: adding a dispersant to the slurry to accelerate the separation of ash particles from coal particles.
Claim 10
Dependent Claim
20 words
A process according to claim 8, wherein the dispersant is selected from the group consisting of starch and water glass.
Claim 11
Dependent Claim
29 words
A process according to claim 1, wherein the oil is selected from the group consisting of gasoline, kerosene, light oil, heavy oil, diesel oil, carbonization liquids and vegetable oils.
Claim 12
Dependent Claim
28 words
A process according to claim 1, wherein the amount of oil introduced is in the range of 5 to 10 times the amount of coal in the slurry.
References Cited (Backward Citations)
CA531380A
Cited
US787814A
Cited
US2744626A
Cited
GB903853A
Cited
US3045818A
Cited
US4089776A
Cited
US4272250A
Cited
US4288231A
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US4332593A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-26 | 1987-12-26 | 1988-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-26 | 1991-12-26 | 1992-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-26 | 1995-12-26 | 1996-06-26 | $7700.00 | Window Closed / Lapsed |