Patent US3775289A successfully refreshed from Google Patents.
US3775289A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing bituminous substance such as a coal tar pitch
Assignee: Nippon Steel Corp
•
Filing: 1971-11-05
•
Granted: 1973-11-27
•
Expires: 1991-11-05
Abstract
Abstract A method for producing bituminous substance such as coal tar pitch which comprises adding sulfuric acid to coal tar produced by a high temperature dry distillation of coal and a bituminous substance produced from the coal tar, then adding petroleum heavy oil to the mixture to precipitate and separate pitch component.
Inventors
- 👤 C Kishi
- 👤 M Tatsuta
- 👤 M Nago
- 👤 K Kibuishi
- 👤 Y Hatakeyama
- 👤 K Miyakawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:39
CPC Classifications
C; C10; C10C; C10C3/00; C10C1/00; C10C1/20
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
95 words
A method for improving coal tar pitch by extraction comprising adding to the pitch a hydrocarbon oil having an aniline point above 20*C and consisting of 0-30 percent of a fraction having a boiling point up to 200*C, 20 to 98 percent of a fraction having a boiling point between 200* and 360*C and 0 to 80 percent of a fraction having a boiling point above 360*C, the ratio of coal tar to said oil being from 1:0.3 to 2.0, and maintaining the temperature between 50* and 250*C to precipitate and separate the pitch component.
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) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |