US3743484A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Regeneration of sulfuric acid pickling waste
Assignee: Daido Chemical Engineering Corp
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Filing: 1970-11-10
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Granted: 1973-07-03
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Expires: 1990-11-10
Abstract
Abstract SULPHURIC ACID PICKLING WASTE IS REGENERATED BY MIXING IT WITH CIRCULATING SULPHURIC ACID. THE RESULTANT LIQUID MIXTURE IS HEATED PRIOR TO CONCENTRATION IN A VACUUM EVAPDISPERSED THEREIN IN A SLURRY CONCENTRATION OF 10 TO 30% ORATOR TO OBTAIN SULFURIC ACID OF A CONCENTRATION OF 40 TO 55% BY WEIGHT AND FERROUS SULFATE MONOHYDRATE CRYSTALS BY WEIGHT. FINALLY THE SULFURIC ACID IS SEPARATED FROM THE FERROUS SULFATE MONOHYDRATE CRYSTALS FOR RECOVERY, AND PART OF THE RECOVERED SULFURIC ACID IS CIRCULATED.
Inventors
- 👤 Y Morimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:57
CPC Classifications
C; C23; C23G; C23G1/00; C23G1/36; B; B01; B01D; B01D9/00; B01D9/0018; B01D9/0022; B01D9/0031; B01D9/0036; B01D9/0059; C01; C01B; C01B17/00; C01B17/69; C01B17/90; C01B17/901; C01G; C01G49/00; C01G49/14; Y; Y10; Y10S; Y10S159/00; Y10S159/19; Y10S423/00; Y10S423/01; Y10S423/02
Claims Analysis
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References Cited (Backward Citations)
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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) | 1976-07-02 | 1977-01-01 | 1977-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-02 | 1981-01-01 | 1981-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-02 | 1985-01-01 | 1985-07-03 | $7700.00 | Window Closed / Lapsed |