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Patent US2999011A successfully refreshed from Google Patents.
US2999011A
Expired / Lapsed
US
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Method for bleaching hydrous titanium dioxide
Assignee: NL Industries Inc
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Filing: 1959-12-31
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Granted: 1961-09-05
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Expires: 1979-12-31
Abstract
No abstract record available.
Inventors
- 👤 Lester E Olmsted
- 👤 Eckard J Puetz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:52
CPC Classifications
C; C22; C22B; C22B34/00; C22B34/10; C22B34/12; C22B34/1204; C22B34/1213; C22B34/1236; C22B34/124; C22B34/125
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
194 words
A METHOD FOR TREATING A TITANIUM HYDRATE SLURRY TO REMOVE IRON AS A COLORED IMPURITY THEREFROM WHICH COMPRISES DIVIDING SAID TITANIUM HYDRATE SLURRY INTO A MINOR AND A MAJOR PORTION, ADDING TO SAID MINOR PORTION CONCENTRATED SULFURIC ACID IN AMOUNT TO PROVIDE A SULFURIC ACID CONCENTRATION IN SAID MINOR PORTION OF FROM 16 TO 40%, REDUCING AND SOLUBILIZING MOST OF THE TITANIUM VALUES IN SAID MINOR PORTION TO THE TRIVALENT STATE AT A TEMPERATURE OF FROM 30*C. TO BOILING TO FORM A BLEACHING SLURRY, ADDING THE BLEACHING SLURRY CONTAINING THE REDUCED AND SOLUBLE TITANIUM VALUES TO THE MAJOR PORTION TO FORM A BLEACHED SLURRY, THE AMOUNT OF SULFURIC ACID IN SAID BLEACHING SLURRY BEING FROM 0.1% TO 2.0% BY WEIGHT, THE AMOUNT OF SAID REDUCED TITANIUM VALUES IN SAID BLEACHING SLURRY BEING SUFFICIENT TO REDUCE THE IRON IN SAID MAJOR PORTION TO A LOWER VALENT COMPOUND AND TO SOLUBILIZE THE SAME, AND TO MAINTAIN AT LEAST 0.05 GRAM PER LITER OF TRIVALENT TITANIUM IN SAID BLEACHES SLURRY, REMOVING THE SOLUBILIZED LOWER VALENT IRON COMPOUND FROM SAID BLEACHED SLURRY BY FILTERING AND WASHING SAID BLEACHED SLURRY TO PRODUCE A TITANIUM HYDRATE SUBSTANTIALLY FREE FROM IRON.
Claim 2
Independent Claim
194 words
A METHOD FOR TREATING A TITANIUM HYDRATE SLURRY TO REMOVE IRON AS A COLORED IMPURITY THEREFROM WHICH COMPRISES DIVIDING SAID TITANIUM HYDRATE SLURRY INTO A MINOR AND A MAJOR PORTION, ADDING TO SAID MINOR PORTION CONCENTRATED SULFURIC ACID IN AMOUNT TO PROVIDE A SULFURIC ACID CONCENTRATION IN SAID MINOR PORTION OF FROM 16 TO 40%, REDUCING AND SOLUBILIZING MOST OF THE TITANIUM VALUES IN SAID MINOR PORTION TO THE TRIVALENT STATE AT A TEMPERATURE OF FROM 30*C. TO BOILING TO FORM A BLEACHING SLURRY, ADDING THE BLEACHING SLURRY CONTAINING THE REDUCED AND SOLUBLE TITANIUM VALUES TO THE MAJOR PORTION TO FORM A BLEACHED SLURRY, THE AMOUNT OF SULFURIC ACID IN SAID BLEACHING SLURRY BEING FROM 0.1% TO 2.0% BY WEIGHT, THE AMOUNT OF SAID REDUCED TITANIUM VALUES IN SAID BLEACHING SLURRY BEING SUFFICIENT TO REDUCE THE IRON IN SAID MAJOR PORTION TO A LOWER VALENT COMPOUND AND TO SOLUBILIZE THE SAME, AND TO MAINTAIN AT LEAST 0.05 GRAM PER LITER OF TRIVALENT TITANIUM IN SAID BLEACHES SLURRY, REMOVING THE SOLUBILIZED LOWER VALENT IRON COMPOUND FROM SAID BLEACHED SLURRY BY FILTERING AND WASHING SAID BLEACHED SLURRY TO PRODUCE A TITANIUM HYDRATE SUBSTANTIALLY FREE FROM IRON.
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) | 1964-09-04 | 1965-03-06 | 1965-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-09-04 | 1969-03-06 | 1969-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-09-04 | 1973-03-06 | 1973-09-05 | $7700.00 | Window Closed / Lapsed |