Patent US4131539A successfully refreshed from Google Patents.
US4131539A
Expired / Lapsed
US
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Removing rutile from zircon electrostatically
Assignee: AGC Inc
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Filing: 1977-02-25
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Granted: 1978-12-26
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Expires: 1997-02-25
Abstract
Abstract Titanium dioxide component is removed from a mineral containing titanium dioxide component which is difficult to be separated by the conventional electrostatic separation.
Inventors
- 👤 Kozo Ojiri
- 👤 Kohzo Sakai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:27
CPC Classifications
C; C22; C22B; C22B34/00; C22B34/10; C22B34/12; C22B34/1204; C22B34/1209; B; B03; B03C; B03C7/00; B03C7/003
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
99 words
A method for removing rutile from zircon sand containing titanium dioxide on the order of one percent, said titanium dioxide being present in the sand at least in part as rutile, which comprises heat treating said zircon sand in a non-oxidizing atmosphere so as to change the electrostatic property of the rutile and removing the rutile from said heat treated sand by an electrostatic separation in an amount sufficient to reduce the titanium dioxide content of the sand to not more than about 0.1 wt.% TiO 2 , said heat treatment being at a temperature greater than 400° C.
Claim 2
Independent Claim
99 words
A method for removing rutile from zircon sand containing titanium dioxide on the order of one percent, said titanium dioxide being present in the sand at least in part as rutile, which comprises heat treating said zircon sand in a non-oxidizing atmosphere so as to change the electrostatic property of the rutile and removing the rutile from said heat treated sand by an electrostatic separation in an amount sufficient to reduce the titanium dioxide content of the sand to not more than about 0.1 wt.% TiO 2 , said heat treatment being at a temperature greater than 400° C.
Claim 3
Dependent Claim
15 words
A method according to claim 1, wherein said electrostatic separation is a high tension separation.
Claim 4
Dependent Claim
20 words
A method according to claim 1, wherein said mineral containing titanium dioxide component is heat-treated in a nitrogen gas atmosphere.
Claim 5
Dependent Claim
22 words
A method according to claim 1, wherein the temperature in the heat-treatment is in a range of 400° C. to 800° C.
Claim 6
Dependent Claim
28 words
A method according to claim 1, wherein said mineal containing titanium dioxide component is heat-treated in a reducing atmosphere containing CO or H 2 before the electrostatic separation.
Claim 7
Dependent Claim
32 words
A method according to claim 1, wherein said mineral containing titanium dioxide component is heat-treated in a neutral atmosphere containing CO 2 at 400° C. to 750° C. before the electrostatic separation.
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) | 1981-12-25 | 1982-06-26 | 1982-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-25 | 1986-06-26 | 1986-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-25 | 1990-06-26 | 1990-12-26 | $7700.00 | Window Closed / Lapsed |