US3839057A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Burned basic phosphate-bonded refractory brick
Assignee: General Refractories Co
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Filing: 1971-07-28
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Granted: 1974-10-01
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Expires: 1991-07-28
Abstract
Abstract Phosphate-bonded basic refractory compositions containing the following compounds in predetermined ratios--CaO:SiO2; P2O5:SiO2; P2O5:CaO and CaO:(P2O5+SiO2) are fired at temperatures from 2,500* to 3,200*F to provide improvements in dimensional stability on firing, improved hot compressive and transverse load resistance, improved compressive creep behavior, or improved thermal spalling resistance. In another embodiment, low silica chrome ore is also included in the phosphate-bonded basic refractory composition which is subjected to firing to improve one or more of the above described properties.
Inventors
- 👤 W Treffner
- 👤 A Foessel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:48
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/03
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
43 words
IN A PROCESS FOR MAKING A BASIC REFRACTORY SHAPE IN WHICH (A) CALCINED MAGNESITE HAVING A SILICA CONTENT BELOW 0.7%; (B) A CALCIUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF CALCIUM CARBONATE AND A HYDRAULIC CEMENT; (C) A SODIUM POLYPHOSPHATE HAVING THE FORMULA:
Claim 2
Dependent Claim
43 words
IN A PROCESS FOR MAKING A BASIC REFRACTORY SHAPE IN WHICH (A) CALCINED MAGNESITE HAVING A SILICA CONTENT BELOW 0.7%; (B) A CALCIUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF CALCIUM CARBONATE AND A HYDRAULIC CEMENT; (C) A SODIUM POLYPHOSPHATE HAVING THE FORMULA:
Claim 3
Dependent Claim
23 words
The improved process of claim 1 in which the refractory shape is fired at 2,800* to 3,200*F for from 1 to 16 hours.
Claim 4
Dependent Claim
30 words
The improved process of claim 1 in which the refractory shape is dried at temperatures in the range of 200*F to 350*F for 4 to 24 hours prior to firing.
Claim 5
Dependent Claim
44 words
In a process for making a basic refractory shape in which (a) calcined magnesite having a silica content below 0.7%; (b) a calcium compound selected from the group consisting of calcium carbonate and a hydraulic cement; and (c) a sodium polyphosphate having the formula:
Claim 6
Dependent Claim
44 words
In a process for making a basic refractory shape in which (a) calcined magnesite having a silica content below 0.7%; (b) a calcium compound selected from the group consisting of calcium carbonate and a hydraulic cement; and (c) a sodium polyphosphate having the formula:
Claim 7
Dependent Claim
23 words
The improved process of claim 4 in which the refractory shape is fired at 2,800*F to 3,200*F for from 1 to 16 hours.
Claim 8
Dependent Claim
30 words
The improved process of claim 4 in which the refractory shape is dried at temperatures in the range of 200*F to 350*F for 4 to 24 hours prior to firing.
Claim 9
Dependent Claim
50 words
The improved process of claim 1 in which the SiO2 content of the mixture is below 0.5%, and the MgO content of the mixture is between 60 to 95%, and the firing temperature is selected in the range of 2,500* to 3,200*F as an inverse function of the MgO content.
Claim 10
Dependent Claim
65 words
The improved process of claim 1 in which the firing temperature is selected to be above 2,850*F. and in which the selection of the MgO content of the refractory shape is correlated with the firing temperature selected, and the MgO content selected varies in an inversely proportional manner within the range of 60 to 77.5% for firing temperatures in the range of 2,850*F. to 3,200*F.
References Cited (Backward Citations)
US3390002A
Cited
US3449138A
Cited
BE717217A
Cited
US3522063A
Cited
US3615777A
Cited
US3479194A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |