Patent US3808014A successfully refreshed from Google Patents.
US3808014A
Expired / Lapsed
US
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Refractory magnesia
Assignee: STEETLEY Manufacturing Ltd
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Filing: 1973-01-31
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Granted: 1974-04-30
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Expires: 1993-01-31
Abstract
Abstract A refractory dead-burned magnesia comprises lime, silica in an amount less than 0.2 percent by weight, based on the weight of the magnesia, R2O3 materials in an amount less than 0.5 percent by weight, based on the weight of the magnesia and zirconia in an amount of from 0.05 percent to 5 percent by weight, based on the weight of the magnesia, the amount of lime in the magnesia being from 0.2 percent to 1.5 percent by weight, based on the weight of the magnesia, in excess of the weight of lime required to ensure a CaO:ZrO2 mole ratio of 1:1. The magnesia in accordance with the invention has utility in the production of high hot strength refractory products.
Inventors
- 👤 D Spencer
- 👤 D Wooldridge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:25
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/03
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
16 words
Magnesia according to claim 1 containing from 0.01 percent to 0.1 percent by weight of silica.
Claim 2
Dependent Claim
17 words
Magnesia according to claim 1 containing from 0.01 percent to 0.2 percent by weight of R2O3 materials.
Claim 3
Dependent Claim
16 words
Magnesia according to claim 1 containing from 0.2 percent to 2 percent by weight of zirconia.
Claim 4
Dependent Claim
32 words
Magnesia according to claim 1 containing from 0.2 percent to 1.0 percent by weight of lime in excess of the weight of lime required to ensure a CaO:ZrO2 mole ratio of 1:1.
Claim 5
Dependent Claim
26 words
Magnesia according to claim 1 containing alumina in an amount of from 0.01 percent to 0.07 percent by weight, based on the weight of the magnesia.
Claim 6
Dependent Claim
27 words
Magnesia according to claim 1 containing ferric oxide in an amount of from 0.01 percent to 0.20 percent by weight, based on the weight of the magnesia.
Claim 7
Dependent Claim
24 words
Magnesia according to claim 1 containing boric oxide in an amount less than 0.05 percent by weight, based on the weight of the magnesia.
Claim 8
Dependent Claim
85 words
Magnesia according to claim 1 containing from 0.2 percent to 1.0 percent by weight of lime in excess of the weight of lime required to ensure a CaO:ZrO2 mole ratio of 1:1, from 0.01 percent to 0.1 percent by weight of silica, from 0.2 percent to 2 percent by weight of zirconia, from 0.01 percent to 0.07 percent by weight of alumina, from 0.01 percent to 0.20 percent by weight of ferric oxide and from 0.005 percent to 0.03 percent by weight of boric oxide.
References Cited (Backward Citations)
US2695242A
Cited
US3312557A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-29 | 1977-10-29 | 1978-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-29 | 1981-10-29 | 1982-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-29 | 1985-10-29 | 1986-04-30 | $7700.00 | Window Closed / Lapsed |