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Patent US4574119A successfully refreshed from Google Patents.
US4574119A
Expired / Lapsed
US
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Chrome-magnesite refractories and method of preparation
Assignee: Indresco Inc
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Filing: 1984-06-11
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Granted: 1986-03-04
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Expires: 2004-06-11
Abstract
Abstract A refractory brick made from a size graded batch comprising 20-30 weight percent magnesite containing less than 0.8 weight percent silica, and the balance a chrome ore. The chrome ore includes oxides of chromium, aluminum and iron wherein the ratio between the oxides of chromium and the oxides of aluminum and iron is greater than 2 to 1. The silica content of the chrome ore is less than 2.7 weight percent, the iron oxide content is less than 17 weight percent, and the chrome ore to magnesite ratio is between 2.33 to 4 to 1.
Inventors
- 👤 John D. Perry
- 👤 David J. Michael
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:56
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/03; C04B35/04; C04B35/043; C04B35/047
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
80 words
A refractory brick made from a size graded batch comprising 20-30 weight percent magnesite containing less than 0.8 weight percent silica, and the remainder a chrome ore whose ratio between the oxides of chromium and the oxides of aluminum and iron is greater than 2 to 1, having a silica content less than 2.7 weight percent, an iron oxide content less than 17 weight percent, and wherein the chrome ore to magnesite ratio is between 2.33 and 4 to 1.
Claim 2
Dependent Claim
80 words
A refractory brick made from a size graded batch comprising 20-30 weight percent magnesite containing less than 0.8 weight percent silica, and the remainder a chrome ore whose ratio between the oxides of chromium and the oxides of aluminum and iron is greater than 2 to 1, having a silica content less than 2.7 weight percent, an iron oxide content less than 17 weight percent, and wherein the chrome ore to magnesite ratio is between 2.33 and 4 to 1.
Claim 3
Dependent Claim
22 words
A refractory brick in accordance with claim 1 wherein the silica content of the chrome ore is less than 2.3 weight percent.
Claim 4
Dependent Claim
18 words
A refractory brick in accordance with claim 1 wherein the brick is used to line a copper converter.
Claim 5
Independent Claim
130 words
A method of manufacturing a refractory brick comprising the steps of: mixing a magnesite ore containing less than 0.8 weight percent silica, and a chrome ore whose ratio between the oxides of chromium and the oxides of aluminum and iron is greater than 2 to 1, the silica content is less than 2.7 weight percent, the iron oxide content is less than 17 weight percent and the ratio between the chrome ore and magnesite is between 2.33 and 4 to 1, wherein the batch comprises 20-30 weight percent magnesite and the balance the chrome ore; adding bond to the batch; pressing the brick-like structures at elevated pressures; drying the brick-like structures; and burning the brick-like structures at a temperature in excess of 3000° F. to form the finished refractory brick.
Claim 6
Independent Claim
130 words
A method of manufacturing a refractory brick comprising the steps of: mixing a magnesite ore containing less than 0.8 weight percent silica, and a chrome ore whose ratio between the oxides of chromium and the oxides of aluminum and iron is greater than 2 to 1, the silica content is less than 2.7 weight percent, the iron oxide content is less than 17 weight percent and the ratio between the chrome ore and magnesite is between 2.33 and 4 to 1, wherein the batch comprises 20-30 weight percent magnesite and the balance the chrome ore; adding bond to the batch; pressing the brick-like structures at elevated pressures; drying the brick-like structures; and burning the brick-like structures at a temperature in excess of 3000° F. to form the finished refractory brick.
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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) | 1989-03-03 | 1989-09-02 | 1990-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-03 | 1993-09-02 | 1994-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-03 | 1997-09-02 | 1998-03-04 | $7700.00 | Window Closed / Lapsed |