US3964899A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Additives to improve slag formation in steelmaking furnaces
Assignee: Foseco International Ltd
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Filing: 1974-11-20
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Granted: 1976-06-22
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Expires: 1994-11-20
Abstract
Abstract In steelmaking, the formation of a lime-based desulphurising slag is promoted by adding, with the lime, an additive including at least 20% by weight Al 2 O 3 and including one or more of oxide of iron, magnesium, manganese and titanium, and melting below 1600°C.
Inventors
- 👤 Evan Thomas Richard Jones
- 👤 Robert Anthony Fishburn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:08
CPC Classifications
C; C21; C21C; C21C5/00; C21C5/28; C21C5/36
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
73 words
A composition for use in the refining of steel as a dry additive to be added with lime to promote dissolution of lime in slag, said additive being in essentially solid form and consisting essentially of, by weight, at least 20% alumina, and at least one oxide selected from the class consisting of iron oxide, magnesium oxide, manganese oxide and titanium oxide, the said additive having a melting point of less than 1600°C.
Claim 2
Dependent Claim
73 words
A composition for use in the refining of steel as a dry additive to be added with lime to promote dissolution of lime in slag, said additive being in essentially solid form and consisting essentially of, by weight, at least 20% alumina, and at least one oxide selected from the class consisting of iron oxide, magnesium oxide, manganese oxide and titanium oxide, the said additive having a melting point of less than 1600°C.
Claim 3
Dependent Claim
14 words
The additive of claim 1 and having a melting point of less than 1500°C.
Claim 4
Dependent Claim
13 words
The additive of claim 1 and including both iron oxide and manganese oxide.
Claim 5
Dependent Claim
13 words
The additive of claim 1 and including both iron oxide and magnesium oxide.
Claim 6
Dependent Claim
19 words
The additive of claim 1 and consisting to an extent of at least 50% by weight of pit solids.
Claim 7
Dependent Claim
24 words
The additive of claim 1 wherein the content of iron, magnesium, manganese and titanium oxides is in the range 20 - 80% by weight.
Claim 8
Dependent Claim
13 words
The additive of claim 1 and including up to 20% by weight fluorspar.
Claim 9
Dependent Claim
30 words
The additive of claim 1 and consisting essentially of a mixture of pit solids and at least one substance selected from the class consisting of millscale, manganese ore and ilmenite.
Claim 10
Dependent Claim
12 words
The additive of claim 1 in the form of a granulated composition.
Claim 11
Dependent Claim
12 words
The additive of claim 1 in the form of a tabletted composition.
Claim 12
Dependent Claim
12 words
The additive of claim 1 in the form of a briquetted composition.
Claim 13
Dependent Claim
88 words
A composition for use in the refining of steel as a dry additive to be added with lime to promote dissolution of lime in slag, said additive being in essentially solid form and consisting essentially of, by weight, at least 20% alumina, and at least one oxide selected from the class consisting of iron oxide, magnesium oxide, manganese oxide and titanium oxide, the said additive having a melting point of less than 1600°C and being in a form selected from the class consisting of granules, tablets and briquettes.
Claim 14
Dependent Claim
88 words
A composition for use in the refining of steel as a dry additive to be added with lime to promote dissolution of lime in slag, said additive being in essentially solid form and consisting essentially of, by weight, at least 20% alumina, and at least one oxide selected from the class consisting of iron oxide, magnesium oxide, manganese oxide and titanium oxide, the said additive having a melting point of less than 1600°C and being in a form selected from the class consisting of granules, tablets and briquettes.
Claim 15
Dependent Claim
80 words
In the method of refining steel in which lime is added to the molten steel to effect the formation of a slag, the improvement which comprises adding with the lime, in order to promote slag formation, in essentially solid form consisting essentially of, by weight, at least 20% alumina, and at least one oxide selected from the class consisting of iron oxide, magnesium oxide, manganese oxide and titanium oxide, the said additive having a melting point of less than 1600°C.
Claim 16
Dependent Claim
80 words
In the method of refining steel in which lime is added to the molten steel to effect the formation of a slag, the improvement which comprises adding with the lime, in order to promote slag formation, in essentially solid form consisting essentially of, by weight, at least 20% alumina, and at least one oxide selected from the class consisting of iron oxide, magnesium oxide, manganese oxide and titanium oxide, the said additive having a melting point of less than 1600°C.
Claim 17
Dependent Claim
18 words
The method of claim 13 wherein the weight ratio of additive to lime is from 1:5 to 1:15.
Claim 18
Dependent Claim
26 words
The method of claim 13 wherein prior to adding the additive and the lime to the molten steel, the additive and the lime are intimately admixed.
Claim 19
Dependent Claim
31 words
The additive of claim 1 consisting essentially of 20-80% by weight alumina and 80-20% by weight, at least one oxide selected from the class consisting of manganese dioxide and titanium dioxide.
Claim 20
Dependent Claim
26 words
The additive of claim 1 consisting essentially of 20-80% by weight alumina and 80-20% by weight of titanium dioxide, manganese dioxide, ferric oxide and magnesium oxide.
Claim 21
Dependent Claim
48 words
The additive of claim 1 consisting essentially of 20-80% by weight alumina and 80-20% by weight of at least one oxide selected from the class consisting of manganese dioxide and titanium dioxide and at least one oxide selected from the class consisting of iron oxide and magnesium oxide.
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) | 1979-06-22 | 1979-12-22 | 1980-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-22 | 1983-12-22 | 1984-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-22 | 1987-12-22 | 1988-06-22 | $7700.00 | Window Closed / Lapsed |