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US4874428A
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Fluidizing a lime-silica slag
Assignee: Armco Steel Co LP
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Filing: 1988-09-12
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Granted: 1989-10-17
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Expires: 2008-09-12
Abstract
Abstract A method of fluidizing a cold lime-silica slag covering a molten metal. An acid flux is prepared from a particulate admixture of sodium fluoroaluminate and sodium silicate. The flux is mixed with the cold slag forming a fluid slag having at least 1% by weight F- and at least 1% by weight Na 2 O. The treated slag has a reduced melting point allowing it to be mechanically skimmed from the molten metal and has a high sulfur capacity.
Inventors
- 👤 Joyce C. Niedringhaus
- 👤 Michael L. Lowry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:58
CPC Classifications
C; C21; C21B; C21B3/00; C21B3/04; C21B3/06; C21C; C21C7/00; C21C7/04; C21C7/076; C21B2400/00; C21B2400/02; Y; Y02; Y02P; Y02P10/00; Y02P10/20; Y02W; Y02W30/00; Y02W30/50
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
87 words
A method of fluidizing a slag, comprising: providing a lime-silica type slag covering a molten metal, providing an acid flux containing a source of fluoride ion and complex sodium compound, mixing said acid flux with said lime-silica slag to form a treated slag containing at least about 1% by weight F - and at least about 1% by weight Na 2 O, whereby the melting point of said treated slag is below the melting point of said lime-silica slag, removing said treated slag from said molten metal.
Claim 2
Independent Claim
87 words
A method of fluidizing a slag, comprising: providing a lime-silica type slag covering a molten metal, providing an acid flux containing a source of fluoride ion and complex sodium compound, mixing said acid flux with said lime-silica slag to form a treated slag containing at least about 1% by weight F - and at least about 1% by weight Na 2 O, whereby the melting point of said treated slag is below the melting point of said lime-silica slag, removing said treated slag from said molten metal.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein said flux is prepared from a particulate admixture of sodium fluoroaluminate and sodium silicate.
Claim 4
Dependent Claim
15 words
The method of claim 2 wherein said mixture includes recycled cryolite and recycled bottle glass.
Claim 5
Dependent Claim
29 words
The method of claim 1 wherein said treated slag comprises 30-40% CaO, 30-40% SiO 2 , 10-15% MgO, and 8-12% Al 2 O 3 , all percentages by weight.
Claim 6
Dependent Claim
23 words
The method of claim 4 wherein said treated slag further includes 1-3% by weight F - and 2-4% by weight Na 2 O.
Claim 7
Independent Claim
82 words
A method of fluidizing a slag, comprising: providing a blast furnace slag covering a molten iron, the temperature of said molten iron being no greater than about 1260° C., preparing an acid flux containing a source of fluoride ion and complex sodium compound, mixing said acid flux with said slag forming a fluid treated slag containing at least about 1% by weight F - and at least about 1% by weight Na 2 O, removing said treated slag from said molten iron.
Claim 8
Independent Claim
82 words
A method of fluidizing a slag, comprising: providing a blast furnace slag covering a molten iron, the temperature of said molten iron being no greater than about 1260° C., preparing an acid flux containing a source of fluoride ion and complex sodium compound, mixing said acid flux with said slag forming a fluid treated slag containing at least about 1% by weight F - and at least about 1% by weight Na 2 O, removing said treated slag from said molten iron.
Claim 9
Dependent Claim
18 words
The method of claim 6 wherein said treated slag has a melting point of at least 1169° C.
Claim 10
Independent Claim
94 words
A method of fluidized a slag, comprising: providing a blast furnace slag covering a molten iron, preparing an acid flux containing a source of fluoride ion and complex sodium compound, mixing said acid flux with said slag to form a fluid treated slag, injecting a desulfurization agent into said molten iron, said treated slag containing at least about 1% by weight F - and at least about 1% by weight Na 2 O, removing said treated slag from said molten iron whereby sulfur in said treated slag does not revert to said molten iron.
Claim 11
Independent Claim
94 words
A method of fluidized a slag, comprising: providing a blast furnace slag covering a molten iron, preparing an acid flux containing a source of fluoride ion and complex sodium compound, mixing said acid flux with said slag to form a fluid treated slag, injecting a desulfurization agent into said molten iron, said treated slag containing at least about 1% by weight F - and at least about 1% by weight Na 2 O, removing said treated slag from said molten iron whereby sulfur in said treated slag does not revert to said molten iron.
Claim 12
Dependent Claim
26 words
The method of claim 8 wherein said treated slag further includes at least 2% by weight Na 2 O to remove impurities from said molten iron.
Claim 13
Independent Claim
119 words
A method of fluidizing a slag, comprising: providing a blast furnace slag covering a molten iron, the temperature of said molten iron no greater than about 1260° C., preparing an acid flux comprising a particulate admixture of sodium fluoroaluminate and sodium silicate, mixing said acid flux with said slag forming a fluid treated slag, injecting a desulfurization agent into said molten iron, removing said treated slag from said molten iron, said treated slag comprising at least about 1% F - , at least about 1% Na 2 O, 30-40% CaO, 30-40% SiO 2 , 10-15% MgO, 8-12% Al 2 O 3 , all percentages by weight, whereby sulfur in said treated slag does not revert to said molten iron.
Claim 14
Independent Claim
119 words
A method of fluidizing a slag, comprising: providing a blast furnace slag covering a molten iron, the temperature of said molten iron no greater than about 1260° C., preparing an acid flux comprising a particulate admixture of sodium fluoroaluminate and sodium silicate, mixing said acid flux with said slag forming a fluid treated slag, injecting a desulfurization agent into said molten iron, removing said treated slag from said molten iron, said treated slag comprising at least about 1% F - , at least about 1% Na 2 O, 30-40% CaO, 30-40% SiO 2 , 10-15% MgO, 8-12% Al 2 O 3 , all percentages by weight, whereby sulfur in said treated slag does not revert to said molten iron.
Claim 15
Dependent Claim
18 words
The method of claim 10 wherein said treated slag has a melting point of at least 1169° C.
Claim 16
Dependent Claim
30 words
The method claim 10 wherein said admixture includes one or more materials from the group consisting essentially of recycled aluminum pot lining, recycled bottle glass, silicon, silica, aluminum, and alumina.
Claim 17
Dependent Claim
30 words
The method of claim 10 wherein said treated slag further includes 1-3% by weight F - and 2-4% by weight Na 2 O to remove impurities from said molten iron.
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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) | 1992-10-16 | 1993-04-17 | 1993-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-16 | 1997-04-17 | 1997-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-16 | 2001-04-17 | 2001-10-17 | $7700.00 | Window Closed / Lapsed |