Claims
- 1. In a method of decreasing the content of undesired gasses in molten steel the steps comprising
- isolating molten steel having a content of undersired gasses and/or sources thereof from ambient atmosphere which, upon solidification, would result in an unacceptably high final content of said gasses from the atmosphere, whereby a non-atmospheric region is established above the molten steel,
- passing a purging agent upwardly through the molten steel from a location beneath the surface exposed to a non-atmospheric region,
- diverting gasses in the region above the molten steel to air ejector means at a rate sufficient to create a sub-atmospheric pressure in the region above the molten steel, and
- discharging the gasses drawn from the region above the molten steel, and additional gasses which may be added to the air ejector means, toward a baghouse containing bag means from the air ejector means at a temperature which is within the temperature tolerance range of the baghouse.
- 2. The method of claim 1 further comprising in that
- the purging agent is passed upwardly through the molten steel at least partially during the time the gasses in the region above the molten steel are diverted by said air ejector means.
- 3. The method of claim 1 further comprising in that
- the gasses diverted from the region above the molten steel, together with solids entrained therein, are passed through a cyclone separator whereby a portion of the entrained solids are removed.
- 4. The method of claim 3 further comprising in that
- the gasses diverted from the region above the molten steel are passed through the cyclone separator prior to their passage through the air ejector means.
- 5. The method of claim 1 further comprising in that
- the gasses discharged from the air ejector means are at a temperature no greater than about 225.degree. and at a pressure which is substantially atmospheric.
- 6. The method of claim 1 further comprising in that
- the gasses discharged from the air ejector means are passed through a baghouse whereby at least a portion of the solids entrained in said gasses as said gasses leave the air ejector means are removed in said baghouse.
- 7. The method of claim 6 further comprising in that
- a pressure differential across the baghouse is applied by means in the flow path of the gasses which is downstream from the air ejector means.
- 8. The method of claim 6 further comprising in that
- a pressure differential across the baghouse is applied by means in the flow path of the gasses which is downstream from the baghouse.
- 9. The method of claim 1 further comprising in that
- the molten steel is subjected to a heating arc.
- 10. The method of claim 9 further comprising in that
- the heating arc is derived from alternating current which is applied directly to the surface of the molten steel from electrode means.
- 11. The method of claim 10 further comprising in that
- the electrode means are selected from the group consisting essentially of three carbon-type electrodes or a single DC electrode.
- 12. The method of claim 1 further comprising in that
- the purging agent is passed upwardly through the molten steel during at least a portion of the time the gasses in the region above the molten steel are diverted from said region by said air ejector means.
- 13. The method of claim 12 further comprising in that
- the rate of gas purge is no less than about 10 scfm per gas purge admission point.
- 14. The method of claim 13 further comprising in that
- the number of gas purge admission locations vary with the quantity of molten steel being treated in the ratios of one gas admission location for up to about 50 short tons of steel, two gas admission locations for from about 50 to about 150 short tons, and three gas admission points for over about 150 short tons.
- 15. In a system for treating molten steel, said system comprising
- structure which forms a non-atmospheric region above molten steel,
- purging agent means located at a position beneath the upper surface of said molten steel,
- air ejector means connected to the non-atmospheric region above the molten steel capable of diverting gasses in said region and solids entrained in said gasses to a discharge point, and
- means for removing solids entrained in said gasses from said gasses prior to discharge of said gasses to the atmosphere.
- 16. The system of claim 15 further comprising in that
- the purging agent means includes means for admitting a purging agent to the molten steel at the rate of no less than about 10 scfm per purging agent admission location.
- 17. The system of claim 16 further comprising in that
- the purging agent admission locations are provided on the basis of one location for up to about 50 short tons of molten steel, two admission locations for from about 50 to about 150 short tons, and three admission locations for over about 150 short tons of molten steel.
- 18. The system of claim 15 further comprising in that
- the air ejector means are arranged to discharge gasses, and solids which may be entrained in said gasses, at a temperature within the temperature tolerance range of a baghouse, and
- the means for removing solids entrained in said gasses include a baghouse.
- 19. The system of claim 18 further comprising in that
- the means for removing solids entrained in said gasses further includes a cyclone separator,
- said cyclone separator being located in the flow path of the gasses at a location which is between the region of sub-atmospheric pressure above the molten steel and the air ejector means.
- 20. In a method of treating molten steel the steps comprising
- isolating the surface of the molten steel from ambient atmosphere,
- creating a sub-atmospheric pressure above the surface of the molten steel by air ejector means,
- passing a purging agent upwardly through the molten steel, and
- subjecting the molten steel to a heating arc.
Parent Case Info
This application is a continuation-in-part of Ser. No. 910,704, filed on Sept. 23, 1988, and now U.S. Pat. No. 4,780,134.
US Referenced Citations (3)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
910704 |
Sep 1988 |
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