CA1193843A - Method of preparing a vessel for treatment of liquid metal therein - Google Patents
Method of preparing a vessel for treatment of liquid metal thereinInfo
- Publication number
- CA1193843A CA1193843A CA000465710A CA465710A CA1193843A CA 1193843 A CA1193843 A CA 1193843A CA 000465710 A CA000465710 A CA 000465710A CA 465710 A CA465710 A CA 465710A CA 1193843 A CA1193843 A CA 1193843A
- Authority
- CA
- Canada
- Prior art keywords
- vessel
- nozzle
- block
- tuyere
- gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
ABSTRACT
A method of preparing a bottom-pour vessel for subsurface gas treatment through a nozzle well in its bottom wall is disclosed. The vessel has a refractory lining and the method includes the steps of inserting a dense refractory nozzle block into the nozzle well, heating the vessel to its operating temperature, fixing a dual concentric tuyere having a central conduit and an outer annular conduit in the nozzle block, fixing a nozzle closure apparatus to the exterior of the vessel and connecting the conduits each to a separate source of gas.
Upon completion of the metallurgical treatment process the tuyere may be removed from the nozzle well leaving a pouring opening controllable by the nozzle closure apparatus.
A method of preparing a bottom-pour vessel for subsurface gas treatment through a nozzle well in its bottom wall is disclosed. The vessel has a refractory lining and the method includes the steps of inserting a dense refractory nozzle block into the nozzle well, heating the vessel to its operating temperature, fixing a dual concentric tuyere having a central conduit and an outer annular conduit in the nozzle block, fixing a nozzle closure apparatus to the exterior of the vessel and connecting the conduits each to a separate source of gas.
Upon completion of the metallurgical treatment process the tuyere may be removed from the nozzle well leaving a pouring opening controllable by the nozzle closure apparatus.
Description
3~1L3 This is a division of co~only assigned ~n~ n Paten-t A~plication Serial No. 412,859 flled October 5, 1982.
BACXGROUN~ OF THE I~VENTION
The present invention relates to the treating of liquid metal in a refining or holdin~ vessel by injection of gas through the pouring outlet in the bottom wall of the vessel, which outle~ is controlled by a slidable ga~e closure mechanism. This invention ~s particularly applicable to the refining of steel in a ladle or other holding vessel.
It is Xnown that various metal refining treatments may be carried out in a vessel by the underbath injection of a gas through the side wall or bottom wall of the vessel. Such treatments inclllde desulfurizing, dephosphorizlng, deoxidation, and making alloy addi*lons~ Heretofore,however,any required piping remained with the vessel and was not detachable therefrom upon completion of the metallurgical treatment.
A common method of injecting a treating gas into a liquid metal bath is through a porous plug in the bottom wall of the vessel. Gas will pass through the interstices of the porous plug into the bath, but molten metal will not pass through the plu~.
Very high pressures are required to force sufficient quantities of gas through the plug ~o accomplish the desired treatment. The present invention avoids the problems inherent in the use of porous plugs ~3~
SUMMARY O~ TE-IE INVENTIOM
The present invention relates to a method of preparing a bottom-pour vessel for subsurface gas treat-ment through a nozzle well in its bot-tom wall. The method includes the utilization of a removable underbath tuyere for injection of the treating gases -through the pouring opening oE the vessel and the utilization of a slidable gate-type nozzle closure mechanism. The tuyere or blowing nozzle is a dual concentric pipe, the central passageway of which is adapted for blowing a treating material therethrough, and the outer annular passageway of which is adapted for blowing a coolant therethrough to prevent deterioration of ~-he pipe duiing the trea~ilg period. The tuyere extends through the pouring opening in the slidable gate, and is anchored in a refractory tuyere block fixed in the nozzle well.
Upon completion ol the metallurgical treatment the tuyere and a portion of the tuyere block are remove~
from the nozzle well leaving a pouring opening controllahle by the slidable gate.
Suitable slidable gate closure ~echanisms are shown in Shapland U.S. Patent 3,501,068 issued March 17, 1970.
BACXGROUN~ OF THE I~VENTION
The present invention relates to the treating of liquid metal in a refining or holdin~ vessel by injection of gas through the pouring outlet in the bottom wall of the vessel, which outle~ is controlled by a slidable ga~e closure mechanism. This invention ~s particularly applicable to the refining of steel in a ladle or other holding vessel.
It is Xnown that various metal refining treatments may be carried out in a vessel by the underbath injection of a gas through the side wall or bottom wall of the vessel. Such treatments inclllde desulfurizing, dephosphorizlng, deoxidation, and making alloy addi*lons~ Heretofore,however,any required piping remained with the vessel and was not detachable therefrom upon completion of the metallurgical treatment.
A common method of injecting a treating gas into a liquid metal bath is through a porous plug in the bottom wall of the vessel. Gas will pass through the interstices of the porous plug into the bath, but molten metal will not pass through the plu~.
Very high pressures are required to force sufficient quantities of gas through the plug ~o accomplish the desired treatment. The present invention avoids the problems inherent in the use of porous plugs ~3~
SUMMARY O~ TE-IE INVENTIOM
The present invention relates to a method of preparing a bottom-pour vessel for subsurface gas treat-ment through a nozzle well in its bot-tom wall. The method includes the utilization of a removable underbath tuyere for injection of the treating gases -through the pouring opening oE the vessel and the utilization of a slidable gate-type nozzle closure mechanism. The tuyere or blowing nozzle is a dual concentric pipe, the central passageway of which is adapted for blowing a treating material therethrough, and the outer annular passageway of which is adapted for blowing a coolant therethrough to prevent deterioration of ~-he pipe duiing the trea~ilg period. The tuyere extends through the pouring opening in the slidable gate, and is anchored in a refractory tuyere block fixed in the nozzle well.
Upon completion ol the metallurgical treatment the tuyere and a portion of the tuyere block are remove~
from the nozzle well leaving a pouring opening controllahle by the slidable gate.
Suitable slidable gate closure ~echanisms are shown in Shapland U.S. Patent 3,501,068 issued March 17, 1970.
- 2 -kh/; ~
~4 ~ ~ ~ ~
BRIEF DESCRIPTION OF THE DRAWINGS
This invention is better understood by referring to the following detailed description and the appended drawings, in which:
Figure 1 is a vertical cross-section of a hot metal vessel taken through the pouring opening and showing the gas injection apparatus in place.
Figure 2 is a vertical cross-section of a portion of Figure 1 on a larger scale.
Figure 3 is a plan view of a portion of the vessel depicted in Figure 2 showing the nozzle well and gas injection à pparatus.
DETAILED DESCRIPTION
As shown in Figure 1, vessel or ladle 10 having a steel shell 12 is lined with refractory 14 and has a pouring opening in its bottom wall. Situated within the pouring opening is a no~zle block 16 which is made of a dense, wear-resistant refractory.
Central to the nozzle block is a vertical opening in which a refractory tuyere block 18 is positioned. Both the nozzle block 16 and the tuyere block 18 are held in posi~ion by a mortar. The nozzle block 16 is preferably tapered downwardly a~ surface 20 toward the pouring opening. Tuyere block 18 has a central orifice in which a central dual concentric tuyere is sîtuated. The tuyere consists of an outer metal pipe 24 and an inner or central metal ~: LS938~3 pipe 26 spaced from the outer pipe by any convenient spacing means to form an annular spac~ 28 between the pipes. The lower interior portion of tuyere block lS is preferably provided with an internal relief indicated at 30, which begins in the region of intersection of the extended line of the tapered surface 20 with the center of the tuyere block. A fixed refractory re~aining plate 32 engages the bottom of the tuyere block 18 to hold it in the operati~e position.
A slidable gate closure mechanism affixed beneath the pouring opening consists of a slidable refractory plate 34 having an open position and a closed position, means for operating the gate such as a pneumatic or hydraulic cylinder 36 attached to plate 34, and suitable suppor~ing means, not shown. Optionally, a pouring nozzle 39 may be attached to the bottom of the sliding gate to mini~ize splash and spatter during the pouring operation.
Valve 40 connects outer tuyere pipe 24 to an external source ~; of coolant 42, and alternatively to an external source of oxygen 44.
Central tuyere pipe 26 is connected through valve 50 to oxygen source 52, to a source of inert gas 54, and to the source 56 of treating material. The treating material can be a solid addition in a carrier ~as, a liquid or any desired treating gas.
The outer tuyere pipe ~4 is tightly cemented in~o the tuyere block 18 only at the top where there is no inner relief.
In operation the nozzle block 16 is rammed into place in the vessel lining 14 while the vessel is cold. The vessel is ~hen heated to operating tempcrature by using conventional vessel preheaters, after which the tuyere block 18 con~aining ~he tuyere pipes 24 and 26 is placed into the nozzle brick and cemented into place from the bottom of the vessel. The refractory suppor~ plate ~3~3 32 is fastened into position ~o retain the tuyere block in ~he blowing position, after which the sliding gate closure apparatus is installed. If desired, a moldable refractory such as gunnite can be placed in region 58 around the tip of the tuyere block within the furnace. The pipes 24 and 26 are connected to the sources of gas supply, flow of a cooling gas from source 42 is initiated through annulus 28. Inert gas from source 54 is started through the central tuyere pipe 26, then liquid me~al is poured into the vessel. Once the metal in the vessel reaches the required level, approximately 70~ of the full level, then the gas trea~ment commences. Normally oxygen will be blown through the central pipe and cooling gas through the outer annulus. At the end of ~he treatment oxygen is fed ~hrough both the central pipe 26 and the annular space 28. The oxygen reacts wi~h the hot metal ~o burn the pipes back into the tuyere blook and along with it the tip of the refractory tuyere block. When ~he tuyere block is burnt back as far as the annular relief 30, tuyere pipes 24 and 26 are no longer connected to the tuyere block 1~, whereupon they are wi~hdrawn and the sliding gate 34 is ~ctivated to close the pouring nozzle.
At this time the vessel is ready for further handling or treatment, such as vacuum degassing, decanting, transport, or cas~ing.
The following is an example of making stainless steel in a ladle utilizing the above-described inYention. In this case, the refractory lining of the ladle. was magnesite containing in excess of 95% MgO. The nozzle block and the tuyere block were also made of plus 95~ MgO magnesite. Tuyere pipes 24 and 26 were made of low-carbon steel. The cooling gas rom source 42 was carbon ~ioxide and the treating gas from source 56 was an oxygen-carbon dioxide mixture. Sixteen tons of liquid steel containing Z0~
chromium,8% nickel and 1.3% carbon were poured into the ladle, which had the invented apparatus situated in its pouring nozzle.
The oxygen-carbon dioxide mixture was blown in~o the molten metal for sixty minutes, followed by an inert gas~o2 mixture for a short `
period, after which time the carbon content had been reduced to 0.005%. A mixture of finely divided lime and fluorspar was then injected into the molten metal along with oxygen to desulfuri~e and dephosphorize the metal. Oxygen alone was then blown ~hrough both the central pipe 26 and the annular space 28 to burn back the tuyere pipes and tuyere block to recess 30. The tuyere pipes were removed and the slide gate 34 was immediately closedO The ladle was then transported to a vacuum degassing station after which the steel was cast into ingots. The resulting steel was a chromium-containing stainless steel having a composi~ion of 18 chrome, 8 nickel stainless steel.
SUMMARY OF THE ACHIEVEMENT
OF THE OBJECTS OF THE INVENTION
From the foregoing, it is readily apparent that the present invention provides a method and apparatus for metallurgically treating molten metal in a refining or holding vessel by injection of treating material through the sub-surface pouring nozzle.
~ ~!
~4 ~ ~ ~ ~
BRIEF DESCRIPTION OF THE DRAWINGS
This invention is better understood by referring to the following detailed description and the appended drawings, in which:
Figure 1 is a vertical cross-section of a hot metal vessel taken through the pouring opening and showing the gas injection apparatus in place.
Figure 2 is a vertical cross-section of a portion of Figure 1 on a larger scale.
Figure 3 is a plan view of a portion of the vessel depicted in Figure 2 showing the nozzle well and gas injection à pparatus.
DETAILED DESCRIPTION
As shown in Figure 1, vessel or ladle 10 having a steel shell 12 is lined with refractory 14 and has a pouring opening in its bottom wall. Situated within the pouring opening is a no~zle block 16 which is made of a dense, wear-resistant refractory.
Central to the nozzle block is a vertical opening in which a refractory tuyere block 18 is positioned. Both the nozzle block 16 and the tuyere block 18 are held in posi~ion by a mortar. The nozzle block 16 is preferably tapered downwardly a~ surface 20 toward the pouring opening. Tuyere block 18 has a central orifice in which a central dual concentric tuyere is sîtuated. The tuyere consists of an outer metal pipe 24 and an inner or central metal ~: LS938~3 pipe 26 spaced from the outer pipe by any convenient spacing means to form an annular spac~ 28 between the pipes. The lower interior portion of tuyere block lS is preferably provided with an internal relief indicated at 30, which begins in the region of intersection of the extended line of the tapered surface 20 with the center of the tuyere block. A fixed refractory re~aining plate 32 engages the bottom of the tuyere block 18 to hold it in the operati~e position.
A slidable gate closure mechanism affixed beneath the pouring opening consists of a slidable refractory plate 34 having an open position and a closed position, means for operating the gate such as a pneumatic or hydraulic cylinder 36 attached to plate 34, and suitable suppor~ing means, not shown. Optionally, a pouring nozzle 39 may be attached to the bottom of the sliding gate to mini~ize splash and spatter during the pouring operation.
Valve 40 connects outer tuyere pipe 24 to an external source ~; of coolant 42, and alternatively to an external source of oxygen 44.
Central tuyere pipe 26 is connected through valve 50 to oxygen source 52, to a source of inert gas 54, and to the source 56 of treating material. The treating material can be a solid addition in a carrier ~as, a liquid or any desired treating gas.
The outer tuyere pipe ~4 is tightly cemented in~o the tuyere block 18 only at the top where there is no inner relief.
In operation the nozzle block 16 is rammed into place in the vessel lining 14 while the vessel is cold. The vessel is ~hen heated to operating tempcrature by using conventional vessel preheaters, after which the tuyere block 18 con~aining ~he tuyere pipes 24 and 26 is placed into the nozzle brick and cemented into place from the bottom of the vessel. The refractory suppor~ plate ~3~3 32 is fastened into position ~o retain the tuyere block in ~he blowing position, after which the sliding gate closure apparatus is installed. If desired, a moldable refractory such as gunnite can be placed in region 58 around the tip of the tuyere block within the furnace. The pipes 24 and 26 are connected to the sources of gas supply, flow of a cooling gas from source 42 is initiated through annulus 28. Inert gas from source 54 is started through the central tuyere pipe 26, then liquid me~al is poured into the vessel. Once the metal in the vessel reaches the required level, approximately 70~ of the full level, then the gas trea~ment commences. Normally oxygen will be blown through the central pipe and cooling gas through the outer annulus. At the end of ~he treatment oxygen is fed ~hrough both the central pipe 26 and the annular space 28. The oxygen reacts wi~h the hot metal ~o burn the pipes back into the tuyere blook and along with it the tip of the refractory tuyere block. When ~he tuyere block is burnt back as far as the annular relief 30, tuyere pipes 24 and 26 are no longer connected to the tuyere block 1~, whereupon they are wi~hdrawn and the sliding gate 34 is ~ctivated to close the pouring nozzle.
At this time the vessel is ready for further handling or treatment, such as vacuum degassing, decanting, transport, or cas~ing.
The following is an example of making stainless steel in a ladle utilizing the above-described inYention. In this case, the refractory lining of the ladle. was magnesite containing in excess of 95% MgO. The nozzle block and the tuyere block were also made of plus 95~ MgO magnesite. Tuyere pipes 24 and 26 were made of low-carbon steel. The cooling gas rom source 42 was carbon ~ioxide and the treating gas from source 56 was an oxygen-carbon dioxide mixture. Sixteen tons of liquid steel containing Z0~
chromium,8% nickel and 1.3% carbon were poured into the ladle, which had the invented apparatus situated in its pouring nozzle.
The oxygen-carbon dioxide mixture was blown in~o the molten metal for sixty minutes, followed by an inert gas~o2 mixture for a short `
period, after which time the carbon content had been reduced to 0.005%. A mixture of finely divided lime and fluorspar was then injected into the molten metal along with oxygen to desulfuri~e and dephosphorize the metal. Oxygen alone was then blown ~hrough both the central pipe 26 and the annular space 28 to burn back the tuyere pipes and tuyere block to recess 30. The tuyere pipes were removed and the slide gate 34 was immediately closedO The ladle was then transported to a vacuum degassing station after which the steel was cast into ingots. The resulting steel was a chromium-containing stainless steel having a composi~ion of 18 chrome, 8 nickel stainless steel.
SUMMARY OF THE ACHIEVEMENT
OF THE OBJECTS OF THE INVENTION
From the foregoing, it is readily apparent that the present invention provides a method and apparatus for metallurgically treating molten metal in a refining or holding vessel by injection of treating material through the sub-surface pouring nozzle.
~ ~!
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of preparing a bottom-pour vessel for subsurface gas treatment through a nozzle well in its bottom wall, said vessel having a refractory lining, said method comprising:
1) inserting a dense refractory nozzle block into the nozzle well within the lining of the vessel and mortaring it into place while the vessel is at ambient temperature;
1) inserting a dense refractory nozzle block into the nozzle well within the lining of the vessel and mortaring it into place while the vessel is at ambient temperature;
2) heating the vessel to operating temperature;
3) inserting a tuyere block into the opening in said nozzle block from the bottom of said vessel and mortaring said tuyere block into position, said tuyere block comprising a refractory brick adapted to fit into the opening in said nozzle block and having a central vertical hole therethrough, an outer pipe fixed in the vertical hole in said tuyere block, its upper end terminating at the upper end of said block and its lower end extending beyond the lower end of said block, and an inner pipe within said outer pipe, its upper end coextensive with said outer pipe and its lower end extending beyond the lower end of said block, said inner pipe carrying projections on its outer surface to form an annular conduit between said inner and outer pipe;
4) fixing a nozzle closure apparatus to the exterior of said vessel in the nozzle-open position with said pipes extending from the nozzle block downwardly through the nozzle opening; and
5) connecting said inner pipe to a first source of gas and connecting the annular conduit to a second gas source.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US308,701 | 1981-10-05 | ||
| US06/308,701 US4424955A (en) | 1981-10-05 | 1981-10-05 | Apparatus for treating liquid metal in a vessel |
| CA000412859A CA1198900A (en) | 1981-10-05 | 1982-10-05 | Method and apparatus for treating liquid metal in a vessel |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000412859A Division CA1198900A (en) | 1981-10-05 | 1982-10-05 | Method and apparatus for treating liquid metal in a vessel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1193843A true CA1193843A (en) | 1985-09-24 |
Family
ID=25669829
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000465710A Expired CA1193843A (en) | 1981-10-05 | 1984-10-17 | Method of preparing a vessel for treatment of liquid metal therein |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1193843A (en) |
-
1984
- 1984-10-17 CA CA000465710A patent/CA1193843A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4638980A (en) | Apparatus and method for maintaining the temperature of molten metal | |
| US4421257A (en) | Metal pouring nozzle with gas inlet | |
| US3825241A (en) | Apparatus for introducing gas to hot metal in a bottom pour vessel | |
| US4736930A (en) | Closure apparatus for a tap hole | |
| KR100287568B1 (en) | Method and apparatus for decarburizing steel melt | |
| US4424955A (en) | Apparatus for treating liquid metal in a vessel | |
| US2956794A (en) | Method and means for blowing gases containing possibly pulverulent material into a bath of molten metal | |
| US4555266A (en) | Method and apparatus for treating liquid metal in a vessel | |
| FR2523007B1 (en) | ||
| US3971547A (en) | Apparatus and method for refining metal | |
| CA1193843A (en) | Method of preparing a vessel for treatment of liquid metal therein | |
| US3897048A (en) | Metallurgical vessel and method of operating same | |
| US4311518A (en) | Homogenization of metal using gas | |
| JPH02501148A (en) | Method for heating molten steel contained in a ladle | |
| US3380509A (en) | Method of pressure treatment of metallic melts, especially steel melts | |
| US4394165A (en) | Method of preliminary desiliconization of molten iron by injecting gaseous oxygen | |
| US5016788A (en) | Pouring spout for servo-assisted opening, device incorporating it and implementation process | |
| DE3369259D1 (en) | Device for the metallurgical treatment of liquid metals | |
| US3819842A (en) | Method and furnace for maintaining the temperature level of metal melts | |
| RU222996U1 (en) | Tundish for continuous steel casting plant | |
| WO1991019012A1 (en) | A method of manufacturing compacted graphite cast iron | |
| KR100327288B1 (en) | Plant and method of adjusting the composition of molten metal such as steel | |
| ES8405444A1 (en) | Method of and installation for emptying metallurgical vessels. | |
| JPS591055A (en) | Method for starting charging of molten steel without oxidation to continuous casting tundish | |
| SU1049171A1 (en) | Apparatus for blowing melt metal |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |