CA2071373A1 - Method and arrangement for purging molten metal in a container with the aid of a gas - Google Patents
Method and arrangement for purging molten metal in a container with the aid of a gasInfo
- Publication number
- CA2071373A1 CA2071373A1 CA002071373A CA2071373A CA2071373A1 CA 2071373 A1 CA2071373 A1 CA 2071373A1 CA 002071373 A CA002071373 A CA 002071373A CA 2071373 A CA2071373 A CA 2071373A CA 2071373 A1 CA2071373 A1 CA 2071373A1
- Authority
- CA
- Canada
- Prior art keywords
- nozzle
- gas
- container
- molten metal
- metal
- 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.)
- Abandoned
Links
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Abstract
A B S T R A C T
In the purging and agitation of molten metal carried in a ladle by injecting a pressurized gas into the molten metal through the intermediary of a nozzle mounted on the wall or on the bottom of the container, there is proposed a method for clearing the nozzle of blockages that are caused by molten metal being drawn into the nozzle-throughflow passage immediately the flow of pressurized gas is cut-off, and freezing on the walls of the nozzle to form a blockage. The inventive method is characterized by passing an electric current through at least part of the nozzle at the same as the supply of pressurized gas is switched on, such as to heat and therewith at least partially melt the metal blockage in the throughflow passage of the nozzle, this at least partially melted metal blockage being forced from the passage by the pressurized gas flowing therethrough.
In the purging and agitation of molten metal carried in a ladle by injecting a pressurized gas into the molten metal through the intermediary of a nozzle mounted on the wall or on the bottom of the container, there is proposed a method for clearing the nozzle of blockages that are caused by molten metal being drawn into the nozzle-throughflow passage immediately the flow of pressurized gas is cut-off, and freezing on the walls of the nozzle to form a blockage. The inventive method is characterized by passing an electric current through at least part of the nozzle at the same as the supply of pressurized gas is switched on, such as to heat and therewith at least partially melt the metal blockage in the throughflow passage of the nozzle, this at least partially melted metal blockage being forced from the passage by the pressurized gas flowing therethrough.
Description
- 2~7~ 3~3 Method ~n~ an~e,~en~ ~,o~ P~rgin~ g~ ~e~
Con~ er ~ he aid o~ ~ Gas.
The present lnvention is concerned with the delivery of a pressurized gas to a mol~en metal bath contained in a container, for the purpose of pur~ing and/or agitating the molt~n metal, in accordance with the preambls o~
Claim 1, and relates to a method of clearing the throughfl~w passage of a gas-delivery nozzle from the solid metal blockages that are liable to occur when the delivery of gas to ~he melt i~; stopped. The invention also relates to an ~rran~ement: acçording to the preamble of Claim 2 ~or carrying out the i~ventive method~
Ladles are used to tran~port and to treat molten metals in the steel, metal and ~erroalloyin~ industries. In order to the agitate and refine, or purge, the melt an inert gas, such as argon, is injected into the melt through the bottom of the ladle. Hitherto, this gas has been supplied through t~e intermediary of so-called purgin~ stones or porous plugs, su~h plugs either con-sisting of a ceramic porous body or a ceramic body which contain~ many very ~ine channels. ~he pores or channels -are so disposed in the plugs that while gas i~ able to pass through, thc molten material i~ unable to penetrate the pores or ~hannels.
Such porou~ plugs are encumbered with several drawbacks.
For example, it can be difficult to cause the plug~ to allow gas to pass therethrough while preventing ~olten metal or slag from enterin~ the pores or channels and freezing on the wall~ thereo~, so as to cause hlockages.
Furthermore, porou~ plugs place a limit on the gas-pressures that can be u~ed, whlch in turn places a limit on the volume of gas that can be injected into the melt.
2~ 3~3 secause of the success obtained with the u~e of nozzles or like devices in converters, it has been desirable to use nozzles for the purpose of injecting purging gas into molten metal contained in ladles, instead of the a~oresaid porous plu~s. Wh~n ~ttempting to replace poroUs plu~s with nozzles, it wa~ ~ound that immediately ~e supply o~ purging gas was interrupted or terminated, molten metal was drawn into the no~zle and ~roze onto the walls of the gas-throughflow passage, therewith lo causing a blockage. Attampts to re~ove thi~ ~rozen met~l plug have gene~ally ~ailed, meaning that the gas wa~
unable to flow through the nozzle. AS a resul~ of this problem, the u~e of nozzles in ladles ~or the a~oresaid purpose has not been pursued. It should be mentioned that this problem does not occur in conv~rters, because a converter can be tipped sideways when purging is not in progress, so that the nozzle opening or nozzle ori-~ice is 14cated above the surfa~e of the m~tal b~th.
Ths object of the present invention i~ ~o eliminat0 the afore~aid problems encountçred with the use o~ nozzles for injecting gases into ladle~, so as to ~nable the porou~ plug~ us~d hither~o ~o be replaced with noz~les.
Thi~ object is achieved ~ith the inventive method and the inventive arrangement, which have the characteris~c ~atures set forth in the charaaterizing clauses of respective method and apparatus claims.
30 The invention will no~ be described in more det~il with reference to two exemplifying embodiments of an inven-tive nozzl~ arrangement.
The inventive nozzle may, ~or example, be mounted on the 35 bottom o~ a ~ol~en metal container, such as a ladle, converter or the like. ~he nozzle is connected to a 2~7~.3~3 container which contains gas under hi~h pre~sure, through the intermediary o~ a valve which functions to c~ntrol the gas ~low and gas pressure.
~ccording to a first embodimen~ of the invention the noZzle, or a part of the no~zle, is compri~d of an electriaally conductive material of s~ch electrical resistance as to generate heat when a~ electric current i6 passed therethrough.
According to a second embodiment the nozzls includes a heating ~ire which i~ connected ~o a sour¢e of electric current and which i~ wound around the nozzle tube or around the region o~ the gas ~hroughflow passage, said tubç preferably being made of a ce~amic material. Pro-vided on ~he b~tto~ end o~ the nozzle i6 a screw-thræad-ed tuba for connection with a quick~couplin~ between the nozzle and the conduit or pipe leading to the ga6-flow control va~ve. The nozzle i~ surrounded by a body of cera~ic material. When injecting gas into the bath of molten metal, the valve of the ~as container is opened to allow ~a~ ~o pass ~rom the container ~hile, at the sam~ ~ime cau~ing ~n electria curr~n~ to be applied to the nozzle, such aæ to heat a~ th~ nozzl~ and therewith melt, or partially melt, the ~rozen metal plug in the nozzle tube or nozzlo thrDugh~low-passage.
This molten, or ~emi-molten me~al, will then b~ b~wn f~om the nozzle ~ube and into the metal bath by the pressurized gas en~ering the no2zle tube, and therewith enable the gas to pass freely throug~ the nozzle. Agita-tion and refinement of the molt~n metal can now take place. The croæs-~ectional area o~ ~he nozzle tube orifice is ~uitably from 0.2 to 15mm , pre~erably from 1.0 to 5.0 mm . When the nozzle is clear, i~e. un~
blocked/ the gas pressure will suitably lie in a range of from 5 t~ 250 barsl preferably from 10 to ~0 bars.
2~7~.3~3 It will be understand from the a~oregoing that when using nozzles ~o deli~er a purging gas ~o molten metal containQd in a ladle, the no~zle will become blocked by the mol~en m~tal which is dra~n into the noææle immedi-5 ately the supply of gas is aut-of-f, by closing the gas-f low control valve, thi~ molten metal ~reezing on the nozæle wall~; and forming a so:Lid plug. In accordance with the invention, when the valve is opened to allow pressurize~ gas to flow from the gas container an elec-~ric current is, at the same time, ~upplisd to thenozzle, which ~ubs~quently become~ hot enough to melt or at least partially melt t~s plug.
The fo~ce of the gas entering the n~zle is then su~fi-ci~nt to push the plug ~rom the noz~le and into the 15 molten metal bath. The gas pressure and ga~ ~low aan then be adjusted to values appropriate to gas-purging purpo~es and also to the geome~ry of the container, i.e.
the ladle or converter/
20 The arrange~ent also includes a monitoring means which monitors the state ~f gas through~low and which func-tions to switch o~f ~he supply o~ electric current to the nozzl~ w~en gas flows freely therethrough
Con~ er ~ he aid o~ ~ Gas.
The present lnvention is concerned with the delivery of a pressurized gas to a mol~en metal bath contained in a container, for the purpose of pur~ing and/or agitating the molt~n metal, in accordance with the preambls o~
Claim 1, and relates to a method of clearing the throughfl~w passage of a gas-delivery nozzle from the solid metal blockages that are liable to occur when the delivery of gas to ~he melt i~; stopped. The invention also relates to an ~rran~ement: acçording to the preamble of Claim 2 ~or carrying out the i~ventive method~
Ladles are used to tran~port and to treat molten metals in the steel, metal and ~erroalloyin~ industries. In order to the agitate and refine, or purge, the melt an inert gas, such as argon, is injected into the melt through the bottom of the ladle. Hitherto, this gas has been supplied through t~e intermediary of so-called purgin~ stones or porous plugs, su~h plugs either con-sisting of a ceramic porous body or a ceramic body which contain~ many very ~ine channels. ~he pores or channels -are so disposed in the plugs that while gas i~ able to pass through, thc molten material i~ unable to penetrate the pores or ~hannels.
Such porou~ plugs are encumbered with several drawbacks.
For example, it can be difficult to cause the plug~ to allow gas to pass therethrough while preventing ~olten metal or slag from enterin~ the pores or channels and freezing on the wall~ thereo~, so as to cause hlockages.
Furthermore, porou~ plugs place a limit on the gas-pressures that can be u~ed, whlch in turn places a limit on the volume of gas that can be injected into the melt.
2~ 3~3 secause of the success obtained with the u~e of nozzles or like devices in converters, it has been desirable to use nozzles for the purpose of injecting purging gas into molten metal contained in ladles, instead of the a~oresaid porous plu~s. Wh~n ~ttempting to replace poroUs plu~s with nozzles, it wa~ ~ound that immediately ~e supply o~ purging gas was interrupted or terminated, molten metal was drawn into the no~zle and ~roze onto the walls of the gas-throughflow passage, therewith lo causing a blockage. Attampts to re~ove thi~ ~rozen met~l plug have gene~ally ~ailed, meaning that the gas wa~
unable to flow through the nozzle. AS a resul~ of this problem, the u~e of nozzles in ladles ~or the a~oresaid purpose has not been pursued. It should be mentioned that this problem does not occur in conv~rters, because a converter can be tipped sideways when purging is not in progress, so that the nozzle opening or nozzle ori-~ice is 14cated above the surfa~e of the m~tal b~th.
Ths object of the present invention i~ ~o eliminat0 the afore~aid problems encountçred with the use o~ nozzles for injecting gases into ladle~, so as to ~nable the porou~ plug~ us~d hither~o ~o be replaced with noz~les.
Thi~ object is achieved ~ith the inventive method and the inventive arrangement, which have the characteris~c ~atures set forth in the charaaterizing clauses of respective method and apparatus claims.
30 The invention will no~ be described in more det~il with reference to two exemplifying embodiments of an inven-tive nozzl~ arrangement.
The inventive nozzle may, ~or example, be mounted on the 35 bottom o~ a ~ol~en metal container, such as a ladle, converter or the like. ~he nozzle is connected to a 2~7~.3~3 container which contains gas under hi~h pre~sure, through the intermediary o~ a valve which functions to c~ntrol the gas ~low and gas pressure.
~ccording to a first embodimen~ of the invention the noZzle, or a part of the no~zle, is compri~d of an electriaally conductive material of s~ch electrical resistance as to generate heat when a~ electric current i6 passed therethrough.
According to a second embodiment the nozzls includes a heating ~ire which i~ connected ~o a sour¢e of electric current and which i~ wound around the nozzle tube or around the region o~ the gas ~hroughflow passage, said tubç preferably being made of a ce~amic material. Pro-vided on ~he b~tto~ end o~ the nozzle i6 a screw-thræad-ed tuba for connection with a quick~couplin~ between the nozzle and the conduit or pipe leading to the ga6-flow control va~ve. The nozzle i~ surrounded by a body of cera~ic material. When injecting gas into the bath of molten metal, the valve of the ~as container is opened to allow ~a~ ~o pass ~rom the container ~hile, at the sam~ ~ime cau~ing ~n electria curr~n~ to be applied to the nozzle, such aæ to heat a~ th~ nozzl~ and therewith melt, or partially melt, the ~rozen metal plug in the nozzle tube or nozzlo thrDugh~low-passage.
This molten, or ~emi-molten me~al, will then b~ b~wn f~om the nozzle ~ube and into the metal bath by the pressurized gas en~ering the no2zle tube, and therewith enable the gas to pass freely throug~ the nozzle. Agita-tion and refinement of the molt~n metal can now take place. The croæs-~ectional area o~ ~he nozzle tube orifice is ~uitably from 0.2 to 15mm , pre~erably from 1.0 to 5.0 mm . When the nozzle is clear, i~e. un~
blocked/ the gas pressure will suitably lie in a range of from 5 t~ 250 barsl preferably from 10 to ~0 bars.
2~7~.3~3 It will be understand from the a~oregoing that when using nozzles ~o deli~er a purging gas ~o molten metal containQd in a ladle, the no~zle will become blocked by the mol~en m~tal which is dra~n into the noææle immedi-5 ately the supply of gas is aut-of-f, by closing the gas-f low control valve, thi~ molten metal ~reezing on the nozæle wall~; and forming a so:Lid plug. In accordance with the invention, when the valve is opened to allow pressurize~ gas to flow from the gas container an elec-~ric current is, at the same time, ~upplisd to thenozzle, which ~ubs~quently become~ hot enough to melt or at least partially melt t~s plug.
The fo~ce of the gas entering the n~zle is then su~fi-ci~nt to push the plug ~rom the noz~le and into the 15 molten metal bath. The gas pressure and ga~ ~low aan then be adjusted to values appropriate to gas-purging purpo~es and also to the geome~ry of the container, i.e.
the ladle or converter/
20 The arrange~ent also includes a monitoring means which monitors the state ~f gas through~low and which func-tions to switch o~f ~he supply o~ electric current to the nozzl~ w~en gas flows freely therethrough
Claims (6)
1. In the injection of pressurized gas into a molten metal bath contained in a container through the interme-diary of a gas-delivery nozzle, for the purpose of agitating and purging the molten metal, said nozzle being mounted on the wall or on the bottom of said container, A method for clearing said nozzle of block-ages that are caused by molten metal being drawn into the nozzle-throughflow passage immediately the flow of pressurized gas is cut off and freezing on the walls of said nozzle to form a blockage, c h a r a c-t e r i z e d by heating the nozzle with the aid of an electric current to a temperature at which the metal blockage will at least partially melt and therewith be removed from the nozzle throughflow passage by the gas which then passes through said nozzle.
2. An arrangement for carrying out the method accord-ing to Claim 1, comprising a container for gas under high pressure, a molten metal container, a nozzle, and a valve which is incorporated in a conduit extending between the nozzle and the gas container, c h a r a c-t e r i z e d in that the nozzle is connected to a source of electric current; and in that when current is applied to the nozzle the arrangement is such as to at least partially melt any metal that may have solidified in the nozzle throughflow passage.
3, An arrangement according to Claim 2, c h a r a c -t e r i z e d in that at least a part of the nozzle is comprised of an electrically conductive material of a kind which will be heated by the current passing there-through.
4. An arrangement according to Claim 2 of Claim 3, c h a r a c t e r i z e d in that the nozzle carries an electric heating fire.
5. An arrangement according to Claim 4, c h a r a c-t e r i z e d in that the heating wire is wound around the through-flow passage of the nozzle.
6. An arrangement according to any one of the preced-ing Claims, c h a r a c t e r i z e d by means for switching off the supply of electric current when the gas flows freely through the nozzle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002071373A CA2071373A1 (en) | 1992-02-16 | 1992-02-16 | Method and arrangement for purging molten metal in a container with the aid of a gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002071373A CA2071373A1 (en) | 1992-02-16 | 1992-02-16 | Method and arrangement for purging molten metal in a container with the aid of a gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2071373A1 true CA2071373A1 (en) | 1993-08-17 |
Family
ID=4150029
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002071373A Abandoned CA2071373A1 (en) | 1992-02-16 | 1992-02-16 | Method and arrangement for purging molten metal in a container with the aid of a gas |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2071373A1 (en) |
-
1992
- 1992-02-16 CA CA002071373A patent/CA2071373A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |