CA1243844A - Method and agents for producing clean steel - Google Patents
Method and agents for producing clean steelInfo
- Publication number
- CA1243844A CA1243844A CA000500936A CA500936A CA1243844A CA 1243844 A CA1243844 A CA 1243844A CA 000500936 A CA000500936 A CA 000500936A CA 500936 A CA500936 A CA 500936A CA 1243844 A CA1243844 A CA 1243844A
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- Prior art keywords
- ladle
- compound
- steel
- lbs
- aluminum
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
A method for producing exceptionally clean steel wherein desulphurization agents are added to the tap ladle during the first one-third volume of steel tapped and then adding a reduced amount of a deoxidizing agent and then adding slag conditioner agents when one-half of the volume of steel is tapped and then adding an expandable ladle cover compound when substantially two-thirds of the volume of steel is tapped. Argon is then blown through the steel at a rate sufficient to create a bubbling action and finally a deoxi-dizing agent is added when the final volume of steel has been tapped.
A method for producing exceptionally clean steel wherein desulphurization agents are added to the tap ladle during the first one-third volume of steel tapped and then adding a reduced amount of a deoxidizing agent and then adding slag conditioner agents when one-half of the volume of steel is tapped and then adding an expandable ladle cover compound when substantially two-thirds of the volume of steel is tapped. Argon is then blown through the steel at a rate sufficient to create a bubbling action and finally a deoxi-dizing agent is added when the final volume of steel has been tapped.
Description
` lZ~3~34~
~ETHOD AND AGE,NTS FO~ PE~ODUC~NG CLEA~I STI:EL.
Background of the Invention Technical Field:
This invention rela-tes to a method and agents Eor pro-ducing exceptionally clean s-teel ~or continuous casting and the like.
Description oC the Prior Art:
The prior art me-thods and agents heretoEore used Eor the cleansing oE steel of non-metallic inclusions are represented by U.S. Paten-ts 2,Z21,784, 4,036,635, 4 J Z17,134, 4,238,227 and 4,290,173.
Patent 2,221,784 discloses the use of additive agents containing silicon, calcium, aluminum and at least one metal selected from the group consisting of titanium and zirconium, the additive being added -to the molten steel in the ladle.
Patent 4,036,635 discloses a steel melt formed under an iron oxide containing slag held back while the steel mel-t is tapped and subjected to deoxidation with silicon or aluminum plus an af-ter treatment with a calcium containing substance such as calcium silicon or calcium carbide.
Patent 4,217,134 discloses -the use of compositions ,~
~2~3~
comprising lime, fluorspar, ancl ground a:Luminum used in a method of desulphurizing molten s-teel by adding the composi-tions to the steel in -the :Ladle or injec-ting the composition in particulate form in-to the molten s-teel.
Paten-t No. 4,238,227 discloses the use of a high amoun-t of aluminum added -to the tap ladle be:Eore the -firs-t one-third volume of steel is tapped and -then adding conventional deoxidizers while the final two-thirds volume of steel is tapped. Argon gas is subsequently blown through -the steel.
Patent 4,490,173 disc]oses -the use of additi.ve composi-tions for flux solubilization, desulphuriza-tion and -the removal of inclusions. The addi-tive composition includes lime and a compound selected from the group consisting of bauxite and mix-tures of calcium alimunate and bauxite.
The present invention eliminates the several problems generally associated with the prior art methods and addi-tives used in at-tempting to produce a clean s-teel particularly suited for use in a continuous caster and incidentally reduces the amount of aluminum as a deoxidizing agent to approximately one-half of the amount heretofore believed :~Z~e3~34~
necessary.
Summary O e the Invent.ion A method and agents for producing excep-tionally clean s-teel results in floa-ting all available non-me-tallic inclusions to the surface of the s-teel being treated in a ladle where they engage and are absorbed by a ladle covering compound,as disclosed in my Paten-t 4,462,834,which contains burnt lime, aluminum dross, fluorspar, and acid -treated graphite. The method begins when the steel is first poured into the ladle from the source, such as a conver-ter, electric furnace, etc.,at which time a desulphurizing composi-tion is added simultaneously with the molten steel; the desulphurizing material comprising calcium eluoride, sodium carbona-te, and calcium hydroxide J
followed by the addition of a deoxidizing agent when about one-third of the volume of steel has been added to the ladle, the deoxidizing agent comprising metallic aluminum; this is followed by the addition of a slag conditioning composition when the ladle is approximately oDe-half full, the slag conditioning composition comprising calcium oxide and calcium and aluminum in an alloy including a small percentage of magnesium, adding an expandable ladle cover and immediately followed by the in-troducti.on of ~rgon gas into the lower portion of -the mel-t in suf-ficien-t volume and a-t a rate of introduction sufficien-t to cause desirable turbulence in -the mol-ten metal comprising the melt. The final step in the method is the addition of a fina~ deoxidizing additive comprising metallic aluminum. The -total amount of metallic aluminum as deoxidizing agents introduced in separate and dis-tinc-t s-teps is approxi-mately one-half the amount of metallic aluminum heretofore believed necessary in deoxidizing mol-ten s-teel.
Description of the Preferred Embodiment Those skilled in the art relating to producing steel will recognize the desirable resul-ts of the presen-t invention which produces exceptionally clean steel which may be any grade of steel with -the leas-t non-metallic content. The method is preferably practiced in a ladle to which molten steel from a conventional source, such as a converter, electric ~urance and the like, is tapped. The ladle may be of any size from 30 tons -to 300 tons capacity and the s-teel intro-duced into the ladle may beat 3000F. or it may vary 200 F.
ei-ther way.
3~
The firs-t step of the method disclosed herein comprises the positioning in -the l.adle O:e a desulphurizing agent comprising a first additi.ve compound consisting of equal amounts of calcium fluoride, sodium carbonate, and calcium hydroxide followed by the in-troduction of molten s-teel in-to the ladle or alternately addi.ng the :Eirst additive compound -to the first s-teel introduced in-to the ladle. The second step in the method is performed when the ladle is half full of molten s-teel and comprises the introduction of a second additive consisting of one-half of the normal metallic aluminum additi.on used in deoxidizing steel together with the addition of a third addi-tive comprising a slag condition-ing compound consisting of equal amounts of calcium oxide and calcium and an aluminum alloy comprising 95% aluminum and 5% magnesium. The fourth step in the method comprises -the addition of an expandable ladle cover w~ich includes burnt lime, aluminum dross, fluorspar, and acid treated graphite-which forms a slag-like layer on the molten metal for absorbing the non-metallic inclusions,simul-taneously creating a stirring and/or similar desirable turbulence in -the ~Z43~
molten metal as by the injec-tion Oe Argon gas -through a bottom ladle plug replacement or a hollow re-Eractory lance, the amount and rate of fiow of -the ~rgon gas being sufficient -to result in the desired turbulence. The introduction Oe -the metallic aluminum addi-tive and the slag conditioning compound results in a chemical reaction tha-t forces the aluminum to disperse to -the ultimate degree withou-t becoming alloyed -to ei-ther the free floating molten refractory in -the molten steel or any of the soluable non-metallics that have been libera-ted from their various alloys.
Those skilled in the art will observe that the non-metallic inclusions normally found in molten steel may be traced to the refractory materia] present as a liner in the converter, electric furnace, etc. and/or the ladle in which the molten me-tal -is received.
Oxygen an,d sulphur in the molten metal are responsible for most of the non-metallic inclusions as sulphur is soluable in steel at all temperatures above the mel-ting point and oxygen is present in steels which are not comple-tely de-oxidized.The deoxidizers, such as aluminum, when added to the 38~
ladle form oxides wl-th the dissolved oxygen in the steel.
The introduc-tion o~ -the slag conditionirlg compound herein-be~ore se-t Eorth and the expanding ladle cover as hereinbe~ore set forth together with -the induced -turbulence forces chemically and physical con-tact of all of -the insoluable non-metallics and the -rree sulphur and free aluminum oxide to rise to the -top o-f the steel in the ladle and contact and be absorbed in the expanding ladle cover compound. The expanding ladle cover compound herein referred -to expands i-ts volume between 50% and 100% and this expansion of volume results in the absorption of the non-metallics that are forced -to the top o~ the molten s-teel by -the induced turbulence.
The products absorbed by the expanding ladle cover compound are held in the cover compound until the molten steel is removed irom the bo-t-tom of the ladle and they do not revert into the molten metal.
The materials in the first additive comprising the calcium fluroide, the sodium carbonate, and the calcium hydroxide are present in equal amounts, the amount o~ each ingredient being between 5 lbs. and 15 lbs. per -ton of molten ~3~
s-teel. The metallic aluminum added when -the ladle is hal~
full is approximately one-fourth the amount o~ aluminum used as a deoxidizer in the prior art. It is the usual prac-tice of adding deoxidizers such as aluminum during tapping to control the amount of aluminum in direct portion to the steel's oxygen conten-t. Since -the oxygen content of the liquid steel is not usually measured, -the aluminum addition is usually de-ter~ined approximately in inverse propora-tion to the carbon content. A curve relating total product oxygen and carbon conten-t oE the liquid steel has been used to determine the optimum amoun-t of aluminum needed to react with the particularly amount of oxygen a-t each carbon content, for example, molten s-teel having a carbon content of 0.10%
is usually treated with 165 lbs. of aluminum per 100 tons of i5 steel or approximately one and three-quarter lbs. per ton.
In practicing the present invention, the amount of metallic aluminum added to the ladle when the same is one-third full and after adding the desulphurizing compound may be an amount between three-quarter of a lb. and one and one-quarter lbs. per ton of molten steel.
~29~3~4~
The second addi.tive compound comprising -the slag conditioner which is added to the ladle immedia-tely af-ter the metallic aluminum or when the ladle is half full comprises the calcium oxide and calcium in equal amounts and wherein -the amount - 5 of each of -the ingredien-ts is between 5 and 15 lbs. per -ton of molten metal. The introduction o~ ~rgon gas in suiflcient quan-tities and at a ra-te to create a desirable turbulence and/or stirring motion of the molten me-tal results in a chemical reaction that forces the me-tallic aluminum to disperse the ultimate degree withou-t becoming alloyed to either the free -Floa-ting molten refrac-tory or any of the insoluable non-metallics tha-t have been liberated from their various alloys in the steel.
Those skilled in -the art will observe that the desulphurizer compound plus the slag conditioner and -the metallic aluminum -to which any other required alloys needed to meet the desired aim chemistry are all in the molten bath and the same is slag--Cree or containsaminimum amount o~ furnace slag and that the expanding ladle cover compound over the complete mol-ten bath forces chemical and physical contact of all of the insol.uable ~2~31~44 non-metallics ancl the Eree sulphu:r and -the Eree meta:llic aluminum tha-t are being subjec-ted to -the turbul.ence to rise to the -top o-~ -the steel ba-th and come in con-tact and be absorbed by the expancling ladle cover compound.
Those skilled in the ar-t will recognize that the cleansing o:E -the steel requires time and temperature control as -the additives cause a rapid heat 105s over an extended period oE time during the tapping cycle which is the time i-t -takes for -the -Eurnace to discharge its molten metal in-to the receiving ladle.
The present invention enables a more accurate and complete control o-E the time of the cleaning cycle and therefore con-trols the temperature by preventing the otherwise rapid heat loss.
A-t a predetermined time and/or predetermined -temperat-ure, the ladle carrylng the clean steel is moved to a trim station and a small additional quantity oi metallic aluminum added as a final deoxidizing agent. The amount o~ the metallic aluminum Einally added to the molten s-teel at the trim station is an amount subs-tantially the same as -tha-t initially added and it will occur to those skilled in the art that the -to-tal ~2'~31~
of the metallic a:Luminum added in -the two s-tages is approxi-mately one-hal-f the metallic aluminum heretofore used as deoxidizers in the cleansi.ng of stee]. by the me-thods hereto-fore known in the ar-t.
It will occur to.those skilled in the art that the required turbulence and/or s-tirring o-f the molten steel may be readily achieved -through the use o:E a gas in-troducing plug in the bottom of the ladle and/or through the use o-f a hollow lance arranged to discharge the gas at or adjacen-t its lower end and it will -further occur to those skilled in the art -that the additives including -the desulphurizing material and the slag conditioning compound and the metallic aluminum may be introduced in small particle size along with the Argon gas.
Al-though but one embodiment of the present invention has been described in the foregoing specification, it will be apparent to those skilled in the art -that various modiEications may be made therein without ~eparting ~rom the spirit O-e the invention and having thus described my invention, what I claim is:
~ETHOD AND AGE,NTS FO~ PE~ODUC~NG CLEA~I STI:EL.
Background of the Invention Technical Field:
This invention rela-tes to a method and agents Eor pro-ducing exceptionally clean s-teel ~or continuous casting and the like.
Description oC the Prior Art:
The prior art me-thods and agents heretoEore used Eor the cleansing oE steel of non-metallic inclusions are represented by U.S. Paten-ts 2,Z21,784, 4,036,635, 4 J Z17,134, 4,238,227 and 4,290,173.
Patent 2,221,784 discloses the use of additive agents containing silicon, calcium, aluminum and at least one metal selected from the group consisting of titanium and zirconium, the additive being added -to the molten steel in the ladle.
Patent 4,036,635 discloses a steel melt formed under an iron oxide containing slag held back while the steel mel-t is tapped and subjected to deoxidation with silicon or aluminum plus an af-ter treatment with a calcium containing substance such as calcium silicon or calcium carbide.
Patent 4,217,134 discloses -the use of compositions ,~
~2~3~
comprising lime, fluorspar, ancl ground a:Luminum used in a method of desulphurizing molten s-teel by adding the composi-tions to the steel in -the :Ladle or injec-ting the composition in particulate form in-to the molten s-teel.
Paten-t No. 4,238,227 discloses the use of a high amoun-t of aluminum added -to the tap ladle be:Eore the -firs-t one-third volume of steel is tapped and -then adding conventional deoxidizers while the final two-thirds volume of steel is tapped. Argon gas is subsequently blown through -the steel.
Patent 4,490,173 disc]oses -the use of additi.ve composi-tions for flux solubilization, desulphuriza-tion and -the removal of inclusions. The addi-tive composition includes lime and a compound selected from the group consisting of bauxite and mix-tures of calcium alimunate and bauxite.
The present invention eliminates the several problems generally associated with the prior art methods and addi-tives used in at-tempting to produce a clean s-teel particularly suited for use in a continuous caster and incidentally reduces the amount of aluminum as a deoxidizing agent to approximately one-half of the amount heretofore believed :~Z~e3~34~
necessary.
Summary O e the Invent.ion A method and agents for producing excep-tionally clean s-teel results in floa-ting all available non-me-tallic inclusions to the surface of the s-teel being treated in a ladle where they engage and are absorbed by a ladle covering compound,as disclosed in my Paten-t 4,462,834,which contains burnt lime, aluminum dross, fluorspar, and acid -treated graphite. The method begins when the steel is first poured into the ladle from the source, such as a conver-ter, electric furnace, etc.,at which time a desulphurizing composi-tion is added simultaneously with the molten steel; the desulphurizing material comprising calcium eluoride, sodium carbona-te, and calcium hydroxide J
followed by the addition of a deoxidizing agent when about one-third of the volume of steel has been added to the ladle, the deoxidizing agent comprising metallic aluminum; this is followed by the addition of a slag conditioning composition when the ladle is approximately oDe-half full, the slag conditioning composition comprising calcium oxide and calcium and aluminum in an alloy including a small percentage of magnesium, adding an expandable ladle cover and immediately followed by the in-troducti.on of ~rgon gas into the lower portion of -the mel-t in suf-ficien-t volume and a-t a rate of introduction sufficien-t to cause desirable turbulence in -the mol-ten metal comprising the melt. The final step in the method is the addition of a fina~ deoxidizing additive comprising metallic aluminum. The -total amount of metallic aluminum as deoxidizing agents introduced in separate and dis-tinc-t s-teps is approxi-mately one-half the amount of metallic aluminum heretofore believed necessary in deoxidizing mol-ten s-teel.
Description of the Preferred Embodiment Those skilled in the art relating to producing steel will recognize the desirable resul-ts of the presen-t invention which produces exceptionally clean steel which may be any grade of steel with -the leas-t non-metallic content. The method is preferably practiced in a ladle to which molten steel from a conventional source, such as a converter, electric ~urance and the like, is tapped. The ladle may be of any size from 30 tons -to 300 tons capacity and the s-teel intro-duced into the ladle may beat 3000F. or it may vary 200 F.
ei-ther way.
3~
The firs-t step of the method disclosed herein comprises the positioning in -the l.adle O:e a desulphurizing agent comprising a first additi.ve compound consisting of equal amounts of calcium fluoride, sodium carbonate, and calcium hydroxide followed by the in-troduction of molten s-teel in-to the ladle or alternately addi.ng the :Eirst additive compound -to the first s-teel introduced in-to the ladle. The second step in the method is performed when the ladle is half full of molten s-teel and comprises the introduction of a second additive consisting of one-half of the normal metallic aluminum additi.on used in deoxidizing steel together with the addition of a third addi-tive comprising a slag condition-ing compound consisting of equal amounts of calcium oxide and calcium and an aluminum alloy comprising 95% aluminum and 5% magnesium. The fourth step in the method comprises -the addition of an expandable ladle cover w~ich includes burnt lime, aluminum dross, fluorspar, and acid treated graphite-which forms a slag-like layer on the molten metal for absorbing the non-metallic inclusions,simul-taneously creating a stirring and/or similar desirable turbulence in -the ~Z43~
molten metal as by the injec-tion Oe Argon gas -through a bottom ladle plug replacement or a hollow re-Eractory lance, the amount and rate of fiow of -the ~rgon gas being sufficient -to result in the desired turbulence. The introduction Oe -the metallic aluminum addi-tive and the slag conditioning compound results in a chemical reaction tha-t forces the aluminum to disperse to -the ultimate degree withou-t becoming alloyed -to ei-ther the free floating molten refractory in -the molten steel or any of the soluable non-metallics that have been libera-ted from their various alloys.
Those skilled in the art will observe that the non-metallic inclusions normally found in molten steel may be traced to the refractory materia] present as a liner in the converter, electric furnace, etc. and/or the ladle in which the molten me-tal -is received.
Oxygen an,d sulphur in the molten metal are responsible for most of the non-metallic inclusions as sulphur is soluable in steel at all temperatures above the mel-ting point and oxygen is present in steels which are not comple-tely de-oxidized.The deoxidizers, such as aluminum, when added to the 38~
ladle form oxides wl-th the dissolved oxygen in the steel.
The introduc-tion o~ -the slag conditionirlg compound herein-be~ore se-t Eorth and the expanding ladle cover as hereinbe~ore set forth together with -the induced -turbulence forces chemically and physical con-tact of all of -the insoluable non-metallics and the -rree sulphur and free aluminum oxide to rise to the -top o-f the steel in the ladle and contact and be absorbed in the expanding ladle cover compound. The expanding ladle cover compound herein referred -to expands i-ts volume between 50% and 100% and this expansion of volume results in the absorption of the non-metallics that are forced -to the top o~ the molten s-teel by -the induced turbulence.
The products absorbed by the expanding ladle cover compound are held in the cover compound until the molten steel is removed irom the bo-t-tom of the ladle and they do not revert into the molten metal.
The materials in the first additive comprising the calcium fluroide, the sodium carbonate, and the calcium hydroxide are present in equal amounts, the amount o~ each ingredient being between 5 lbs. and 15 lbs. per -ton of molten ~3~
s-teel. The metallic aluminum added when -the ladle is hal~
full is approximately one-fourth the amount o~ aluminum used as a deoxidizer in the prior art. It is the usual prac-tice of adding deoxidizers such as aluminum during tapping to control the amount of aluminum in direct portion to the steel's oxygen conten-t. Since -the oxygen content of the liquid steel is not usually measured, -the aluminum addition is usually de-ter~ined approximately in inverse propora-tion to the carbon content. A curve relating total product oxygen and carbon conten-t oE the liquid steel has been used to determine the optimum amoun-t of aluminum needed to react with the particularly amount of oxygen a-t each carbon content, for example, molten s-teel having a carbon content of 0.10%
is usually treated with 165 lbs. of aluminum per 100 tons of i5 steel or approximately one and three-quarter lbs. per ton.
In practicing the present invention, the amount of metallic aluminum added to the ladle when the same is one-third full and after adding the desulphurizing compound may be an amount between three-quarter of a lb. and one and one-quarter lbs. per ton of molten steel.
~29~3~4~
The second addi.tive compound comprising -the slag conditioner which is added to the ladle immedia-tely af-ter the metallic aluminum or when the ladle is half full comprises the calcium oxide and calcium in equal amounts and wherein -the amount - 5 of each of -the ingredien-ts is between 5 and 15 lbs. per -ton of molten metal. The introduction o~ ~rgon gas in suiflcient quan-tities and at a ra-te to create a desirable turbulence and/or stirring motion of the molten me-tal results in a chemical reaction that forces the me-tallic aluminum to disperse the ultimate degree withou-t becoming alloyed to either the free -Floa-ting molten refrac-tory or any of the insoluable non-metallics tha-t have been liberated from their various alloys in the steel.
Those skilled in -the art will observe that the desulphurizer compound plus the slag conditioner and -the metallic aluminum -to which any other required alloys needed to meet the desired aim chemistry are all in the molten bath and the same is slag--Cree or containsaminimum amount o~ furnace slag and that the expanding ladle cover compound over the complete mol-ten bath forces chemical and physical contact of all of the insol.uable ~2~31~44 non-metallics ancl the Eree sulphu:r and -the Eree meta:llic aluminum tha-t are being subjec-ted to -the turbul.ence to rise to the -top o-~ -the steel ba-th and come in con-tact and be absorbed by the expancling ladle cover compound.
Those skilled in the ar-t will recognize that the cleansing o:E -the steel requires time and temperature control as -the additives cause a rapid heat 105s over an extended period oE time during the tapping cycle which is the time i-t -takes for -the -Eurnace to discharge its molten metal in-to the receiving ladle.
The present invention enables a more accurate and complete control o-E the time of the cleaning cycle and therefore con-trols the temperature by preventing the otherwise rapid heat loss.
A-t a predetermined time and/or predetermined -temperat-ure, the ladle carrylng the clean steel is moved to a trim station and a small additional quantity oi metallic aluminum added as a final deoxidizing agent. The amount o~ the metallic aluminum Einally added to the molten s-teel at the trim station is an amount subs-tantially the same as -tha-t initially added and it will occur to those skilled in the art that the -to-tal ~2'~31~
of the metallic a:Luminum added in -the two s-tages is approxi-mately one-hal-f the metallic aluminum heretofore used as deoxidizers in the cleansi.ng of stee]. by the me-thods hereto-fore known in the ar-t.
It will occur to.those skilled in the art that the required turbulence and/or s-tirring o-f the molten steel may be readily achieved -through the use o:E a gas in-troducing plug in the bottom of the ladle and/or through the use o-f a hollow lance arranged to discharge the gas at or adjacen-t its lower end and it will -further occur to those skilled in the art -that the additives including -the desulphurizing material and the slag conditioning compound and the metallic aluminum may be introduced in small particle size along with the Argon gas.
Al-though but one embodiment of the present invention has been described in the foregoing specification, it will be apparent to those skilled in the art -that various modiEications may be made therein without ~eparting ~rom the spirit O-e the invention and having thus described my invention, what I claim is:
Claims (6)
1. A process for treating molten steel to remove insoluble non-metallic inclusions, sulphur and aluminum oxide therefrom, which includes the steps of tapping a heat of molten steel into a ladle and sequentially adding a desulphurization compound consisting of equal parts of calcium fluoride, sodium carbonate, and calcium hydroxide, adding granular metallic aluminum as a deoxidizing reactant agent, adding equal parts of calcium oxide and an aluminum alloy, the major portion of which is aluminum and a minor portion magnesium, as a slag conditioning compound, adding burnt lime, aluminum dross, flurospar and acid treated graphite as an expandable ladle covering compound and injecting an inert gas sufficient to create turbulence and stirring motion in the molten steel and adding additional granular metallic aluminum, the desulphuriza-tion compound being added with the first volume of steel tapped into the ladle, the first mentioned deoxidizing reacting agent, and the slag condition compound being added when approximately one-half of the volume of steel is tapped into the ladle, the expandable ladle covering compound being added immediately thereafter and the second mentioned granular metallic aluminum as a deoxidizing reactant agent being added after the addition of the expandable ladle cover compound and before the full volume of steel is tapped into the ladle whereby said turbulence forces chemically and physical contact of all of said insoluble metallic inclusions and the free sulphur and free aluminum oxide to rise to the top of the ladle and be absorbed in the expandable ladle covering compound so that clean molten steel can be withdrawn from the ladle below said expandable ladle covering compound.
2. The process of claim 1 wherein the amount of the desulphurizing compound consists of from 5 lbs.
to 15 lbs. of calcium fluoride per ton of the total amount of molten steel to be treated, from 5 lbs. to 15 lbs.
of sodium carbonate per ton of the total amount of molten steel to be treated and from 5 lbs. to 15 lbs. of calcium hydroxide per ton of the total amount of molten steel to be treated.
to 15 lbs. of calcium fluoride per ton of the total amount of molten steel to be treated, from 5 lbs. to 15 lbs.
of sodium carbonate per ton of the total amount of molten steel to be treated and from 5 lbs. to 15 lbs. of calcium hydroxide per ton of the total amount of molten steel to be treated.
3. The process of claim 1 and wherein the amount of deoxidizing reactant agent of each of said additions is between about three-fourths of a pound to about one and one-quarter pounds per ton of the total amount of molten steel to be treated.
4. The process of claim 1 wherein the predetermined amount of the slag conditioning compound consists of between about 5 lbs. and about 30 lbs. per ton of the total amount of molten steel to be treated.
5. The process of claim 1 wherein the amount of the expandable ladle covering compound is between about 5 lbs. to about 15 lbs. per ton of the total amount of molten steel to be treated.
6. The process of claim 1 wherein the expandable ladle covering compound includes burnt lime in amounts between 56% and 60% by weight, aluminum dross including Al2O3 in amounts between 22% and 30% by weight, fuorspar in amounts between 7% and 9% by weight, and acid treated graphite in amounts between 1% and 4% by weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000500936A CA1243844A (en) | 1986-02-03 | 1986-02-03 | Method and agents for producing clean steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000500936A CA1243844A (en) | 1986-02-03 | 1986-02-03 | Method and agents for producing clean steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1243844A true CA1243844A (en) | 1988-11-01 |
Family
ID=4132402
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000500936A Expired CA1243844A (en) | 1986-02-03 | 1986-02-03 | Method and agents for producing clean steel |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1243844A (en) |
-
1986
- 1986-02-03 CA CA000500936A patent/CA1243844A/en not_active Expired
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