CA2852813C - Composite briquette for steelmaking or ironmaking furnace charge - Google Patents
Composite briquette for steelmaking or ironmaking furnace charge Download PDFInfo
- Publication number
- CA2852813C CA2852813C CA2852813A CA2852813A CA2852813C CA 2852813 C CA2852813 C CA 2852813C CA 2852813 A CA2852813 A CA 2852813A CA 2852813 A CA2852813 A CA 2852813A CA 2852813 C CA2852813 C CA 2852813C
- Authority
- CA
- Canada
- Prior art keywords
- briquette
- charge
- furnace
- binder
- slag
- 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.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/0046—Making spongy iron or liquid steel, by direct processes making metallised agglomerates or iron oxide
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/12—Making spongy iron or liquid steel, by direct processes in electric furnaces
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/52—Manufacture of steel in electric furnaces
- C21C5/54—Processes yielding slags of special composition
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C2300/00—Process aspects
- C21C2300/02—Foam creation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
A briquette for addition to the charge in a steelmaking or ironmaking furnace comprises a quantity of carbon fines, a material in powdered form, the material selected from the group consisting of iron powder and iron oxide, the material densifying the briquette and suppressing the slippery nature of the carbon fines, a quantity of magnesium carbonate, and a binder.
Description
COMPOSITE BRIQUETTE FOR STEELMAKING OR IRONMAKING
FURNACE CHARGE
Field 100011 The present invention relates generally to ferrous metallurgy and in particular, to a composite briquette for a steelmaking or ironmaking furnace charge, Background
FURNACE CHARGE
Field 100011 The present invention relates generally to ferrous metallurgy and in particular, to a composite briquette for a steelmaking or ironmaking furnace charge, Background
[0002] In the field of steelmaking, an electric fiamace charge is typically made from scrap metal, carbon and fluxes such as lime and/or dolime, all in pieces having a ' minimum size of 0.5 inch.
[0003] It is known to add specific materials to a furnace charge in the form of briquettes. However, carbon, which is an essential part of the mixture of materials, is quite slippery in its powdered or comminuted form, Consequently, carbon is typically employed in a non-pulverized state, for example as coke. It would be of advantage to be able to utilize carbon "fines", for example those recovered from a dust collector, and to recycle such fines in their powdered or dust state. A further problem relates to the density of carbon, which is quite low compared generally to the metals.
For example, when carbon is added to the furnace via a charge bucket, it will tend to float on top of the. liquid metal, thus decreasing the yield of carbon in solution in the steel.
For example, when carbon is added to the furnace via a charge bucket, it will tend to float on top of the. liquid metal, thus decreasing the yield of carbon in solution in the steel.
[0004] Further, it would also be of advantage to improve the quality of the slag through the addition of the briquette.
[00051 Improvements are generally desired. It is therefore an object at least to provide a novel composite briquette for steelmaking or ironmaking furnace charge.
Summary of the Invention [0006] In one aspect, there is provided a composite briquette for addition to a charge in a steelmaking furnace, the briquette comprising: a quantity of carbon fines;
a quantity of iron powder, the iron powder densifying the briquette and suppressing the slippery nature of the carbon fines; a quantity of magnesium carbonate; a quantity of limestone; and a binder, wherein 50 % of the total briquette weight is the carbon tines, 25 % of the total briquette weight is the iron powder, and the remainder of the total briquette weight, apart from the binder, is magnesium carbonate and limestone.
[0007] The briquette may comprise from 1 to 10 % by weight of the binder.
[POW The binder may comprisc molasses and lime.
[0009] In one embodiment, there is provided use of the briquette as addition to the charge in the steelmaking furnace, the furnace being an electric arc furnace or a basic oxygen furnace.
[00010] In another aspect, there is provided a method of improving a slag-covered charge in a steelmaking furnace, the slag-covered charge comprising a charge covered with slag, the method comprising: making a mixture of: a quantity of carbon fines, a quantity of iron powder, a quantity of magnesium oarbonate, a quantity of limestone, and a binder; compressing a portion of said mixture in a suitable mold to make a briquette, said iron powder densifying the briquette and suppressing the slippery nature of the carbon fines, wherein 50 % of the total briquette weight is the carbon fines, 25 % of the total briquette weight is the iron powder, and the remainder of the total briquette weight, apart from the binder, is magnesium carbonate and limestone; and introducing said briquette to the charge below the slag in the steelmaking furnace so that said iron powder contained in the briquette causes the briquette to sink into the charge.
[00011] The mixture may comprise from 1 to 10 % by weight of the binder.
1000121 - The binder may comprise molasses and lime.
1000131 Upon introducing the briquette to the charge, CO2 may be generated such that the CO2 foams the slag from underneath.
[00014] = The furnace may be an electric arc furnace or a basic oxygen furnaoe, [000151 The furnace may be another type of furnace.
=
Detailed Description of the Embodiments [00016] The following is directed to a composite briquette for addition to the charge in a steelmaking or ironmaking furnace, and which comprises magnesium carbonate (MgCO3).
[00017] Magnesium carbonate is known to thermally decompose at a lower temperature than dolomite (CaMg(CO3)2) and limestone (CaCO3). Specifically, MgCO3 thermally decomposes into magnesium oxide (MgO) and carbon dioxide (CO2) at about 402 C, while CaMg(CO3)2 and CaCO3 each thermally decompose into their constituent oxides at about 730 C and about 825 C, respectively. As a result, when added to the charge in a steelmaking or ironmaking furnace, magnesium carbonate thermally decomposes more quickly, and more readily, than limestone or dolomite.
[00018] Table 1 shows a non-limiting example of a mixture from which a suitable briquette can be fashioned:
TABLE 1:
Carbon C 50%
Powdered iron Fe 25 %
Magnesium carbonate MgCO3 25 %
Total 100 %
[00019] In the table above, deviations from the indicated percentages may occur, up to about 5% to either side of the indicated level. The ingredients may be combined with a suitable binder, such as for example industrial molasses and powdered lime, and the binder may make up 1 to 20 %, or more, of the total weight of the briquette.
[00020] The example illustrated in Table 1 specifies powdered iron.
However, this teaching is not intended to be restrictive, as it is possible to use one or more of iron, iron oxide, chromium, chromium oxide, nickel, and nickel oxide to achieve the same effect. If iron oxide is used, the reaction products will be iron and CO2 gas, as well as caloric heat that results from burning of the iron oxide. The iron will revert to the bath, thus increasing its yield.
[00051 Improvements are generally desired. It is therefore an object at least to provide a novel composite briquette for steelmaking or ironmaking furnace charge.
Summary of the Invention [0006] In one aspect, there is provided a composite briquette for addition to a charge in a steelmaking furnace, the briquette comprising: a quantity of carbon fines;
a quantity of iron powder, the iron powder densifying the briquette and suppressing the slippery nature of the carbon fines; a quantity of magnesium carbonate; a quantity of limestone; and a binder, wherein 50 % of the total briquette weight is the carbon tines, 25 % of the total briquette weight is the iron powder, and the remainder of the total briquette weight, apart from the binder, is magnesium carbonate and limestone.
[0007] The briquette may comprise from 1 to 10 % by weight of the binder.
[POW The binder may comprisc molasses and lime.
[0009] In one embodiment, there is provided use of the briquette as addition to the charge in the steelmaking furnace, the furnace being an electric arc furnace or a basic oxygen furnace.
[00010] In another aspect, there is provided a method of improving a slag-covered charge in a steelmaking furnace, the slag-covered charge comprising a charge covered with slag, the method comprising: making a mixture of: a quantity of carbon fines, a quantity of iron powder, a quantity of magnesium oarbonate, a quantity of limestone, and a binder; compressing a portion of said mixture in a suitable mold to make a briquette, said iron powder densifying the briquette and suppressing the slippery nature of the carbon fines, wherein 50 % of the total briquette weight is the carbon fines, 25 % of the total briquette weight is the iron powder, and the remainder of the total briquette weight, apart from the binder, is magnesium carbonate and limestone; and introducing said briquette to the charge below the slag in the steelmaking furnace so that said iron powder contained in the briquette causes the briquette to sink into the charge.
[00011] The mixture may comprise from 1 to 10 % by weight of the binder.
1000121 - The binder may comprise molasses and lime.
1000131 Upon introducing the briquette to the charge, CO2 may be generated such that the CO2 foams the slag from underneath.
[00014] = The furnace may be an electric arc furnace or a basic oxygen furnaoe, [000151 The furnace may be another type of furnace.
=
Detailed Description of the Embodiments [00016] The following is directed to a composite briquette for addition to the charge in a steelmaking or ironmaking furnace, and which comprises magnesium carbonate (MgCO3).
[00017] Magnesium carbonate is known to thermally decompose at a lower temperature than dolomite (CaMg(CO3)2) and limestone (CaCO3). Specifically, MgCO3 thermally decomposes into magnesium oxide (MgO) and carbon dioxide (CO2) at about 402 C, while CaMg(CO3)2 and CaCO3 each thermally decompose into their constituent oxides at about 730 C and about 825 C, respectively. As a result, when added to the charge in a steelmaking or ironmaking furnace, magnesium carbonate thermally decomposes more quickly, and more readily, than limestone or dolomite.
[00018] Table 1 shows a non-limiting example of a mixture from which a suitable briquette can be fashioned:
TABLE 1:
Carbon C 50%
Powdered iron Fe 25 %
Magnesium carbonate MgCO3 25 %
Total 100 %
[00019] In the table above, deviations from the indicated percentages may occur, up to about 5% to either side of the indicated level. The ingredients may be combined with a suitable binder, such as for example industrial molasses and powdered lime, and the binder may make up 1 to 20 %, or more, of the total weight of the briquette.
[00020] The example illustrated in Table 1 specifies powdered iron.
However, this teaching is not intended to be restrictive, as it is possible to use one or more of iron, iron oxide, chromium, chromium oxide, nickel, and nickel oxide to achieve the same effect. If iron oxide is used, the reaction products will be iron and CO2 gas, as well as caloric heat that results from burning of the iron oxide. The iron will revert to the bath, thus increasing its yield.
- 5 -[000211 The magnesium carbonate could be combined with limestone and/or dolomite, each of which will produce CO2 gas with the same effect as above.
Dolime, lime, and/or magnesium oxide may also be included.
1000221 The ironmaking furnace may be, for example, a blast furnace. The steelmaking furnace may be, for example, an electric arc furnace, a basic oxygen furnace, and the like.
[00023] In use, the briquette is added to the charge in a steelmaking or ironmaking furnace, in such a manner that it is immersed within the charge.
The briquette dissolves and reacts with the contents of the charge. The powdered iron reverts to the bath, thus increasing its yield. The magnesium carbonate thermally decomposes into magnesium oxide (MgO) and carbon dioxide (CO2). The magnesium oxide (MgO) produced is absorbed by the slag. The CO2 produced has the effect of foaming the slag from underneath, as the location where the CO2 is generated is buried within the charge.
[00024] As will be appreciated, the low decomposition temperature of magnesium carbonate advantageously allows the slag thickness to be increased more rapidly than, and with less energy consumption than, other substances such as limestone, dolomite, and the like. As will be understood, the rapid formation of a thick slag decreases the amount of oxidation of iron in the bath, which improves of the yield of the reaction. Additionally, if the steelmaking furnace is an electric arc furnace, the increased thickness of the slag advantageously causes the arc to be more localized within the bath and under the slag, which improves efficiency of the electric arc furnace and thereby allows melt times to be shortened. These performance characteristics help mitigate the environmental impact of steelmaking and ironmaking operations, and conserve resources.
1000251 As will be appreciated, the accompanying production of CO2 gas that occurs upon decomposition of magnesium carbonate causes bubbling under the surface of the bath, which advantageously causes mixing and improves the quality of the slag, and namely the foaminess, consistency and stability of the slag.
1000261 As will be appreciated, the addition of MgO to the slag advantageously results in formation of a protective layer of MgO on the walls of the furnace.
As will be understood, as the melt is being drained from the furnace, the slag contacts the wall
Dolime, lime, and/or magnesium oxide may also be included.
1000221 The ironmaking furnace may be, for example, a blast furnace. The steelmaking furnace may be, for example, an electric arc furnace, a basic oxygen furnace, and the like.
[00023] In use, the briquette is added to the charge in a steelmaking or ironmaking furnace, in such a manner that it is immersed within the charge.
The briquette dissolves and reacts with the contents of the charge. The powdered iron reverts to the bath, thus increasing its yield. The magnesium carbonate thermally decomposes into magnesium oxide (MgO) and carbon dioxide (CO2). The magnesium oxide (MgO) produced is absorbed by the slag. The CO2 produced has the effect of foaming the slag from underneath, as the location where the CO2 is generated is buried within the charge.
[00024] As will be appreciated, the low decomposition temperature of magnesium carbonate advantageously allows the slag thickness to be increased more rapidly than, and with less energy consumption than, other substances such as limestone, dolomite, and the like. As will be understood, the rapid formation of a thick slag decreases the amount of oxidation of iron in the bath, which improves of the yield of the reaction. Additionally, if the steelmaking furnace is an electric arc furnace, the increased thickness of the slag advantageously causes the arc to be more localized within the bath and under the slag, which improves efficiency of the electric arc furnace and thereby allows melt times to be shortened. These performance characteristics help mitigate the environmental impact of steelmaking and ironmaking operations, and conserve resources.
1000251 As will be appreciated, the accompanying production of CO2 gas that occurs upon decomposition of magnesium carbonate causes bubbling under the surface of the bath, which advantageously causes mixing and improves the quality of the slag, and namely the foaminess, consistency and stability of the slag.
1000261 As will be appreciated, the addition of MgO to the slag advantageously results in formation of a protective layer of MgO on the walls of the furnace.
As will be understood, as the melt is being drained from the furnace, the slag contacts the wall
- 6 -surfaces of the furnace and deposits a layer of MgO thereon. As a result, a new protective refractory coating is automatically deposited on the walls of the furnace with each use, which eliminates the need for separate application of a protective wall coating that would otherwise form part of routine furnace maintenance.
[00027] The briquette is not limited to the composition described above, and in other embodiments, the briquette may alternatively have other compositions.
For example, in another embodiment, magnesium carbonate may be added to the charge of a steelmaking or ironmaking furnace for improving the quality of the slag.
[00028] For example, powdered magnesium carbonate ore may be combined with a suitable binder, such as for example industrial molasses and powdered lime, and compressed in a suitable mold to make a briquette. The binder may make up 1 to 20 c1/0, or more, of the total weight of the briquette.
[00029] The magnesium carbonate could be combined with one or more other substances. Such substances may comprise, for example, limestone and/or dolomite, each of which will produce CO2 gas upon decomposition, and/or any of dolime, lime, and magnesium oxide. Still other substances may be combined with the magnesium carbonate.
1000301 The ironmaking furnace may be, for example, a blast furnace. The steelmaking furnace may be, for example, an electric arc furnace, a basic oxygen furnace, and the like.
[00031] In use, the briquette is added to the charge in a steelmaking or ironmaking furnace, in such a manner that it is immersed within the charge.
The briquette dissolves and reacts with the contents of the charge. The magnesium carbonate thermally decomposes into magnesium oxide (MgO) and carbon dioxide (C07). The magnesium oxide (MgO) produced is absorbed by the slag. The Ca) produced has the effect of foaming the slag from underneath, as the location where the CO, is generated is buried within the charge.
1000321 In another embodiment, magnesium carbonate ore, in absence of a binder, may be added in powdered or granular form to the charge of a steelmaking or ironmaking furnace for improving the quality of the slag.
[00033] The following examples illustrate various applications of the above-described embodiments.
e
[00027] The briquette is not limited to the composition described above, and in other embodiments, the briquette may alternatively have other compositions.
For example, in another embodiment, magnesium carbonate may be added to the charge of a steelmaking or ironmaking furnace for improving the quality of the slag.
[00028] For example, powdered magnesium carbonate ore may be combined with a suitable binder, such as for example industrial molasses and powdered lime, and compressed in a suitable mold to make a briquette. The binder may make up 1 to 20 c1/0, or more, of the total weight of the briquette.
[00029] The magnesium carbonate could be combined with one or more other substances. Such substances may comprise, for example, limestone and/or dolomite, each of which will produce CO2 gas upon decomposition, and/or any of dolime, lime, and magnesium oxide. Still other substances may be combined with the magnesium carbonate.
1000301 The ironmaking furnace may be, for example, a blast furnace. The steelmaking furnace may be, for example, an electric arc furnace, a basic oxygen furnace, and the like.
[00031] In use, the briquette is added to the charge in a steelmaking or ironmaking furnace, in such a manner that it is immersed within the charge.
The briquette dissolves and reacts with the contents of the charge. The magnesium carbonate thermally decomposes into magnesium oxide (MgO) and carbon dioxide (C07). The magnesium oxide (MgO) produced is absorbed by the slag. The Ca) produced has the effect of foaming the slag from underneath, as the location where the CO, is generated is buried within the charge.
1000321 In another embodiment, magnesium carbonate ore, in absence of a binder, may be added in powdered or granular form to the charge of a steelmaking or ironmaking furnace for improving the quality of the slag.
[00033] The following examples illustrate various applications of the above-described embodiments.
e
- 7 -[00034] EXAMPLE 1 [00035] In this example, a briquette having the composition shown in Table 2 was made:
TABLE 2:
Carbon 43.7%
Fe 22.5%
CaO 12.2%
MgO 6.6%
S 2.9%
L.O.I. 12.1 %
[00036] The dolime could be replaced with magnesium carbonate, which will produce CO2 gas, with the foaming effect described above.
[00037] The L.O.I. is mainly attributed to the decomposition of the dolomite and the binder used. The layer of CO and CO2 produced will protect the bath from oxidation and enhance the carbon yield.
[00038] The manufacturing process by which the briquette is formed has the effect of densification, with the following typical values: loose carbon prior to compression has a density of approximately 0.63 to 0.65 g/cm3. If a briquette is manufactured from the loose carbon only, the density can be raised into the range of 1.6 to 1.75 grams/cc. However, utilizing the formulation given at the beginning of this example, and compressing the formulation, will yield a density in the range of 2.4 to 2.6 grams/cc.
[00039] The densification due to compression has the effect of increasing the efficiency of the carbon addition, since the carbon is allowed to penetrate the bath, rather than simply floating on top of the bath.
[00041] In this example, a briquette ("Briquette A") having the post-calcination composition shown in Table 3 was made:
TABLE 2:
Carbon 43.7%
Fe 22.5%
CaO 12.2%
MgO 6.6%
S 2.9%
L.O.I. 12.1 %
[00036] The dolime could be replaced with magnesium carbonate, which will produce CO2 gas, with the foaming effect described above.
[00037] The L.O.I. is mainly attributed to the decomposition of the dolomite and the binder used. The layer of CO and CO2 produced will protect the bath from oxidation and enhance the carbon yield.
[00038] The manufacturing process by which the briquette is formed has the effect of densification, with the following typical values: loose carbon prior to compression has a density of approximately 0.63 to 0.65 g/cm3. If a briquette is manufactured from the loose carbon only, the density can be raised into the range of 1.6 to 1.75 grams/cc. However, utilizing the formulation given at the beginning of this example, and compressing the formulation, will yield a density in the range of 2.4 to 2.6 grams/cc.
[00039] The densification due to compression has the effect of increasing the efficiency of the carbon addition, since the carbon is allowed to penetrate the bath, rather than simply floating on top of the bath.
[00041] In this example, a briquette ("Briquette A") having the post-calcination composition shown in Table 3 was made:
- 8 -TABLE 3:
MgO 92.19%
CaO 2.46%
A1203 0.85 %
Si02 2.58 %
TiO2 O.14%
Fe203 0.71 %
Cr203 0.02 %
MnO O.05%
< 0.001 %
Moisture 1.0%
Total 100%
[00042] The briquette was formed by providing a mixture of powdered magnesium carbonate ore and a binder, combined in a weight ratio of 90:10, and compressing the mixture in a suitable mold. The binder was a mixture of industrial molasses and powdered lime, combined in a weight ratio of 3:2.
[00043] The briquette had a generally square shape and a size of 40 mm per side, with a density of 2.18 g/cm3 and a white colour. The briquette had a L.O.I.
value of 35.0 %, which is mainly attributed to the decomposition of the magnesium carbonate and the binder. Notably, the L.O.I. value of the briquette is lower than the L.O.I. value of the powderized mixture of Example 3.
[00044] The briquette was used during reactions in a 125 tonne electric arc furnace. A summary of the performance of the briquette ("Briquette A") during the reactions is shown in Table 4. For comparison, a summary of the performance of a standard conventional additive, namely crushed brick ("standard practice"), during the reactions is also shown:
MgO 92.19%
CaO 2.46%
A1203 0.85 %
Si02 2.58 %
TiO2 O.14%
Fe203 0.71 %
Cr203 0.02 %
MnO O.05%
< 0.001 %
Moisture 1.0%
Total 100%
[00042] The briquette was formed by providing a mixture of powdered magnesium carbonate ore and a binder, combined in a weight ratio of 90:10, and compressing the mixture in a suitable mold. The binder was a mixture of industrial molasses and powdered lime, combined in a weight ratio of 3:2.
[00043] The briquette had a generally square shape and a size of 40 mm per side, with a density of 2.18 g/cm3 and a white colour. The briquette had a L.O.I.
value of 35.0 %, which is mainly attributed to the decomposition of the magnesium carbonate and the binder. Notably, the L.O.I. value of the briquette is lower than the L.O.I. value of the powderized mixture of Example 3.
[00044] The briquette was used during reactions in a 125 tonne electric arc furnace. A summary of the performance of the briquette ("Briquette A") during the reactions is shown in Table 4. For comparison, a summary of the performance of a standard conventional additive, namely crushed brick ("standard practice"), during the reactions is also shown:
- 9 -TABLE 4:
Standard Briquette A difference Practice Number of Heats 44 11 Quantity added (lbs) 3500 3500 Actual MgO added (lbs) 3220 2100 -34.78 %
Average MgO in solution (%) 8.79 1.75 9.20 1.88 +4.66 %
Briquette A with lst charge (%) 10.69 1.80 Briquette A with 2nd charge 7.95 0.62 (%) [00045] As may be seen, the use of Briquette A results in a reduction of the actual MgO added by about 35 /0, while advantageously increasing the average MgO
in the slag by about 4.5 %. The amount of Mg0 in the slag is about 34% higher when the Briquette A was added with the first charge (i.e. when little or no slag layer previously existed) than when the Briquette A was added with the second charge.
[00046] The decomposition of magnesium carbonate within Briquette A
produces fine, active MgO particles, which are absorbed by the slag. It was observed that when Briquette A was added and the briquettes penetrated the slag so as to be buried in the charge, tiny bubbles of CO2 were seen to form.
[00047] The average composition of the slag after the reactions, by weight percent, is shown in Table 5:
TABLE 5:
Standard Briquette A difference Practice CaO 36.07 3.72 36.41 + 3.04 + 0.93 %
A1203 6.99 1.98 7.68 0.99 + 9.87 `)/0 Si02 11.83 3.75 13.23 1.44 + 11.83%
Fe203 27.71 7.32 24.59 5.53 - 11.26 %
Mn203 5.46 1.03 5.31 0.37 - 2.82 %
Standard Briquette A difference Practice Number of Heats 44 11 Quantity added (lbs) 3500 3500 Actual MgO added (lbs) 3220 2100 -34.78 %
Average MgO in solution (%) 8.79 1.75 9.20 1.88 +4.66 %
Briquette A with lst charge (%) 10.69 1.80 Briquette A with 2nd charge 7.95 0.62 (%) [00045] As may be seen, the use of Briquette A results in a reduction of the actual MgO added by about 35 /0, while advantageously increasing the average MgO
in the slag by about 4.5 %. The amount of Mg0 in the slag is about 34% higher when the Briquette A was added with the first charge (i.e. when little or no slag layer previously existed) than when the Briquette A was added with the second charge.
[00046] The decomposition of magnesium carbonate within Briquette A
produces fine, active MgO particles, which are absorbed by the slag. It was observed that when Briquette A was added and the briquettes penetrated the slag so as to be buried in the charge, tiny bubbles of CO2 were seen to form.
[00047] The average composition of the slag after the reactions, by weight percent, is shown in Table 5:
TABLE 5:
Standard Briquette A difference Practice CaO 36.07 3.72 36.41 + 3.04 + 0.93 %
A1203 6.99 1.98 7.68 0.99 + 9.87 `)/0 Si02 11.83 3.75 13.23 1.44 + 11.83%
Fe203 27.71 7.32 24.59 5.53 - 11.26 %
Mn203 5.46 1.03 5.31 0.37 - 2.82 %
- 10 -[000481 As may be seen, the use of Briquette A results in a reduction of the iron content of the slag by more than 11%, as compared to standard practice.
This may be attributed to the ability of the magnesium carbonate to rapidly decompose and contribute to or form the slag, which allows a protective barrier to more quickly form on the bath surface. As a result, less of the iron in the bath is oxidized during the reaction, which advantageously increases the yield of the reaction.
1000491 During the test, 22 heats were carried out using crushed brick, followed by 11 heats carried out using Briquette A, followed by 22 heats carried out using crushed brick. The operational performance of the 125 tonne electric arc furnace before, during, and after the addition of Briquette A is shown in Table 6:
TABLE 6:
Standard Standard Standard Briquette A
Practice Practice Practice (before test) (after test) (avg) Power usage 427.0 24.1 428.0 14.4 427.5 420.0 9.9 (KWh/T) [00050] As may be seen, the amount of power required for the reaction is lower when Briquette A is used, as compared to standard practice.
1000521 Magnesium carbonate may alternatively be added to the charge in powderized form. A powderized mixture having the post-calcination composition shown in Table 7 was used :
TABLE 7:
MgO 97.0%
CaO 2.0%
A1203 0.2 %
Si 02 0.3 %
Fe203 0.5 %
Total 100 %
This may be attributed to the ability of the magnesium carbonate to rapidly decompose and contribute to or form the slag, which allows a protective barrier to more quickly form on the bath surface. As a result, less of the iron in the bath is oxidized during the reaction, which advantageously increases the yield of the reaction.
1000491 During the test, 22 heats were carried out using crushed brick, followed by 11 heats carried out using Briquette A, followed by 22 heats carried out using crushed brick. The operational performance of the 125 tonne electric arc furnace before, during, and after the addition of Briquette A is shown in Table 6:
TABLE 6:
Standard Standard Standard Briquette A
Practice Practice Practice (before test) (after test) (avg) Power usage 427.0 24.1 428.0 14.4 427.5 420.0 9.9 (KWh/T) [00050] As may be seen, the amount of power required for the reaction is lower when Briquette A is used, as compared to standard practice.
1000521 Magnesium carbonate may alternatively be added to the charge in powderized form. A powderized mixture having the post-calcination composition shown in Table 7 was used :
TABLE 7:
MgO 97.0%
CaO 2.0%
A1203 0.2 %
Si 02 0.3 %
Fe203 0.5 %
Total 100 %
- 11 -[00053] The powderized mixture had a density of 2.28 g/cm3 and a white colour.
[00054] The powderized mixture was used during a reaction in a 125 tonne electric arc furnace.
[00055] The powderized mixture had a L.O.I. value of 51.1 %. Notably, the L.O.I. value of the powderized mixture is greater than the L.O.I. value of the briquette of Example 2.
[00056] Although embodiments have been described above, those of skill in the art will appreciate that variations and modifications may be made without departing from the scope thereof as defined by the appended claims.
[00054] The powderized mixture was used during a reaction in a 125 tonne electric arc furnace.
[00055] The powderized mixture had a L.O.I. value of 51.1 %. Notably, the L.O.I. value of the powderized mixture is greater than the L.O.I. value of the briquette of Example 2.
[00056] Although embodiments have been described above, those of skill in the art will appreciate that variations and modifications may be made without departing from the scope thereof as defined by the appended claims.
Claims (7)
1. A composite briquette for addition to a charge in a steelmaking furnace, the briquette comprising:
a quantity of carbon fines;
a quantity of iron powder, the iron powder densifying the briquette and suppressing the slippery nature of the carbon fines;
a quantity of magnesium carbonate;
a quantity of limestone; and a binder, wherein 50 % of the total briquette weight is the carbon fines, 25 % of the total briquette weight is the iron powder, and the remainder of the total briquette weight, apart from the binder, is magnesium carbonate and limestone, and wherein the binder comprises molasses and lime.
a quantity of carbon fines;
a quantity of iron powder, the iron powder densifying the briquette and suppressing the slippery nature of the carbon fines;
a quantity of magnesium carbonate;
a quantity of limestone; and a binder, wherein 50 % of the total briquette weight is the carbon fines, 25 % of the total briquette weight is the iron powder, and the remainder of the total briquette weight, apart from the binder, is magnesium carbonate and limestone, and wherein the binder comprises molasses and lime.
2. The briquette of claim 1, wherein the briquette comprises from 1 to 10 % by weight of the binder.
3. Use of the briquette of claim 1 or 2 as addition to the charge in the steelmaking furnace, the furnace being an electric arc furnace or a basic oxygen furnace.
4. A method of improving a slag-covered charge in a steelmaking furnace, the slag-covered charge comprising a charge covered with slag, the method comprising:
making a mixture of: a quantity of carbon fines, a quantity of iron powder, a quantity of magnesium carbonate, a quantity of limestone, and a binder, wherein the binder comprises molasses and lime;
compressing a portion of said mixture in a suitable mold to make a briquette, said iron powder densifying the briquette and suppressing the slippery nature of the carbon fines, wherein 50 % of the total briquette weight is the carbon fines, 25 % of the total briquette weight is the iron powder, and the remainder of the total briquette weight, apart from the binder, is magnesium carbonate and limestone;
and introducing said briquette to the charge below the slag in the steelmaking furnace so that said iron powder contained in the briquette causes the briquette to sink into the charge.
making a mixture of: a quantity of carbon fines, a quantity of iron powder, a quantity of magnesium carbonate, a quantity of limestone, and a binder, wherein the binder comprises molasses and lime;
compressing a portion of said mixture in a suitable mold to make a briquette, said iron powder densifying the briquette and suppressing the slippery nature of the carbon fines, wherein 50 % of the total briquette weight is the carbon fines, 25 % of the total briquette weight is the iron powder, and the remainder of the total briquette weight, apart from the binder, is magnesium carbonate and limestone;
and introducing said briquette to the charge below the slag in the steelmaking furnace so that said iron powder contained in the briquette causes the briquette to sink into the charge.
5. The method of claim 4, wherein the mixture comprises from 1 to 10 %
by weight of the binder.
by weight of the binder.
6. The method of claim 5 or 6, whereby upon introducing the briquette to the charge, CO2 is generated such that the CO2 foams the slag from underneath.
7. The method of any one of claims 4 to 6, wherein the furnace is an electric arc furnace or a basic oxygen furnace.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2852813A CA2852813C (en) | 2014-05-29 | 2014-05-29 | Composite briquette for steelmaking or ironmaking furnace charge |
| CA2861315A CA2861315C (en) | 2014-05-29 | 2014-08-29 | Composite briquette for steelmaking or ironmaking furnace charge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2852813A CA2852813C (en) | 2014-05-29 | 2014-05-29 | Composite briquette for steelmaking or ironmaking furnace charge |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2852813A1 CA2852813A1 (en) | 2014-08-11 |
| CA2852813C true CA2852813C (en) | 2017-10-03 |
Family
ID=51349144
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2852813A Active CA2852813C (en) | 2014-05-29 | 2014-05-29 | Composite briquette for steelmaking or ironmaking furnace charge |
| CA2861315A Active CA2861315C (en) | 2014-05-29 | 2014-08-29 | Composite briquette for steelmaking or ironmaking furnace charge |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2861315A Active CA2861315C (en) | 2014-05-29 | 2014-08-29 | Composite briquette for steelmaking or ironmaking furnace charge |
Country Status (1)
| Country | Link |
|---|---|
| CA (2) | CA2852813C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016190857A1 (en) * | 2015-05-27 | 2016-12-01 | Harsco Corporation | Ionic agricultural particle, ionic agricultural composition, and process of forming an ionic agricultural composition |
-
2014
- 2014-05-29 CA CA2852813A patent/CA2852813C/en active Active
- 2014-08-29 CA CA2861315A patent/CA2861315C/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CA2861315A1 (en) | 2014-10-31 |
| CA2861315C (en) | 2017-02-21 |
| CA2852813A1 (en) | 2014-08-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9499878B2 (en) | Composite briquette for steelmaking or ironmaking furnace charge | |
| KR100694012B1 (en) | Slag conditioner composition, preparation method thereof and method for use in steel production | |
| KR101258450B1 (en) | Process for producing foamed slag | |
| JP6599465B2 (en) | Dephosphorization process from molten metal during the refining process | |
| KR101475125B1 (en) | Unfired carbon-containing agglomerate for blast furnaces and production method therefor | |
| CN102251073A (en) | Deoxidizing and carburizing agent for semisteel, and preparation and application methods thereof | |
| US9499755B2 (en) | Composite briquette for steelmaking or ironmaking furnace charge | |
| CA2241574C (en) | Composite briquette for electric furnace charge | |
| CN104726643A (en) | Technique for using calcium carbonate carbon spheres in LF (ladle furnace) steelmaking | |
| CA2852813C (en) | Composite briquette for steelmaking or ironmaking furnace charge | |
| CN102718508A (en) | Application of magnesite composite material preparation method in nickel-iron high carbon ferrochrome production by submerged arc furnace | |
| RU2352648C2 (en) | Charge for manufacturing of bricks for metallurgical production | |
| RU2321647C1 (en) | Iron-containing waste material such as scale briquetting method for melting | |
| RU2213788C2 (en) | Method of steel-making in electric-arc furnace | |
| US10392574B2 (en) | Charge carbon briquette for electric arc steelmaking furnace | |
| WO2018204773A1 (en) | Cokeless sinter blend compositions | |
| JP2001303116A (en) | Hot metal desulfurizing agent and its use | |
| CN102560008B (en) | Submerged arc slag for refining aluminum-containing low-silicon steel ladle and preparation method for submerged arc slag | |
| RU2657258C1 (en) | High-temperature magnesium flux for steel-fuel furnace and method of high-temperature magnesium flux producing for steel-fuel furnace | |
| RU2298584C2 (en) | Briquette for smelting steel | |
| SU1018987A1 (en) | Method for making exothermic briquets | |
| RU2403295C1 (en) | Briquette for washing of blast furnace (versions) and manufacturing method thereof | |
| Kushnarev et al. | Experience with MgO-bearing materials for raising the stability of converter linings | |
| RU2201976C2 (en) | Charge for production of briquettes for melting ferroalloys | |
| KR20120137414A (en) | Briquette for producing a foamed slag effect in eaf technology in stainless steel production |