CA2861315C - Composite briquette for steelmaking or ironmaking furnace charge - Google Patents
Composite briquette for steelmaking or ironmaking furnace charge Download PDFInfo
- Publication number
- CA2861315C CA2861315C CA2861315A CA2861315A CA2861315C CA 2861315 C CA2861315 C CA 2861315C CA 2861315 A CA2861315 A CA 2861315A CA 2861315 A CA2861315 A CA 2861315A CA 2861315 C CA2861315 C CA 2861315C
- Authority
- CA
- Canada
- Prior art keywords
- briquette
- furnace
- charge
- magnesium carbonate
- binder
- 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 at least 15 % by weight of magnesium carbonate, and a binder.
Description
COMPOSITE BRIQUETTE FOR STEELMAKING OR IRONMAKING
FURNACE CHARGE
Field PH] The present invention relates generally to ferrous metallurgy and in particular, to a composite briquette for a steelmaking or ironmaking furnace charge.
Background [00021 In the field of steelmaking, an electric furnace 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 (about 12.7 mm).
[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 metallurgical 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.
[0004] It would also be of advantage to improve the quality of the slag through the addition of a briquette.
10005] It is an object at least to provide a novel composite briquette for a 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: at least 80 % by weight of magnesium carbonate; and from 1 to 20 % by weight of a binder, the binder comprising molasses and lime.
[0007] The briquette may comprise about 90 % by weight magnesium carbonate and about 10 % by weight of the binder.
FURNACE CHARGE
Field PH] The present invention relates generally to ferrous metallurgy and in particular, to a composite briquette for a steelmaking or ironmaking furnace charge.
Background [00021 In the field of steelmaking, an electric furnace 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 (about 12.7 mm).
[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 metallurgical 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.
[0004] It would also be of advantage to improve the quality of the slag through the addition of a briquette.
10005] It is an object at least to provide a novel composite briquette for a 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: at least 80 % by weight of magnesium carbonate; and from 1 to 20 % by weight of a binder, the binder comprising molasses and lime.
[0007] The briquette may comprise about 90 % by weight magnesium carbonate and about 10 % by weight of the binder.
- 2 -[0008] The briquette may further comprise one or more substances selected from the group consisting of limestone (CaCO3), dolomite (CaMg(CO3)2), dolime (Ca0=Mg0), burnt lime (CaO), hydrated lime (Ca(OH)2), and magnesium oxide (MgO).
[0009] The briquette may further comprise one or more carbonaceous substances selected from the group consisting of: metallurgical coke, carbon fines, anthracite, and non-anthracitic coal.
[00010] The briquette may comprise from 5 to 19 % by weight of the carbonaceous substances.
[00011] The briquette may further comprise from 1 to 15 % by weight of magnesium oxide.
[00012] The magnesium carbonate may be powdered magnesium carbonate ore, and wherein briquette, after calcining, may further comprise one or more substances selected from the group consisting of: CaO, A1203, Si02, and Fe203.
[00013] The furnace may be an electric arc furnace or a basic oxygen furnace.
[00014] In one embodiment, there is provided the 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.
[00015] 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: compressing a quantity of magnesium carbonate and a binder in a suitable mold to make a briquette, the binder comprising molasses and lime, the briquette comprising at least 80 % by weight magnesium carbonate and from 1 to 20 % by weight of the binder; and introducing said briquette to the charge below the slag in the steelmaking furnace, whereby upon introducing the briquette to the charge, CO2 is generated, such that the CO,) foams the slag from underneath.
[00016] The briquette may comprise about 90 % by weight magnesium carbonate and about 10 % by weight of the binder.
[00017] The briquette may further comprise one or more carbonaceous substances selected from the group consisting of: metallurgical coke, carbon fines,
[0009] The briquette may further comprise one or more carbonaceous substances selected from the group consisting of: metallurgical coke, carbon fines, anthracite, and non-anthracitic coal.
[00010] The briquette may comprise from 5 to 19 % by weight of the carbonaceous substances.
[00011] The briquette may further comprise from 1 to 15 % by weight of magnesium oxide.
[00012] The magnesium carbonate may be powdered magnesium carbonate ore, and wherein briquette, after calcining, may further comprise one or more substances selected from the group consisting of: CaO, A1203, Si02, and Fe203.
[00013] The furnace may be an electric arc furnace or a basic oxygen furnace.
[00014] In one embodiment, there is provided the 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.
[00015] 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: compressing a quantity of magnesium carbonate and a binder in a suitable mold to make a briquette, the binder comprising molasses and lime, the briquette comprising at least 80 % by weight magnesium carbonate and from 1 to 20 % by weight of the binder; and introducing said briquette to the charge below the slag in the steelmaking furnace, whereby upon introducing the briquette to the charge, CO2 is generated, such that the CO,) foams the slag from underneath.
[00016] The briquette may comprise about 90 % by weight magnesium carbonate and about 10 % by weight of the binder.
[00017] The briquette may further comprise one or more carbonaceous substances selected from the group consisting of: metallurgical coke, carbon fines,
- 3 -anthracite, and non-anthracitic coal. The briquette may comprise from 5 to 19 A by weight of the carbonaceous substances.
[00018] The magnesium carbonate may be powdered magnesium carbonate ore, and the briquette, after calcining, may further comprise one or more substances selected from the group consisting of: CaO, A1203, Si02, and Fe203.
[000191 The furnace may be an electric arc furnace or a basic oxygen furnace.
[00020] In another 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.
[00021] The briquette may further comprise one or more selected from the group consisting of: burnt lime, hydrated lime, dolomite, and dolime.
[00022] 50 % of the total briquette weight may be carbon fines, 25 % of the total briquette weight may be iron powder, and the remainder of the total briquette weight, apart from the binder, may be magnesium carbonate and limestone.
[00023] The briquette may comprise from 1 to 20 % by weight of the binder.
[00024] The furnace may be an electric arc furnace or a basic oxygen furnace.
[00025] In one embodiment, there is provided the 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.
[00026] 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 carbonate, 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; 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.
[00027] The mixture may further comprise one or more selected from the group consisting of: burnt lime, hydrated lime, dolomite, and dolime.
[00018] The magnesium carbonate may be powdered magnesium carbonate ore, and the briquette, after calcining, may further comprise one or more substances selected from the group consisting of: CaO, A1203, Si02, and Fe203.
[000191 The furnace may be an electric arc furnace or a basic oxygen furnace.
[00020] In another 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.
[00021] The briquette may further comprise one or more selected from the group consisting of: burnt lime, hydrated lime, dolomite, and dolime.
[00022] 50 % of the total briquette weight may be carbon fines, 25 % of the total briquette weight may be iron powder, and the remainder of the total briquette weight, apart from the binder, may be magnesium carbonate and limestone.
[00023] The briquette may comprise from 1 to 20 % by weight of the binder.
[00024] The furnace may be an electric arc furnace or a basic oxygen furnace.
[00025] In one embodiment, there is provided the 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.
[00026] 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 carbonate, 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; 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.
[00027] The mixture may further comprise one or more selected from the group consisting of: burnt lime, hydrated lime, dolomite, and dolime.
- 4 -[00028] 50 % of the total briquette weight may be carbon fines, 25 % of the total briquette weight may be iron powder, and the remainder of the total briquette weight, apart from the binder, may be magnesium carbonate and limestone.
[00029] Upon introducing the briquette to the charge, CO2 may be generated such that the CO2 foams the slag from underneath.
[00030] The mixture may comprise from 1 to 20 % by weight of the binder.
[00031] The binder may comprise molasses and hydrated lime.
[00032] The furnace may be an electric arc furnace or a basic oxygen furnace.
[00029] Upon introducing the briquette to the charge, CO2 may be generated such that the CO2 foams the slag from underneath.
[00030] The mixture may comprise from 1 to 20 % by weight of the binder.
[00031] The binder may comprise molasses and hydrated lime.
[00032] The furnace may be an electric arc furnace or a basic oxygen furnace.
- 5 -Detailed Description of the Embodiments [00033] 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).
[00034] 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.
[00035] Table 1 shows a non-limiting example of a mixture from which a briquette can be fashioned:
TABLE 1:
Carbon C 50%
Powdered iron Fe 25 %
Magnesium carbonate MgCO3 25 %
Total 100 %
1000361 In the table above, deviations from the indicated percentages are permissible. In this embodiment, the carbon is in the form of loose carbon fines recovered from a dust collector, such as a dust collector of an electric arc furnace, and
[00034] 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.
[00035] Table 1 shows a non-limiting example of a mixture from which a briquette can be fashioned:
TABLE 1:
Carbon C 50%
Powdered iron Fe 25 %
Magnesium carbonate MgCO3 25 %
Total 100 %
1000361 In the table above, deviations from the indicated percentages are permissible. In this embodiment, the carbon is in the form of loose carbon fines recovered from a dust collector, such as a dust collector of an electric arc furnace, and
- 6 -the magnesium carbonate is in the form of powdered magnesium carbonate ore.
The mixture may be combined with a suitable binder, such as for example industrial molasses and powdered hydrated lime (Ca(OH)2), and the binder may make up 1 to 20 %, or more, of the total weight of the briquette.
[00037] 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.
[00038] The magnesium carbonate could be combined with limestone and/or dolomite, each of which will produce CO2 gas. Dolime (CaO MgO), burnt lime (CaO), hydrated lime (Ca(OH)2), and/or magnesium oxide (MgO) may also be included.
[00039] 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. Preferably, the furnace is a blast furnace or an electric arc furnace.
[00040] 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 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.
[00041] 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 the reaction yield. Additionally, if the steelmaking furnace is an electric arc furnace, the
The mixture may be combined with a suitable binder, such as for example industrial molasses and powdered hydrated lime (Ca(OH)2), and the binder may make up 1 to 20 %, or more, of the total weight of the briquette.
[00037] 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.
[00038] The magnesium carbonate could be combined with limestone and/or dolomite, each of which will produce CO2 gas. Dolime (CaO MgO), burnt lime (CaO), hydrated lime (Ca(OH)2), and/or magnesium oxide (MgO) may also be included.
[00039] 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. Preferably, the furnace is a blast furnace or an electric arc furnace.
[00040] 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 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.
[00041] 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 the reaction yield. Additionally, if the steelmaking furnace is an electric arc furnace, the
- 7 -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.
[00042] 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.
[00043] 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 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.
[00044] Preferably, the briquette comprises from 20 to 80 % by weight of the carbon fines. More preferably, the briquette comprises 30 to 70 % by weight of the binder, more preferably 40 to 60 %, most preferably about 45 %.
[00045] Although in the embodiment described above, the carbon is in the form of carbon fines, in other embodiments, the carbon may alternatively be in the form of one or more other carbonaceous substances, such as for example such as metallurgical coke, anthracite, non-anthracitic coal, and the like.
[00046] 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 to improve the quality of the slag.
[00047] For example, powdered magnesium carbonate ore may be combined with a suitable binder, such as for example industrial molasses and powdered hydrated lime, and compressed in a suitable mold to make a briquette. The binder may make up 1 to 20 %, or more, of the total weight of the briquette.
=
[00042] 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.
[00043] 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 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.
[00044] Preferably, the briquette comprises from 20 to 80 % by weight of the carbon fines. More preferably, the briquette comprises 30 to 70 % by weight of the binder, more preferably 40 to 60 %, most preferably about 45 %.
[00045] Although in the embodiment described above, the carbon is in the form of carbon fines, in other embodiments, the carbon may alternatively be in the form of one or more other carbonaceous substances, such as for example such as metallurgical coke, anthracite, non-anthracitic coal, and the like.
[00046] 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 to improve the quality of the slag.
[00047] For example, powdered magnesium carbonate ore may be combined with a suitable binder, such as for example industrial molasses and powdered hydrated lime, and compressed in a suitable mold to make a briquette. The binder may make up 1 to 20 %, or more, of the total weight of the briquette.
=
- 8 -[00048] The amount of magnesium carbonate in the briquette may be selected according to the particular characteristics of the furnace and to the particular steel grade. Preferably, the briquette comprises at least 15 % by weight of magnesium carbonate. More preferably, the briquette comprises 50 to 95 % by weight of magnesium carbonate, still more preferably 70 to 95 %, and most preferably 90%.
1000491 The magnesium carbonate could be combined with one or more other substances, if adjustment of slag functionalities (e.g. alumina gettering, desulphurization, etc.) is desired. Such substances may comprise, for example, limestone and/or dolomite, each of which will produce CO2 gas upon decomposition, and/or any of dolime, burnt lime, hydrated lime, and magnesium oxide. Still other substances may be combined with the magnesium carbonate. As will be understood, an advantage of using a binder comprising hydrated lime is the efficient and controlled addition of CaO to the slag for predictable adjustment of slag functionalities.
1000501 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. Preferably, the furnace is a blast furnace or an electric arc furnace.
[00051] 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 (CO2). The 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.
[00052] 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.
1000531 In still another embodiment, the briquette may alternatively comprise a mixture of magnesium carbonate and one or more carbonaceous substances, such as metallurgical coke, carbon fines, anthracite, non-anthracitic coal, and the like. For example, powdered magnesium carbonate ore and powdered metallurgical coke may
1000491 The magnesium carbonate could be combined with one or more other substances, if adjustment of slag functionalities (e.g. alumina gettering, desulphurization, etc.) is desired. Such substances may comprise, for example, limestone and/or dolomite, each of which will produce CO2 gas upon decomposition, and/or any of dolime, burnt lime, hydrated lime, and magnesium oxide. Still other substances may be combined with the magnesium carbonate. As will be understood, an advantage of using a binder comprising hydrated lime is the efficient and controlled addition of CaO to the slag for predictable adjustment of slag functionalities.
1000501 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. Preferably, the furnace is a blast furnace or an electric arc furnace.
[00051] 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 (CO2). The 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.
[00052] 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.
1000531 In still another embodiment, the briquette may alternatively comprise a mixture of magnesium carbonate and one or more carbonaceous substances, such as metallurgical coke, carbon fines, anthracite, non-anthracitic coal, and the like. For example, powdered magnesium carbonate ore and powdered metallurgical coke may
- 9 -be combined with a suitable binder, such as for example industrial molasses and powdered hydrated lime, and compressed in a suitable mold to make a briquette.
The binder may make up 1 to 20 %, or more, of the total weight of the briquette.
[00054] The amount of magnesium carbonate in the briquette may be selected according to the particular characteristics of the furnace and to the particular steel grade. Preferably, the briquette comprises at least 15 % by weight of magnesium carbonate. Preferably, the briquette comprises 30 to 90 % by weight of magnesium carbonate, more preferably 40 to 90 %, most preferably about 50 to about 75 %.
[00055] Preferably, the briquette comprises from 5 to 50 % by weight of the one or more carbonaceous substances. More preferably, the briquette comprises
The binder may make up 1 to 20 %, or more, of the total weight of the briquette.
[00054] The amount of magnesium carbonate in the briquette may be selected according to the particular characteristics of the furnace and to the particular steel grade. Preferably, the briquette comprises at least 15 % by weight of magnesium carbonate. Preferably, the briquette comprises 30 to 90 % by weight of magnesium carbonate, more preferably 40 to 90 %, most preferably about 50 to about 75 %.
[00055] Preferably, the briquette comprises from 5 to 50 % by weight of the one or more carbonaceous substances. More preferably, the briquette comprises
10 to 40 % by weight of the binder, more still preferably 10 to 35 %, most preferably either about 14 % or about 30 %.
[00056] One or more other substances could be combined with the powdered magnesium carbonate ore and powdered metallurgical coke, if adjustment of slag functionalities (e.g. alumina gettering, desulphurization, etc.) is desired.
Such substances may comprise, for example, limestone and/or dolomite, each of which will produce CO2 gas upon decomposition, and/or any of dolime, burnt lime, hydrated lime, and magnesium oxide. Still other substances may be combined with the magnesium carbonate and powdered metallurgical coke.
[00057] 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. Preferably, the furnace is a blast furnace or an electric arc furnace.
[00058] 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 (CO2). The 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.
[00059] As will be appreciated, the combination of a carbonaceous substance with one or more denser compounds, such as magnesium carbonate, in briquette form advantageously enables carbon to be introduced into the bath in a more facile manner, as compared to adding loose carbonaceous powder, and thereby increases the carbon addition efficiency. This higher carbon addition efficiency advantageously allows the final carbon composition in the bath and in the slag to be more accurately predicted.
[00060] Although in the embodiments described above, the binder comprises industrial molasses and hydrated lime, in other embodiments, the binder may alternatively comprise dextrin and water, which may for example be combined in a 7:3 weight ratio. Still other suitable binders may alternatively be used.
[00061] In the embodiments described above, the briquette may comprise from 1 to 20 % or more, by weight, of the binder. Preferably, the briquette comprises from 1 to 15 % by weight of the binder. More preferably, the briquette comprises 5 to 15 % by weight of the binder, more preferably 7 to 12 %, most preferably 10 %.
[00062] Although in the embodiments described above, the powdered magnesium carbonate is in the form of powdered magnesium carbonate ore, in other embodiments, other suitable sources of magnesium carbonate may alternatively be used.
[00063] The briquette of the embodiments described above may be made from powders having particle sizes within any suitable range.
[00064] The following examples illustrate various applications of the above-described embodiments.
[00065] EXAMPLE 1 [00066] In this example, a briquette having the composition (wt %) shown in Table 2, was made:
TABLE 2:
Carbon fines 43.6 %
Fe 22.1 %
Dolomite 24.3 %
Molasses 6.0 %
Lime (hyd.) 4.0 %
[00067] The briquette was formed by providing a mixture of loose carbon fines (particle size range of about 0.8 to about 1.0 mm) recovered from a dust collector of
[00056] One or more other substances could be combined with the powdered magnesium carbonate ore and powdered metallurgical coke, if adjustment of slag functionalities (e.g. alumina gettering, desulphurization, etc.) is desired.
Such substances may comprise, for example, limestone and/or dolomite, each of which will produce CO2 gas upon decomposition, and/or any of dolime, burnt lime, hydrated lime, and magnesium oxide. Still other substances may be combined with the magnesium carbonate and powdered metallurgical coke.
[00057] 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. Preferably, the furnace is a blast furnace or an electric arc furnace.
[00058] 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 (CO2). The 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.
[00059] As will be appreciated, the combination of a carbonaceous substance with one or more denser compounds, such as magnesium carbonate, in briquette form advantageously enables carbon to be introduced into the bath in a more facile manner, as compared to adding loose carbonaceous powder, and thereby increases the carbon addition efficiency. This higher carbon addition efficiency advantageously allows the final carbon composition in the bath and in the slag to be more accurately predicted.
[00060] Although in the embodiments described above, the binder comprises industrial molasses and hydrated lime, in other embodiments, the binder may alternatively comprise dextrin and water, which may for example be combined in a 7:3 weight ratio. Still other suitable binders may alternatively be used.
[00061] In the embodiments described above, the briquette may comprise from 1 to 20 % or more, by weight, of the binder. Preferably, the briquette comprises from 1 to 15 % by weight of the binder. More preferably, the briquette comprises 5 to 15 % by weight of the binder, more preferably 7 to 12 %, most preferably 10 %.
[00062] Although in the embodiments described above, the powdered magnesium carbonate is in the form of powdered magnesium carbonate ore, in other embodiments, other suitable sources of magnesium carbonate may alternatively be used.
[00063] The briquette of the embodiments described above may be made from powders having particle sizes within any suitable range.
[00064] The following examples illustrate various applications of the above-described embodiments.
[00065] EXAMPLE 1 [00066] In this example, a briquette having the composition (wt %) shown in Table 2, was made:
TABLE 2:
Carbon fines 43.6 %
Fe 22.1 %
Dolomite 24.3 %
Molasses 6.0 %
Lime (hyd.) 4.0 %
[00067] The briquette was formed by providing a mixture of loose carbon fines (particle size range of about 0.8 to about 1.0 mm) recovered from a dust collector of
- 11 -an electric arc furnace, powdered iron (particle size range of about 0.4 to about 0.6 mm), and a powdered dolomite ore (particle size range of about 0.8 to about 4.8 mm), together with a binder consisting of a mixture of industrial molasses and powdered hydrated lime.
[00068] As will be understood, the powdered iron could be replaced with powdered iron oxide (Fe203), which will produce CO2 gas and contribute to the foaming effect described above.
[00069] The briquette had the post-calcination composition (wt %) shown in Table 3:
TABLE 3:
43.7%
Fe 22.5 %
CaO 12.2%
MgO 6.6%
2.9%
L.O.I. 12.1 %
[00070] 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.
[00071] 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 g/cm3. 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 g/cm3.
[00072] 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.
[00073] EXAMPLE 2
[00068] As will be understood, the powdered iron could be replaced with powdered iron oxide (Fe203), which will produce CO2 gas and contribute to the foaming effect described above.
[00069] The briquette had the post-calcination composition (wt %) shown in Table 3:
TABLE 3:
43.7%
Fe 22.5 %
CaO 12.2%
MgO 6.6%
2.9%
L.O.I. 12.1 %
[00070] 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.
[00071] 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 g/cm3. 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 g/cm3.
[00072] 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.
[00073] EXAMPLE 2
- 12 -[00074] In this example, a briquette having the post-calcination composition (wt %) shown in Table 4 was made:
TABLE 4:
MgO 92.19%
CaO 2.46%
A1203 0.85 %
Si02 2.58 %
TiO2 0.14%
Fe203 0.71 %
Cr203 0.02 %
MnO 0.05%
< 0.001 %
Moisture 1.0%
Total 100%
[00075] The briquette was formed by providing a mixture of powdered magnesium carbonate ore (particle size range of about 0.8 to about 4.8 mm) 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 hydrated lime, combined in a weight ratio of 3:2.
[00076] The briquette had a generally square shape and a size of about 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 loose powder of Example 3.
[00077] 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 5. For comparison, a summary of the performance of a standard conventional additive, namely crushed brick ("standard practice"), during the reactions is also shown:
TABLE 4:
MgO 92.19%
CaO 2.46%
A1203 0.85 %
Si02 2.58 %
TiO2 0.14%
Fe203 0.71 %
Cr203 0.02 %
MnO 0.05%
< 0.001 %
Moisture 1.0%
Total 100%
[00075] The briquette was formed by providing a mixture of powdered magnesium carbonate ore (particle size range of about 0.8 to about 4.8 mm) 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 hydrated lime, combined in a weight ratio of 3:2.
[00076] The briquette had a generally square shape and a size of about 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 loose powder of Example 3.
[00077] 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 5. For comparison, a summary of the performance of a standard conventional additive, namely crushed brick ("standard practice"), during the reactions is also shown:
- 13 -TABLE 5:
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 soln. (wt %) 8.79 1.75 9.20 1.88 +4.66 %
Briquette A with 1st charge (wt 10.69 1.80 Briquette A with 2' charge (wt 7.95 0.62 %) [00078] As may be seen, the use of Briquette A results in a reduction of the actual MgO added by about 35 %, while advantageously increasing the average MgO
in the slag by about 4.5 %. The amount of MgO 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.
[00079] The decomposition of magnesium carbonate within Briquette A
produces fine, active MgO particles, which are absorbed by the slag. It was observed that when Briquettes A were added and the briquettes penetrated the slag so as to be buried in the charge, tiny bubbles of CO2 were seen to form.
[00080] The average composition of the slag after the reactions, by weight percent, is shown in Table 6:
TABLE 6:
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 %
Si02 11.83 3.75 13.23 1.44 + 11.83%
Fe2O3 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 soln. (wt %) 8.79 1.75 9.20 1.88 +4.66 %
Briquette A with 1st charge (wt 10.69 1.80 Briquette A with 2' charge (wt 7.95 0.62 %) [00078] As may be seen, the use of Briquette A results in a reduction of the actual MgO added by about 35 %, while advantageously increasing the average MgO
in the slag by about 4.5 %. The amount of MgO 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.
[00079] The decomposition of magnesium carbonate within Briquette A
produces fine, active MgO particles, which are absorbed by the slag. It was observed that when Briquettes A were added and the briquettes penetrated the slag so as to be buried in the charge, tiny bubbles of CO2 were seen to form.
[00080] The average composition of the slag after the reactions, by weight percent, is shown in Table 6:
TABLE 6:
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 %
Si02 11.83 3.75 13.23 1.44 + 11.83%
Fe2O3 27.71 7.32 24.59 5.53 - 11.26%
Mn203 5.46 1.03 5.31 0.37 - 2.82 %
- 14 -[00081] 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.
[00082] 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 7:
TABLE 7:
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) [00083] As may be seen, the amount of power required for the reaction is lower when Briquette A is used, as compared to standard practice.
[00084] EXAMPLE 3 [00085] Magnesium carbonate may alternatively be added to the charge in the form of a loose powder. A loose, powdered magnesium carbonate ore (particle size range of about 0.8 to about 4.8 mm) having the post-calcination composition (wt %) shown in Table 8 was used:
TABLE 8:
MgO 97.0%
CaO 2.0%
A1203 0.2 %
SiO2 0.3 %
Fe203 0.5 %
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.
[00082] 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 7:
TABLE 7:
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) [00083] As may be seen, the amount of power required for the reaction is lower when Briquette A is used, as compared to standard practice.
[00084] EXAMPLE 3 [00085] Magnesium carbonate may alternatively be added to the charge in the form of a loose powder. A loose, powdered magnesium carbonate ore (particle size range of about 0.8 to about 4.8 mm) having the post-calcination composition (wt %) shown in Table 8 was used:
TABLE 8:
MgO 97.0%
CaO 2.0%
A1203 0.2 %
SiO2 0.3 %
Fe203 0.5 %
- 15 -Total 100%
[00086] The loose powder had a density of 2.28 g/cm3 and a white colour.
[00087] The loose powder was used during a reaction in a 125 tonne electric arc furnace.
[00088] The loose powder had a L.O.I. value of 51.1 %. Notably, the L.O.I.
value of the loose powder is greater than the L.O.I. value of the briquette of Example 2.
[00089] EXAMPLE 4 [00090] In this example, a briquette having the composition (wt %) shown in Table 9 was made:
TABLE 9:
Metallurgical 30.3 %
coke MgO 9.1%
MgCO3 51.6%
Molasses 5.4 %
Lime (hyd.) 3.6%
[00091] The briquette was formed by providing a mixture of powdered metallurgical coke (particle size range of about 0.8 to about 1.0 mm), powdered magnesium oxide (particle size range of about 0.4 to about 0.6 mm), and powdered magnesium carbonate ore (particle size range of about 0.8 to about 4.8 mm), together with a binder consisting of a mixture of industrial molasses and powdered hydrated lime.
[00092] The briquette had a generally square shape and a size of about 54 mm per side, with a density of about 2.0 g/cm3 and a black colour.
[00093] The briquette had the post-calcination composition (wt %) shown in Table 10:
[00086] The loose powder had a density of 2.28 g/cm3 and a white colour.
[00087] The loose powder was used during a reaction in a 125 tonne electric arc furnace.
[00088] The loose powder had a L.O.I. value of 51.1 %. Notably, the L.O.I.
value of the loose powder is greater than the L.O.I. value of the briquette of Example 2.
[00089] EXAMPLE 4 [00090] In this example, a briquette having the composition (wt %) shown in Table 9 was made:
TABLE 9:
Metallurgical 30.3 %
coke MgO 9.1%
MgCO3 51.6%
Molasses 5.4 %
Lime (hyd.) 3.6%
[00091] The briquette was formed by providing a mixture of powdered metallurgical coke (particle size range of about 0.8 to about 1.0 mm), powdered magnesium oxide (particle size range of about 0.4 to about 0.6 mm), and powdered magnesium carbonate ore (particle size range of about 0.8 to about 4.8 mm), together with a binder consisting of a mixture of industrial molasses and powdered hydrated lime.
[00092] The briquette had a generally square shape and a size of about 54 mm per side, with a density of about 2.0 g/cm3 and a black colour.
[00093] The briquette had the post-calcination composition (wt %) shown in Table 10:
- 16 -TABLE 10:
C 28.7%
Fe 0.5%
CaO 3.5%
MgO 35.3%
A1203 0.5 %
Si02 1.7%
N 0.1%
L.O.I. 29.7 %
[00094] The briquette had a L.O.I. value of 29.7 %, which is mainly attributed to the decomposition of the magnesium carbonate and the binder.
[00095] The density of the briquette, namely 2.0 g/cm3, is greater than that of loose powdered metallurgical coke, which has a density of about 0.5 g/cm3. As will be appreciated, the higher density of the briquette 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.
[00096] EXAMPLE 5 [00097] In this example, a briquette having the composition (wt %) shown in Table 11 was made:
TABLE 11:
Metallurgical 14.0 A
coke MgCO3 76.0 %
Molasses 6.0%
Lime (hyd.) 4.0 %
[00098] The briquette was formed by providing a mixture of powdered metallurgical coke (particle size range of about 0.8 to about 1.0 mm) and powdered magnesium carbonate ore (particle size range of about 0.8 to about 4.8 mm), together =
C 28.7%
Fe 0.5%
CaO 3.5%
MgO 35.3%
A1203 0.5 %
Si02 1.7%
N 0.1%
L.O.I. 29.7 %
[00094] The briquette had a L.O.I. value of 29.7 %, which is mainly attributed to the decomposition of the magnesium carbonate and the binder.
[00095] The density of the briquette, namely 2.0 g/cm3, is greater than that of loose powdered metallurgical coke, which has a density of about 0.5 g/cm3. As will be appreciated, the higher density of the briquette 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.
[00096] EXAMPLE 5 [00097] In this example, a briquette having the composition (wt %) shown in Table 11 was made:
TABLE 11:
Metallurgical 14.0 A
coke MgCO3 76.0 %
Molasses 6.0%
Lime (hyd.) 4.0 %
[00098] The briquette was formed by providing a mixture of powdered metallurgical coke (particle size range of about 0.8 to about 1.0 mm) and powdered magnesium carbonate ore (particle size range of about 0.8 to about 4.8 mm), together =
- 17 -with a binder consisting of a mixture of industrial molasses and powdered hydrated lime.
[00099] The briquette had a generally square shape and a size of about 54 mm per side, with a density of about 2.0 g/cm3 and a black colour.
[000100] The briquette had the post-calcination composition (wt %) shown in Table 12:
TABLE 12:
14.1%
FeO 0.2 %
CaO 3.4%
MgO 38.7%
A1203 0.1 %
Si 02 0.6 %
0.1%
L.O.I. 42.8 %
[000101] The briquette had a L.O.I. value of 42.8 %, which is mainly attributed to the decomposition of the magnesium carbonate and the binder.
[000102] The density of the briquette, namely 2.0 g/cm3, is greater than that of loose powdered metallurgical coke, which has a density of about 0.5 g/cm3. As will be appreciated, the higher density of the briquette 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.
[000103] 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.
[00099] The briquette had a generally square shape and a size of about 54 mm per side, with a density of about 2.0 g/cm3 and a black colour.
[000100] The briquette had the post-calcination composition (wt %) shown in Table 12:
TABLE 12:
14.1%
FeO 0.2 %
CaO 3.4%
MgO 38.7%
A1203 0.1 %
Si 02 0.6 %
0.1%
L.O.I. 42.8 %
[000101] The briquette had a L.O.I. value of 42.8 %, which is mainly attributed to the decomposition of the magnesium carbonate and the binder.
[000102] The density of the briquette, namely 2.0 g/cm3, is greater than that of loose powdered metallurgical coke, which has a density of about 0.5 g/cm3. As will be appreciated, the higher density of the briquette 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.
[000103] 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:
at least 80 % by weight of magnesium carbonate; and from 1 to 20 % by weight of a binder, the binder comprising molasses and lime.
at least 80 % by weight of magnesium carbonate; and from 1 to 20 % by weight of a binder, the binder comprising molasses and lime.
2. The briquette of claim 1, wherein the briquette comprises about 90%
by weight magnesium carbonate and about 10 % by weight of the binder.
by weight magnesium carbonate and about 10 % by weight of the binder.
3. The briquette of claim 1 or 2, wherein the furnace is an electric arc furnace or a basic oxygen furnace.
4. 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.
5. 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:
compressing a quantity of magnesium carbonate and a binder in a suitable mold to make a briquette, the binder comprising molasses and lime, the briquette comprising at least 80 % by weight magnesium carbonate and from 1 to % by weight of the binder; and introducing said briquette to the charge below the slag in the steelmaking furnace, whereby upon introducing the briquette to the charge, CO2 is generated, such that the CO2 foams the slag from underneath.
compressing a quantity of magnesium carbonate and a binder in a suitable mold to make a briquette, the binder comprising molasses and lime, the briquette comprising at least 80 % by weight magnesium carbonate and from 1 to % by weight of the binder; and introducing said briquette to the charge below the slag in the steelmaking furnace, whereby upon introducing the briquette to the charge, CO2 is generated, such that the CO2 foams the slag from underneath.
6. The method of claim 5, wherein the briquette comprises about 90% by weight magnesium carbonate and about 10 % by weight of the binder.
7. The method of claim 5 or 6, wherein the furnace is an electric arc furnace or a basic oxygen furnace.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2861315A CA2861315C (en) | 2014-05-29 | 2014-08-29 | Composite briquette for steelmaking or ironmaking furnace charge |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2852813 | 2014-05-29 | ||
| 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 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2861315A1 CA2861315A1 (en) | 2014-10-31 |
| CA2861315C true CA2861315C (en) | 2017-02-21 |
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 Before (1)
| 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 |
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 |
| CA2852813A1 (en) | 2014-08-11 |
| CA2852813C (en) | 2017-10-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2949765B1 (en) | Composite briquette and method for making a steelmaking furnace charge | |
| KR100694012B1 (en) | A slag conditioner composition, process for manufacture and method of use in steel production | |
| KR100958987B1 (en) | Lime-based additive for steel smelting and the preparation method thereof | |
| CA2729876C (en) | Process for producing foamed slag | |
| CA2972936C (en) | Process for dephosphorization of molten metal during a refining process | |
| US9499755B2 (en) | Composite briquette for steelmaking or ironmaking furnace charge | |
| CN102251073B (en) | Deoxidizing and carburizing agent for semisteel, and preparation and application methods thereof | |
| JP2019525880A (en) | Heat treated briquettes containing "raw" calcium-magnesium compound and calcium ferrite and method for making the same | |
| CA2241574C (en) | Composite briquette for electric furnace charge | |
| JP2007277664A (en) | Lime-based flux for refining | |
| CA2861315C (en) | Composite briquette for steelmaking or ironmaking furnace charge | |
| RU2506326C2 (en) | Extrusion-type briquette (breks) - component of blast-furnace charge | |
| CN103667688B (en) | Method for performing boron and iron separation on paigeite | |
| RU2321647C1 (en) | Iron-containing waste material such as scale briquetting method for melting | |
| WO2018204773A1 (en) | Cokeless sinter blend compositions | |
| Pal | Utilization of Microfines in Iron and Steel Making | |
| 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 | |
| PL219537B1 (en) | Method for recovery of iron wastes | |
| UA20811U (en) | Method for charge preparation for the melting | |
| UA81853C2 (en) | Iron-containing briquette | |
| KR20010018676A (en) | A recarburizer composition utilizing wastes | |
| JP2009030144A (en) | Method for producing sintered ore |