AU2017388174A1 - Sintered ore manufacturing method - Google Patents
Sintered ore manufacturing method Download PDFInfo
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- AU2017388174A1 AU2017388174A1 AU2017388174A AU2017388174A AU2017388174A1 AU 2017388174 A1 AU2017388174 A1 AU 2017388174A1 AU 2017388174 A AU2017388174 A AU 2017388174A AU 2017388174 A AU2017388174 A AU 2017388174A AU 2017388174 A1 AU2017388174 A1 AU 2017388174A1
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- iron
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/16—Sintering; Agglomerating
- C22B1/20—Sintering; Agglomerating in sintering machines with movable grates
- C22B1/205—Sintering; Agglomerating in sintering machines with movable grates regulation of the sintering process
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/16—Sintering; Agglomerating
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/24—Binding; Briquetting ; Granulating
- C22B1/2406—Binding; Briquetting ; Granulating pelletizing
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Abstract
The purpose of the present invention is to manufacture, without the use of iron oxide powder containing metallic iron, such as iron manufacturing dust or mill scale, a carbon composite sintered ore (carbon composite agglomerated ore) with a two-layer structure in which an iron-containing raw material and a carbon material are disposed adjacently and the periphery of a carbon material core is covered with a mixed powder comprising powder of the iron-containing raw material and powder of a CaO-containing raw material. Provided is a sintered ore manufacturing method in which a carbon composite sintered ore is manufactured by sintering, on a pallet of a sintering machine, carbon composite pelletized particles with a two-layer structure in which a carbon material core is covered with a mixed powder containing a powder of an iron-containing raw material and a powder of a CaO-containing raw material, wherein the water content of the carbon composite pelletized particles at the time of pelletization is 8–10 mass% of the total mass of the carbon material core, the mixed powder, and the water content.
Description
DESCRIPTION
Title of Invention: METHOD FOR MANUFACTURING SINTERED ORE Technical Field [0001]
The present invention relates to a method for manufacturing sintered ore, which is used as a raw material for making iron in a blast furnace or the like. More specifically, the present invention relates to a method for manufacturing, by using a sintering machine, carbon material-containing sintered ore (carbon material-containing agglomerated ore) having a two-layer structure in which a carbon material core is covered with mixed powder containing iron-containing raw material powder such as iron ore powder and CaO-containing raw material powder.
Background Art [0002]
In an iron-making method with a blast furnace, nowadays, lump ore, sintered ore, pellets, and so forth are used as raw materials for making iron. Here, sintered ore is a kind of agglomerated ore which is manufactured by charging quasiparticles, which are raw materials for manufacturing sintered ore, onto a pallet circulating in a sintering machine, by burning solid fuels contained in the quasiparticles to perform sintering, by crushing and granulating an obtained sintered cake, and by collecting particles having a particle diameter egual to or more than a certain size as a product. The above-mentioned guasi-particles are manufactured by adding an appropriate amount of water to a granulating raw material containing iron-containing raw materials, CaO-containing raw materials, auxiliary raw materials which are other than the CaO-containing raw materials and which are used as melting point-adjusting agents, and solid fuels (carbon materials) such as coke breeze and anthracite, which are used as coagulating raw materials, and so forth and by performing mixing and granulating through the use of a drum mixer or the like. [0003]
Examples of the iron-containing raw materials constituting the guasi-particles include iron ore having a particle diameter of 10 mm or less and dust, mill scale, and so forth, which are generated in a steel plant. Examples of the CaO-containing raw materials include limestone, guicklime, slag, and so forth. Examples of auxiliary raw materials which are other than the CaO-containing raw materials and which are used as melting point-adjusting agents include Si02-containing raw materials such as silica stone, serpentine, dolomite, and nickel refining slag and MgO-containing raw materials such as magnesia clinker and dolomite .
[0004]
In addition, pellets are raw materials for making iron which are manufactured through an iron ore-crushing process, an adjusting process, and a granulating process, through which green pellets are manufactured in a granulating machine, and processes through which the green pellets are dried, baked, and cooled, and pellets are also a kind of agglomerated ore.
[0005]
Nowadays, agglomerated ore which is manufactured by closely arranging iron-containing raw materials such as iron ore and dust and carbon materials such as coke is receiving much attention. This is because, for example, by closely arranging iron-containing raw materials such as iron ore and carbon materials in a single agglomerated ore, the reduction reaction (exothermic reaction) of the iron-containing raw materials and the gasification reaction (endothermic reaction) of the carbon materials are repeated at a high rate, and thus it is possible to increase reduction efficiency and to decrease the interior temperature of a blast furnace or the like.
[0006]
As an example of the agglomerated ore described above, Patent Literature 1 discloses a pellet which is used as a raw material for making iron which is manufactured by adding carbon materials such as coal and coke and starch to iron containing raw material powder generated in iron-making processes such as blast furnace dust, converter dust, mill scale, sludge, and iron ore powder, or a mixture thereof, by performing mixing and kneading, and by granulating the mixture after having added a starch solution in a granulating machine. However, in the case of the pellet disclosed in Patent Literature 1, since carbon materials in the pellet are burnt out when baking is performed, the close arrangement of iron-containing raw materials such as iron ore and carbon materials is not realized. Even in the case where the particle diameter of iron ore and carbon materials is simply decreased to realize the close arrangement in the pellet-manufacturing process, since there is an excessive increase in the flow resistance of a gas, which propagates heat, there is a decrease, rather than increase, in reaction rate, which results in a decrease in reduction efficiency. [0007]
Therefore, some techniques for closely arranging ironcontaining raw materials and carbon materials have been proposed (refer to, for example, Patent Literatures 2 to 5). In the case of such disclosed techniques, basically, after having mixed iron-containing raw materials such as iron ore and carbon materials such as coke, the mixture is used as a raw material for making iron in a blast furnace or the like after the mixture has been agglomerated by performing hot forming or in a raw state, that is, in an unbaked state. However, since such an agglomerated raw material is an unbaked raw material composed of a homogeneous mixture or multi-layer granulated raw materials, there is insufficient strength, which results in severe disintegration. Therefore, charging such an agglomerated raw material into a blast furnace or the like causes disintegration due to dehydration and disintegration due to reduction so that there is a decrease in the gas permeability of the blast furnace, which results in a problem in that the amount of such a raw material available for use is restricted.
[0008]
In addition, techniques for solving the problems of the techniques according to Patent Literatures 2 to 5 have been proposed. For example, Patent Literature 6 proposes a method for manufacturing an iron-making agglomerated ore by forming cores composed of a raw material containing 5 mass% or more of metallic iron and/or 5 mass% or more of carbon, by covering the cores with a raw material containing 10 mass% or more of metallic iron and 5 mass% or less of carbon to form one or more external layers, and by then performing baking in an oxidizing atmosphere having a temperature of 300°C to 1300°C to form agglomerated ore. However, in the case of the manufacturing method disclosed in Patent Literature 6, since it is necessary to use metallic iron as a raw material, and since the amount of the raw material available for use is restricted, there is a problem in that the production quantity of iron-making agglomerated ore is restricted.
[0009]
Therefore, as examples of a technique for solving the above-described problems of Patent Literatures 1 to 6, techniques utilizing carbon material-containing agglomerated ore have been proposed.
[0010]
For example, Patent Literature 7 proposes a technique for manufacturing carbon material-containing agglomerated ore by covering carbon material cores formed of small lump coke with metallic iron-containing iron oxide powder such as iron dust and mill scale to form iron oxide shells having a low oxidation degree through the use of a granulating machine, and by then performing an oxidation treatment of heating the iron oxide shells in atmospheric air at a temperature of 200°C or higher and lower than 300°C for 0.5 hours to 5 hours to form hard thin layers of iron oxide having a high oxidation degree only on the surfaces of the above-mentioned iron oxide shells.
[0011]
In addition, Patent Literature 8 proposes a technique for manufacturing carbon material-containing agglomerated ore containing coke powder having a particle size of 3 mm or less dispersed in iron oxide powder or iron ore powder by mixing and granulating iron oxide powder such as iron dust and mill scale or iron ore and carbon materials through the use of a granulating machine, by covering the outer surface of the granulated raw material with metallic iron-containing iron oxide powder to form iron oxide shells having a low oxidation degree, and by then performing an oxidation treatment of heating the iron oxide shells in atmospheric air at a temperature of 200°C or higher and lower than 300°C for 0.5 hours to 5 hours to form, only on the surfaces of the above-mentioned iron oxide shells, hard thin layers of iron oxide having a high oxidation degree.
[0012]
In addition, Non Patent Literature 1 describes the results of the evaluation of reactivity in an atmosphere of a blast furnace performed on carbon material-containing sintered ore prepared by covering green balls with anthracite to form pellet feed covered with anthracite, by charging the pellet feed onto bedding ore in a pot-type testing apparatus, by charging sintering raw materials onto the green balls, and by then performing sintering.
Citation List
Patent Literature [0013]
PTL 1: Japanese Unexamined Patent Application
| Publication | No. 2001-348625 |
| PTL 2 : | Japanese Unexamined Patent Application |
| Publication | No. 2001-294944 |
| PTL 3: | Japanese Unexamined Patent Application |
| Publication | No. 2001-303143 |
| PTL 4 : | Japanese Unexamined Patent Application |
| Publication | No. 2005-344181 |
| PTL 5: | Japanese Unexamined Patent Application |
| Publication | No. 2002-241853 |
| PTL 6: | Japanese Unexamined Patent Application |
| Publication | No. 10-183262 |
| PTL 7 : | Japanese Unexamined Patent Application |
| Publication | No. 2011-195943 |
| PTL 8 : | Japanese Unexamined Patent Application |
| Publication | No. 2011-225926 |
| Non Patent | Literature |
[0014]
| NPL 1: | CAMP-ISIJ, vol. 24 (2011), p. 194 |
Summary of Invention
Technical Problem [0015]
As described above, Patent Literature 7 and Patent
Literature 8 disclose carbon material-containing agglomerated ore having an appropriate size and sufficient strength as a raw material for making iron and a structure in which iron-containing raw materials and carbon materials are closely arranged so that an iron-making reaction tends to easily occur and so that it is possible to perform lowtemperature reduction.
[0016]
However, in the case of Patent Literature 7 and Patent Literature 8, since covering layers composed of iron oxide shells having a low oxidation degree are formed by using metallic iron-containing iron oxide powder, and since raw materials such as iron dust and mill scale, which can preferably be used as such metallic iron-containing iron oxide powder, are generated in restricted amounts, there is a problem in that the production quantity of carbon material-containing agglomerated ore is restricted. Even in the case where metallic iron-containing iron oxide powder is purposefully manufactured as a raw material for carbon material-containing agglomerated ore, since there is an increase in the manufacturing costs of carbon materialcontaining agglomerated ore, there is a problem of a decrease, rather than an increase, in the efficiency of a pig iron-making process. In addition, in Patent Literature 7 and Patent Literature 8, there is no mention of a method for manufacturing carbon material-containing granulated particles which are used for manufacturing carbon material10 containing agglomerated ore.
[0017]
The present invention has been completed in view of the situation described above, and an object of the present invention is to provide a method for manufacturing sintered ore with which it is possible to manufacture carbon material-containing sintered ore (carbon material-containing agglomerated ore) having a two-layer structure in which iron-containing raw materials and carbon materials are closely arranged without using metallic iron-containing iron oxide powder such as iron dust and mill scale, that is, without production quantity being restricted.
Solution to Problem [0018]
The present inventors, to solve the problems described above, diligently conducted investigations and, as a result, found that it is possible to manufacture carbon materialcontaining sintered ore having a two-layer structure in which iron-containing raw materials and carbon materials are closely arranged without using metallic iron-containing iron oxide powder such as iron dust and mill scale by first manufacturing carbon material-containing granulated particles having a two-layer structure in which a carbon material core is covered with mixed powder containing iron ore powder and CaO-containing raw material powder and by then baking the two-layer particles in a sintering machine along with quasi-particles, which are conventional raw materials used for manufacturing sintered ore. In addition, it was found that controlling water content when the abovementioned carbon material-containing granulated particles are manufactured to be 8 mass% to 10 mass% with respect to the total mass of the above-mentioned mixed powder, the above-mentioned carbon material cores, and the water, that is, controlling the water content of the carbon materialcontaining granulated particles at the time of granulation to be 8 mass% to 10 mass%, is effective from the viewpoint of the strength of the obtained carbon material-containing granulated particles.
[0019]
The present invention has been completed on the basis of the knowledge described above, and the subject matter of the present invention is as follows.
[1] A method for manufacturing sintered ore, the method including baking carbon material-containing granulated particles having a two-layer structure in which a carbon material core is covered with mixed powder containing ironcontaining raw material powder and CaO-containing raw material powder on a pallet in a sintering machine to obtain carbon material-containing sintered ore, in which the carbon material-containing granulated particles have a water content of 8 mass% to 10 mass% with respect to a total mass of the mixed powder, the carbon material cores, and water at a time of granulation.
[2] The method for manufacturing sintered ore according to item [1] above, in which the iron-containing raw material powder is iron ore powder, and the mixed powder contains iron ore powder and CaO-containing raw material powder.
[3] The method for manufacturing sintered ore according to item [1] or [2] above, in which the carbon materialcontaining granulated particles are baked on the pallet in the sintering machine along with a sintering raw material in a form of quasi-particles which are manufactured by adding water to iron-containing raw materials, CaO-containing raw materials, and solid fuels (carbon materials) and by then performing mixing and granulating.
[4] The method for manufacturing sintered ore according to item [3] above, in which the sintering raw material in the form of quasi-particles further contains auxiliary raw materials which are other than the CaO-containing raw materials and which are used as melting point-adjusting agents .
[5] The method for manufacturing sintered ore according to any one of items [1] to [4] above, in which part of the water contained in the carbon material-containing granulated particles is contained in the mixed powder in advance before granulating is performed.
[6] The method for manufacturing sintered ore according to any one of items [1] to [5] above, in which part of the water contained in the carbon material-containing granulated particles is newly added at the time of granulation. Advantageous Effects of Invention [0020]
According to the present invention, it is possible to manufacture carbon material-containing sintered ore (carbon material-containing agglomerated ore) having a two-layer structure in which a carbon material core is covered with mixed powder containing iron-containing raw material powder such as iron ore powder and CaO-containing raw material powder without using metallic iron-containing iron oxide powder such as iron dust and mill scale.
[0021]
In addition, since the water content of carbon material-containing granulated particles is controlled to be 8 mass% to 10 mass% at the time of granulation, it is possible to manufacture carbon material-containing granulated particles having sufficient strength to resist load applied by surrounding charged raw materials when the carbon material-containing granulated particles are baked in a sintering machine along with conventional sintering raw materials for manufacturing sintered ore in the form of quasi-particles. With this, since the external layers of the carbon material-containing granulated particles are not broken, the carbon material cores are not exposed, which results in the carbon materials efficiently remaining in the sintered ore.
Brief Description of Drawings [0022] [Fig. 1] Fig. 1 is a schematic diagram illustrating an example of a granulating apparatus for manufacturing carbon material-containing granulated particles for manufacturing carbon material-containing sintered ore.
[Fig. 2] Fig. 2 is a graph illustrating the variations of the crushing strength of carbon material-containing granulated particles with respect to the water content of carbon material-containing granulated particles at the time of granulation.
[Fig. 3] Fig. 3 is a graph illustrating the variations of the maximum attained temperature in the lower part of a sintered layer with respect to the water content of carbon material-containing granulated particles at the time of granulation .
[Fig. 4] Fig. 4 is a graph illustrating the variations of the reducibility of carbon material-containing sintered ore and the residual carbon concentration of carbon material-containing sintered ore with respect to the water content of carbon material-containing granulated particles at the time of granulation.
[Fig. 5] Fig. 5 is a graph illustrating the crushing strength of carbon material-containing granulated particles in levels 11 to 14 in EXAMPLE 2.
Description of Embodiments [0023]
Hereafter, the present invention will be specifically described.
[0024]
The present invention is a technique in which carbon material-containing sintered ore having a two-layer structure in which iron-containing raw materials and carbon materials are closely arranged is manufactured by baking carbon material-containing granulated particles having a two-layer structure in which a carbon material core is covered with mixed powder containing iron-containing raw material powder such as iron ore powder and CaO-containing raw material powder in a sintering machine. In the present description, a carbon material-containing granulated particle having a carbon material core and a covering layer surrounding the core which is formed by using carbon materials as a core and by covering the carbon material core with mixed powder containing iron-containing raw material powder and CaO-containing raw material powder is defined as a two-layer carbon material-containing granulated particle. [0025]
When a sintering treatment is performed in a sintering machine to manufacture two-layer carbon material-containing sintered ore, by performing a sintering treatment on carbonmaterial-containing granulated particles along with quasiparticles, which are conventional raw materials used for manufacturing sintered ore, it is possible to effectively utilize the combustion heat of solid fuels contained in the quasi-particles, which are conventional raw materials used for manufacturing sintered ore, as a heat source for the baking of the carbon material-containing granulated particles, and thus it is possible to easily manufacture carbon material-containing sintered ore (carbon materialcontaining agglomerated ore).
[0026]
Incidentally, sintering raw materials in the form of quasi-particles, which are conventional raw materials used for manufacturing sintered ore, are manufactured by adding an appropriate amount of water to a granulating raw material containing iron-containing raw materials, CaO-containing raw materials, auxiliary raw materials which are other than the CaO-containing raw materials and which are used as melting point-adjusting agents, and solid fuels (carbon materials) such as coke breeze and anthracite, which are used as coagulating raw materials, and so forth, and by performing mixing and granulating through the use of a drum mixer or the like. Examples of the iron-containing raw materials include iron ore having a particle diameter of 10 mm or less and dust, mill scale, and so forth, which are generated in a steel plant. Examples of the CaO-containing raw materials include limestone, quicklime, slag, and so forth. Examples of auxiliary raw materials which are other than the CaOcontaining raw materials and which are used as melting point-adjusting agents include Si02-containing raw materials such as silica stone, serpentine, dolomite, and nickel refining slag and MgO-containing raw materials such as magnesia clinker and dolomite.
[0027]
Fig. 1 illustrates an example of a granulating apparatus for manufacturing carbon material-containing granulated particles for manufacturing carbon materialcontaining sintered ore. In Fig. 1, reference 1 denotes a granulating apparatus, 2a denotes a hopper which holds ironcontaining raw material powder, 2b denotes a hopper which holds CaO-containing raw material powder, 2c denotes a hopper which holds carbon materials, 3a, 3b, 3c, and 3d denote transporting machines, 4 denotes a kneading machine, 5 denotes a granulating machine, and 6 denotes a feed-water pump. With reference to Fig. 1, the method for manufacturing carbon material-containing granulated particles which are used when carbon material-containing sintered ore is manufactured in the present invention will be described.
[0028]
Iron-containing raw material powder and CaO-containing raw material powder which is used as a melting pointadjusting agent are charged into the kneading machine 4 through the transporting machine 3a, and the iron-containing raw material powder and the CaO-containing raw material powder are homogeneously mixed in the kneading machine 4. Mixed powder which is prepared by homogeneously mixing the iron-containing raw material powder and the CaO-containing raw material powder is discharged from the kneading machine 4, and the discharged mixed powder is charged into the granulating machine 5 through the transporting machine 3c. At the same time or almost at the same time as the charging of the mixed powder into the granulating machine 5, carbon materials (coke particles) having a particle diameter of 3.0 mm or more, which are used as core particles, are charged into the granulating machine 5 through the transporting machine 3b and the transporting machine 3c.
[0029]
Here, the term iron-containing raw material powder refers to a mixture of one, two, or more of powder concentrate, which is obtained after the beneficiation of iron ore, iron ore powder, which is obtained by crushing iron ore, and iron dust, mill scale, and so forth, which are generated in a steel plant. Although it is not necessary to put a particular limitation on the particle diameter of the iron-containing raw material powder as long as it is possible to use the powder for granulation, there is no problem in the case where the particle diameter is about 1.0 mm or less. Although the present invention has been developed to manufacture carbon material-containing sintered ore having a two-layer structure in which iron-containing raw materials and carbon materials are closely arranged without using iron oxide powder containing metallic iron such as iron dust and mill scale, the present invention does not prevent, for example, iron dust or mill scale, which is generated in a steel plant, from being used as an ironcontaining raw material.
[0030]
In addition, examples of CaO-containing raw material powder which can preferably be used when carbon materialcontaining granulated particles are manufactured include mixed powder of one, two, or all of guicklime (CaO), limestone (CaCOa) , and lime hydrate (Ca(OH)2). Although it is not necessary to put a particular limitation on the particle diameter of the CaO-containing raw material powder as long as it is possible to use the powder for granulation, there is no problem in the case where the particle diameter is about 1.0 mm or less.
[0031]
By feeding water to mixed powder, which is prepared in the kneading machine 4, through the feed-water pump 6, and/or by feeding water to the granulating machine 5 through the feed-water pump 6, the water content with respect to a granulating raw material (the total mass of the carbon materials, the mixed powder, and the water) at the time of granulation in the granulating machine 5 is controlled to be 8 mass% to 10 mass%. By controlling the water content of carbon material-containing granulated particles at the time of granulation to be 8 mass% to 10 mass%, carbon materials having a large particle diameter, which are used as cores, are covered with the mixed powder, which is prepared by homogeneously mixing the iron-containing raw material powder and the CaO-containing raw material powder, due to the liquid-bridge force of the water. Thus, carbon materialcontaining granulated particles having a two-layer structure in which a carbon material core is covered with mixed powder containing iron-containing raw material powder and CaOcontaining raw material powder are formed. The formed carbon material-containing granulated particles have a carbon material core diameter of 3 mm to 10 mm, a covering layer thickness of 7 mm or less, and a particle diameter of 8.0 mm or more and 24.0 mm or less.
[0032]
Subsequently, the carbon material-containing granulated particles manufactured as described above are transported to, for example, a Dwight Lloyd-type sintering machine, then joined with conventional sintering raw materials for manufacturing sintered ore in the form of quasi-particles, and a mixture of the carbon material-containing granulated particles and the conventional sintering raw materials for manufacturing sintered ore in the form of quasi-particles is transported to a surge hopper in the sintering machine. In this case, to effectively utilize the combustion heat of solid fuels contained in the sintering raw materials in the form of quasi-particles as a heat source for the baking of the carbon material-containing granulated particles, it is preferable that the joining be controlled so that the mass ratio of the carbon material-containing granulated particles to the sintering raw materials in the form of quasiparticles is 1:9 to 3:7.
[0033]
Incidentally, as described above, sintering raw materials in the form of quasi-particles, which are conventional raw materials used for manufacturing sintered ore, are manufactured by adding an appropriate amount of water to a granulating raw material containing iron ore, CaO-containing raw materials such as limestone and quicklime, auxiliary raw materials which are used as melting pointadjusting agents such as Si02-containing raw materials such as silica stone, serpentine, and nickel refining slag, and solid fuels (carbon materials) such as coke breeze and anthracite, and so forth, and by performing mixing and granulating through the use of a drum mixer or the like, and, hereinafter, the conventional sintering raw materials in the form of quasi-particles are also referred to as quasiparticles for sintering raw materials.
[0034]
Through the surge hopper which holds the carbon material-containing granulated particles and the quasiparticles for sintering raw materials, the mixture of the carbon material-containing granulated particles and the quasi-particles for sintering raw materials is charged on to a pallet circulating in the sintering machine. Subsequently, a sintering treatment is performed on the carbon materialcontaining granulated particles and the quasi-particles for sintering raw materials.
[0035]
In the sintering treatment, the solid fuels contained in the quasi-particles for sintering raw materials, which have been charged onto the pallet, are ignited in an igniting furnace in the sintering machine. After the ignition, since the solid fuels contained in the quasiparticles for sintering raw materials are burnt sequentially from the upper part to the lower part of a charged raw material layer, a sintering reaction and a melting reaction among the quasi-particles for sintering raw materials progress due to the combustion heat of the solid fuels, which results in conventional sintered ore being manufactured. At the same time, since covering layers which are formed on the surfaces of the carbon material-containing granulated particles by using mixed powder containing ironcontaining raw material powder and CaO-containing raw material powder are baked due to the combustion heat of the solid fuels contained in the quasi-particles for sintering raw materials, a sintering reaction and a melting reaction progress in the covering layers, which results in carbon material-containing sintered ore composed of particles having unburnt carbon materials therein and strong covering layers containing iron-containing raw material powder and CaO-containing raw material powder thereon being manufactured.
[0036]
After the sintering treatment has been performed, a formed sinter cake, which is composed of a mixture of the carbon material-containing sintered ore and the conventional sintered ore, is crushed and granulated, and particles having a particle diameter equal to or more than a predetermined size are collected as product sintered ore. Although the collected carbon material-containing sintered ore is collected in a state in which the conventional sintered ore is fusion-bonded to the carbon materialcontaining sintered ore, there is no problem when the sintered ore is used as a raw material for making iron in a blast furnace.
[0037]
Incidentally, since carbon material-containing granulated particles, whose grain diameter is larger than that of conventional quasi-particles for sintering raw materials, tend to be located in the middle and lower parts of a pallet, which are the parts in which temperature tends to be higher than in the upper part of the pallet when sintering is performed, due to segregation which occurs when charging onto the pallet in a sintering machine is performed, it is possible to allow the sintering reaction of the carbon material-containing granulated particles and the conventional sintering raw materials to progress sufficiently.
[0038]
In the case where only iron ore powder is used as ironcontaining raw material powder, since carbon material25 containing sintered ore is manufactured without using metallic iron-containing iron oxide powder such as iron dust and mill scale and by using an existing sintering machine, it is possible to manufacture carbon material-containing sintered ore without preparing a new baking machine and in large quantity without production quantity being restricted. [0039]
Therefore, in the present invention, it is preferable that only iron ore powder be used as iron-containing raw material powder and that mixed powder composed of iron ore powder and CaO-containing raw material powder be used as mixed powder covering a carbon material core.
[0040]
When carbon material-containing granulated particles are manufactured, by controlling the water content of a granulating raw material (a mixture of carbon materials, mixed powder, and water) to be fed into a granulating machine to be 8 mass% to 10 mass%, it is possible to perform granulation by using a conventionally used granulating machine such as a disc pelletizer or a drum mixer or by using both.
[0041]
In the present invention, the upper limit of the water content at the time of granulation is set to be 10 mass% to prevent the formation of granulated particles having an excessively large particle diameter, because granulated particles having a particle diameter much larger than 24.0 mm, which is the upper limit of the particle diameter in a granulating machine, are formed in the case where the water content is excessively large. That is, in the case where the water content at the time of granulation is more than 10 mass%, since gaps between the particles of iron-containing raw material powder are filled with more water than necessary for bridging, the water functions as a lubricant to significantly decrease the strength of such granulated particles having an excessively large particle diameter, which results in the covering layers of the particles being broken due to load applied by surrounding charged raw materials in a sintering layer. Therefore, carbon material cores are exposed, which results in the carbon material cores being lost due to combustion. In addition, as a result of the covering layers of granulated particles having an excessively large particle diameter being broken, air flow channels are blocked in a sintering layer, which may result in a deterioration in gas permeability in a sintering process .
[0042]
On the other hand, the lower limit of the water content at the time of granulation is set to be 8 mass%, because there is insufficient water used for bridging the particles of iron-containing raw material powder in the case where the water content at the time of granulation is less than 8 mass%, which results in granulated particles not being formed or results in granulated particles having very low strength being formed. In this case also, as in the case where the water content is excessively large, since the covering layers of the granulated particles are broken in a sintering layer, carbon material cores are exposed, which results in the carbon material cores being lost due to combustion .
[0043]
In the case where carbon material cores are lost, since the above-described effect of increasing the reaction rate due to the close arrangement of iron-containing raw materials and carbon materials is not realized, it is not possible to realize the effect of improving reducibility.
[0044]
As described above, according to the present invention, it is possible to manufacture carbon material-containing sintered ore having a two-layer structure in which a carbon material core is covered with mixed powder containing ironcontaining raw material powder and CaO-containing raw material powder without using metallic iron-containing iron oxide powder such as iron dust and mill scale.
[0045]
In addition, since the water content of carbon material-containing granulated particles is controlled to be 8 mass% to 10 mass% at the time of granulation, it is possible to manufacture carbon material-containing granulated particles having sufficient strength to resist load applied by surrounding charged raw materials when the carbon material-containing granulated particles are baked in a sintering machine along with quasi-particles for sintering raw materials, which are conventional raw materials used for manufacturing sintered ore. With this, since the external layers of the carbon material-containing granulated particles are not broken, the carbon material cores are not exposed, which results in the carbon materials efficiently remaining in the sintered ore.
[0046]
Here, the present invention is not limited to the embodiment described above, and, for example, a sintering technique in which gas fuels may be fed in addition to the combustion heat of solid fuels contained in conventional quasi-particles for sintering raw materials as heat sources for baking carbon material-containing granulated particles or a sintering technique in which enriched oxygen gas is fed may be used.
EXAMPLE 1 [0047]
Tests for investigating the effects of the water content at the time of granulation on carbon materialcontaining granulated particles and carbon materialcontaining sintered ore which was manufactured by baking the carbon material-containing granulated particles were conducted by manufacturing two-layer carbon materialcontaining granulated particles with various water contents at the time of granulation, by mixing the obtained carbon material-containing granulated particles with separately manufactured quasi-particles for sintering raw materials, which are conventional raw materials for sintered ore, and by performing a sintering treatment in a sintering machine on a mixture of the carbon material-containing granulated particles and the quasi-particles for sintering raw materials. The two-layer carbon material-containing granulated particles were manufactured by using the granulating apparatus illustrated in Fig. 1.
[0048]
For two-layer carbon material-containing granulated particles, dried coke having a particle diameter of 4 mm to 5 mm was used as carbon material cores, and dried pellet feed powder (hematite (Fe2O3) : 97.7 mass%) having a particle diameter of 250 pm or less was used as iron-containing raw material powder for forming covering layers, with which the carbon material cores were covered. In addition, quicklime (CaO) having a particle diameter of 200 pm or less, which was used as a melting point-adjusting agent, was used as CaO-containing raw material powder for forming covering layers, with which the carbon material cores were covered. By charging these raw materials into a granulating machine, by mixing them, by adding water to the raw materials in the granulating machine through spray nozzles, and by performing granulation, granulated particles having a covering layer thickness of 3 mm or more and a particle diameter of 12 mm to 16 mm were manufactured and used in the tests. The water content of the carbon material-containing granulated particles at the time of granulating was fixed at 6 levels ranging from 6 mass% to 11 mass%, that is, levels 1 to 6.
The water content of the carbon material-containing granulated particles at the time of granulating at levels 1 to 6 are given in Table 1.
[0049] [Table 1]
| Water Content at Time of Granulation (mass%) | Note | |
| Level 1 | 6.0 | Comparative Example |
| Level 2 | 7.0 | Comparative Example |
| Level 3 | 8.0 | Example |
| Level 4 | 9.0 | Example |
| Level 5 | 10.0 | Example |
| Level 6 | 11.0 | Comparative Example |
[0050]
On the other hand, for quasi-particles for sintering raw materials, which are conventional raw materials for sintering ore, iron ore powder, limestone, which was added as an auxiliary raw material so that the CaO content in the quasi-particles for sintering raw materials was 10 mass%, and coke powder, which was added as a solid fuel so that the coke content in the quasi-particles for sintering raw materials was 5 mass%, were used as granulating raw materials. By charging these raw materials into a drum mixer, by stirring and mixing them, and by performing granulation, quasi-particles for sintering raw materials having an arithmetical mean particle diameter of 2.9 mm were manufactured and used in the tests.
[0051]
The crushing strength of the carbon material-containing granulated particles at levels 1 to 6 manufactured as described above was determined by using the method prescribed in JIS M 8717. In addition, the carbon materialcontaining granulated particles at each of levels 1 to 6 and the quasi-particles for sintering raw materials, which had been manufactured as described above, were mixed so that the ratio of the carbon material-containing granulated particles to the quasi-particles for sintering raw materials was 2:8, and the mixture of the carbon material-containing granulated particles and the quasi-particles for sintering raw materials was subjected to a sintering treatment by using a pot-type sintering testing apparatus having a lattice-like circular plate and a height of 400 mm and a diameter of 300 mm.
[0052]
Fig. 2 illustrates the variations of the crushing strength of carbon material-containing granulated particles with respect to the water content of carbon materialcontaining granulated particles at the time of granulation. As a result of calculation, it is necessary that the covering layer of a carbon material-containing granulated particle has a strength of 1.0 MPa or more to resist load applied by surrounding charged raw materials without being broken in the lower part of a sintering layer. As indicated in Fig. 2, it is clarified that, in the case where the water content of carbon material-containing granulated particles at the time of granulation was 8 mass% to 10 mass%, the crushing strength was 1.0 MPa or more, which means that the above-described condition was satisfied.
[0053]
Fig. 3 illustrates the variations of the maximum attained temperature in the lower part of a sintered layer with respect to the water content of carbon materialcontaining granulated particles at the time of granulation. As indicated in Fig. 3, it is clarified that, while the maximum attained temperature was 1340 °C or lower in the case where the water content is 8 mass% to 10 mass%, there is an increase in the maximum attained temperature in the case where the water content is 6 mass%, 7 mass%, or 11 mass%.
The coke breeze content of quasi-particles for sintering raw materials, which are conventional raw materials used for manufacturing sintered ore and subjected to a sintering treatment at the same time as the carbon material-containing granulated particles, is identical in any case. Therefore, it is considered that, in the case where the water content was 6 mass%, 7 mass%, or 11 mass%, since the covering layer of a carbon material-containing granulated particle was broken, part of the carbon material core was burnt, which resulted in an increase in the maximum attained temperature. [0054]
In addition, Fig. 4 illustrates the variations of the reducibility of carbon material-containing sintered ore and the residual carbon concentration of carbon materialcontaining sintered ore with respect to the water content of carbon material-containing granulated particles at the time of granulation. As indicated in Fig. 4, it is clarified that, in the case where the water content was 6 mass%, 7 mass%, or 11 mass%, there was a decrease in residual carbon concentration. From this result and the result indicated in Fig. 3 described above, it is clarified that part of the carbon material core was burnt in the case where the water content was 6 mass%, 7 mass%, or 11 mass%. In addition, there was a deterioration in reducibility due to a decrease in residual carbon concentration in carbon materialcontaining sintered ore.
EXAMPLE 2 [0055]
Two-layer carbon material-containing granulated particles were manufactured by using the same method as used in EXAMPLE 1 under conditions that the ratio of the amount of water added to the mixed powder in advance before granulation was performed and the amount of water added by using spray nozzles at the time of granulation was changed to 4 levels, that is, levels 11 to 14, so that the total water content was 9 mass%, with which crushing strength was high in the test in EXAMPLE 1, and a test for investigating the crushing strength of the obtained carbon material containing granulated particles was conducted. The carbon material core, the iron-containing raw material powder, and the CaO-containing raw material powder used as the raw materials for the carbon material-containing granulated particles were the same as those used in EXAMPLE 1.
[0056]
The combinations of the amount of water added to the mixed powder in advance and the amount of water added by using spray nozzles at the time of granulation at levels 11 to 14 are given in Table 2.
[0057] [Table 2]
| Water Content of Mixed Powder before Granulation (mass%) | Water Content Added in Granulation Machine (mass%) | Total Water Content at Time of Granulation (mass%) | Note | |
| Level 11 | 0 | 9 | 9 | Example |
| Level 12 | 3 | 6 | 9 | Example |
| Level 13 | 6 | 3 | 9 | Example |
| Level 14 | 9 | 0 | 9 | Example |
[0058]
Fig. 5 illustrates the crushing strength of carbon material-containing granulated particles in levels 11 to 14. As indicated in Fig. 5, it is clarified that there was no significant difference in the crushing strength of carbon material-containing granulated particles between the levels. Therefore, it is clarified that the total water content of carbon material-containing granulated particles is important regardless whether the water is added to mixed powder in advance or at the time of granulation.
Reference Signs List [0059] granulating apparatus
2a, 2b, 2c hopper
3a, 3b, 3c, 3d transporting machine kneading machine granulating machine feed-water pump
Claims (6)
- CLAIMS [Claim 1]A method for manufacturing sintered ore, the method comprising baking carbon material-containing granulated particles having a two-layer structure in which a carbon material core is covered with mixed powder containing ironcontaining raw material powder and CaO-containing raw material powder on a pallet in a sintering machine to obtain carbon material-containing sintered ore, wherein the carbon material-containing granulated particles have a water content of 8 mass% to 10 mass% with respect to a total mass of the mixed powder, the carbon material cores, and water at a time of granulation.
- [Claim 2]The method for manufacturing sintered ore according to Claim 1, wherein the iron-containing raw material powder is iron ore powder, and the mixed powder contains iron ore powder and CaO-containing raw material powder.
- [Claim 3]The method for manufacturing sintered ore according to Claim 1 or 2, wherein the carbon material-containing granulated particles are baked on the pallet in the sintering machine along with a sintering raw material in a form of guasi-particles which are manufactured by adding water to iron-containing raw materials, CaO-containing raw materials, and solid fuels (carbon materials) and by then performing mixing and granulating.
- [Claim 4]The method for manufacturing sintered ore according to Claim 3, wherein the sintering raw material in the form of quasi-particles further contains auxiliary raw materials which are other than the CaO-containing raw materials and which are used as melting point-adjusting agents.
- [Claim 5]The method for manufacturing sintered ore according to any one of Claims 1 to 4, wherein part of the water contained in the carbon material-containing granulated particles is contained in the mixed powder in advance before granulating is performed.
- [Claim 6]The method for manufacturing sintered ore according to any one of Claims 1 to 5, wherein part of the water contained in the carbon material-containing granulated particles is newly added at the time of granulation.
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| PCT/JP2017/045638 WO2018123750A1 (en) | 2016-12-28 | 2017-12-20 | Sintered ore manufacturing method |
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| EP4407054A1 (en) * | 2021-09-24 | 2024-07-31 | Nippon Steel Corporation | Agglomerated ore and method for producing same |
| CN114990328B (en) * | 2022-04-14 | 2024-06-11 | 北京巨亚国际环境科技股份有限公司 | Tunnel type mineral powder sintering equipment and sintering method |
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| JPH02228428A (en) * | 1989-03-02 | 1990-09-11 | Sumitomo Metal Ind Ltd | Charging material for blast furnace and its production |
| JPH10183262A (en) | 1996-12-24 | 1998-07-14 | Nippon Steel Corp | Agglomerate for iron-making and production thereof |
| JP3502008B2 (en) | 2000-04-07 | 2004-03-02 | 株式会社神戸製鋼所 | Manufacturing method of carbonized interior agglomerates |
| JP3502011B2 (en) | 2000-04-24 | 2004-03-02 | 株式会社神戸製鋼所 | Manufacturing method of carbonized interior agglomerates |
| JP2001348625A (en) | 2000-06-08 | 2001-12-18 | Nippon Steel Corp | Method for producing pellet for iron-marking raw material |
| JP2002241853A (en) | 2001-02-13 | 2002-08-28 | Nippon Steel Corp | Non-burning agglomerate for blast furnace |
| WO2004018716A1 (en) * | 2002-08-21 | 2004-03-04 | Nippon Steel Corporation | Method of granulating sintering material for iron manufacturing |
| JP4490735B2 (en) | 2004-06-04 | 2010-06-30 | 株式会社神戸製鋼所 | Manufacturing method of carbonized material agglomerates |
| JP5540806B2 (en) | 2010-03-24 | 2014-07-02 | Ｊｆｅスチール株式会社 | Carbon steel interior agglomerate for iron making and method for producing the same |
| JP5540859B2 (en) | 2010-04-19 | 2014-07-02 | Ｊｆｅスチール株式会社 | Carbon steel interior agglomerate for iron making and method for producing the same |
| JP5051317B1 (en) * | 2010-07-30 | 2012-10-17 | Ｊｆｅスチール株式会社 | Method for manufacturing raw materials for sintering |
| JP5423611B2 (en) * | 2010-08-09 | 2014-02-19 | 新日鐵住金株式会社 | Method for producing sintered ore |
| CN104204243B (en) * | 2012-03-22 | 2016-05-04 | 杰富意钢铁株式会社 | Method of adjustment and the sintering deposit raw meal of raw meal for sintering deposit |
| JP5790966B2 (en) * | 2013-07-10 | 2015-10-07 | Ｊｆｅスチール株式会社 | Method for producing carbonaceous interior sinter |
| JP2015137379A (en) * | 2014-01-21 | 2015-07-30 | 日新製鋼株式会社 | Non-burning carbonaceous material interior ore for blast furnace and manufacturing method therefor |
| JP6540359B2 (en) * | 2014-11-21 | 2019-07-10 | 日本製鉄株式会社 | Modified carbon material for producing sintered ore and method for producing sintered ore using the same |
| CN106148681A (en) * | 2016-08-30 | 2016-11-23 | 山东钢铁股份有限公司 | Reduce compound preparation facilities and the preparation method of sintering machine solid fuel consumption |
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