KR20170106513A - Carbon material-containing granulated particles in production of sintered ore, method for producing the same - Google Patents

Abstract

A raw material coke having a grain size of 3 to 15 mm serving as a carbonaceous core, an iron ore powder having a particle size of 250 탆 or less serving as an outer layer, and a CaO-containing raw material are charged into a pelletizer, mixed and assembled, To form pseudo particles (incorporated particles in which the carbonaceous material is embedded). The sintered raw material obtained by mixing conventional granules with embedded particulate materials is formed into pallets of a sintering machine to form a charging layer. The combustion heat of the carbon materials contained in the conventional granulated particles is used as a sintering source . In addition, by using these, iron oxide-containing iron oxide-containing iron oxide powder such as iron dust or mill scale is not used, and the production amount is not limited, and the iron-containing raw material and the carbonaceous material are arranged close to each other.

Description

Technical Field [0001] The present invention relates to a granular particle having a built-in carbon material for producing sintered ores and a method for producing the same,

The present invention relates to a technique for producing sintered ores used in a blast furnace or the like as a raw material for a steelmaking process, and more specifically, to a method for producing sintered ores by using the granulated particles, And a method for producing the same.

In the blast furnace method, iron-containing raw materials such as iron ores and sintered ores are mainly used as iron sources. Here, the sintered ores may be made of iron oxide or iron oxide having a particle diameter of 10 mm or less, SiO ₂ -containing raw materials such as quartz or serpentine, refined nickel slag, and CaO-containing raw materials such as limestone and quicklime, An appropriate amount of water is added to an assembly raw material composed of a solid fuel (carbonaceous material) as a condensation material, and mixed with a drum mixer or the like to form a raw material for sinter as a pseudo-particle, A sintered cake obtained by burning and sintering the carbonaceous material contained in the pseudo-particles, crushing the obtained sintered cake, sizing, and recovering one or more kinds of large- to be.

Recently, attention has been paid to an iron source such as iron ore or dust and a carbon material such as coke as close-packed as the above-mentioned intense light. This is because, for example, when iron source such as iron ore and carbonaceous material are arranged close to each other in one compact light, the reduction reaction (exothermic reaction) on the iron source side and the gasification reaction (endothermic reaction) , The steel making efficiency is improved and the furnace temperature of the furnace or the like may be lowered.

Examples of the above-mentioned coarse light include coal, coke, and coke, which are separately or mixed with iron-containing powders generated in a steelmaking process such as blast furnace, converter dust, rolling scale, sludge, or iron ore powder disclosed in Patent Document 1 And starch are added, mixed and kneaded, and further, the starch solution is fed into a pelletizer and assembled. However, the coarse light disclosed in Patent Document 1 does not actually contain iron-containing raw materials such as iron ore and carbonaceous materials in close proximity because the carbonaceous material in the pellets disappears at the time of producing the sintered ores. In addition, simply reducing the particle size of iron ore or carbonaceous material for the purpose of close-spacing causes the movement resistance of the gas propagating through the heat to become excessively large, resulting in a lowering of the reaction rate, thereby lowering the ironing efficiency.

Thus, several techniques have been proposed for the purpose of closely positioning iron ore and carbonaceous materials (see, for example, Patent Documents 2 to 5). The techniques disclosed in these documents are basically the same as those in the first embodiment except that iron-containing raw materials such as iron ore are mixed with carbonaceous materials such as coke and then compacted by hot forming, or raw materials are used without being fired, To use. However, since these compacted materials are arsenic-containing ones composed of a uniform mixture or a multilayered granulated product, they are insufficient in strength and are vigorous in powdering, so if they are charged into a blast furnace or the like, dehydration and reduction and differentiation are caused, The air permeability of the blast furnace is deteriorated, so that the use amount thereof is limited.

As a technology for solving the problems of the above-described Patent Documents 2 to 5, for example, Patent Document 6 discloses a method of forming nuclei with a raw material containing 5 wt% or more of metallic iron and / or 5% , At least one outer layer containing the iron and at least 5 wt% of carbon and at least one outer layer containing the core is formed and then fired in an oxidizing atmosphere at a temperature of 300 to 1300 ° C to obtain a compacted iron- Light has been proposed. However, it is necessary to use metallic iron for the raw coarse raw material disclosed in Patent Document 6, and there is a problem that there is a limitation in the amount that can be produced as raw coarse raw iron because there is a quantitative restriction on the raw material to be used.

Therefore, as a technique for overcoming the above-described problems of Patent Documents 1 to 6, a technique of a carbonaceous compacted light has been proposed. For example, Patent Document 7 discloses a method in which a metal iron-containing iron oxide powder such as a steel dust or a mill scale is coated on the periphery of a carbonaceous core made of a dissolvable coke to form an iron oxide shell having a low oxidation degree, A technique of obtaining a carbonaceous internal massive light by forming a hard thin layer of iron oxide having a high oxidation degree only on the surface of the iron oxide shell by performing oxidation treatment by heating at a temperature of 200 DEG C or more and less than 300 DEG C for 0.5 to 5 hours, Document 8 discloses a method for producing iron oxide powder by mixing iron oxide powder or iron oxide powder such as iron-based dust or mill scale with carbonaceous materials using a paver and then coating the iron oxide-containing iron oxide powder on the outer surface of the iron oxide powder, A coke powder having a size of 3 mm or less is dispersed in iron oxide powder or iron ore powder in a dispersed state The technology for obtaining a compacted light oil is disclosed.

In addition, Non-Patent Document 1 discloses a green ball in which an anthracite coal is covered with a green ball and an anthracite coal is coated with a pellet feed, and this green ball is charged on a bedding ore of a pot testing apparatus, The results of evaluating the reactivity in the atmosphere in the blast furnace for the carbon containing sintered ores having been sintered by charging the raw materials have been reported.

Japanese Patent Application Laid-Open No. 2001-348625 Japanese Patent Publication No. 3502008 Japanese Patent Publication No. 3502011 Japanese Patent Application Laid-Open No. 2005-344181 Japanese Patent Application Laid-Open No. 2002-241853 Japanese Patent Application Laid-Open No. 10-183262 Japanese Laid-Open Patent Publication No. 2011-195943 Japanese Laid-Open Patent Publication No. 2011-225926

 CAMP-ISIJ vol. 24 (2011), 194

According to the techniques disclosed in the above Patent Documents 7 and 8, the iron-containing raw material and the carbonaceous material are disposed in close proximity to each other so as to have a suitable size and sufficient strength as raw materials for the steel making, Light can be obtained. However, in the above technique, since the wettability with the carbonaceous material is deteriorated when the amount of the metal iron is large, it is difficult to coat the metal iron-containing iron oxide powder on the surface of the carbonaceous material and the iron oxide shell with low oxidation degree is formed. There is a problem in that the production cost is expensive in terms of necessity and that the amount of iron oxide-containing iron oxide powder such as iron dust and wheat scale is small so that the production amount is limited.

In the technique disclosed in the above non-patent document 1, an anthracite coal is enclosed in the periphery of the green ball because it is not present in the sintering raw material in the surroundings. This is because the pellet feed layer coated with anthracite is melted, Exposed, burned, or lost.

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and an object of the present invention is to provide a process for producing iron oxide- A method for producing sintered ores having a built-in carbonaceous material (sintered ores) in which a carbonaceous material is disposed in close proximity can be obtained, and a method for producing the same is proposed.

SUMMARY OF THE INVENTION The inventors of the present invention have conducted intensive studies for solving the above problems. As a result, an iron ore powder (pellet feed (PF)) having a particle diameter of 250 mu m or less and a CaO-containing raw material of a melting point adjuster added as an outer layer raw material was used as the carbonaceous core of the center portion as the carbonaceous core- It is effective to prepare a sintered light (compacted light) by assembling the pseudo-particles by using a sintering aid and charging it into a sintering machine as a part of the sintering raw material, and have come to develop the present invention.

That is, the present invention is a pseudo granule for manufacturing sintered ores, which is a pseudo particle formed by forming an outer layer composed mainly of iron ore powder and CaO-containing raw material around a carbonaceous core and a core of the carbonaceous material.

The iron ore powder in the particulate built-up granulated particle of the present invention is characterized by being a pellet feed having a particle diameter of 10 to 1000 탆.

The pellet feed of the particulate built-up granulated particle of the present invention is characterized by having a particle diameter of 250 탆 or less.

The outer layer of the particulate built-up granules of the present invention has a melting point of 1200 ° C or higher and 1500 ° C or lower.

The carbonaceous material to be the carbonaceous core in the carbonaceous built-up granule of the present invention is characterized by being coke particles having a particle diameter of 3 mm or more.

Further, the thickness of the outer layer in the embedding granular particle of the present invention is 2 mm or more.

The particulate built-in granulated particle of the present invention is characterized by having a particle diameter of 8 mm or more.

Further, the present invention is a method for producing a coarse particulate bearing material as described in any one of the above, wherein the coal core, the iron ore powder as the outer layer, and the CaO-containing material as the melting point adjusting agent are charged into a pelletizer, mixed, To form pseudo-particles, which is a method for producing granules containing carbonaceous materials for producing sintered ores.

In addition, the present invention relates to a process for producing a sintered material, comprising the steps of: charging the sintered raw material obtained by mixing any of the above-mentioned abodes with built-up abrasive particles in a usual assembled particle into a pallet of a sintering machine to form a loading layer; A method for producing a sintered ores of a carbonaceous material, which produces sintered ores by using combustion heat of a carbonaceous material.

The method for producing a carbon-containing sintered ore according to the present invention is characterized in that a large amount of the carbonaceous built-up granulated particles is charged on the lower layer side of the charging layer.

Further, in the method for producing a carbon-containing sintered ore according to the present invention, the conventional granulated particles are characterized by having a particle size smaller than that of the granulated particles embedded in a carbon material, which is assembled with a drum mixer.

According to the present invention, inexpensive and high-purity iron ore powder (pellet feed (PF)) is used instead of iron oxide powder having a low production amount with a limited amount of generation such as various iron dusts and mill scale generated in ironworks, In addition, since the oxidation treatment is not necessary, it is possible to manufacture the granulated particles containing carbon materials for producing sintered ores at low cost. In addition, since the above-mentioned built-up particulate built-up particles of the present invention can be used as a sintered light by using a conventional sintering machine, it is possible to produce a sintered body of a carbonaceous material in a large amount and at a low cost. In addition, since the iron-containing sintered ores according to the present invention have a sufficient strength and a structure in which the iron-containing raw material and the carbonaceous material are closely arranged when used as a raw material for a blast furnace or the like, It is possible to reduce the internal temperature and the fuel cost, thereby contributing to the reduction of the manufacturing cost.

Fig. 1 is a view for explaining the influence of the distance between the iron-containing raw material and the carbonaceous material on the reaction rate.
FIG. 2 is a view for explaining the iron-based reaction (reduction reaction, gasification reaction) between the iron-containing raw material and the carbonaceous material in comparison with the conventional furnace and the carbon-containing sintered ores of the present invention.
3 is a view for explaining a reduction reaction and a gasification reaction in a carbon-containing sintered ore.
Fig. 4 is a state diagram of the Fe ₂ O ₃ -CaO 2 elementary system.
Fig. 5 is a view for explaining the reaction in the outer layer at the time of sintering the particulate built-up granules. Fig.
6 is a state diagram of the SiO ₂ -Fe ₂ O ₃ -CaO 3 scintillator.
Fig. 7 is a view showing an example of a method for producing the carbon-containing built-up granules and the carbon-containing embedded sintered ores according to the present invention.
8 is a view for explaining a sintering test pot used in the embodiment.
Fig. 9 is an external view of the sintered light (compacted light) obtained in the sintering experiment of the example.
10 is a micrograph of a section of a carbonaceous built-in sintered ores according to the present invention.
11 is a view showing an EPMA analysis result of a carbonaceous built-in sintered light section according to the present invention.
Fig. 12 is a view showing the redox index RI and the reduction differentiation index RDI of the carbon-containing built-in sintered ores according to the present invention, as compared with a conventional sintered ores.

For example, in the blast furnace method, iron-containing raw materials such as iron ores and sintered ores are heated to a high temperature by combustion heat of a carbonaceous material such as coke, and are reduced to produce cast iron. At this time, the charging of the iron raw material from the furnace top of the blast furnace is usually carried out in the form of a layer by separating the iron-containing raw material and the carbonaceous material, each of which is sized to about 20 to 40 mm. In this case, if the layer thickness of the iron-containing raw material layer and the carbonaceous material layer is made thinner, the distance between the iron-containing raw material and the carbonaceous material becomes small, and it is considered that the reduction reaction rate can be increased. However, as described above, simply mixing the iron-containing raw material and the carbonaceous material with each other increases the moving resistance of the gas as the heat transfer means, and the reaction rate is rather slow.

Therefore, recently, as a concept of the concept shown in Fig. 1, there has been studied as a method of increasing the reaction speed, such as ferro-coke, carbon monoxide intrinsic light, ultrafine. Here, the ferro-coke is a technique in which a carbon material is mixed with iron ore (an iron-containing raw material), baked and solidified as a raw material for the steel making process. The carbonized raw intrinsic light is a technique in which iron- Further, the above-mentioned micro-finishing is a technique mainly used for refining the carbon material.

The way of thinking of these technologies is based on the theory shown in Fig. 2 shows the relationship between the heat exchange when the iron ore and the carbon material are in close proximity, the reduction reaction of the iron ore and the gasification reaction of the carbon material (coke). On the iron ore side, reduction reaction occurs in which Fe ₂ O ₃ reacts with CO to form Fe and CO ₂ . This reaction is an exothermic reaction. On the other hand, on the side of the carbonaceous material, a gasification reaction (gas reforming reaction) called " quay-head reaction " occurs in which CO ₂ and C react to generate CO. This reaction is an endothermic reaction (hereinafter both reactions are sometimes referred to as " seasonal reactions ").

Here, as shown in Fig. 2 (a), when the iron-containing raw material and the carbonaceous material are charged in layers in the blast furnace, since the exothermic reduction reaction and the endothermic gasification reaction occur at respective sites, It is necessary to transfer the gas to the heat transfer or the supply of CO and CO ₂ required for the heat treatment. On the other hand, as shown in Fig. 2 (b), when the iron ore is in close proximity to the carbonaceous material, the reduction reaction as the exothermic reaction and the gasification reaction as the endothermic reaction are repeated at high speed.

Therefore, it is believed that the close proximity of the iron-containing raw material and the carbonaceous material to each other, that is, the iron-containing raw material and the carbonaceous material, are effective in enhancing the iron-making reaction. Under such a conception, the carbon-containing compacted light in which the iron-containing raw material and the carbonaceous material are mixed in advance and the carbonaceous material is embedded in the iron-containing raw material is the ultimate form.

When the heat required for the above-described gasification reaction lies in the inside of the carbon monoxide-containing intense light in the carbon monoxide intensive light in which the carbonaceous-iron-containing raw material is disposed in close proximity, as shown in Fig. 3, The reduction reaction in which Fe _n O _m is reduced by CO occurs and CO ₂ generated by the reduction reaction causes the following gasification reaction so that the reaction occurs from the inside to the outside of the coarse light sequentially, _n O _m are sequentially reduced to form Fe (metal iron). As described above, since the reduction reaction and the gasification reaction progress inside the compacted light, the supply of heat from the outside is minimized, and the temperature in the furnace can be reduced accordingly.

However, in order to realize the above-described idea, it is a condition that the carbonaceous built-in intense light (sintered ores) can be stably produced. However, in order to produce the carbon monoxide intensive light, there is a problem that the burning coke contained in the granulated particles (pseudo particles) burns and disappears in the process of sintering. As long as this problem can not be solved, none.

Therefore, the present invention provides a pseudo-particle containing a carbonless coke as a carbonaceous core at its center and coated with an iron ore powder having a melting point adjusted around the carbonaceous core as a particle for producing a carbonaceous built-in compact, Thereby solving the above problem.

That is, the carbon monoxide intensive light of the present invention is the same as the conventional carbon monoxide intussusceptional light in that the carbonaceous core is used as the carbonaceous core of the central part of the assembled particles (pseudo particles). However, in the present invention, by covering the periphery of the carbonaceous core with the iron ore powder and adding the quicklime to the iron ore powder to lower the melting point and forming a dense outer layer at the time of sintering, And differs from the prior art in terms of prevention of combustion and disappearance.

Here, as the iron ore powder, it is preferable to use a pellet feed having a grain size of 10 to 1000 mu m, more preferably 250 mu m or less. This pellet feed is excellent in that it is mainly composed of high-quality (high Fe, low gravel) hematite and magnetite as main components and can be obtained inexpensively in large quantities as fine ores having a size of 1 mm or less of 90% or more.

In addition to the pellet feed, the iron ore powder used in the present invention may be mill scale, transfer exhaust gas recovery dust (OG dust), tailing occurring during election, etc., , And they may be mixed with a pellet feed.

However, as can be seen from the Fe ₂ O ₃ -CaO 2 original state diagram shown in FIG. 4, the melting point of the magnetite, particularly the high-grade magnetite, is as high as about 1580 ° C. and is higher than the sintering temperature Much higher, and are not melted at normal sintering temperatures, i.e., no sintering reaction takes place.

Therefore, in the present invention, by adding the CaO-containing raw material to the iron ore powder, the melting point of the outer layer is lowered to melt at a temperature (1200 ° C or higher) at the time of sintering to form a fused layer, Layer, thereby preventing burning and loss of the carbonaceous core containing the carbonaceous built-up granulated particles and allowing the carbonaceous core to remain.

With the above structure, even if there is air intrusion during sintering firing, embedded carbonaceous nuclei can be present. This is because, as shown in Fig. 5, by the reaction of C forming intrinsic core and intruding O ₂ by the oxygen blocking effect of the outer layer formed around the core of the built-up particulate material (pseudo particle) The CO gas is maintained in a reducing atmosphere, and it is considered that the carbonaceous material can be remained.

Here, the temperature of the melting point to be adjusted is preferably in the range of 1200 to 1500 占 폚, more preferably 1200 to 1400 占 폚, from the viewpoint of promoting the melting on the sintering machine. When the temperature is less than 1200 ° C, no melt is produced, and calcium ferrite having the highest strength among the constituent minerals of the sintered ores and having relatively high reducibility is not produced. On the other hand, if the temperature is higher than 1500 ° C., it is not melted on the sintering machine and is not fused with the sintered organs mainly composed of calcium ferrite.

The added amount of calcium oxide CaO to be added as an adjuster of the melting point is such that the pellet feed (PF) used for the outer layer is added to the pellet feed (PF) having a gangue component (hematite (Fe ₂ O ₃ ) mass%) is used, it may be determined from the Fe ₂ O ₃ -CaO 2 elemental state diagram shown in FIG. 4 described above. In the case that the use of PF many gangue components, using the SiO ₂ -Fe ₂ O ₃ -CaO ₃ binary phase diagram considered the gangue component of SiO ₂ as shown in Figure 6 may be determined the amount of addition of CaO. The quicklime also functions as a binder in addition to serving as a melting point adjusting agent.

In addition, from the viewpoint of inhibiting the burning and disappearance of the carbonaceous core at the time of sintering, the carbonaceous built-up granulated particles (pseudo particle) of the present invention can be obtained by setting the size of the carbonaceous core to 3 mm or more, It is preferable that the thickness of the outer layer formed around the outer circumferential surface is 2 mm or more and the particle diameter is controlled in an appropriate range. Here, the size of the carbonaceous material refers to the length of the carbonaceous material.

That is, in the carbon-bearing built-up granulated particle of the present invention, it is preferable that the carbonaceous core used as the granulation nucleus is a carbonaceous material having a low volatile content such as an anthracite such as a liquefied coke and / or a horny cement. Particularly, the dissolving coke is preferable because it does not generate gas even when heated, in addition to being easy to obtain. In order to prevent the burning and disappearance of the carbonaceous core in the sintering process, the particle size of the carbonaceous material to be the core is preferably not more than 3 mm but not more than 3 mm. More preferably at least 4 mm, and even more preferably at least 5 mm.

The outer layer formed around the carbonaceous core preferably has a thickness of 2 mm or more. If it is less than 2 mm, there is a possibility that the oxygen barrier layer will not sufficiently function even if a fine outer layer is formed by melting at the time of sintering. In addition, since the carbonaceous core has many irregularities, There is. Normally, since the granulated particles are heated from the outside, the center side is not heated well at the time of heating. Therefore, the thicker the outer layer, the lower the melting point of the outer layer is preferably adjusted. Therefore, it is more preferably in the range of 3 to 7 mm.

The particle diameter of the built-in particulate built-up particles (similar particles) of the present invention formed using the carbonaceous material as a core is 7 mm in the minimum particle size from the minimum particle size and the minimum outer layer thickness. However, It is preferable to set the particle diameter to not less than 8 mm in order to sufficiently raise the temperature to the center of the particles in the sintering process in consideration of the temperature distribution in the granulated particles. More preferably 10 mm or more, and further preferably 20 mm or more.

It is also preferable to increase the grain size of the sintered raw material (granulated particles) from the viewpoint of segregation loading on the lower side of the sintered layer when the sintered raw material is introduced into a sintering machine to be described later. Here, the conventional coarse grains refer to a coarse material containing iron ore powder, a carbonaceous material, and a CaO-containing raw material as a raw material for assembly, which is assembled with a particle size of 2 to 4 mm (arithmetic average diameter) by a drum mixer or a pelletizer, (Hereinafter referred to as the same). The particle diameter in the present invention means the particle diameter measured by sieving.

Next, a manufacturing method of the sintered ore-containing built-up granulated particles of the present invention and the granulated particles thereof as raw materials for sintering will be described.

Fig. 7 shows an example of the manufacturing method of the carbon-containing built-up granules and the carbon-containing embedded sintered ores according to the present invention. (PF) which is an iron ore powder of 250 탆 or less and a burnt lime CaO as a melting point adjusting agent are charged into a pelletizer, mixed and assembled to form a carbonaceous material having a size of 8 mm or more It is made into built-up granulated particles (pseudo-particles). The raw material may be added at the same time, since coke particles having a large particle diameter become nuclei and are assembled. The charging ratio of the coke particles and PF is determined so that the thickness of the PF layer of the outer layer is 2 mm or more with respect to the coke particles serving as the nuclear particles.

Then, the carbon-containing built-up granules (pseudo-particles) thus obtained are mixed with conventional granulated granules (pseudo-particles) for sintering obtained by stirring and mixing conventional raw materials with a drum mixer or the like, Is carried into the surge hopper of the sintering machine and charged into the pallet from which the sintering machine circulates. In addition, since the particle size of the carbonaceous built-up granulated particles (pseudo particles) is larger than that of ordinary granulated granules (pseudo particles) for sintering, a large number of particles are likely to be formed in the middle and lower layers So that the sintering reaction can be sufficiently promoted.

As described above, since the carbon-containing sintered ores (compacted light) of the present invention can be produced using a practical sintering machine, it can be mass-produced at low cost. In addition, the pellet feed (PF) to be the raw material of the outer layer can be obtained in a large amount at low cost, and therefore there is no restriction on production.

Example 1

Using the sintering test pot shown in Fig. 8, the following sintering experiment was carried out using the embedding granules of the present invention, in which the granular coke was coated with PF, and the conventional granulated particles as raw materials for sintering.

 For the conventional granulated particles (pseudo particles), an iron ore powder as an assembly raw material, an amount of limestone in which CaO is 10 mass% as an additive, and a coke powder in an amount of 5 mass% The mixture was charged into a mixer, stirred and mixed, and was assembled with an average arithmetic diameter of 2.9 mm.

On the other hand, as for the built-up granules (similar particles), three types of carbonless coke having particle diameters of 3 mm, 4 mm and 8 mm as the carbonaceous core, and Anglo American-PF having an average particle diameter of 250 μm or less as the outer layer raw material (iron ore powder) (Fe ₂ O ₃ ): 97.7%) and CaO (quicklime) as a melting point adjusting agent were charged in a pelletizer and assembled so that the outer layer had a thickness of 2 mm or more and a particle diameter of 8 to 20 mm, The pellets of T1 to T7 shown in Table 1 were used.

In addition, in the production of the carbonaceous material embedded granulated particles, the added amount of CaO (calcium oxide) is, since the it is almost 100% Hema in PF used as the outer layer material tight (Fe ₂ O _3), and Fe ₂ O ₃ shown in Fig. 5 (T6) when the melting point is 1500 ° C, 10 mass% (T1 to T3) when the melting point is 1450 ° C, and 17 mass% (T1 to T3) when the melting point is 1300 ° C using a binary system diagram of CaO. mass% (T4, T5). Further, the granulated particles of T4 in Table 1 are comparative examples in which 2 mass% of carbon materials are mixed in the PF of the outer layer as in the case of conventional granulated particles. T7 in Table 1 is a comparative example in which the melting point of the outer layer is not adjusted (no addition of CaO, melting point: 1580 DEG C).

In the sintering experiment, a sintering pot having an inner diameter of 300 mmφ and a height of 400 mm of the raw material loading portion shown in FIG. 8 was used, and on the lower layer side (133 mm) of the raw material loading portion, Conventional granulated particles are mixed at a ratio of 1: 1 in a mass ratio to uniformly blend the granular particles embedded in the granules so as to be embedded in conventional granules, and 2/3 (267 mm) Thereafter, the upper surface of the charging layer was ignited, and the air above the test pot was sucked into the charging layer with a blower disposed below the testing pot, thereby burning the carbonaceous material in the sintering raw material. Here, the reason why the granular particles incorporated in the lower layer side are buried in the conventional granular particles is that only the combustion heat of the surrounding conventional granular particles is used, and the difference between the conventional granular particles and the outer layers of the granular particles This is because the sintering reaction is carried out to obtain the sintered organs which are burnt without burning the carbonaceous material of the core. For this purpose, one-third of the lower layer side where the temperature is likely to rise during sintering is advantageous.

An external view of the sintered light (compacted light) obtained in the sintering experiment is shown in Fig.

From this figure, it can be seen that, in the assembled particles of T1 to T3, T5 and T6 according to the present invention, besides the carbon-containing sintered compact was obtained, it was fused with the ordinary sintered compact in the surrounding area. In other words, in this example, in addition to the sintered light in which the carbonaceous material is in a built-in state, the carbonaceous built-in sintered light integrated with the sintered light existing in the surroundings is obtained. Therefore, do.

On the other hand, the sintered ores obtained from the granulated particles T7 which were not subjected to the adjustment of the melting point remained in the single spheres without fusing with the ordinary sintered ores around the spheres. Therefore, when the built-in particulate built up particles not subjected to the adjustment of the melting point of the outer layer are charged into the actual sintering apparatus, not only the sintered body with the carbonaceous material embedded therein is obtained but also the firing with the surrounding sintered light does not proceed. It is expected that the differentiation rate is increased and the yield is greatly lowered.

Further, in the case of the granulated particles T4 in which 2 mass% of coke was mixed in the outer layer, the superfusion state was reversely reversed, and the particles did not remain as pellets in the resulting sintered ores.

Fig. 10 shows a photomicrograph of a carbonaceous built-in sintered ore T5, which is integrated with the sintered ores that are appropriately sintered and are present around the sintered ores. From this figure, it can be seen that, in the sintered organs subjected to proper sintering, the PF layer covers the carbonaceous core, and the fused layer is observed between the PF and the other sintering raw material in the PF layer surface layer, And the PF layer is fused to the surrounding sintered raw material. Therefore, there is no possibility that the strength of the sintered ores is lowered by the presence of the carbonaceous built-in sintered ores.

Fig. 11 shows the result of performing element mapping using the EPMA for the section of the carbon-containing sintered ores T5 subjected to appropriate sintering. That the carbon remains in the pellet remaining in the sintered ore, that is, the carbonaceous material contained therein is present, and that the Fe concentration is increased in a part of the periphery of the carbon and metal iron is generated by reduction Able to know.

The reason why such a reduction reaction occurs is as follows.

In the case of the carbonaceous built-up granulated particles, the carbonaceous nucleus composed of the coke-free particles is located at the center of the granulated carbonaceous material. Therefore, in the same manner as in the iron-making reaction of the sintered ores shown in Fig. 2 (b), the reduction reaction occurring between the iron oxide powder and the coke particles and the gasification reaction of the coke, And it is believed that metal iron was produced at the stage of the sintered ores production.

Therefore, when the carbon-containing sintered ores according to the present invention are charged in the blast furnace, it is expected that the iron-based reaction will be faster and more efficient than the conventional sintered ores and further proceed at a lower temperature.

Example 2

The built-in particulate granules T5 produced in Example 1 and the conventional granulated particles were charged into the sintering pot shown in Fig. 8 in the same manner as in Example 1, and the sintering experiment was carried out to obtain the lower layer side 1 / 3 (133 mm) and a conventional sintered light obtained from 2/3 (267 mm) of the upper layer side of the raw material loading portion by the method specified in JIS M 8713, and the degree of reduction (RI) The reduction differentiation index RDI was measured by the method defined in JIS M 8720.

12 (a) shows the change of the reducing index (reduction ratio) RI according to the reduction time. The carbon-bearing sintered ores according to the present invention have a reduction ratio higher than that of a conventional sintered ore, Is high.

12 (b) shows the relationship between the redox index RI and the reduction redox index RDI of the carbon-containing sintered ores according to the present invention, as compared with the relationship between the redox index RI and the reduction redox index RDI of ordinary sintered ores , It can be seen that the anticorrosive sintered ores according to the present invention are superior to the conventional sintered ores in that both the reducing index RI and the reducing differentiation index RDI are excellent.

Industrial availability

The technique of the present invention is not limited to the above-described embodiments. For example, as a sintering heat source, in addition to the carbonaceous material added in the raw material for sintering, a sintering technique for supplying gaseous fuel, ).

Claims (8)

Wherein the core particle is coated and formed around the core of the carbonaceous material and made of pseudo-particles comprising an outer layer composed of the iron ore powder and the CaO-containing material. The method according to claim 1,
Wherein the iron ore powder is a pellet feed having a particle size of 10 to 1000 占 퐉. 3. The method of claim 2,
Wherein the pellet feed has a particle diameter of 250 탆 or less. 4. The method according to any one of claims 1 to 3,
Wherein the outer layer has a melting point of 1200 DEG C or more and 1500 DEG C or less. 5. The method according to any one of claims 1 to 4,
Wherein the carbonaceous material to be the carbonaceous core is coke particles having a particle diameter of 3 mm or more. 6. The method according to any one of claims 1 to 5,
Wherein the outer layer has a thickness of at least 2 mm. 7. The method according to any one of claims 1 to 6,
Wherein the granulated particle has a particle diameter of 8 mm or more. 9. A method for producing the granulated particulate built-up material for producing sintered ores according to any one of claims 1 to 7,
A method for manufacturing a sintered ore-forming granular material for sintered ores by pouring and mixing an outer layer of iron oxide powder as an outer layer and a CaO-containing material as an outer layer of a pelletizer into a pelletizer, Way.

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