JP2020200489A - Manufacturing method of non-calcined coal-containing mass ore for blast furnace and manufacturing apparatus - Google Patents

Abstract

To provide technique capable of stably and in a large amount manufacturing non-calcined coal-containing mass ore for blast furnaces having high strength, even when T.C. is 15 mass% or larger and a blending ratio of a hydraulic binder is slight.SOLUTION: Into a coal-containing mass ore raw material in which, 87.0 to 97.5% in total of an iron-containing raw material, a carbon-containing raw material, and other raw material are blended by adjusting a blending ratio, such that, by mass ratio, a hydraulic binder is 2.0 to 9.0%, a fine particle silica source is 0.5 to 4.0% and a ratio (T.C) of carbon contained in the coal-containing mass ore is 15 to 40%, 9.0 to 14.0% of water is added and transferred, while continuously mixing, a connection part for transferring to a second extrusion part by vacuum deaerating the first extrusion part and the mixed raw material continuously supplied therefrom, the mixed raw material supplied from the connection part and vacuum deaerated is extruded in a molding part provided with a many holes to continuously extrude to produce a molded body, the continuous molding is performed in the range of the packing density of 50 to 95 vol% due to the mixed raw material of the second extrusion part.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for producing a non-calcined coal-containing agglomerate ore used as a raw material for a steelmaking furnace such as a blast furnace or a rigid melting furnace.

Normally, in a blast furnace, raw materials such as sintered ore and massive coke are charged from the upper part of the furnace, and air is blown from the lower part of the furnace to ventilate the reducing gas generated from the massive coke and blown air from the lower part of the furnace to the upper part of the furnace. However, pig iron is obtained by reducing and dissolving iron oxide in the raw material. The raw material for a blast furnace is required to have a strength that does not pulverize in the furnace in order to ensure the ventilation of the reducing gas in the blast furnace. Further, since the blast furnace raw material is exposed to a high temperature of 1500 ° C. or higher in the lower part of the furnace, strength at a high temperature is also required. For this reason, the mainstream raw materials for blast furnaces are raw materials that have been fired in advance at a high temperature of 1000 ° C. or higher, such as sinter and calcined pellets.

Further, a non-calcined agglomerate ore in which a fine powdery raw material is mixed with a hydraulic binder, granulated by adding water, and then cured to increase the strength of the granulated product has been known for a long time. Since this uncalcined agglomerate can be charged into the blast furnace as it is without calcination, it is a technology that can suppress CO ₂ emissions while suppressing the energy consumption required for heating and calcination. As a raw material for non-fired agglomerates, there is a possibility that even low-grade iron ore, which has low sinterability and is difficult to bake in chunks, can be used. It also has the meaning of expanding the types of iron sources used in blast furnaces, preserving high-quality iron ore that is feared to be depleted, and making effective use of the entire earth's resources.

On the other hand, in recent years, "non-calcination coal-containing agglomerate ore" technology has been proposed as a technology that can achieve both the need for reducing coke consumption in a blast furnace and the need for reducing CO ₂ (Patent Documents 1 and 2, non-patent). Reference 1 etc.). By adding a carbon-containing raw material to the fine powder raw material of the above-mentioned non-fired blast furnace, that is, when the blast furnace contains a carbonaceous material, the relationship between the reduced gas temperature and the gas composition (ηCO = CO ₂ / (CO + CO ₂ )). ), Even in the heat storage zone and reduction reaction equilibrium zone of the blast furnace shaft where the progress of the reduction reaction of iron oxide is restricted, the reduction reaction is carried out by the internal carbon in the unfired agglomerate in the temperature range of 900 to 1100 ° C. As a result, the reduction rate is improved, and the effect of reducing the ratio of reducing materials during blast furnace operation can be expected.

From the above, it is desired that the non-calcined coal-containing agglomerate for blast furnace has a high carbon content and high strength so as not to be pulverized in the blast furnace. For example, in Patent Document 1 which is typical of the conventional non-calcination coal-containing agglomerate ore technology for a blast furnace, the carbon content of the non-calcination carbon-containing agglomerate is set to an appropriate value of 15% by mass or more and 25% by mass or less. However, in response to the problem that the carbon content in the non-calcined carbon-containing agglomerate increases and the strength decreases when it exceeds 15% by mass, first, "a fine powder iron-containing raw material and a fine powder coke are mixed, and then water content is further increased. After adding a part of the above and kneading, a method of preventing a decrease in strength is proposed by adding early-strength cement to the kneaded product. As a result, instead of the early-strength cement, which was conventionally buried in the pores on the surface of the fine powdered coke and could not exert its effect as an adhesive, the pores of the coke were buried with the fine powdered iron-containing raw material. The strength development effect of strong cement can be efficiently exhibited.

However, in this method, non-calcined coal-containing agglomerates that do not pulverize even when charged into a blast furnace (crushing strength> 980 N / piece; each represents the crushing strength per uncalcined agglomerated ore; N is Newton. In order to produce (), 10% by mass or more of early-strength cement is blended. When the amount of this non-calcined coal-containing lump ore used in the blast furnace was increased, the early-strength cement proceeded with a dehydration reaction (endothermic reaction) at 400 to 500 ° C., so 10% by mass of the early-strength cement was added. Excessive use of coal-containing lump ore lowers the temperature inside the blast furnace, causing a delay in the reduction of the blast furnace interior container, and the effect of reducing the ratio of reducing agents cannot be obtained. In addition, since the early-strength cement component becomes slag in the blast furnace, there is a problem that the amount of slag increases.

Further, in Non-Patent Document 1, by blending 3% by mass of a carbon-containing agglomerate ore having a carbon content (TC) of about 20% by mass as a raw material for a blast furnace, the effect of reducing the ratio of reducing agents during blast furnace operation is achieved. However, it is stated that the effect of reducing the reducing agent ratio did not appear when 6% by mass was added.
The reason for this is that it is necessary to add 10 to 11% by mass of cement in order to secure the crushing strength of the carbon-containing agglomerate ore having a carbon content (TC) of about 20% by mass to withstand blast furnace charging. It is said that this is because the water of crystallization derived from cement contained in the carbon-containing lump ore increases and causes a dehydration endothermic reaction in the blast furnace, which lowers the temperature of the blast furnace shaft and delays the reduction.

Therefore, in order to maximize the effect of reducing the reducing agent ratio of the blast furnace, it is necessary to increase the charging ratio of the coal-containing agglomerate ore into the blast furnace. Here, in order to increase the charge of the coal-containing lump ore into the blast furnace to 3% by mass or more, the carbon content (TC) is increased, while the temperature drop in the blast furnace is avoided and the coal-containing lump ore is charged. In order to improve the crushing strength, even if the compounding ratio of hydraulic binder such as cement is 9% by mass or less, the development of a manufacturing method to increase the strength of carbon-containing agglomerate ore so that it will not be pulverized during blast furnace loading is required. You will need it.

Therefore, in Patent Document 2, as a method for increasing the room temperature crushing strength of the non-fired carbon-containing pellets for blast furnace, "a water-hard binder and at least one of a starch binder or a clay-based binder" is added as a "binder". Non-firing carbon-containing material with strength (> 1000N / piece) that does not pulverize even if the water-hard binder content is 3 to 10% by mass even if the carbonaceous material-containing raw material is mixed in 10 to 30% by mass or charged into a blast furnace. It is said that it can produce blast furnace.

However, both the starch binder and the clay-based binder have very high viscosities, and at the water addition rate (7% by mass) as shown in Patent Document 2, the roll briquette method having a very large compressive force is optimal. .. Generally, when molded by the roll briquette method, a large amount of powder and fragments are generated, so that there is a drawback that the product yield is low (generally 70% or less). Molding is possible with the disc pelletizer method, but the disc pelletizer device is only a small device and is not suitable for industrial mass production.

On the other hand, if a large amount of water is added to the raw material to reduce the viscosity of the raw material, it can be molded by other molding methods (extrusion molding method, pan pelletizer granulation method, etc.). When the water contained in the blast furnace dries, it becomes voids and reduces the crushing strength, and a large amount of powder is generated when the blast furnace is loaded, or the molded bodies adhere to each other during curing after molding and become large lumps. There is also a problem that productivity is poor in that the yield of the molded product is lowered because the crushing treatment is required before loading.

Further, as shown in Patent Document 3, as a method of improving the cold strength of the non-calcined agglomerate without increasing the cement, the mixture of the agglomerate raw material and water is vibrated to separate the air in the mixture. A method for producing non-calcined agglomerates has been proposed in which the strength of the agglomerates is improved by removing them. According to this production method, since the air in the mixed raw material is separated and removed, it is possible to improve the strength of the agglomerate ore without increasing the amount of cement.

However, since the method for producing a non-calcined agglomerate ore shown in Patent Document 3 is a batch method, there is a problem that the non-calcined agglomerate cannot be continuously produced and the productivity is poor.

As described above, conventionally, in order to set the ratio (TC) of the carbon content contained in the raw material (in the coal-containing agglomerate ore raw material) excluding the water content in the non-calcined agglomerate ore to 15% by mass or more. A method for producing a coal-containing agglomerate ore having a high reducing agent ratio reduction effect by blending a carbon-containing raw material or the like has been proposed. However, since a large amount of carbon-containing raw materials and the like lowers the strength of the molded body, in order to avoid this, a hydraulic binder is blended in an amount of about 10% by mass in the conventional manufacturing method to secure the required strength of the molded body. It was.

Hydrate derived from a water-hard binder causes a dehydration reaction (a large endothermic decomposition reaction) in the blast furnace. Therefore, if a large amount of uncalcined coal-containing agglomerate ore containing a large amount of the water-hard binder is used in the blast furnace, as described above. The endothermic decomposition reaction causes temperature stagnation in the furnace. Therefore, it is difficult to use 3% by mass or more of the non-calcined coal-containing agglomerate ore containing about 10% by mass of a hydraulic binder in a blast furnace.

Further, as a measure for reducing the blending ratio of the hydraulic binder, a plurality of production methods have been proposed, but they are not suitable for mass production.

From the above, T.I. C. To establish a stable and mass-produced production method for blast furnace non-calcination coal-bearing agglomerates that can achieve high strength even when the content is 15% by mass or more and the content of the water-hard binder is 9% by mass or less. Therefore, it has been desired to expand the use of uncalcined coal-containing agglomerates in blast furnaces.

Japanese Unexamined Patent Publication No. 2012-82501 Japanese Unexamined Patent Publication No. 2012-21163 Japanese Unexamined Patent Publication No. 2014-136818 Japanese Unexamined Patent Publication No. 60-187631

Yokoyama, Higuchi et al .: Iron and Steel (100) 2014,601)

The present invention relates to T.I. C. Provided is a manufacturing method / manufacturing apparatus capable of stably and mass-producing high-strength uncalcined coal-containing agglomerate ore for a blast furnace even if the content is 15% by mass or more and the compounding ratio of the hydraulic binder is small.
The method for producing a non-calcined coal-containing lump ore for a blast furnace of the present invention uses a raw material for a coal-containing lump ore.
・ Carbon-containing raw materials that are reducing agents,
・ Iron-containing raw materials that are iron sources,
・ And other raw materials,
For these three raw materials,
-Hydraulic binders such as cement (adhesives, hereinafter referred to as hydraulic binders) and
・ It is premised that a fine silica source is added, and then water is added and mixed, and then molded to produce a coal-containing agglomerate ore.

As described above, T.I. C. As a result of diligent studies by the inventors in order to stably and mass-produce a high-strength non-calcined coal-containing agglomerate ore for blast furnaces with a content of 15% by mass or more and a small proportion of water-hard binder. By adopting the vacuum extrusion molding method, the porosity is reduced, and in addition, the particle size control of the raw material and the addition of a fine silica source as an additive increase the filling rate of the raw material particles, and the strength is high even if the water-hard binder is reduced. Succeeded in producing a non-calcined coal-containing agglomerate ore. That is,
(1) A method for producing a non-calcined carbon-containing agglomerate for a blast furnace used as a raw material for a blast furnace in steelmaking, in which a water-hard binder is added in an amount of 2.0 to 9.0% by mass in terms of zero water content. , The iron-containing raw material, carbon so that the fine silica source is 0.5 to 4.0% by mass and the ratio of carbon contained in the coal-containing blast furnace raw material (TC) is 15 to 40% by mass. Water when the total of the raw material and water is 100% by mass in the carbon-containing blast furnace raw material containing 87.0 to 97.5% by mass in total by adjusting the mixing ratio of the contained raw material and other raw materials. The first method is to add a mass ratio of 9.0 to 14.0 mass%, transfer the mixture while continuously mixing, and push the mixed raw material into a dam formed of a perforated plate installed in front of the transfer direction. The first extrusion section (kneading section) that forms the material seal and the connection section (vacuum chamber) that vacuum degass the mixed raw material continuously supplied from the outlet side of the dam and transfers it to the second extrusion section. By pushing the vacuum degassed mixed raw material supplied from the connection part (vacuum chamber) into the molding part having a large number of holes, the molded body is continuously extruded while forming a second material seal. A method for producing a carbon-containing lump ore using a production apparatus composed of a second extrusion section for producing the above, wherein the filling ratio of the second extrusion section with the mixed raw material is 50 to 95% by mass. This is a method for producing a non-calcined carbon-containing agglomerate ore for a blast furnace, which is characterized by continuous molding within the above range.
(2) The non-calcination coal-containing for blast furnace according to (1), wherein the pressure at the connection portion (vacuum chamber) of the production apparatus for the non-calcination coal-containing agglomerate for blast furnace is -50 kPaG or less. This is a method for producing agglomerate ore.
(3) Further, the average particle size of the fine particle silica source is 15% or less of the average particle size of the mixed raw material of the non-calcined coal-containing agglomerate excluding the fine particle silica source. The method for producing a non-calcined coal-containing agglomerate ore for a blast furnace according to (1) or (2), which is characteristic.
(4) Further, T.I., which is used as a raw material for a blast furnace in steelmaking. C. Is an apparatus for producing a non-calcined carbon-containing agglomerate ore for a blast furnace in an amount of 15% by mass or more. A first extruded portion (kneading portion) in which a first material seal is formed by pushing a mixed raw material into a dam formed of a perforated plate installed in front of the transfer direction and provided with a means for transferring. A connecting portion (vacuum chamber) that vacuum degass the mixed raw material continuously supplied from the outlet side of the dam and transfers it to the second extrusion portion, and a vacuum degassing unit that is supplied from the connecting portion (vacuum chamber). The mixed raw material was pushed into a molding section having a large number of holes, so that a second material seal was formed and continuously extruded to produce a molded body. This is an equipment for producing uncalcined coal-containing agglomerates for blast furnaces.

By adopting the method for producing a non-calcined coal-containing agglomerate ore for a blast furnace, which is extruded while vacuum degassing according to the present invention, and its apparatus, and blending a fine silica source into a mixed raw material, a coal-containing agglomerate raw material can be produced. T. C. It is possible to produce a non-calcined coal-containing agglomerate ore with high strength with a hydraulic binder such as cement at a blending ratio of 9.0 mass% or less, even if a large amount is blended so as to be 15% by mass or more. became. This makes it possible to use up to 9% by mass of coal-containing agglomerates, which could only be used up to 3% by mass due to the endothermic decomposition reaction, in the blast furnace, which contributes to low-reducing agent ratio operation.

T.I. in coal-containing lump ore. C. It is a figure which shows the relationship between the reduction material ratio reduction amount. This is an example of a vacuum extruding machine according to the present invention. It is a graph which shows the relationship between the vacuum pressure and the crushing strength between a connection | molding part. It is a figure which shows the determination of the filling rate of a raw material, and the upper and lower limit image of the filling rate.

As described above, the raw material of the non-calcined carbon-containing agglomerate is generally composed of three kinds of a carbon-containing raw material as a reducing agent, an iron-containing raw material as an iron source, and other raw materials. Then, a hydraulic binder and a fine silica source are mixed with these three kinds of raw materials to prepare a coal-containing agglomerate ore raw material, and water is further added and mixed, and then molded to obtain a coal-containing agglomerate ore.

The carbon-containing raw material is preferably fine powder obtained by carbonizing coal, such as powdered coke obtained by crushing coke to a predetermined particle size or dust collected from a coke oven, but contains a large amount of carbon content generated from anthracite, coal, or a blast furnace. Dust or the like may be used.

The iron-containing raw materials include iron ore crushed to a predetermined particle size, iron ore fine powder (pellet feed), and dust, sludge, and scale containing a relatively small amount of carbon and a large amount of iron components generated in the iron-making process. Etc. can also be used. Further, grinding debris from a rolling roll or an aggregate such as iron ore or sinter that has fallen during the transportation process of the ironmaking process may be used, or powder generated during the molding process of the coal-containing agglomerate ore. And fragments are also included in the iron-containing raw materials.

The other raw materials refer to sludge, slag, etc., which generate a small amount of iron component (iron content is 30% by mass or less) or do not contain iron component, particularly in the iron making process. Carbon may be contained due to the low iron content.

The coal-containing lump ore also contributes to zero emissions of steelworks. Currently, most of the by-products generated in steelworks are recycled in the steelworks or commercialized and sold as by-products, but some of them are difficult to recycle or commercialize. Sludge and some slag are typical examples of these items that are difficult to recycle within the company. The other raw materials refer to raw materials that are difficult to recycle in such steelworks, and by actively recycling them as raw materials for coal-containing agglomerates, it is possible to contribute to zero emissions of steelworks. There is an advantage that the particle size of the raw material can be positively adjusted by the addition thereof and the fluidity of the raw material when water is added can be controlled (advantage in using the extrusion molding method described later).

As shown in Table 1, dust and sludge may contain more or less carbon. In the present invention, as will be described later, T.I. C. Since it is characterized by determining the physical properties of the carbon-containing raw material, the iron-containing raw material, and other raw materials that are generally used, the compounding ratio as the raw material is not classified. C. Define the range of. The mass% in Table 1 is an example and is not limited to this range.

The hydraulic binder is sometimes referred to simply as cement, and means a binder having a function of increasing the cold crushing strength of the granulated product by hardening by a hydration reaction with water contained in the raw material or added water. To do. Water-hard binders include Portland cement (specified by JIS R 5210), mixed cement (blast furnace cement (specified by JIS R 5211)), silica cement (specified by JIS R 5212), and fly ash cement containing calcium silicate. (Specified in JIS R 5213)), ultrafast hard cement, blast furnace slag, etc. are used, but the present invention is not limited thereto.

Further, the fine silica source includes not only silica fume and microsilica but also fly ash.

In addition, as shown in Table 1, some T.I. C. However, since the fraction itself of the hydraulic binder and the fine silica source is small and the influence is considered to be small, T.I. C. Does not count.

The conditions required for coal-containing agglomerates and the manufacturing conditions for achieving them are as follows.

Coal-containing lump ore raw material and T.I. C. ;
Conventionally, T.I., in a non-calcined coal-containing agglomerate ore, has a theoretical carbon content required to reduce iron oxide in a non-calcined coal-bearing agglomerate. C. Is defined as "carbon equivalent" and is used as a guideline for the degree of reduction of iron oxide by carbon.
The T.I. C. The lower limit of 15% by mass corresponds to carbon equivalent: 1.2 or more. If iron oxide particles and carbon particles are adjacent to each other in a non-calcined coal-containing agglomerate when used in a blast furnace, a solid reduction reaction inside the coal-containing agglomerate while the temperature is gradually rising inside the blast furnace. Progresses. Furthermore, surplus carbon that is not adjacent to iron oxide particles is gasified by the solution loss reaction, and gas reduction promotes the reduction of iron-containing raw materials for blast furnaces such as sinter and iron ore around unfired coal-containing agglomerates. You can also expect to do it.

FIG. 1 shows T.I. C. The relationship between and the amount of reduction in the reducing agent ratio is shown. This was used in a blast furnace by using a reduction test device (BIS furnace) that can simulate the reduction reaction in the blast furnace under load, and replacing the unfired coal-containing agglomerate ore with 10% by mass of ordinary sintered ore. This is the result of evaluating the effect of reducing the ratio of reducing agents at the time. T.I. in coal-containing lump ore. C. When the amount is less than 15 mass, the effect of reducing the reducing agent ratio is 0.2 kg / kg-C or less, but T.I. C. However, when the content is 15% by mass or more, the reducing agent ratio reducing effect is about 0.4 kg / kg-C. For this reason, in order to maximize the effect of reducing the ratio of reducing agents by charging the blast furnace, T.I. C. It was a prerequisite of the present invention that the content was 15% by mass or more. Regarding the above-mentioned unit: kg / kg-C, kg of the molecule is the total amount of reduced weight of the reducing material, and kg-C of the molecule is the amount of carbon contained in the carbon-containing agglomerate ore charged in the blast furnace. It is an index showing how much the carbon content contained in the coal-containing agglomerate ore gives the effect of reducing the ratio of the reducing material.

On the other hand, if the carbon-containing raw material of the coal-containing agglomerate ore raw material is further increased, it is said that the required strength of the uncalcined coal-containing agglomerate ore cannot be maintained in the blast furnace. As a result of verifying the upper limit value in the present invention, T.I. C. When it exceeds = 40% by mass, molding becomes difficult.

For the above reasons, T.I. C. Is blended so as to be 15 to 40% by mass. The upper and lower limits of the carbon-containing raw material, the iron-containing raw material, and other raw materials are not particularly specified, but the carbon-containing lump ore raw material includes T. C. In addition, it is preferable that the iron component content is high. Because, T.I. C. This is because other than the iron component becomes slag, which increases the amount of unnecessary heat input.

Therefore, the blending ratio of the coal-containing agglomerate ore raw material is 2.0 to 9.0% by mass for the hydraulic binder and 0.5 to 4.0% by mass for the fine silica source, as will be described later. T.I. C. The total of the three raw materials of the carbon-containing raw material, the iron-containing raw material, and the other raw materials is 87.0 to 97.5% by mass so that the ratio is 15 to 40%.

Here, for example, when powdered coke is used as the carbon-containing raw material, the carbon content of the powdered coke is about 75 to 85% by mass, so that T.I. C. If we try to make 15-40%, the minimum = 15 ÷ 0.85 × 0.87 ≒ 15.3% by mass, the maximum = 40 ÷ 0.75 × 0.975 ≈ 52.0% by mass, and the carbon content The raw material is blended into the coal-containing agglomerate ore so as to be 15.3 to 52.0% by mass, and the above three raw materials are combined and the difference from 87.0 to 97.5% by mass is carbon-free iron. Add the contained raw materials and other raw materials.

Further, for example, when blast furnace dust collection dust having a high carbon component (carbon component = about 30 to 40%) is used as a carbon-containing raw material, the minimum content of carbon component in the carbon-containing agglomerate ore = 15 mass is satisfied. Since 15 ÷ 0.40 × 0.87 ≈ 32.6 mass% and 40 ÷ 0.30 × 0.975> 100% to satisfy the maximum content = 40 mass%, carbon in the carbon-containing agglomerate ore The blending ratio of the contained raw materials is 32.6 to 97.5% by mass.

Hydraulic binder;
A hydraulic binder is added to the coal-containing lump ore raw material in order to develop a strength (> 1100 N / piece) that does not pulverize even when charged into a blast furnace. The hydraulic binder in the coal-containing agglomerate ore changes to connective tissue such as calcium silicate hydrate during the curing period, and improves the strength of the agglomerate ore. However, a part of this connective tissue is decomposed by an endothermic reaction at 400 to 500 ° C. or higher inside the blast furnace. Due to this endothermic reaction, the temperature inside the furnace is lowered, the temperature range of 400 to 500 ° C. is lowered toward the lower part of the furnace, and the gas reduction reaction at the upper part is delayed. For this reason, if a certain amount or more of cement is charged into the blast furnace, poor reduction in the furnace will occur, and even if a sufficient amount of carbon is mixed inside the coal-containing lump ore, the amount of lump coke used in the blast furnace will be reduced. become unable. Therefore, it is preferable that the amount of the hydraulic binder is small.

When the ratio of the carbon-containing raw material in the coal-containing agglomerate raw material increases, the strength of the agglomerate ore decreases in inverse proportion. C. = When producing a non-calcined coal-containing agglomerate of 15 to 40% by mass, it is necessary to increase the blending amount of the hydraulic binder in the conventional production method. This is because the strength of the coal-containing agglomerate ore is proportional to the amount of the hydraulic binder compounded. Here, when the hydraulic binder is less than 2.0% by mass, the strength improving action / effect as a binder cannot be sufficiently exhibited. Further, although the strength improving effect is sufficiently exhibited even if it exceeds 9.0% by mass, the non-firing carbon-containing lump that is not pulverized in the process of transporting to the blast furnace and the process of charging is already at 9.0% by mass or less. It is possible to greatly clear the crushing strength of the sinter of 1100 N / piece or more, and the addition of more than that may lower the temperature in the blast furnace and hinder the reduction, increase the cost, increase the amount of blast furnace slag, and the above-mentioned Kay. It is useless because it promotes the cooling of the blast furnace due to the decomposition of calcium silicate hydrate. For the above reasons, the amount of the hydraulic binder added is 2.0 to 9.0% by mass.

Fine silica source;
As a method for producing the coal-containing agglomerate ore, a method of extrusion molding while vacuum degassing, which will be described later, is adopted. Therefore, air that becomes a void after molding is discharged in advance in the molding machine, and the particles of the molded body after agglomeration are indirectly discharged. The number of points can be increased, and the strength of the molded body can be improved. On the other hand, a raw material suitable for the extrusion molding method is a relatively highly fluid plastic raw material (which is stationary when no force is applied to the raw material, but flows (deforms) when a small force is applied). It is a raw material called kneaded soil, paste, etc.). Generally, a method of increasing the amount of water is used as a method of improving the fluidity of the raw material. However, in the coal-containing agglomerate ore, the water contained in the mixed raw material becomes void when dried. The particle indirect points cannot be increased, and the strength of the produced coal-containing agglomerate ore decreases.

Therefore, in the present invention, as a method for increasing the fluidity without increasing the water content, it is decided to add a fine particulate matter sufficiently smaller than the average particle size of the mixed raw material. When fine particulate matter is added to the mixed raw material, it penetrates between the raw material particles and coats the particles to exert an effect like a bearing that lubricates the particles, and the fluidity of the mixed raw material is improved. In addition, the fine particulate matter that coats the surface of the raw material particles is partially filled with contact points between the particles to increase the number of contacts, and partly enters the gaps between the raw material particles (by being replaced with water). By increasing the rate, the strength of the coal-containing agglomerate can be improved. The main component of the fine particulate matter is fine silica, which is stable at room temperature and is commercially available as a by-product, as represented by silica fume and fly ash, and a relatively abundant amount can be easily obtained. In addition, there are three advantages that the hardening reaction of cement is promoted during curing after molding, and the strength of the molded product can be expected to be improved.

Also, when the particles have a close-packed structure (from a geometric calculation), the minimum diameter of the particle gaps is 15% of the particle diameter, so the average particle size of the fine particle silica source is the average of the mixed raw materials. It is preferably 15% or less of the particle size. With this particle size, it is possible to penetrate between the raw material particles without resistance, which contributes to increasing the strength of the non-calcined coal-containing agglomerate ore. At present, the average particle size of the mixed raw material is about 60 to 100 μm, but the average particle size of silica fume, which is a typical fine particle silica source, is 0.1-0.2 μm, and the average particle size of fly ash is 10 to 20 μm. The above conditions can be almost satisfied. In this way, by selecting the type of fine silica source according to the average particle size of the mixed raw material or adjusting the particle size by pulverization, the effect of improving the strength can be exhibited, which is preferable.

In this example, the addition rate of an appropriate fine silica source is about 0.5 to 4.0% by mass, and the optimum addition rate is 0.5 to 2.0% by mass. The reason is that if the amount is 0.5% by mass or less, the amount of the fine silica source that covers the surface of the raw material particles is too small to sufficiently exert the effect of the bearing, so that it is necessary to add excess water, and the produced carbon-containing carbon is produced. The strength of the agglomerate is reduced. On the contrary, if it exceeds 4.0% by mass, the fluidity increases and it is not necessary to increase the water content, but the cost of the fine silica source becomes too high and the cost effectiveness becomes negative. From this, it is preferable that the addition rate of the fine silica source is small, 0.5 to 4.0% by mass is appropriate, and 0.5 to 2.0% by mass is optimal. The appropriate addition rate ranges from 0.5 to 4.0% by mass because the effect size differs depending on the type of fine silica source and the return on investment fluctuates due to market price fluctuations. However, the appropriate addition rate in the event of significant price fluctuations in the future is not limited to this.

moisture;
The blending ratio of the coal-containing agglomerate ore raw material is a mass ratio in terms of zero water content (= the raw material is completely dry = only the raw material solid with 0% water content). Moisture is added, but the water content is adjusted to 9.0 to 14.0 mass% as a ratio to the total 100 mass% with the mass ratio converted to zero moisture on the left.

Production method;
<Adoption of vacuum extrusion molding method>
In the present invention, by adopting the vacuum extrusion molding method as the manufacturing method, the number of contact points between the raw material particles can be increased, that is, the voids can be reduced and the strength of the molded body can be increased. As a result of evaluating the quality of the molded product obtained by changing the pressure in the vacuum chamber, it was found that the quality of the molded product obtained changes depending on the degree of vacuum in the vacuum chamber (vacuum chamber pressure).

<Example of vacuum extrusion molding machine according to the present invention, extrusion molding method, and formation of material seal>
An example of the vacuum extruding machine according to the present invention shows its structure in FIG. It is necessary to stably maintain the vacuum chamber at a high negative pressure while continuously and stably supplying and discharging raw materials using the vacuum extruding machine. For this reason, it is important to stably maintain the vacuum chamber at a high negative pressure (high degree of vacuum) by filling the gaps in the equipment structure before and after the vacuum chamber with raw materials, that is, by continuously forming material seals. Become.

The coal-containing lump ore manufacturing apparatus 10 includes a mixer 1, a charging port 2, a first extrusion section 3, a connecting pipe 4, a second extrusion section 5, a molding section 6, and a vacuum pump 7.
The first extruded portion 3 (also referred to as a kneaded portion) is a uniaxial screw feeder having a cylindrical casing 3a and a screw 3b rotatably arranged inside the casing 3a and continuously formed vertically. Is. The screw 3b is rotated by a driving means (not shown). The upper part of the base of the casing 3a is connected to the inlet 2 by a connecting pipe 8. A weir 3c formed of a perforated plate is arranged at the tip of the casing 3a. In the present embodiment, the weir 3c formed of the perforated plate has a structure in which a large number of holes are formed in a thick plate-shaped disk.

A second extrusion portion 5 is arranged below the first extrusion portion 3. The tip of the first extrusion 3 and the base of the second extrusion 5 are connected by a connecting pipe 4 (also referred to as a vacuum chamber). The connecting pipe 4 is connected to the vacuum pump 7 by a vacuum pump connecting pipe 9.
The second extrusion portion 5 (also referred to as an extrusion molding portion) is a uniaxial type having a cylindrical casing 5a and a screw 5b rotatably arranged inside the casing 5a and continuously formed vertically. It is a screw feeder. The screw 5b is rotated by a driving means (not shown). A molding portion 6 is attached to the tip of the casing 5a. In the present embodiment, the molded portion 6 has a structure in which a large number of holes are formed in a thick disk-shaped disk.

Each of the raw materials of the coal-containing lump ore is supplied to the mixer 1 so as to have a predetermined blending ratio, and water is added and mixed to produce a mixed raw material. The mixed raw material is continuously or intermittently charged into the inlet 2. The mixed raw material charged into the charging port 2 is supplied into the first extrusion section 3 through the connecting pipe 8 and is gradually compressed by the screw 3b to reach the weir 3c formed of the perforated plate. At this time, by adjusting the rotation speed of the screw 3b and the supply speed of the mixed raw material so that all the holes of the weir 3c formed of the perforated plate are filled with the mixed raw material, the weir 3c formed of the perforated plate is formed. A material seal is formed. Since the mixed raw material is continuously supplied by the screw 3b, the mixed raw material is continuously discharged and supplied into the connecting pipe 4 while always forming a material seal on the back surface of the weir 3c formed of the perforated plate. Will be done. The hole shape of the perforated plate (weir c) is not particularly limited, but it is important to adjust the hole diameter and aperture ratio according to the physical properties of the mixed raw material so that the material seal can be easily formed. Is.

Since the inside of the connecting pipe 4 is evacuated by the operation of the vacuum pump 7 connected by the vacuum pump connecting pipe 9, the mixed raw material supplied to the connecting pipe 4 is degassed, and the raw material particles in the raw material are surely separated from each other. By contacting and densifying, the strength of the produced unfired coal-containing agglomerate can be increased.

The mixed raw material densified in the connecting pipe 4 is supplied to the second extrusion section 5. The mixed raw material supplied to the second extrusion section 5 is extruded into the molding section 6 by the screw 5b.
As described above, in the example of the coal-containing agglomerate ore manufacturing apparatus according to the present invention, the material seal is used to continuously extrude while vacuum degassing, so that the productivity can be improved. It is possible. In the present embodiment, if the particle size of each raw material is 8 mm or less (maximum particle size is 8 mm, average particle size is about 60 to 100 μm), when extruding with the screws 3b and 5b, the mixed raw materials are the screws 3b and 5b. , Casing 3a, 5a, weir 3c formed of perforated plate, and molded portion 6 can pass through the gaps of each, so that they do not mesh with each other, which is preferable. When the mixed raw material passes through the molding portion 6, it is molded into the cross-sectional shape of the molding portion 6. The mixed raw material extruded from the molding portion 6 is broken by its own weight and molded into a molded product having a predetermined length.

The shape of the molded product is determined by the cross-sectional shape of the molded portion 6, and the holes can be formed not only in a cylinder but also in a prism such as a quadrangular prism or a hexagonal prism, but it is most desirable to form the molded product in a cylindrical shape. The reason is described below.

When comparing the ventilation pressure drop of the packed bed of the blast furnace in the coal-containing agglomerates of various tendencies, the columnar shape shows the lowest pressure drop. Further, as compared with prisms, columnar coal-containing agglomerates are characterized in that they are less likely to be pulverized when the walls in the packed bed or the coal-bearing agglomerates rub against each other or when a drop impact occurs. While agglomerates with a diameter of 30 mm to 40 mm have the highest crushing strength, the raw material charging mechanism into the blast furnace has a structure suitable for transporting raw materials with a diameter of 20 mm or less in accordance with the existing sintered ore. Therefore, it is desirable to mold it into a cylinder with a diameter of about 10 to 20 mm.

The molded products are piled up in a covered curing yard and cured in the curing yard for a predetermined period of time. During the curing period, the molded product solidifies and is gradually dehydrated by natural drying to complete the production of a coal-containing agglomerate ore.

<Conditions for continuous stable manufacturing>
In the embodiment of the present invention, in order to continue stably producing a dense and strong molded body, the vacuum chamber is maintained at a high negative pressure while continuously supplying the raw material into the connecting pipe 4 (a vacuum chamber called a vacuum chamber). At the same time, it is necessary to extrude the mixed raw material supplied into the vacuum chamber into the extrusion molding section 6. That is, in order to prevent air from entering through the holes of the perforated plate 3c or the molded portion 6, the inside of all the holes of the weir 3c formed of the perforated plate and the inside of all the holes of the molded portion 6 are constantly filled with the mixed raw material. It is important to maintain the material seal and maintain a high negative pressure between the connecting pipe 4 and the molded portion 6. Therefore, the conditions under which the material seal can be maintained using a continuous vacuum extrusion molding device were investigated.

As a test condition, the iron-containing raw material, the carbon-containing raw material, the water-hard binder, and the fine silica source are weighed so as to have a predetermined composition, and put into a uniaxial paddle type continuous mixer, and a predetermined amount of water is used. Was added and mixed for 2 minutes to 2 minutes and 30 seconds. The mixed raw material is put into an extrusion molding apparatus composed of a uniaxial screw type kneader and a uniaxial screw type extrusion molding unit, and the extrusion speed (the speed at which the raw material passes through the hole of the molding unit 6) is 40 to 40 to. The molding test was carried out after adjusting the speed to 100 mm / s.

Here, the effect of these factors on the material seal by changing the supply amount of the mixed raw material to the kneading portion, the rotation speed of the screws (3b, 5b), and the filling rate of the raw material in each casing (3a, 5a). investigated.

A weir 3c formed of a perforated plate is installed on the entrance side of the vacuum chamber, and the mixed raw material is continuously pushed by the screw 3b toward the weir 3c formed of the perforated plate to form the first material seal. In order to continuously form this first material seal, the mechanical resistance when the mixed raw material is pushed into the weir 3c formed of the perforated plate and passes through each hole is adjusted, that is, according to the physical properties of the raw material. It was found that it is effective to adjust the pore diameter, total aperture ratio, and thickness of the perforated plate.

The molding portion 6 installed at the tip of the extruded molding portion 5 is a perforated thick plate, and has a structure similar to that of the weir 3c formed by the perforated plate on the vacuum chamber entry side. It was found that it is effective to adjust the number of holes and the plate thickness in order to form the material seal, as in the case of the vacuum chamber entry side.

<Optimal vacuum conditions>
The test results of the coal-containing agglomerate ore agglomerated by changing the negative pressure between the connecting pipe 4 and the molding portion 6 by the extrusion molding method described above are shown below. Weigh the iron-containing raw material, carbon-containing raw material, water-hard binder, and fine silica source so that the raw materials have a predetermined composition, add the entire amount to the mixer, mix for 1 minute, and then add the predetermined amount of water to 3 It was mixed for 1 minute to prepare a mixed raw material. The mixed raw material was put into an extrusion molding apparatus, and a molding test was carried out by setting the extrusion speed (the speed at which the raw material passes through the holes of the molding portion 6) to 10 mm / s.

The agglomerated coal-containing agglomerate ore was air-cured at room temperature for 1 day, then placed in a constant temperature and humidity chamber at 80 ° C. for 2 days to be cured, and then air-cooled to 30 ° C. to carry out a crushing strength test. The crushing strength was measured in accordance with JIS M8718 "Iron ore pellet crushing strength test method", and a load was applied to one sample at a specified pressurizing rate, and the load when the sample broke was defined as the crushing strength. ..

Table 2 shows the compounding conditions of the raw materials.

When the pressure value between the connecting pipe 4 and the molded portion 6 at the time of molding is −50 kPaG, the variation in crushing strength changes greatly. In particular, as shown in FIG. 3, it was found that the closer the pressure between the connecting pipe 4 to the molded portion 6 is to the vacuum pressure, the higher the quality (higher strength), and the vacuum chamber pressure is in the range of -60 kPaG or more and -50 kPaG. Although the normal temperature crushing strength of the molded body is 1100 N / piece or more, which is the target value, the crushing strength of the molded body varies greatly and varies toward the low strength side. The crushing strength that varies on the low strength side has not reached the target. By shifting the pressure between the connecting pipe 4 to the molded portion 6 to a lower level, that is, to the vacuum side, variations in bulk density and crushing strength are reduced, and the normal temperature crushing strength of the molded body is 1100 N / piece, which is the target value. It was confirmed that it exceeded.

The raw material for the blast furnace needs to have a strength that does not pulverize when it is transported to the blast furnace and charged into the furnace in order to ensure the ventilation of the reducing gas in the blast furnace. As a result of the blast furnace operation test of the non-calcined coal-containing lump ore, if the room temperature crushing strength per molded body is 1100 N / piece or more, pulverization in the blast furnace can be suppressed and the ventilation of the reducing gas can be improved. It was found that it could be secured, and this is the target strength of the coal-containing lump ore.

The reason for this was estimated as follows. If the pressure between the connecting pipe 4 and the molding portion 6 is high, the air in the molding raw material is not sufficiently discharged, so that the molding is performed with a large amount of air entrained in the mixed raw material. This molded body has a low bulk density and low strength. On the other hand, a portion that does not involve much air also becomes a molded body, and this molded body has a large bulk density and high strength. It is considered that the difference in the amount of air entrained in the molded body causes a variation in strength, and the higher the pressure between the connecting pipe 4 and the molded portion 6, the greater the variation. On the contrary, when the pressure between the connecting pipe 4 and the molded portion 6 becomes low, the amount of air remaining in the mixed material is reduced, and it is considered that the strength variation is reduced.

As described above, the feature of the vacuum extrusion molding machine according to the present invention is the high negative pressure of -50 kPaG or less between the connecting pipe 4 and the molding portion 6 while continuously supplying the raw material to the vacuum chamber called the vacuum chamber. While maintaining a high degree of vacuum), the raw material supplied between the connecting pipe 4 and the molding portion 6 is extruded into the molding portion for molding.

Next, other conditions required for stable extrusion molding were investigated. Table 3 shows the contents and results of this survey.

The second material seal can be formed by installing the molded portion 6 of the perforated plate adjusted to the extruded molding portion 5 as described above. However, in actual production, the flow resistance of the raw material changes (operation fluctuation) or the screw rotation speed changes (operation action), so that the raw material supply speed to the molding unit 6 changes.

For example, if the water content of the raw material becomes excessive, the flow resistance of the raw material decreases, and the raw material is discharged before the second material seal is formed, so that the pressure in the vacuum chamber cannot be stably maintained. The same change occurs in the rotation speed UP of the screw 5b. As a result of investigating these phenomena, if the mixed raw material filling rate of the second extrusion portion 5 is less than 50% by volume, the second material seal is likely to collapse when the supply speed to the molding portion 6 increases. Do you get it.

On the other hand, when the flow resistance of the raw material increases or the rotation speed of the screw 5b is decreased, the raw material supply speed to the molding portion 6 decreases, and the second extrusion portion 5 extends to the connecting pipe 4 (vacuum chamber). It was found that the raw material was excessively deposited, and the screw 5b in the second extrusion portion 5 was overloaded and easily stopped. As a result of the investigation, it was found that when the filling rate of the second extruded portion 5 exceeds 95% by volume, poor discharge of the molded product is likely to occur when the supply speed to the molded portion is reduced.

Therefore, the rotation speed of the screw 5b of the second extrusion portion 5, the rotation speed of the screw 3b of the first extrusion portion 3 upstream of the connecting pipe 4 (vacuum chamber), and the physical properties of the raw material are adjusted as needed, and the second extrusion portion 5 is used. It has been found that by continuously controlling the raw material filling rate of 50% by volume or more and 95% by volume or less (essential condition), stable and continuous production of a molded product is possible even if there is a change in operation.

The raw material filling rate of the second extrusion section 5 is the ratio of the raw material to the volume of the cylindrical space (excluding the volume of the screw) in which the screw 5b of the second extrusion section 5 is rotating. Say. By controlling the raw material filling rate to 50% by volume or more and 95% by volume or less by increasing or decreasing the rotation speed of the screw 5b of the second extrusion portion 5 and increasing or decreasing the amount of raw material supplied, stable and continuous molding becomes possible.

As for the determination of the raw material filling rate, for example, as shown in FIG. 4, a visual determination is generally performed by visually observing the extruded molded portion from an observation window attached to the upper part of the vacuum chamber. This time, in order to determine the raw material filling rate from the screw range that can be seen from the observation window, for example, the relationship between the range where the screw blades are hidden by the raw material and the raw material filling rate is investigated in advance, and filling is performed simply by looking at the screw from the observation window. Although the rate can be determined, for example, even if a level meter (microwave type level meter, proximity sensor, various level switches, etc.) is installed in each part of the extrusion molding part and the filling rate is calculated from the level measurement value. good.

As described above, regarding the control range of the raw material filling rate, continuous stable molding is possible if it is 50% by volume or more and 95% by volume or less, but it is even better if it is 50% by volume or more and 70% by volume or less, and further 50% by volume. It is optimal if it is 60% by volume or more. The reason is that by controlling the filling rate to be constant, the force with which the screw of the extrusion molding portion presses against the perforated plate is stabilized, so that the variation of the discharged molded body is reduced.

As described above, as a method for producing a non-calcined carbon-containing agglomerate for a blast furnace, an iron-containing raw material containing iron oxide, a carbon-containing raw material, a water-hard binder, and a small amount of fine silica source are mixed, and water is added. After mixing, the vacuum chamber pressure is set to -50 kPaG or less and extrusion molding is performed while vacuum degassing, so that even if the amount of the water-hard binder in the raw material is 2 to 9% by mass, it is charged into the blast furnace. It is possible to produce a coal-containing agglomerate ore having a crushing strength of 1100 N / piece or more required for the above.

In the present embodiment, the screw 3b is a uniaxial type and the screw 5b is a uniaxial type, but the screw 3b may be a biaxial type or the screw 5b may be a biaxial type.

Although the present invention has been described above in relation to the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed in the present specification. , The method of producing a coal-containing agglomerate ore and the coal-containing agglomerate with such a change can be appropriately changed as long as it does not contradict the gist or idea of the invention that can be read from the claims and the entire specification. Must be understood as being included in the scope.

Next, examples of the present invention will be described, but the present invention is not limited thereto. As the coal-containing agglomerate ore raw material, a carbon-containing raw material, an iron-containing raw material, and other raw materials are used, and T. C. It was adjusted to be 15 to 40%. As the carbon-containing raw material, coke breeze (TC = 84%) and iron-making dust (TC = 23%) having a high carbon content were sieved with a 5 mm sieve, and the sieve was used. As an iron-containing raw material, ore M (Australian powder ore) and ore C (Canada powder ore) were mixed, crushed with a ball mill, sieved with a 5 mm sieve, and used under the sieve. As the hydraulic binder, early-strength cement and ultra-fast-hardening cement were used.
Silica fume and fly ash were used as the fine silica source.

As for the compounding conditions of the coal-containing agglomerate ore, the carbon-containing raw material, the iron-containing raw material, the hydraulic binder, and the fine silica source are weighed so as to be the compounding shown in Table 4, and the total amount is a uniaxial paddle type continuous type. After being put into a mixer and mixed for 1 minute, a predetermined amount of water was added and mixed for 3 minutes to prepare a mixing raw material. The mixed raw material is put into an extrusion molding apparatus composed of a uniaxial screw type kneader and a uniaxial screw type extrusion molding unit, and the extrusion speed (the speed at which the raw material passes through the hole of the molding unit 6) is 10 mm /. The molding test was carried out after adjusting so as to be s. The diameter of the holes (perforated) in the extruded portion was set to φ16 mm.
The agglomerated coal-containing agglomerate ore was air-cured at room temperature for 1 day, then placed in a constant temperature and humidity chamber at 80 ° C. for 2 days to be cured, and then air-cooled to 30 ° C. to carry out a crushing strength test. The crushing strength was measured in accordance with JIS M8718 "Iron ore pellet crushing strength test method", and a load was applied to one sample at a specified pressurizing rate, and the load when the sample broke was defined as the crushing strength. .. In addition, the pass is 1100 N / piece or more, which is the target crushing strength, vacuum release or extrusion is not possible during molding, powder is not generated in the molded product, the molded product does not become large lumps, and reduction when using a blast furnace. It was assumed that the material reduction effect was not bad. Table 4 is an example, and Table 5 is a comparative example.

In Table 4, Examples 1 to 17 are described in T.I. C. Under the condition of = 20-40% by mass, water-hard binder = 2.0-9.0% by mass, fine silica source = 0.5-4.0% by mass, molded product moisture = 9.0-14.0% by mass. %, And the filling rate of the second extrusion portion of the vacuum extrusion molding machine was 50 to 95% by mass, and all of them exceeded the target strength of 1100 N / piece.

Comparative Example 1 is based on T.I. C. Is an example of out of the upper limit. T. C. When it exceeds 40% by mass, the fluidity of the mixed raw material decreases and vacuum release begins to occur, and finally vacuum extrusion molding itself becomes impossible. Comparative Example 2 is an example in which the blending ratio of the hydraulic binder is out of the lower limit, and Comparative Example 3 is an example in which the blending ratio of the fine silica source is out of the lower limit. The hydraulic binder has a role of hardening by a chemical reaction with water, and the fine silica source has a role of improving the strength by increasing the number of contacts with the raw material particles, and neither of them can secure the target strength unless the compounding conditions are satisfied. Comparative Example 4 is an example of extrusion molding without applying a vacuum. The strength of the molded body did not reach the target value.

Comparative Example 5 and Comparative Example 6 are examples of the water content of the molded product exceeding the lower limit and the upper limit, respectively. If the water content is too small, the fluidity of the raw material will be significantly reduced, the extrusion resistance of the screw will increase, and extrusion (molding) will not be possible. On the contrary, if the water content becomes excessive, extrusion can be performed without any problem, but the target strength is not reached, and as shown in Table 5, when the molded products are piled up and cured after molding, the molded bodies adhere to each other and become large lumps. , When used in a blast furnace, the problem of crushing occurs in advance.

Comparative Example 7 and Comparative Example 8 are examples in which the filling rate of the second extruded portion is out of the lower limit and out of the upper limit during vacuum extrusion molding, respectively. If the filling rate deviates from the lower limit, it becomes difficult to continuously form a material seal at the tip of the extruded portion, vacuum is released intermittently, and the raw material of the molded product is discharged as a powder. This phenomenon occurs and the yield of the molded product decreases. Further, if the filling rate becomes excessive, the extrusion load increases and the raw material stays in the extrusion molding portion, which makes continuous molding difficult.

Example 16 is an example in which the average particle size of the fine silica source exceeds 15% of the average particle size of the mixed raw material of the non-calcined coal-containing lump ore excluding the fine silica source. Example 17 is an example in which the degree of vacuum of the extrusion molding machine exceeds −50 kPaG. Both have reached the target value of strength but are close to the lower limit, which is not a preferable example.

Table 5 shows a comparative example of the moisture content of the molded product exceeding the upper and lower limits, and will be described in more detail. As shown in Table 6, when a coal-containing agglomerate ore is produced by the vacuum extrusion molding method under the above conditions, molding becomes difficult when the water content of the molded bodies is less than 9% by mass, and when the water content of the molded bodies exceeds 14%, the molded bodies are separated from each other. The problem of adhesion and agglomeration became clear. Therefore, the appropriate moisture value is set to 9 to 14% by mass.

1 Mixer 2 Input port 3 First extrusion section (kneading section)
3a Casing 3b Screw 3c Weir formed of perforated plate 4 Connection pipe (vacuum chamber)
5 Second extrusion section (extrusion molding section)
5a Casing 5b Screw 6 Molding part 7 Vacuum pump 8 Connection pipe 9 Vacuum pump connection pipe 10 Coal-containing agglomerate production equipment

Claims (4)

A method for producing a non-calcined carbon-containing agglomerate ore for a blast furnace having a carbon content (TC) of 15% by mass or more, which is used as a raw material for a blast furnace in steelmaking.
2.0 to 9.0% by mass of hydraulic binder, 0.5 to 4.0% by mass of fine silica source, and the ratio of carbon contained in the coal-containing agglomerate ore raw material in terms of mass ratio converted to zero water content ( A coal-containing lump containing 87.0 to 97.5% by mass by adjusting the blending ratio of iron-containing raw material, carbon-containing raw material, and other raw materials so that TC) is 15 to 40% by mass. For raw materials for mineral ore
When the total of the raw material and water is 100% by mass, the mass ratio of water is 9.0 to 14.0% by mass, and the mixture is continuously mixed and transferred, and a perforated plate installed in front of the transfer direction. The first extrusion part (kneading part) that forms the first material seal by pushing the mixed raw material into the weir formed by
A connection part (vacuum chamber) that vacuum degass the mixed raw material continuously supplied from the outlet side of the weir and transfers it to the second extrusion part.
By pushing the vacuum degassed mixed raw material supplied from the connection part (vacuum chamber) into the molding part having a large number of holes, it is continuously extruded while forming a second material seal to manufacture a molded body. With the second extrusion part
It is a method of manufacturing a coal-containing agglomerate ore using a manufacturing apparatus composed of
A method for producing a non-calcined coal-containing agglomerate ore for a blast furnace, which comprises continuously molding the second extrusion portion with a mixed raw material in a filling rate of 50 to 95% by volume. The production of the non-calcined coal-containing agglomerate for a blast furnace according to claim 1, wherein the pressure of the connection portion (vacuum chamber) of the production apparatus for the non-calcined coal-containing agglomerate for a blast furnace is −50 kPaG or less. Method. The average particle size of the fine-grained silica source is 15% or less of the average particle size of the mixed raw material of the non-calcined coal-containing agglomerate excluding the fine-grained silica source. Item 3. The method for producing a non-calcined coal-containing agglomerate for a blast furnace according to Item 1 or 2. T.I., which is used as a raw material for blast furnaces in steelmaking. C. Is a production device for uncalcined coal-containing agglomerates for blast furnaces with a mass of 15% by mass or more.
A weir provided with means for continuously mixing and transferring water to a raw material consisting of a carbon-containing raw material, a water-hard binder, a fine silica source, and an iron-containing raw material, and a weir formed of a perforated plate installed in front of the transfer direction. The first extrusion part (kneading part) where the first material seal is formed by pushing the mixed raw material, and
A connection part (vacuum chamber) that vacuum degass the mixed raw material continuously supplied from the outlet side of the weir and transfers it to the second extrusion part.
The vacuum degassed mixed raw material supplied from the connection portion (vacuum chamber) is pushed into the molding portion having a large number of holes, so that the molded body is continuously extruded while forming the second material seal. With a second extrusion to manufacture
Equipment for manufacturing non-calcined coal-bearing agglomerates for blast furnaces.