JP2005194543A - Method for manufacturing partially reduced agglomerated ore - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively utilize an ore with much water of crystallization as a raw material of iron and steel, while inhibiting a melt of a partially reduced agglomerated ore formed in a sintering process from clogging in a grate to aggravate permeability of a bed. <P>SOLUTION: The method for manufacturing a partially reduced agglomerated ore comprises the steps of: blending 10 to 20 mass% charcoal material to 100 mass% sintering raw material containing a powder iron ore and a lime-based auxiliary material as main components; granulating the blend to form an inner layer; coating it with an outer layer containing 1 to 4 mass% charcoal material with respect to 100 mass% sintering raw material to form pseudo-particles 40 having a dual layer structure; charging them into a downward sucking endless and movable sintering machine 200; and firing them to directly reduce the powder iron ore with fixed carbon inside the pseudo-particles, wherein the firing is carried out after the bed 13 consisting of the pseudo-particles 40 and the ore 50 with much water of crystallization, of which the ore forms a sole ore layer, has been formed on a moving grate 11 of the sintering machine 200. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for producing a semi-reduced agglomerated mineral obtained by reducing a part of iron oxide used as a blast furnace raw material by using a sintering process.

  Conventionally, as a blast furnace raw material, a sintered ore obtained by mixing and sintering granulated iron ore, a solvent medium, a powdered carbon material, and the like, which are sintering raw materials, has been used.

  With regard to such sintered ore, a semi-reduced sintered ore that can compensate for part of the reduction reaction conventionally performed in the blast furnace in the sintering reaction process and reduce the carbon intensity in the sintering and blast furnace total. Is attracting attention. In this semi-reduced sintered ore, in the course of the sintering reaction, not only the carbon material for supplying the amount of heat necessary for conventional agglomeration, but also carbon acting as a reducing material is supplied, and the reaction is endothermic. Since it is necessary to replenish the amount of heat necessary for the reduction reaction, the amount of carbon material to be added inevitably increases.

  For example, in Patent Document 1, powdered coke and anthracite are blended and granulated into powdered ore to form an inner layer, and powdered ore, auxiliary materials, powdered coal and anthracitic coal are mixed and coated to form a two-layer pseudo particle as an outer layer. A technology is disclosed in which the pseudo particles are mixed and granulated as a part of the sintering raw material, and then sintered with a sintering machine to produce a sintered ore. A part of the sintered ore is reduced by a direct reduction reaction between the melt produced from the slag and the solid carbon in the inner layer pulverized coal material or anthracite coal. In this technology, after the temperature reaches 1100 ° C., for the first time, the melt and C of powdered coke and anthracite coal undergo a direct reduction reaction of FeO + C = Fe + CO−36350 kcal / kmol, and metal Fe is partly formed in the sintered ore. Generated.

  However, the technique disclosed in Patent Document 1 has the following problems. That is, first, in FeO + C = Fe + CO, which is rate-limiting, it is easy to generate a melt by reacting with gangue components and lime auxiliary materials (flux) in the ore when it is reduced to FeO at a high temperature. However, since the amount of melt increases, the viscosity decreases as the temperature rises and the melt flows more easily. For this reason, there is concern that the flowing melt closes the grate gap of the pallet of the sintering machine, lowers the air permeability of the bed, and inhibits the sintering reaction.

Secondly, in the case of partially reduced sintered ore, it is necessary to burn 3 to 4 times as much carbonaceous material in the sintering machine as compared with the production of ordinary sintered ore. The exhaust gas temperature becomes a high temperature of 400 to 600 ° C., which is larger than the normal value of 400 ° C. or less, and may adversely affect the exhaust gas treatment equipment such as ducts and wind boxes.
JP-A-4-210432

The present invention has been made in view of such circumstances, and provides a method for producing a semi-reduced agglomerated ore that can suppress the inhibition of the sintering reaction caused by clogging of the grate due to the melt in the sintering process. It is to provide.
Moreover, this invention is providing the manufacturing method of the semi-reduction agglomerated mineral which can prevent the damage of the waste gas equipment resulting from the high temperature of the waste gas in the sintering process.

  Moreover, this invention is providing the manufacturing method of the semi-reduction agglomerated ore which can charge the high crystal water ore which passed through the sintering process to a blast furnace with a high yield.

The present invention provides the following (1) to (4).
(1) Carbonaceous material is blended in an amount of 10 to 20% by mass with respect to 100% by mass of a sintered raw material mainly composed of fine iron ore and a lime-based auxiliary material, and granulated to form an inner layer. Pseudoparticles with a two-layer structure formed by coating an outer layer containing 1 to 4% by mass of carbonaceous material with respect to 100% by mass of the sintered raw material are charged into a sintering machine and fired, and then powdered by fixed carbon inside the pseudoparticles. In producing agglomerated minerals that are partly reduced by directly reducing iron ore, a high crystal water ore is charged as a bed layer, and the pseudo particles are charged thereon, and the sintering machine A method for producing a semi-reduced agglomerated ore characterized by firing at a temperature.

  (2) Carbonaceous material is blended in an amount of 10 to 20% by mass with respect to 100% by mass of sintered raw material mainly composed of fine iron ore and lime-based auxiliary material, and granulated to form an inner layer. Pseudoparticles with a two-layer structure formed by coating an outer layer containing 1 to 4% by mass of carbonaceous material with respect to 100% by mass of the sintered raw material are charged into a sintering machine and fired, and then powdered by fixed carbon inside the pseudoparticles. In producing iron agglomerates by reducing iron ore directly, high crystal water ore is charged on the bedrock ore and the pseudo particles are charged on the sinter. A method for producing a semi-reduced agglomerated ore characterized by firing with a kneader.

(3) The method for producing a semi-reduced agglomerate according to (2), wherein the high crystal water ore has a particle size of 5 mm or more.
(4) In the said (1)-(3), the said agglomerated mineral contains 5 mass% or more metallic iron, The manufacturing method of the semi-reduced agglomerated mineral characterized by the above-mentioned.

As described above, in the present invention, the high crystal water ore is used as a bedstone in the agglomeration process by sintering the semi-reduced sinter.
In this semi-reduced sintered ore manufacturing process, the amount of carbonaceous material increases, so the thickness of the combustion zone increases, and the amount of heat at the bottom of the bed becomes abundant, so the amount of heat required for the dehydration reaction of the high crystal water ore is Sufficient supply is possible. In addition, when sintering using a high-crystal water ore as a conventional ore-bed bedding ore (for example, Japanese Patent Publication No. 6-29469), After dehydration on the sinter machine, it collapses in the classification process before charging the blast furnace, and most of it returns to return ore, and this return ore is again used as a raw material that has been dehydrated and reduced (stabilized). It will be granulated and fired.

On the other hand, in the case of the present invention, the melt mainly composed of FeO—SiO ₂ and FeO—CaO flows down to the floor layer in the lower part of the bed, so that the goethite quality is dehydrated at around 400 ° C. It shrinks and cracks and reacts rapidly with the crystal water ore which is very easy to assimilate with the melt and agglomerates. For this reason, the proportion of crystal water ore to be returned to ore is greatly reduced, and most of the crystal water ore can be charged into the blast furnace as it is in one sintering process, greatly increasing the yield in the sintering process of crystal water ore. To improve.

  Since the melt enters the flooring layer, most of it melts and solidifies by cooling to a temperature below the melting point before reaching the great, but some reaches the great and looks at the great bar. There is a possibility of clogging. For this reason, the bedding layer may be formed only by the high crystal water ore, but preferably, the layer of the high crystal water ore is formed at a thickness of 10 to 20 mm on the upper part of the normal bedding ore made of a sintered product ore. It is more effective to prevent the melt from falling off to the great side.

  The particle diameter of the high crystal water ore is desirably 5 mm or more in order to ensure the air permeability of the bed and prevent the falling from the gap of the great bar. Considering the assimilation property with the melt, it is difficult to react up to the inside of the ore with a large particle size, so it is 12 mm or less, preferably 10 mm or less.

According to the present invention, it is possible to suppress the air permeability inhibition of the sintering reaction due to clogging of the grate due to the melt in the sintering process of the semi-reduced agglomerate.
In addition, it is possible to prevent the exhaust gas equipment from being damaged due to the high temperature of the exhaust gas during the sintering process of the semi-reduced agglomerate.
In addition, it becomes possible to charge the high crystal water ore after the sintering process into the blast furnace with a high yield.

Hereinafter, embodiments of the present invention will be specifically described.
FIG. 1 is a schematic diagram showing a semi-reduced agglomerated production facility for carrying out a method for producing a semi-reduced agglomerated mineral which is an embodiment of the present invention. This facility includes a pseudo particle manufacturing facility 100, a downward suction type endless moving type sintering machine 200, and a floor covering material supply facility 300 for supplying high crystal water ore and a product sintered ore for floor covering deposits. ing.

  The pseudo particle manufacturing facility 100 includes a fine iron ore hopper 1 for storing fine iron ore, a return hopper 2 for storing return ore, a lime-based auxiliary material hopper 3 for storing a lime-based auxiliary material as a solvent, Inner layer powder coke hopper 4 for storing inner layer powder coke (carbon material), primary drum mixer 5, disc pelletizer 6, and outer layer powder coke hopper 7 for storing outer layer powder coke (carbon material) The secondary drum mixer 8 is provided. The fine iron ore supplied from the fine iron ore hopper 1, the return ore supplied from the return ore hopper 2, and the lime-based auxiliary material supplied from the lime-based auxiliary material hopper 3 constitute the sintered raw material. The return ore is not necessarily supplied.

The floor covering material supply equipment 300 is a product provided as necessary to supply the high crystal water ore hopper 21 for storing the high crystal water ore 50 for flooring and the product sintered ore 60 used for flooring. And a sintered ore hopper 22.
The high crystal water ore 50 for flooring is made of, for example, pisolite containing about 10% by mass of crystal water or maramamba containing about 5% by mass of crystal water.

  The lower suction type endless moving type sintering machine 200 has an endless moving type moving grate 11. At the upstream end in the moving direction of the moving great 11, a conveyor 25 for supplying the high crystal water ore 50 constituting the bed layer onto the moving great 11, and a pseudo particle 40 described later which is a sintering raw material. Are placed in order in the moving direction, and the high crystal water ore 50 and the pseudo particles 40 are sequentially loaded on the moving great 11, thereby allowing the floor layer 13a and the sintering raw material thereon to be placed. A layered bed 13 composed of the layer 13b is formed.

  An ignition furnace 12 is provided in the movement path of the moving great 11, and the quasi particles 40 on the moving great 11 are ignited when passing through the ignition furnace 12 and the sintering of the bed 13 is started. A crusher (not shown) is provided on the exit side of the moving grate 11, and the sintered ore dropped from the moving grate 11 is pulverized by this agglomerator, supplied to the sieve 14, and supplied to the blast furnace.

  A plurality of wind boxes 15 are arranged immediately below the moving grate 11 along the traveling direction of the moving grate 11, and a vertical duct 16 is connected to each wind box 15. As a result, the gas above the bed 13 passes through the bed 13 by the wind box 15 and the vertical duct 16 and is sucked as exhaust gas 19a. A gas supply hood 19 is provided on the downstream side of the ignition furnace 12 above the bed 13. And the area | region in which the gas supply hood 19 is provided comprises a sintering machine suction part.

  The vertical duct 16 is connected to a main exhaust gas duct 17 disposed horizontally, and exhaust gas 19 a is discharged through the main exhaust gas duct 17. An exhaust gas circulation duct 18 is connected to the main exhaust gas duct 17, and the exhaust gas circulation duct 18 is connected to a gas supply hood 19. The exhaust gas circulation duct 18 is provided with a blower 18a. A part of the exhaust gas 19 a is configured to recirculate to the gas supply hood 19 via the exhaust gas circulation duct 18.

The gas supply hood 19 is supplied with the atmosphere and N ₂ gas via the exhaust gas circulation duct 18, and the oxygen concentration of the gas sucked to the moving great 11 side is adjusted to 8 to 12%. It is like that. Moreover, the temperature of this gas is adjusted to 250-600 degreeC. In order to adjust the gas supplied from the gas supply hood 19 and sucked to the moving great 11 side to this temperature, in addition to the sintered exhaust gas sensible heat, heat from another hot air generating furnace (not shown) is supplied to the exhaust gas circulation duct 18. May be supplied. In addition, when temperature control can fully be achieved by sintering exhaust gas sensible heat, the heat from another hot-air generation furnace is not necessarily required.

  An electric dust collector 30 and a main blower 31 are connected to the main exhaust gas duct 17, and the gas above the bed 13 is sucked by the main blower 31, and the wind box 15, the vertical duct 16, the main exhaust gas duct 17, and the electric dust collector 30. Etc., and is discharged from the chimney 32.

  In the equipment configured in this way, first, a predetermined amount of powdered iron ore that is a sintering raw material, return ore and lime-based auxiliary raw material, and powdered coke as a carbonaceous material are cut out from each hopper of the pseudo particle manufacturing equipment 100 to a primary drum mixer. 5 and mix while adding water. Subsequently, the mixed raw material is supplied to the disk pelletizer 6 and granulated while adding water. Thereby, the raw pellet of the state in which the powder coke was dispersed in the powdered ore is formed. Next, the raw pellets granulated by the disk pelletizer 6 are supplied to the secondary drum mixer 8 and mixed while adding water and the powder coke cut out from the powder coke hopper 7 for the outer layer. At this time, when the moisture of the raw pellet is high, the addition of moisture is unnecessary. As a result, powder coke is coated on the surface of the raw pellets, and pseudo particles 40 are produced. If granulation is sufficiently performed by the primary drum mixer 5 according to the raw material conditions, the granulation step by the disk pelletizer 6 may be omitted.

  As shown in FIG. 2, the pseudo particles 40 produced in this way are composed of an inner layer 43 and charcoal in a state where powder coke 42 as a carbon material is dispersed in a sintered raw material 41 made of iron ore and a lime-based auxiliary material. It has a two-layer structure with an outer layer 44 made of powdered coke as a material. The inner layer 43 is composed of 10 to 20% by mass of powdered coke that is a carbonaceous material with respect to 100% by mass of the sintered raw material, and the outer layer 44 is 1% of the powdered coke that is a carbonaceous material with respect to 100% by mass of the sintered raw material. ˜4 mass%. The content of the lime-based auxiliary material in the sintered material is preferably 4 to 10% by mass.

  In addition, from the viewpoint of maintaining good reactivity, the fine iron ore preferably has a particle size of 8 mm or less and 80% or more, and the powder coke (carbon material) has a particle size of 3 mm or less. It is preferable that it is 80% or more.

  The pseudo-particles 40 having the above-described structure are such that the powder coke 42 dispersed in the sintering raw material 41 of the inner layer 43 mainly contributes to the reduction of the sintering raw material in the downward suction type endless moving type sintering machine 200. The composing powder coke mainly contributes to sintering. That is, the functions are separated between the inner layer coke and the outer layer coke, and reduction and sintering proceed simultaneously.

  Here, the amount of the powder coke (carbon material) in the inner layer 43 is 10 to 20% by mass, within this range, iron ore in the pseudo particles can be effectively reduced, and unreacted. This is because coke hardly remains. Moreover, by setting the amount of powder coke (carbon material) in the outer layer 44 to 1 to 4% by mass with respect to 100% by mass of the sintering raw material, the pseudo particles can be appropriately sintered.

Next, an example of the sintering process in the present embodiment will be described.
The floor layer is laid down with a predetermined thickness on the moving grate 11 that is moving from the conveyor 25 located on the most upstream side in the moving direction of the endless moving type moving grate 11 of the downward suction type endless moving type sintering machine 200. The high crystal water ore 50 constituting 13a passes under the conveyor 10 by moving to the moving great 11, and at this time, the pseudo particles 40 granulated as described above have a predetermined thickness and high crystallinity. The whole surface is supplied so as to cover the floor layer 13a of the water ore 50, and the sintered raw material layer 13b is formed.

  Thereby, as illustrated in FIG. 3, in the moving great 11, the pseudo particles 40 constituting the sintered raw material layer 13 b are formed on the high crystal water ore 50 constituting the floor covering layer 13 a having a predetermined thickness. The bed 13 in a state of being laminated to a predetermined thickness is formed.

  The bed 13 is ignited on the surface by passing through the ignition furnace 12, and the ignited bed 13 is positioned on the upper side via the wind box 15 when passing under the gas supply hood 19. The high-crystal water ore 50 and the pseudo-particles 40 constituting the bed 13 are sintered into agglomerates by being fired while sucking gas downward from the gas supply hood 19. The exhaust gas 19a that has passed through the moving great 11 is captured by the wind box 15 and reaches the main exhaust gas duct 17 from the vertical duct 16, and a part of the exhaust gas 19a is returned to the gas supply hood 19 through the exhaust gas circulation duct 18 and reused. The other part is discharged from the chimney 32 to the atmosphere via the electric dust collector 30 and the main blower 31.

  Here, in the manufacturing process of the semi-reduced sintered ore as in the present embodiment, since the amount of the carbonaceous material of the pseudo particles 40 increases as described above, the thickness of the combustion zone in the bed 13 increases. In the lower part, the amount of heat is abundant, so that the amount of heat necessary for the dehydration reaction of the high crystal water ore 50 constituting the floor layer 13a is sufficiently supplied at the lower part of the bed 13.

  In addition, since the amount of heat generated in the pseudo particles 40 of the sintering raw material layer 13b is consumed by the dehydration reaction of the high crystal water ore 50 of the floor layer 13a, the amount of carbon material of the pseudo particles 40 increases as described above. Even so, the temperature of the exhaust gas 19a is prevented from excessively rising, and is suppressed to about 400 ° C. as an example sufficient for the semi-reduced sintered ore. As a result, problems such as overheating and damage to the wind box 15 and the main exhaust duct 17 through which the exhaust gas 19a passes are prevented.

Further, in the case of the present embodiment, in the lower part of the bed 13, a melt mainly composed of FeO—SiO ₂ and FeO—CaO generated from the pseudo particles 40 of the sintered raw material layer 13 b constitutes the floor layer 13 a. The high-crystalline water ore 50 flows down to the high-crystal water ore 50, so that the goethite quality dehydrates and shrinks near 400 ° C, cracks are generated, and it is very easy to assimilate with the melt. By reacting, the floor layer 13a and the sintering raw material layer 13b are integrally agglomerated. For this reason, the ratio of the high-crystal water ore 50 that is returned to ore after sintering due to poor agglomeration or the like is greatly reduced, and the blast furnace as it is together with the sintered ore of the pseudo particles 40 in a single sintering. The yield in the sintering process of the high crystal water ore 50 is greatly improved.

  The semi-reduced agglomerate made from the pseudo particles 40 and the high crystal water ore 50 obtained as a result of sintering in this manner falls from the end of the moving great 11 and is crushed by an unshown agglomerator on the outlet side. The fallen sintered ore is pulverized and supplied to the sieve 14, and further supplied to a blast furnace (not shown).

  Thus, in this Embodiment, the excess calorie | heat amount generate | occur | produced from the carbonaceous material of the pseudo particle 40 increased for the reduction reaction is used for the dehydration reaction in the sintering process of the high crystal water ore 50 of the floor layer 13a. The high-crystal water ore 50 that can be used effectively and can prevent the exhaust gas 19a from being overheated, and the melt generated from the pseudo particles 40 and flowing down in the bed 13 is dehydrated and contracted to generate cracks. The assimilation and rapid agglomeration ensure that the sintering yield of the entire sintering raw material including the high crystal water ore 50 is improved.

  In the above description, the case where the floor layer 13a is constituted by a single layer of the high crystal water ore 50 is exemplified, but not limited thereto, as illustrated in FIG. It is good also as a multilayer structure which consists of the flooring layer 13c of the product sintered ore 60 supplied, and the flooring layer 13a of the high crystal water ore 50 on it.

  In that case, although not particularly illustrated, a plurality of conveyors 25 are installed in the moving direction of the moving great 11, the product sintered ore 60 is supplied by the most upstream conveyor 25, and the product is produced by the conveyor 25 located on the downstream side thereof. By supplying the high crystal water ore 50 on the sintered ore 60, a multi-layered flooring layer can be formed. Further, by supplying pseudo particles 40 from the conveyor 10 located on the most downstream side, a multi-layered floor covering layer 13c and a floor covering layer 13a and a sintered raw material layer 13b thereon are formed. The bed 13-1 can be configured.

  That is, in the case of a single layer of the high crystal water ore 50, the melt enters the inside of the high crystal water ore 50 constituting the bed layer 13a, so that the melt is cooled to a temperature below the melting point before reaching the moving great 11. Most of them solidify, but some may reach the moving great 11 and clog the great bar. For this reason, the bedding layer may be formed only by the high crystal water ore 50, but desirably, it is 10 on the upper portion of the bedding layer 13c made of a normal product sintered ore 60 as illustrated in FIG. Forming the floor layer 13a of the high crystal water ore 50 with a thickness of ˜20 mm and making the floor layer multi-layered is more effective for preventing the melt from falling off to the moving grate 11 side.

The results of tests conducted to confirm the effects of the present invention will be described below.
In Example 1 shown below, the pseudo particles 40 illustrated in FIG. 2 described above (in which the inner layer includes 12% by mass of carbonaceous material and the outer layer includes 3% by mass of carbonaceous material) are sintered raw materials (sintered raw material layer 13b). ), And a high crystal water ore from Australia (pisolite: crystal water 8.75 mass%) is used as the floor layer 13a.

  In Example 2, the same sintering raw material (sintering raw material layer 13b) as in Example 1 was used, and the flooring was composed of a flooring layer 13c made of a product sintered ore 60 and an Australian high crystal water ore (pisolite). : The floor layer 13a composed of 8.75% by mass of crystal water).

  On the other hand, Comparative Example 1 uses a sintered raw material (pseudo particles having no outer layer of carbonaceous material) containing 3.7% by mass of carbonaceous material with respect to 100% by mass of the fine ore and lime-based auxiliary raw material, The case where the product sintered ore is used as the flooring layer is shown, and Comparative Example 2 shows the case where the same sintering raw material as in Comparative Example 1 is used and pisolite is used as the flooring layer.

  Moreover, the comparative example 3 has shown the case where the pseudo | simulation particle 40 same as the above-mentioned Example 1 and Example 2 is used as a sintering raw material, and the product sintered ore is used as the flooring layer 13a.

  Below, the detail of each comparative example and an Example is shown. In addition, Table 1 shows the blending conditions of the raw materials and the measurement results of the specifications at that time.

Comparative Example 1:
In the downward suction type endless moving type sintering machine 200 having an effective firing area of 400 m ^2, a product sintered ore having a particle diameter of 8 to 15 mm is used as a floor covering with a thickness of 50 mm, and a raw material layer made of pseudo particles 40 is formed thereon. The sinter was produced at a production rate of 1.50 t / m ² / hr.
That is, with respect to 100% by mass of sintered raw material in which auxiliary materials of quick lime: 13 t / hr and limestone: 62 t / hr are blended with fine ore: 550 t / hr, fine coke: 23 t / hr (3. 7% by mass) was used as a sintering raw material.

Comparative Example 2:
In the downward suction type endless moving type sintering machine 200 having an effective firing area of 400 m ² , Australian high crystal water ore (pisolite: crystal water 8.75 mass%) having a particle size of 5 to 20 mm is deposited on the floor with a thickness of 50 mm. A raw material layer was formed thereon, and sintered ore was produced at a production rate of 1.50 t / m ² / hr. The mixing conditions of the raw materials at that time are the same as those in Comparative Example 1.

Comparative Example 3:
In the downward suction type endless transfer type sintering machine 200 having an effective firing area of 400 m ² , the product sintered ore is used as a floor covering with a thickness of 50 mm, and a raw material layer is formed thereon, with a production rate of 1.50 t / m. Sinter was produced at ² / hr.
That is, powder coke: 75 t / hr (12 mass) as a carbonaceous material with respect to 100 mass% of the sintered raw material in which the auxiliary raw materials of quick lime: 13 t / hr and limestone: 62 t / hr are blended with fine ore: 550 t / hr. %) In the inner layer, powder coke: 19 t / hr (3.0 mass%) in the outer layer, and blended pseudo particles were used as the sintering raw material.

Example 1:
In the downward suction type endless moving type sintering machine 200 having an effective firing area of 400 m ² , Australian high crystal water ore (pisolite: crystal water 8.75 mass%) having a particle size of 5 to 20 mm is deposited on the floor with a thickness of 50 mm. The raw material layer was formed thereon, and the sintered ore was manufactured at the same production rate as in Comparative Example 1. Table 1 shows the blending conditions of the raw materials at that time.
That is, powder coke: 75 t / hr (12 mass) as a carbonaceous material with respect to 100 mass% of the sintered raw material in which the auxiliary raw materials of quick lime: 13 t / hr and limestone: 62 t / hr are blended with fine ore: 550 t / hr. %) In the inner layer, and pseudo-coke mixed with powder coke: 19 t / hr (3.0 mass%) in the outer layer was used as a sintering raw material.

Example 2:
In the downward suction type endless moving type sintering machine 200 having an effective firing area of 400 m ² , an Australian high crystal water ore (pisolite: crystal) having a particle size of 5 to 20 mm is formed on the floor layer (thickness 50 mm) of Comparative Example 1. Water (8.75% by mass) was laid at a thickness of 40 mm, a raw material layer was formed thereon, and sintered ore was produced at a production rate of 1.50 t / m ² / hr. Table 1 shows the blending conditions of the raw materials at that time.

  The sintered ore produced in Example 1 and Example 2 contained 6.2% by mass and 6.8% by mass of metallic iron, respectively. The reduction rate was 37% by mass in Example 1 and 33% by mass in Example 2.

  On the other hand, the reduction rates of Comparative Example 1 and Comparative Example 2 were 1.8% and 1.3%, respectively. Moreover, metallic iron was not seen. In Comparative Example 3, sintering was forced to be interrupted due to clogging of the Great, so the content of metallic iron, the strength of the sintered ore, the amount of returned ore, etc. could not be measured.

  As is clear from the results of Comparative Example 1 and Comparative Example 2 in Table 1, when there is little carbonaceous material and the calorific value is small, pisolite is used as a floor covering layer 13a as compared with the case where a product sintered ore is used. In the case of the above, there is much return ore, which indicates the technical problem of Patent Document 2 described above.

  Moreover, in the case of the comparative example 3, it is a case where the sintering raw material is the same as Example 1 of this invention, and a product sintered ore is used as a bedding ore. 11 clogging makes sintering difficult.

  On the other hand, in the case of Example 1 of the present invention, when the high crystal water ore 50 is used as the floor covering layer 13a under the same sintering raw material conditions as in Comparative Example 3, Comparative Example 1 and Comparative Example Higher sinter strength (tumbler strength, 10 mm value: residual rate of sintered ore with a particle size of 10 mm or more) than that of any of Example 2 was obtained, and much less return ore was obtained, resulting in a higher yield in the sintering process. Has been achieved.

  Moreover, Example 2 which made the flooring layer into the multilayer of the product sintered ore 60 and the high crystal water ore 50 is superior to both the sintered ore strength and the return ore compared to Example 1 of the single layer. In the case where the high crystal water ore 50 is used as a flooring, it can be seen that it is more effective to use the product sintered ore 60 to make a multilayer.

  As described above, according to the present invention, the inhibition of bed air permeability and sintering reaction due to clogging of the grate due to the melt in the sintering process of the semi-reduced agglomerated ore is suppressed. The effect that the sintering process of a reduction sintered ore can be stabilized is acquired. In addition, it is possible to prevent the exhaust gas equipment from being damaged due to the high temperature of the exhaust gas during the sintering process of the semi-reduced agglomerate. In addition, the high crystal water ore that has undergone the sintering process can be charged into the blast furnace at a high yield, and the high crystal water ore can be efficiently and effectively used as a steel raw material.

The schematic diagram which shows an example of the manufacturing equipment which enforces the manufacturing method of the semi-reduction agglomerated mineral which is one embodiment of this invention. Sectional drawing which shows the pseudo-particle of the two-layer structure used as a sintering raw material in the manufacturing method of the semi-reduced agglomerate which is one embodiment of this invention. The schematic diagram which shows an example of a structure of the bed on a moving great in the manufacturing method of the semi-reduction agglomerated mineral which is one embodiment of this invention. The schematic diagram which shows an example of a structure of the bed on a moving great in the manufacturing method of the semi-reduction agglomerate which is other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Powdered iron ore hopper 2 Returning hopper 3 Lime system auxiliary material hopper 4 Inner layer powder coke hopper 5 Primary drum mixer 6 Disc pelletizer 7 Outer layer powder coke hopper 8 Secondary drum mixer 10 Conveyor 11 Moving grate 12 Ignition furnace 13 Bed 13- 1 bed 13a flooring layer 13b sintering raw material layer 13c flooring layer 14 sieve 15 wind box 16 vertical duct 17 main exhaust gas duct 18 exhaust gas circulation duct 18a blower 19 gas supply hood 21 high crystal water ore hopper 22 product sintered ore hopper 25 Conveyor 30 Electric dust collector 31 Main blower 32 Chimney 40 Pseudo particle 41 Sintering raw material 42 Powder coke 43 Inner layer 44 Outer layer 50 High crystal water ore 60 Product sintered ore 100 Pseudo particle production equipment 200 Downward suction type endless moving type sintering machine 300 Floor Flooring supply equipment

Claims (4)

  Carbonaceous material is blended in an amount of 10 to 20% by mass with respect to 100% by mass of the sintered raw material mainly composed of fine iron ore and lime-based auxiliary materials, and granulated to form an inner layer. A pseudo particle having a two-layer structure formed by coating an outer layer containing 1 to 4% by mass of a carbonaceous material with respect to 100% by mass is charged into a sintering machine and fired, and fine iron ore is fixed by fixed carbon inside the pseudo particle. In producing agglomerated minerals that are reduced directly and partially reduced, high crystal water ore is charged as a bed layer, and the pseudo particles are charged thereon and fired by the sintering machine. A method for producing a semi-reduced agglomerated ore characterized by:   Carbonaceous material is blended in an amount of 10 to 20% by mass with respect to 100% by mass of the sintered raw material mainly composed of fine iron ore and lime-based auxiliary materials, and granulated to form an inner layer. A pseudo particle having a two-layer structure formed by coating an outer layer containing 1 to 4% by mass of a carbonaceous material with respect to 100% by mass is charged into a sintering machine and fired, and fine iron ore is fixed by fixed carbon inside the pseudo particle. In producing agglomerated minerals that are reduced directly and partially reduced, high crystal water ore is charged on the bedrock ore, and the pseudo particles are charged on the ore and put into the sintering machine. A method for producing a semi-reduced agglomerated ore characterized by firing.   The method for producing a semi-reduced agglomerated mineral according to claim 2, wherein the high-crystal water ore has a particle size of 5 mm or more.   The method for producing a semi-reduced agglomerated mineral according to any one of claims 1 to 3, wherein the agglomerated mineral contains 5 mass% or more of metallic iron.

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