JP2011047006A - Method for producing sintered ore of raw material for blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide such a method for producing sintered ore that the air-flow resistance of a hot blast gas is difficult to increase at a temperature inside the furnace even after the sintered ore has been charged into the blast furnace, and that even if a binder for granulation, which has been added in a granulation step, is thermally decomposed in a baking step, carbon (C) or an inorganic material (Si or the like) remains between iron ores. <P>SOLUTION: The method for producing the sintered ore of a raw material for the blast furnace is a method of adding the binder for forming the raw material to be sintered into a lump shape and imparting strength to the lump, into the raw material to be sintered, granulating or molding the raw material and baking the resultant product, and includes: adding 2-12 pts.mass of at least one of a water-soluble phenol resin, water glass, a polyimide, a polysiloxane and colloidal silica to 100 pts.mass of the raw material to be sintered, as the binder; mixing the binder with the raw material to be sintered and stirring the mixture; and then granulating or molding the mixture. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a sintered ore as a raw material for a blast furnace of an iron making facility, and particularly contains a large amount of carbon sources such as coke grains, anthracite grains, and fuel grains containing 30% by mass or more of carbon in the sintered ore. The present invention relates to a method for producing a carbon-containing sintered ore.

  In the hot metal production process performed using a blast furnace, it is necessary to maintain the porosity in the packed bed of the raw material and the reducing agent at a certain value or higher in order to efficiently distribute the reducing gas in the packed bed of the raw material in the furnace. Therefore, it is desirable that the strength of maintaining the size of the granule inside the furnace such as iron raw material is large, and it is important to suppress pulverization. Especially in large blast furnaces, the high strength of sintered pellets obtained by sintering powdered ore with the heat of combustion of charcoal or by forming the powdered ore into a spherical shape with a pelletizer and then heat-curing at about 900 ° C or higher. Is desired. That is, it is desirable that the blast furnace of the steelmaking equipment should not be crushed or pulverized by maintaining the strength even after the sintered ore and fired pellets are charged, and the hot air gas ventilation resistance in the blast furnace is difficult to increase. It is considered as ore and fired pellets.

  For example, as disclosed in Patent Document 1, in order to improve the combustion efficiency of powdered coke and anthracite when sintering the sintered material, there are many powdered coke and anthracite on the surface of the pseudo particles of the sintered material. Some ideas have been made.

On the other hand, studies on sintered ore that is not subjected to high-temperature heat treatment at 900 ° C. or higher have been promoted particularly for the purpose of energy saving. This sintered ore is made of iron ore powder, iron-making dust, etc. with a binder of a hydraulic binder made of a cement component such as Ca ₃ Al ₂ O ₆ and a relatively low temperature condition using steam waste heat at about 400 ° C. It is manufactured by curing for a certain period of time.

  When a hydraulic binder such as cement is used, the crushing strength at room temperature can be sufficiently secured, the transfer using a belt conveyor becomes easy, and the temperature of the top of the blast furnace up to 200 to 400 ° C. In the region, the shape can be maintained. However, since cement hydrate thermally decomposes at a high temperature range of 400 ° C or higher, the strength of sintered ore is significantly reduced, and air permeability is reduced due to pulverization inside and near the bottom of the blast furnace. It was also pointed out.

  In order to solve such a problem, Patent Document 2 discloses a non-fired agglomerated mineral (molded) obtained by adding and mixing a sticky hydrocarbon mixture such as asphalt or pitch as a binder to a powdered ore and compressing and curing the mixture. Body) is shown. According to the same literature, the non-fired agglomerated minerals evaporate the volatiles in the binder from about 200 ° C., and the viscosity of the binder increases, so that the strength of the molded body increases. Almost complete, and the amorphous (amorphous) carbon binds the fine ore particles, further increasing the strength of the compact.

  However, this method requires a step of heating and melting the sticky hydrocarbon mixture, and also when charged in a blast furnace, the temperature range from the melting point of the hydrocarbon mixture to the initial carbonization range, that is, about 200 ° C. to 500 ° C. In this region, the hydrocarbon mixture is melted. For this reason, deformation of the sintered ore and coarsening due to fusion with the adjacent sintered ore occur, so that sufficient air permeability cannot be expected.

In addition, as a conventional granulation method, Patent Document 3 discloses an inner layer formed by granulating a powder mixture composed of fine ore, fine coke and reverse ore, and quick lime as a binder of the fine powder mixture on the surface of the inner layer, A pellet for sintered ore characterized by comprising an outer layer formed by adding one or more of slaked lime, calcined dolomite or bentonite is described.
However, the method of Patent Document 3 is a method of reducing the amount of binder added while ensuring a predetermined pellet strength by adding a predetermined amount of binder only to the outer layer, and the coke content of the inner layer is the average blending value of the whole pellet Therefore, it is not a technique for producing a carbon-containing sintered ore containing a large amount of carbon source such as coke grains in the sintered ore. For this reason, development of the manufacturing method of the carbon-containing sintered ore containing a large amount of carbon anticipated to reduce the fuel ratio of a blast furnace and to improve a tapping ratio significantly was desired.

  Moreover, as a conventional method for adding a binder, Patent Document 4 describes a method for producing an ore raw material for a blast furnace characterized by using an aqueous solution of a phenol resin, an organic solvent solution, and powder. However, the method of Patent Document 4 does not focus on the dispersion between ores, and more specifically, it does not dilute a high-concentration aqueous solution of 50 mass% or more, and has a high concentration and high viscosity. However, it is not a technique for producing a granulated material with higher strength that can be dispersed between ores. For this reason, development of the manufacturing method of the blast furnace raw material which is anticipated to improve the dispersibility at the time of mixing | blending to an ore at low cost and excellent in reproducibility was desired.

Japanese Patent Publication No.55-15536 JP 60-248831 A JP 63-12131 A JP 2009-030113 A

  Accordingly, an object of the present invention is to have a crushing strength of 1000 N / grain or more at normal temperature and a crushing strength of 100 N / grain or more sufficient to ensure air permeability in a blast furnace even in a temperature range up to 900 ° C. when heated. At the same time, from the viewpoint of energy saving, it can be agglomerated in a relatively low temperature range from room temperature to 400 ° C., and even after the sintered ore is charged in the blast furnace, An object of the present invention is to provide an agglomerate for iron making in which ventilation resistance hardly increases.

  On the other hand, even if the granulation binder added in the granulation process is pyrolyzed in the sintering process of the sinter charged into the blast furnace, carbon (C) or inorganic material (Si, etc.) is present between the iron ores. By remaining, a large amount of carbon is expected to improve the high-temperature reduction / softening and melting properties of sintered ore, which is important for the blast furnace bottom reaction, reduce the fuel ratio of the blast furnace, and greatly improve the output ratio Another object of the present invention is to provide a method for producing a carbon-containing source ore containing selenium.

As a result of intensive studies on the sintered ore that can solve the above-mentioned problems, the present inventors have found that the iron oxide raw material is a water-soluble phenol resin (residual carbon ratio of 30%), water glass (CaO-SiO ₂ after pyrolysis, etc.) By blending at least one of polyimide (same Si ₃ N ₄ ), polysiloxane (similar SiO ₂ ), colloidal silica (same SiO ₂ ) between the particles of fine ore as a binder, 1000N / grain or more at room temperature The present inventors have found that a crushing strength of 100 N / grain or more can be obtained at a high temperature in the furnace.

That is, unlike the conventional alumina cement, the present inventor does not generate Al ₂ O ₃ which becomes an obstacle to molten metal fluidity in the blast furnace, and does not newly increase complicated processes, and does not increase the high temperature of the sintered ore. We found a granulation method that can stabilize the ventilation of blast furnace operation because the strength can be increased.

The present invention has been made on the basis of such findings, and the gist thereof will be described below. The method of the present invention comprises:
(1) A method for producing a sintered ore of a raw material for a blast furnace, which is granulated or molded by adding a binder for making the sintered raw material agglomerated and giving strength to the sintered raw material, As a binder, at least one of a water-soluble phenol resin, water glass, polyimide, polysiloxane, and colloidal silica is added to 2 to 12 parts by mass with respect to 100 parts by mass of the sintering material, and mixed with the sintering material. A method for producing a sintered ore of a raw material for a blast furnace, which is granulated or shaped after stirring.
(2) The method for producing a sintered ore of a raw material for a blast furnace as described in (1), wherein a residual carbon ratio of the water-soluble phenol resin is 30% or more.
(3) The method for producing a sintered ore of a raw material for a blast furnace as described in (1), wherein the composition after pyrolysis of the water glass is at least CaO—SiO ₂ .
(4) The method for producing a sintered ore of a raw material for a blast furnace as described in (1), wherein the composition of the polyimide after pyrolysis is Si ₃ N ₄ .
(5) The method for producing a sintered ore of a raw material for a blast furnace as described in (1), wherein the composition after pyrolysis of the polysiloxane is SiO ₂ .
(6) The method for producing a sintered ore of a raw material for a blast furnace according to (1), wherein the composition after pyrolysis of the colloidal silica is SiO ₂ .
(7) Any one of (1) to (6), wherein the granulated product formed by granulation is any one of a rolling molded product, a molded product, and a crushed product of the molded product. The manufacturing method of the sintered ore of the raw material for blast furnaces as described in 1 ..

  The sintered ore produced by the method for producing sintered ore of the raw material for blast furnace of the present invention has a residual carbon of 30% by mass or more even when heated to 900 ° C. in addition to the binder function of a cured phenol resin at room temperature. As a result, a crushing strength of 1000 N / grain or more at room temperature and 100 N / grain or more at 900 ° C. can be maintained.

Similarly, water glass (CaO-SiO ₂ after pyrolysis, etc.), polyimide (Si ₃ N ₄ ), polysiloxane (SiO ₂ ), colloidal silica (SiO ₂ ), volatilizes even when heated to 900 ° C. By leaving 30% by mass or more of the inorganic component, it is possible to maintain a crushing strength of 1000 N / grain or more at normal temperature and 100 N / grain or more even at 900 ° C.

  Therefore, it has excellent performance such that it is less pulverized at the time of conveying the sintered ore belt conveyor and in the blast furnace, and has a reducing action of iron ore due to heating of the phenol resin and residual coal. For this reason, the ventilation stability of the blast furnace equipment is ensured, stable operation is possible, and reduction of the fuel ratio of the blast furnace and a significant improvement of the output ratio are realized by the reduction action.

It is a schematic diagram showing the cross section of a granulated material.

  The reasons for the limitation of the granulating binder (binder) component of the blast furnace raw material defined in the present invention will be described below. The sintered ore produced by the method of the present invention is used as an iron raw material in a blast furnace. Examples of the iron raw material include fine ore and massive iron ore, but are not limited to this, and can be used as an iron raw material for a blast furnace, and cannot be charged into the blast furnace as it is. If it is a thing.

  A typical example of powdered ore is a sintered ore called reverse ore generated in the iron ore sintering process. In the conventional general sintering process, this sintered ore is used in the sintering process. It is sent back and reused as a raw material for sintering. Most of this sintered ore powder is generated in the particle size sorting (screen, sieving) process when obtaining the product sintered ore, but some of it is also generated when transporting the belt conveyor to the blast furnace and around the blast furnace. is there. In the conventional sintering process, the product yield is about 80%, and the remaining 20% is returned to the sintering step as a return ore (sintered ore powder). In other words, it is not used as it is as a product sinter, but it is circulated and reused in the particle size sorting and sintering process.

  Therefore, by using such a powdery sintered ore as the iron raw material of the sintered ore of the present invention, the total yield of the sintered ore can be greatly improved.

  The massive iron ore includes iron ore grains. Moreover, any of iron ore having a small particle size and iron ore having a small particle size generated in the sizing process may be used. Two or more different types of blast furnace raw materials may be blended and used. The particle size of the blast furnace raw material including this reverse ore is generally 5.5 mm or less.

  The water-soluble phenol resin itself functions as a binder (binder) at room temperature, and carbon generated by carbonization functions as a binder (binder) in a high temperature range of 400 ° C. to 900 ° C. A suitable addition amount is 2 to 12 parts by mass. If it is less than 2 parts by mass, it is difficult to form a granulated product, and if it exceeds 12 parts by mass, the strength of the granulated product after pyrolysis is unfavorable.

  The water-soluble phenol resin present as a binder in the sintered ore of the present invention is a water-soluble resin containing a phenol resin precursor in a molecular skeleton. The most common combination is a 1: 0.5 to 2 blend of phenol and formaldehyde.

  Phenolic resin precursors have various forms such as water solubility, solubility in organic solvents, solid powders, etc. In the present invention, in addition to safety during spraying and cost, they can be dispersed among the most important powder ores. Focusing on water solubility from an easy point, a water-soluble phenol resin was selected.

  In the production of a phenol resin, an acid or alkali catalyst is usually added when the phenolic raw material and the aldehyde raw material are reacted. The one using an acid catalyst is called a novolak type, and the one using an alkali catalyst is called a resol type. In the case of the most common combination of phenol and formaldehyde, the novolak type phenol resin precursor using an acid catalyst is a variety of condensates having a molecular weight of 2000 or less in which phenol is mainly connected in a straight chain by a methylene bond. In the case of a resol type using a catalyst, it is a mixture of methylolphenol mainly composed of trimethylolphenol, dimer (dimer) and trimer (trimer) thereof. In the present invention, both a resol type and a novolac type can be used.

  In general, the resol type self-crosslinks by heating to 150 ° C. or higher, but the novolac type requires a curing agent such as hexamethylenetetramine. The curing agent may be added by a method suitable for each agglomeration method, but is limited to water solubility.

  Further, the phenol resin used in the present invention includes a water-soluble phenol-urea resin in which a part of phenols is substituted with urea.

  The phenol resin dispersed and added in the blast furnace as a binder for sintered ore is thermally decomposed and partially volatilized, but remains as carbon (residue after pyrolysis) between the particles in the sintered ore. . In general, the amount of carbon remaining without volatilization after the thermal decomposition of the resin can be represented by the residual carbon ratio (% by mass).

  The ratio of carbon remaining when heated to 500 ° C. or higher in the atmosphere (residual carbon ratio) is approximately 0% for general resins such as acrylic and polyvinyl alcohol, whereas phenol resin is as high as 30% by mass or higher. Therefore, the sintered ore of the present invention agglomerated with a phenol resin as a binder has a crushing strength of 1000 N / grain or more due to the binder function of the phenol resin itself from normal temperature to about 400 ° C. from the time of charging the blast furnace to the top of the furnace. The phenol resin is gradually pyrolyzed and carbonized from inside the furnace at 400 ° C. or higher. At 500 ° C. or higher, the phenol resin functions as an interparticle component of the fine ore after carbonization, thereby exhibiting a crushing strength of 100 N / grain or higher even during heat up to 900 ° C.

  The addition amount of the phenol resin is required so that the sintered ore exhibits a crushing strength of 1000 N / grain or more at room temperature. The specific amount of addition varies depending on conditions such as the particle size distribution of the iron oxide raw material, so it cannot be uniquely defined, but generally the required crushing strength and binder dispersibility, mixing time, cost, etc. From the above aspect, about 2 to 12 parts by mass is appropriate as a ratio in the sintered ore (product). An agglomerated mineral having a crushing strength of 1000 N / grain or more at normal temperature using a phenol resin as a binder can maintain a hot crushing strength of 100 N / grain or more in a temperature range up to 900 ° C.

  The sintered ore of the raw material for blast furnaces according to the method of the present invention is mainly composed of iron raw material, binder and powdered coke, but other components such as various dispersants, hardening accelerators as necessary. One or more kinds of agents, cement, limestone fine powder, fly ash, silica fine powder and the like can be blended in an appropriate amount as long as the effects of the present invention are not impaired. The total amount of these other components in the sintered ore is 4% by mass or less, more preferably about 2% by mass.

  As for the particle size of the sintered ore of the raw material for blast furnaces by the method of this invention, about 5.5-25 mm is preferable. If the particle size of the sintered ore is less than 5.5 mm, the air permeability of the raw material packed layer when charged in the furnace deteriorates. On the other hand, if the particle size exceeds 25 mm, the reduction takes a long time and is not reduced. This is because the iron oxide remains.

  As the agglomeration method of the raw material for obtaining the sintered ore of the blast furnace raw material by the method of the present invention, a known agglomeration method can be used, but a method suitable for the form of the phenol resin precursor to be used is selected. There is a need. For example, a solution-like phenol resin precursor can be easily mixed with an iron raw material, but in the case of a powdered phenol resin precursor, it is better to mix with an iron raw material while heating to a melting point or higher. There is a tendency that a higher crushing strength can be obtained than when granulating as it is. Specific examples of agglomeration methods that can be industrially mass-produced include methods such as granulation, molding, and crushing of molded products. Sintered ore obtained by these agglomeration methods includes granulated products, moldings, and the like. It becomes a crushed body of a product and a molded product.

A rotary granulator can be used for granulation, and a briquetting machine or the like can be used for molding. However, the present invention is not limited to these, and any equipment that can be used for granulation and molding can be used. For example, in a granulation method or a molding method, a raw material and a resin solution are mixed and stirred (kneaded), and then granulated or molded. The molding method may be a method of pressurizing after filling the mold.
A rotary granulator includes a drum mixer, a disk pelletizer, a pug mill, and the like, and a roll type is a typical example of a molding machine. After mixing, by mixing, granulating, or shaping, the surface of the granular or powdered iron raw material is coated with a binder (binder) to form a block mixture.

Mix in primary and secondary mixers together with other sintering materials such as main materials (mineral ore, sieving powder, etc.), auxiliary materials (limestone, serpentine, etc.), powdered coke, anthracite, etc. After granulation, it is charged into a sintering machine and fired at about 900 ° C.
Or, the main raw materials (sintered ore, sieving powder, etc.), auxiliary raw materials (limestone, serpentine, etc.), powdered coke, anthracite, etc., which are ordinary sintering raw materials, are mixed with a primary mixer, granulated, A carbon source such as anthracite is added, then mixed and granulated with a secondary mixer, and then charged into a sintering machine and fired in the same manner.

  The granulated and shaped sintered ore is heat treated to thermally cure the phenol resin precursor, thereby becoming a product of the sintered ore of the blast furnace raw material. In general, the phenol resin precursor can be cured by heating to 150 ° C. or higher to obtain a three-dimensionally crosslinked phenol resin. However, the optimum conditions such as the heating temperature and the heating time are the phenol resin precursor to be used. Therefore, it is only necessary to select conditions suitable for each.

  Moreover, even if it is not sufficiently heat-cured, if a crushing strength of 1000 N / grain or more at normal temperature and 100 N / grain or more at 900 ° C. is developed, it may be a sintered ore product.

Water glass (CaO-SiO ₂ after pyrolysis, etc.), polyimide (same Si ₃ N ₄ ), polysiloxane (same SiO ₂ ), colloidal silica (same SiO ₂ ), 30 mass that does not volatilize when heated to 900 ° C % Of inorganic components remain, so that a crushing strength of 1000 N / grain or more at room temperature and 100 N / grain or more at 900 ° C. can be maintained. More preferably, for water glass, the CaO component is 30% by mass or more, the SiO ₂ component is 50% by mass or more, and the other is preferably MgO, Al ₂ O ₃ , B ₂ O ₃ , Na ₂ O or K ₂ O , Cr ₂ O ₃ , PbO ₂ and Li ₂ O are 5% or less. Similar to the water-soluble phenolic resin, 2 to 12 parts by mass is a suitable addition amount. If it is less than 2 parts by mass, it is difficult to form a granulated product, and if it exceeds 12 parts by mass, the strength of the granulated product after thermal decomposition is significantly reduced, which is not preferable. The difference from water-soluble phenolic resin is that it is expected to improve the high temperature reducibility of sintered ore, which is important for blast furnace lower reaction, to reduce the fuel ratio of blast furnace, and to greatly improve the output ratio. The carbon is not included.

  The addition effect of the water-soluble phenol resin for forming the carbon source starts to occur when the viscosity of the mixture with the iron raw material after the addition of the water-soluble phenol resin is 1.5 mPa · s or more, but is 5,000 mPa · s. If it exceeds s, adverse effects such as the coarse granulated material becoming dense will become remarkable. More preferably, the granulation efficiency is high in the range of 5 mPa · s to 1,000 mPa · s. Therefore, in this invention, it is preferable to control the viscosity of the mixture with water-soluble phenol addition to 1.5 to 5,000 mPa · s. In addition, the phenol resin in the aqueous solution is more effective when the molecular weight is low, and the molecular weight is preferably 300,000 or less.

In the present invention, when the mass of the iron raw material is 100, water-soluble phenol resin, water glass (CaO-SiO ₂ after pyrolysis, etc.), polyimide (Si ₃ N ₄ ), polysiloxane (SiO ₂ ), colloidal It is preferable to mix silica (the same SiO ₂ ) so that the ratio of the external number is 2 parts by mass or more. This is because when the addition ratio is 2 parts by mass or more, the effect of binding the particles of the iron raw material, which is the matrix, starts to appear significantly. In the present invention, the upper limit ratio of water-soluble phenol resin, water glass (CaO-SiO ₂ after pyrolysis, etc.), polyimide (same Si ₃ N ₄ ), polysiloxane (same SiO ₂ ), colloidal silica (same SiO ₂ ) If the amount exceeds 30 parts by mass, the bonding between these binders increases, and the room temperature to high temperature strength reaches its peak, which is not suitable. From the economical point of view, the upper limit of the ratio is preferably 30 parts by mass.

  The reason why the residual carbon ratio of the phenol resin is set to 30% by mass or more in the present invention is that the expression of high-temperature strength and the promoting action of the reduction reaction of the iron raw material become remarkable at 30% by mass or more.

First, an iron raw material containing 20% by mass of reverse ore (sintered ore powder) having a particle size of less than 5 mm was adjusted to a particle size of φ5 to 10 mm by a sieving method. As shown in Table 1, aqueous solution of water-soluble phenol resin, water glass (CaO-SiO ₂ after pyrolysis, etc.), polyimide (same Si ₃ N ₄ ), polysiloxane (same SiO ₂ ), colloidal silica (similar SiO ₂ ) Was diluted by adding water having the amount of water described in the rightmost column, and then added and mixed while gradually spraying the iron raw material.

This was granulated at room temperature using a rolling granulator (drum mixer, φ750 × L1,200 mm, rotation speed 40 rpm), and the resulting granulated product was heated at 200 ° C. for 20 minutes using a constant temperature and humidity machine. Heat to cure the water-soluble phenolic resin, water glass (CaO-SiO ₂ after pyrolysis, etc.), polyimide (Si ₃ N ₄ ), polysiloxane (SiO ₂ ), colloidal silica (SiO ₂ ) The added granulated product was heated and dried at 120 ° C. for 60 minutes using a thermo-hygrostat, and a granulated product having a diameter of 5.5 to 25 mm was produced by crushing and classification.

[Invention Examples 1 and 2]
As a water-soluble phenol resin, “Vinal KC-1300” (trade name, non-volatile content: 70 mass%, viscosity: 120 mPa · s at 25 ° C.) manufactured by Kanae Chemical Industry Co., Ltd. 1408A "(trade name, non-volatile content 55.1% by mass, viscosity 33 mPa · s at 25 ° C). The residual carbon ratios of KC-1300 and KC-1408A are 50% by mass and 35% by mass, respectively. In the agglomeration of the iron raw material, the iron oxide raw material and the water-soluble phenol resin were mixed and granulated.

[Invention Examples 3, 4, 5, 6]
Water glass (CaO—SiO ₂ after pyrolysis, etc.), polyimide (the same Si ₃ N ₄ ), polysiloxane (the same SiO ₂ ) and colloidal silica (the same SiO ₂ ) were added, mixed and granulated. Residues after pyrolysis at 900 ° C. in each atmosphere are 60, 40, 50, and 30% by mass.

[Invention Examples 7, 8, 9, 10]
As the water-soluble phenol resin, “Vinal KC-1300”, “Vinal KC-1408A” manufactured by Kanae Chemical Industries, Ltd., water glass (CaO—SiO ₂ after pyrolysis, etc.), polyimide (the same Si ₃ N ₄ ), Polysiloxane (the same SiO ₂ ) and colloidal silica (the same SiO ₂ ) were added simultaneously, mixed and granulated.
In the agglomeration of iron raw material, a mixture of iron oxide raw material and phenol resin, etc., with the water content shown in the right column of Table 1 added, is granulated at room temperature using a rotary granulator. did. The obtained granulated material was heated at 200 ° C. for 20 minutes using a constant temperature and humidity machine to thermally cure the phenol resin, and the other binders were dried to produce a granulated product before sintering.

[Comparative Examples 11 and 12]
Instead of phenol resin as a binder, acrylic emulsion ("AS-1800" manufactured by Toa Gosei Co., Ltd. (trade name, solid concentration 45% by mass), "AS-2000" made by acrylic emulsion Toa Gosei Co., Ltd.) (Trade name, solid content concentration: 35% by mass), and the iron raw material mixed with this binder is granulated at room temperature using a rolling granulator according to Invention Example 1, at 120 ° C. The granulated product before sintering was manufactured by heating at 60 ° C. The residual carbon ratio at 500 ° C. in a nitrogen atmosphere of the resin component of the acrylic emulsion used was 1% by mass or less.

[Comparative Example 13]
Blast furnace cement (Portland cement) was used as a binder instead of the present invention. After mixing iron raw material and blast furnace cement, adding 1.2 times as much water as cement, granulate it at room temperature using a rolling granulator, and cure this granulated material at room temperature for 5 days. did.

  About the granulated material of Invention Examples 1-10 and Comparative Examples 11-13 obtained as described above, three levels of room temperature (22 ° C.), 500 ° C., and 900 ° C. for particles having a particle size of 20 to 21 mm. The crushing strength was measured at a temperature of.

  In crushing strength measurement, after holding at each measurement temperature for 2 hours or more in an air atmosphere, one granulated product in a compression test using an autograph (maximum load 500 kgf (4900N)) made by Shimadzu Corporation. The load which crushes was measured. Eight grains were measured under the same conditions, and the average value thereof was taken as the crushing strength at each temperature level of each sample.

  Table 2 shows the compositions of the agglomerates of the invention examples and comparative examples and the crushing strength at each temperature. According to this, the agglomerate of the present invention has a crushing strength of 1000 N / grain or more at room temperature, and 100 N / grain or more at each temperature of 500 ° C. and 900 ° C. other than room temperature. On the other hand, in Comparative Examples 11 and 12 using an acrylic emulsion as a binder, the crushing strength exceeds 1000 N / grain at room temperature, but is lower than 100 N / grain at 500 ° C. or higher, and the shape at 900 ° C. in Comparative Example 12 has a shape. It was pulverized without keeping. Moreover, in the comparative example 13 which uses blast furnace cement as a binder, crushing strength is less than 100 N / grain at 900 degreeC or more. It can be seen that in the high temperature region of 500 ° C. or higher, the crushing strength of the comparative example is significantly inferior to that of the inventive example.

According to the present invention, by increasing the carbon source in the water-soluble phenolic resin, a large amount of carbon source remains in the sintered ore, and the sintered ore quality such as cold strength, reduced powdering property, reducibility, etc. is maintained. However, the characteristics of the high-temperature reduction / softening and melting properties, which are the most important for the blast furnace lower reaction, were greatly improved.
In particular, the reduced powdering property (RDI) and the reducible property (JIS-RI) of Invention Examples 1, 2, 7, 8, 9, and 10 are 3 examples of comparative examples for any granulated product after sintering. There was no significant difference. Therefore, since the ventilation resistance at the lower part of the blast furnace is improved, the output ratio can be greatly improved.

In addition, when water glass (CaO-SiO ₂ etc. after pyrolysis), polyimide (Si ₃ N ₄ ), polysiloxane (SiO ₂ ), colloidal silica (SiO ₂ ) is added, In addition, a large amount of inorganic components can be allowed to remain, and the high-temperature strength characteristics that are most important for stabilizing the cold strength and the ventilation resistance in the blast furnace can be greatly improved. Therefore, the effect which contributes to the fuel ratio reduction of the blast furnace of the carbon-containing sintered ore obtained by this invention and an improvement in a tapping ratio is great.

1 Iron raw material and powdered coke, reverse ore 2 Binder (at least one of water-soluble phenol resin, water glass, polyimide, polysiloxane, colloidal silica)

Claims (7)

A method for producing a sintered ore of a raw material for a blast furnace, which is granulated or molded by adding a binder for making the sintered raw material agglomerated and giving strength to the sintered raw material,
As the binder, at least one of water-soluble phenol resin, water glass, polyimide, polysiloxane, and colloidal silica is added to 2 to 12 parts by mass with respect to 100 parts by mass of the sintering material, and mixed with the sintering material. A method for producing a sintered ore of a raw material for a blast furnace, characterized by granulating or forming after stirring.   The method for producing a sintered ore of a raw material for a blast furnace according to claim 1, wherein the residual carbon ratio of the water-soluble phenol resin is 30% or more. The method of producing sintered ore of the blast furnace raw material according to claim 1, wherein the composition after the thermal decomposition of the water glass is at least CaO-SiO _2. 2. The method for producing a sintered ore of a raw material for a blast furnace according to claim 1, wherein the composition of the polyimide after pyrolysis is Si ₃ N ₄ . The method of producing sintered ore of the blast furnace raw material according to claim 1, wherein the composition after the thermal decomposition of the polysiloxane is SiO _{2. 2. The} method for producing a sintered ore of a raw material for a blast furnace according to claim 1, wherein the composition after pyrolysis of the colloidal silica is SiO2.   The granulated product formed by the granulation is any one of a rolling molded product, a molded product, and a crushed product of the molded product, for a blast furnace according to any one of claims 1 to 6. Manufacturing method of raw material sintered ore.

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