JP2005154822A - Method of producing sintered ore - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing sintered ore with improved productivity by improving the granulation properties of a sintering raw material, and simultaneously, maintaining and improving its ignitionability to the sintering raw material layer by segregating fuel such as coke on the upper layer of the sintering raw material layers. <P>SOLUTION: The method of producing sintered ore with a sintering raw material for iron manufacture including powder iron ore comprises: a stage wherein a part or the whole of fuel is added after a stage wherein the sintering raw material is subjected to granulation treatment in the presence of one or more kinds of high polymer compounds selected from the group consisting of (1), (2), (3) and (4): (1) a high polymer compound derived with a monomer, per monomer molecule, having at least one kind of group selected from the group consisting of a carboxyl group, a sulfonic group and their salts by one or two as an essential component, wherein the ratio of the monomer is 10 to 100 mol% to the whole quantity of monomers as the raw material for the high molecular compound; (2) a β-naphthalene sulfonate-formalin condensate; (3) a melamine sulfonate-formalin condensate; and (4) an aromatic aminosulfonic acid polymer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a method for producing a sintered ore. More specifically, the present invention relates to a method for producing sintered ore that is a raw material for charging a blast furnace in a iron making process.

The iron making process is generally performed by charging sintered ore made of iron ore, lump ore, and pellets together with coke into a blast furnace. This sintered ore is pre-processed with sintering raw materials including iron ore, auxiliary raw materials, fuel, etc., filled in a sintering machine to a specific height to form a sintering bed, and then fired by firing the surface layer It is manufactured by doing. As a sintering machine, a downward suction type is usually adopted, and air necessary for sintering is circulated by suctioning from below the sintering raw material, and fuel is supplied downward from above the sintering raw material. By burning, the sintering raw material is sintered. For this reason, if the sintering raw material contains a lot of fine powder, the air permeability decreases due to clogging and the like, and the combustion rate of coke, which is the fuel, becomes slow, so the production efficiency of the sintered ore decreases. It becomes.

Therefore, in order to improve the air permeability in the sintering bed and improve the productivity, a pretreatment such as granulating the sintered raw material to form pseudo particles is performed. For example, granulation operations such as mixing iron ore as a raw material for sintering, auxiliary materials, fuel, and the like, adding a small amount of water, and stirring with a granulator are performed. The pseudo particles are generally particles in which fine particles of 0.5 mm or less are attached to the particles of 1 to 3 mm or more. The actions required for such granulation are to improve the quasi-granulating property in which fine particles adhere to the periphery of the core particles, and to make the quasi-particles difficult to collapse in the sintering process.
Recently, with the depletion of excellent agglomerates, the deterioration of powdered ore has also become severe, and the granulation properties of sintered raw materials tend to be worse than before. Technology that is highly effective is highly desired.

As a conventional granulation method of a sintering raw material, it is known to use a polymer compound such as polyacrylic acid as a binder for granulation of iron ore containing fine iron ore (for example, Patent Document 1, 2, 3 and 4). However, these technologies have room for improvement. That is, the sintering machine that sinters the sintering raw material adopts a downward suction type, and by sucking from below the sintering raw material, the air necessary for sintering is circulated and from above the sintering raw material downward. The raw material for sintering is sintered by burning the fuel. Here, the sintering raw material is ignited from above. Since the granulation property of coke is relatively low and the particle size is smaller than the average particle size of iron ore, the average content of coke in small particles or pseudo particles of small particle size becomes high. Normally, when charging pseudo particles from a drum feeder into a sintering bed, it is bent and inserted so that small particles are lined up through a sloping plate, etc., and the coke content in the upper layer of the sintering raw material layer is set. Higher to facilitate ignition from the top. On the other hand, by using a polymer compound such as polyacrylic acid as a granulation binder for iron ore containing fine iron ore, the granulation property of the sintering raw material is remarkably improved. Sintered raw material layer such that coke adheres to large pseudo particles and exists in the lower layer of the sintering raw material layer in the sintering bed or is embedded in the adhering powder layer in the pseudo particles. The content of coke in the upper layer is lowered. As a result, the ignitability in the ignition furnace tends to be inferior, or the coke contained in the pseudo particles tends not to burn. Therefore, it is necessary to improve the granulation property of the sintered raw material, and at the same time, a technique is required in which a fuel such as coke is deflected to the upper layer of the sintered raw material layer or is made into a pseudo particle.
JP 59-50129 (page 1-3) JP-A-61-61630 (first page) JP 10-502417 A (page 1-3) International Publication No. 02/066688 pamphlet (pages 155-159)

The present invention has been made in view of the above situation, and at the same time, improves the granulation property of the sintered raw material, and at the same time, causes the fuel such as coke to be deflected to the upper layer of the sintered raw material layer to ignite the sintered raw material layer. An object of the present invention is to provide a method for producing a sintered ore with improved productivity by maintaining and improving the properties.

As a result of various studies on the method for producing sintered ore, the present inventors have been selected from the group consisting of carboxyl groups, sulfonic acid groups and salts thereof as a granulating binder in order to granulate the sintered raw material. If the polymer compound having at least one kind of group is used, excellent granulation properties will be exhibited, but fuel such as coke having relatively low granulation properties is also granulated and embedded in pseudo particles. Paying attention to the fact that it is difficult to maintain the ignition of the sintered raw material layer, as a granulating binder, (1) one or two carboxyl groups, sulfonic acid groups and A polymer compound derived from a monomer having at least one group selected from the group consisting of these salts as an essential component, and the monomer is a raw material of the polymer compound 10 to 10 of the total monomer amount The polymer compound is selected from the group consisting of a high molecular compound of 00 mol%, (2) β-naphthalenesulfonate formalin condensate, (3) melamine sulfonate formalin condensate, and (4) aromatic aminosulfonic acid polymer. When one or more kinds of polymer compounds are used, the sintering raw material is sufficiently formed by having a step of adding part or all of the fuel after granulating the sintering raw material in the presence of the polymer compound. Even in the case of grain processing, the existence position of the fuel such as coke with respect to the particle size distribution of the raw material after granulation treatment is improved, and the content of coke above the sintering raw material layer is increased. It has been found that the ignitability can be sufficiently maintained and further improved. Further, in addition to the above-described effects, it has been found that there is an effect that the granulation property of the sintered raw material is improved, and thereby the productivity of the sintered ore is remarkably improved, and the above-mentioned problems are solved brilliantly. I came up with the idea that I could do it. This is because the amount of the polymer compound adsorbed on the coke is relatively large, and when the coke is added after granulation of the sintering raw material, the polymer compound is adsorbed on the coke and the granulation property of the sintering raw material is lowered. It is considered that the polymer compound effectively acted. As a result, the granulation property is further improved, the air permeability in the sintering machine is improved, and the ignition to the sintering raw material layer can be sufficiently maintained and improved even with a small amount of coke. The inventors have found that a sintered ore can be efficiently produced by synergistically exhibiting the effect, and have achieved the present invention.

That is, the present invention is a method for producing sintered ore by using a sintered raw material for iron making containing fine iron ore, and the method for producing the sintered ore comprises (1), (2), (3) and ( 4) A method for producing a sintered ore having a step of adding a part or all of a fuel after a step of granulating a sintered raw material in the presence of one or more kinds of polymer compounds selected from the group consisting of 4).
(1) A polymer derived from, as an essential component, a monomer having one or two at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group, and a salt thereof per monomer molecule A polymer compound, wherein the monomer is 10 to 100 mol% of the total amount of monomers as a raw material of the polymer compound.
(2) β-naphthalene sulfonate formalin condensate.
(3) Melamine sulfonate formalin condensate.
(4) Aromatic aminosulfonic acid polymer.
The present invention is described in detail below.

The method for producing sintered ore according to the present invention has a step of adding a part or all of the fuel after the step of granulating the sintered raw material in the presence of the polymer compound as the granulating binder. Will be performed.
In the present invention, “adding part or all of the fuel after the step of granulating the sintered raw material” means that at least a part or all of the fuel added later is added to the sintered raw material in this case. It means a sintered raw material, and it means that the addition of all the fuel is finished after the start of the granulation process of the sintered raw material. The fuel may be added so that it is not granulated to the extent that the effects of the present invention cannot be exerted by being granulated and embedded in the pseudo-particles. It can be carried out by delaying part or all of the addition. For example, it can be carried out by mixing a part of the fuel and granulating the sintered raw material and then adding the remaining fuel.
The sintered raw material means iron ore, auxiliary raw materials, fuel and the like. The fuel in the present invention is preferably one or more selected from the group consisting of coke, anthracite, and dust generated from steelworks and / or factories other than steelworks. Moreover, it is preferable that the dust which generate | occur | produces from factories other than the said steelworks and / or steelworks is a dust whose carbon content which can be combusted is 5 mass% or more.

The amount of fuel used in the present invention is preferably 1 part by weight or more and 100 parts by weight or less with respect to 100 parts by weight of the sintering raw material filled in the sintering machine. It is preferable. If the amount is less than 1 part by weight, it may be difficult to maintain the ignition of the sintering material layer, and if it exceeds 10 parts by weight, the effect of facilitating maintaining the ignition of the sintering material layer is further improved. There is a risk of not. More preferably, it is 2 parts by weight or more and 6 parts by weight or less.
However, in the present invention, the amount of fuel used is calculated as the mass in terms of carbon contained when the fuel is dust generated from other than steelworks and / or steelworks.

In the present invention, as described above, after granulating the sintered raw material other than the fuel together with a part of the fuel, the remaining fuel may be added. In this case, the ratio of the fuel in the fuel addition step Is preferably 5% by mass or more when the total amount of all the fuels used in the production method of the present invention, that is, the fuel added in the granulation process step and the fuel addition step is 100% by mass. That is, the ratio of the fuel added in the step of adding part or all of the fuel in the present invention is preferably 5 to 100% by mass with respect to the total amount of fuel. More preferably, it is 30 mass% or more, More preferably, it is 40 mass% or more, Most preferably, it is 60 mass% or more. If it is less than 5% by mass, the effect of suppressing the interior of the fuel to the pseudo particles becomes insufficient, and the ignitability of the raw material layer in the sintered bed tends to be reduced.
The preferable amount of fuel added after the granulating step is 0.2 parts by weight or more, more preferably 0.3 parts by weight or more, and most preferably 1 part by weight with respect to the sintered raw material. That's it.

In addition, after starting the granulation treatment with the polymer compound, some (remaining) fuel is added after the GI index of the granulated product (pseudoparticle) having a particle size of 0.25 mm or less becomes 50 or more. It is preferable to do so. More preferably, the GI index is 80 or more.
The GI index is one of evaluation methods disclosed in Steel Manufacturing Research No. 288 (1976), page 9, and represents the ratio of fine particles adhering around the core particles. The GI index was measured by drying the pseudo particles obtained by granulation operation at 80 ° C. for 1 hour and then classifying with a sieve to obtain the particle size (pseudo particle size). Preferably in accordance with the method described in No. (1976), page 9, and calculated by the following formula.
GI index = {(ratio of raw material of 0.25 mm or less before granulation−ratio of raw material of 0.25 mm or less after granulation) / (ratio of raw material of 0.25 mm or less before granulation)} × 100

In the present invention, the entire amount of the iron-making sintered raw material excluding a part of the fuel may be granulated at once. However, after granulating a part of the iron-producing sintered raw material in advance, A granulation method may be used in which a raw material is added. At this time, a part or all of the fuel is added. (A) Addition after starting granulation of a part of the sintered raw material for iron making (B) a form to be added after partial granulation of the iron-making sintered raw material is completed, (c) a form to be added while mixing the remaining iron-making sintered raw material, (d) the remaining Any of the forms added after mixing and processing the iron-making sintered raw material may be used, but the raw material of 0.25 mm or less in all the iron-making sintered raw materials, that is, the iron-making sintered raw material to be granulated in advance And the raw material of 0.25 mm or less contained in the sintering raw material for iron making added later is less than 50% by granulation. It is preferred to add some or all of the fuel after Tsu. Moreover, you may combine said (a)-(d).
A specific example (flow) of the method of adding the remaining fuel is shown in FIG. In FIG. 1, a, b, c, and d are specific examples of addition positions in the methods (a), (b), (c), and (d), respectively.

Further, in addition to the fuel addition step, a method of charging from above after forming a sintering bed in a sintering machine is suitable. As a method of charging from above, (1) fuel or fuel is used. A method in which a large amount of sintered raw material is charged into the upper layer of the fuel raw material layer and (2) a method in which liquid fuel, liquid fuel such as coke slurry, etc. are sprayed from above are suitable. FIG. 2 shows a specific example (schematic diagram) of the method (1). In FIG. 2, the fuel or the sintered raw material containing a large amount of fuel is cut out from the hopper 7, and the other sintered raw materials are cut out from the surge hopper 5. FIG. 3 shows a specific example (schematic diagram) of the method (2). In FIG. 3, liquid fuel or liquid fuel such as coke slurry is added from the spray nozzle 19, and other sintered raw materials are cut out from the surge hopper 5.

In the present invention, it is preferable to include a step of adding fuel and a step of mixing the fuel after the granulation step. In this case, the fuel addition process and the fuel mixing process are performed while the granulation process is performed or after the granulation process is completed. Alternatively, the fuel mixing process may be performed after the fuel addition process is completed.
For example, as a preferred example, after the granulation treatment of the sintered raw material excluding a part of the fuel is completed, a step of adding the remaining fuel is performed on a belt conveyor or the like, and then the step of further mixing the pseudo particles The method by which is performed is mentioned. In the granulator, it is also within the scope of the present invention that the step of adding the remaining fuel is performed while the granulation process is in progress. It is preferable that the addition of the fuel is completed. The progress of the granulation process depends on the type and amount of the polymer compound added and the timing of adding the polymer compound, so it cannot be said unconditionally. What is necessary is just to carry out so that the GI index | exponent of a raw material may become the range mentioned above, and it can determine easily by performing a preliminary test.

As the granulating apparatus used in the present invention, for example, a pan pelletizer, a mulmerizer, a drum mixer, an Eirich mixer, a Laedige mixer, etc. are suitable. In the granulating process, among these, a drum mixer is used. It is preferable to use it. That is, the method for producing a sintered ore according to the present invention preferably includes a step of adding fuel and a step of mixing and mixing the fuel after the step of granulating with a drum mixer. It is one of the preferred embodiments of the invention. In addition, although it does not specifically limit as a mixing method in a fuel mixing process, It is preferable to use the said granulation apparatus.

In the granulation treatment step, a sintering raw material is granulated using a polymer compound, but the form using such a polymer compound is not particularly limited, and the sintering raw material in the granulation treatment step is used. May be added once, or may be added in multiple portions. In addition to the polymer compound, a granulating agent as described below may be used in combination as the granulating agent. The granulating agent means a compound or the like used for improving the granulating property when the sintering raw material is granulated.

The amount of the polymer compound used may be appropriately set according to the granulating property of the sintering raw material, the type of the polymer compound, the type of equipment to be used, etc. It is preferable that the polymer compound be 0.001 part by weight or more with respect to 100 parts by weight, and it is preferable that the polymer compound be 2 parts by weight or less. If the amount is less than 0.001 part by weight, the effect of the present invention may not be sufficiently exhibited without being sufficiently granulated. There is a possibility that problems such as the amount of addition being excessively large, a large amount of the sintered raw material can be formed, and sintering becomes difficult. More preferably, the polymer compound is made 0.003 part by weight or more, and is made to be 1 part by weight or less.

As the granulating agent other than the polymer compound, a known granulating agent can be used in addition to the polymer compound group A. Examples of such a treating agent include quick lime, bentonite, and lignin sulfite. One or more of salts (pulp waste liquid), starch, sugar, molasses, water glass, cement, gelatin, corn starch and the like can be used, and among these, quick lime is preferably used.
The amount of the granulation treatment agent used in the granulation treatment step is preferably 0.05 parts by weight or more and 3 parts by weight or less with respect to 100 parts by weight of the sintering raw material in the granulation treatment step. It is preferable to do. More preferably, it is 0.1 parts by weight or more and 2 parts by weight or less.

In the granulation treatment step, the granulation treatment may be performed using fine particles having an average particle size of 200 μm or less in order to prevent the pseudo particles from collapsing in the sintered bed or the like. As fine particles having the above average particle diameter, calcium carbonate, fly ash, kaolin clay, silica, talc, bentonite, dolomite, silica fume, anhydrous gypsum, pellet feed, petal, dust, etc. are suitable. 1 type or 2 types or more can be used. Preferably, it is at least one selected from the group consisting of calcium carbonate, fly ash, kaolin clay, silica, talc and silica fume. More preferred are calcium carbonate, fly ash and silica fume. The average particle size of such fine particles is preferably 0.01 μm or more, and preferably 100 μm or less. More preferably, it is 0.02 μm or more and 50 μm or less. Most preferably, it is 0.1 μm or more and 20 μm or less.

The amount of the fine particles having an average particle size of 200 μm or less is preferably 0.1 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the sintering raw material in the granulation treatment step. Is preferred. More preferably, it is 0.3 parts by weight or more and 1.5 parts by weight or less.

The productivity of the sintered ore in the present invention can be measured by the product yield and production rate of the sintered ore. For example, the product yield can be measured by sintering after sintering in the sintering pot test. It can be evaluated by measuring the ratio of particles having a particle size of 5 mm or more when 50 kg of ore (sinter cake) is dropped five times on a steel plate from a height of 2 m. The production rate can be calculated by the following equation.
Production rate (t / day / m ² ) = total mass of particles having a particle size of 5 mm or more after product yield evaluation (t) / sintering time (day) / surface area of sintering machine (pan) (m ² )

The method for producing a sintered ore according to the present invention is based on an inexpensive production method capable of stable operation since the ignition failure of the sintered layer is suppressed and the productivity of the sintering machine is improved. Such a sintered ore produced by the method for producing a sintered ore of the present invention is one of the preferred embodiments of the present invention. Such a sinter is produced by the method for producing a sinter according to the present invention, which is stable and can be produced, since a polymer compound and a fuel can be used effectively by adding a fuel later. Is useful.

In the method for producing a sintered ore of the present invention, as the granulating binder, the polymer compound (1), (2) β-naphthalene sulfonate formalin condensate, (3) melamine sulfonate formalin condensate And (4) one or more polymer compounds selected from the group consisting of aromatic aminosulfonic acid polymers (polymer compound group A).
Hereinafter, the polymer compound (1) will be described.
The polymer compound of (1) above requires a monomer having one or two groups selected from the group consisting of a carboxyl group, a sulfonic acid group and a salt thereof per monomer molecule. At least one selected from the group consisting of a polymer compound derived as a component, that is, a monomer having a carboxyl group, a monomer having a sulfonic acid group, and a monomer having one or two salts thereof It can be obtained by polymerizing a monomer composition essentially comprising a monomer.
Examples of such a polymer compound include (I) a polymer compound having a carboxyl group and / or a salt thereof, (II) a polymer compound having a sulfonic acid group and / or a salt thereof, (III) a carboxyl group and / or a salt thereof. Any one or two or more of the salt and the polymer compound having a sulfonic acid group and / or a salt thereof may be mentioned.

In the polymer compound of the above (1), one or more monomers can be used as a raw material, but the monomer has a total monomer amount of the raw material of the polymer compound. From a monomer having a carboxyl group, a monomer having a sulfonic acid group, and a monomer having a salt thereof to a polymer compound of 10 to 100 mol%, that is, 100 mol% of the total monomer composition It is formed by polymerizing a monomer composition containing 10 mol% or more of one or more monomers selected from the group consisting of: When the content of the monomer having a carboxyl group, the monomer having a sulfonic acid group and the monomer having a salt thereof in the monomer composition is less than 10 mol%, a sufficient granulation effect can be obtained. There is a risk of not being able to. More preferably, it is 30 mol% or more, and particularly preferably 50 mol% or more.
In the polymer compound, a salt of a carboxyl group or a sulfonic acid group is a group having a structure in which a hydrogen atom in a carboxyl group or a sulfonic acid group is replaced with a metal atom or the like, and means a group in the form of a salt. To do.

The monomer having a carboxyl group or a salt thereof has a carboxyl group such as (meth) acrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, crotonic acid, acrylamide glycolic acid, etc. Monomers and their salts are preferred. These may be used alone or in combination of two or more. Among these, (meth) acrylic acid and / or a salt thereof is more preferable. That is, the polymer compound having a carboxyl group and / or a salt thereof in the present invention is preferably a compound obtained by (co) polymerizing a monomer having (meth) acrylic acid and / or a salt thereof as a main component. More preferred is acrylic acid and / or a salt thereof. Moreover, as a salt, alkali metal salts, such as sodium and potassium; Alkaline earth metal salts, such as calcium and magnesium; Ammonium salt; Organic amici salts, such as monoethanolamine and triethanolamine, are suitable. Among these, alkali metal salts such as sodium and potassium, and ammonium salts are preferable, and sodium salts are more preferable.

Examples of the monomer having a sulfonic acid group or a salt thereof include sulfonic acid groups such as vinyl sulfonic acid, styrene sulfonic acid, sulfoethyl (meth) acrylate, and 2-acrylamido-2-methylpropane sulfonic acid. Preferred are monomers having a salt thereof and salts thereof. These may be used alone or in combination of two or more.

In addition to the monomer having a carboxyl group, the monomer having a sulfonic acid group, and the monomer having a salt thereof, the above-mentioned monomer may be other copolymerizable with these monomers. One type or two or more types of monomers may be included.
Examples of the other copolymerizable monomers include 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxypropyl acid phosphate, 2- (meth) acryloyloxy-3-chloropropyl acid phosphate, 2 -Monomers having an acidic phosphate group such as (meth) acryloyloxyethylphenyl phosphate; monomers having an acid group such as a vinyl acid monomer such as vinylphenol, and salts thereof are preferred.

Examples of the other copolymerizable monomers also include polyalkylene glycol (meth) acrylates such as polyethylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate, and methoxypolyethyleneglycol monoacrylate; Polyalkylene glycol monoalkenyl ether monomer formed by adding ethylene oxide to methyl-3-buten-1-ol; polyethylene glycol monoethenyl ether monomer formed by adding ethylene oxide to allyl alcohol; A monomer having a polyalkylene glycol chain such as maleic acid polyethylene glycol half ester to which polyethylene glycol has been added is preferred. Among these monomers having a polyalkylene glycol chain, a monomer having a polyalkylene glycol chain having a chain length of 5 mol or more and 100 mol or less in terms of ethylene oxide is easy to obtain, It is preferable from the viewpoints of improvement in polymerizability and polymerizability. More preferably, it is a monomer having a polyalkylene glycol chain having a chain length of 10 mol or more and 100 mol or less in terms of ethylene oxide.

As said other copolymerizable monomer, the following compound can be used besides the thing mentioned above.
Methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylic acid (N, N-dimethylaminoethyl), (meth) acrylic acid (N, N-diethylaminoethyl) C1-C18 (meth) acrylic acid alkyl esters such as aminoethyl (meth) acrylate; (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (Meth) acrylamide and its derivatives such as (meth) acrylamide; vinyl acetate; (meth) acrylonitrile; base-containing monomers such as N-vinyl-2-pyrrolidone, vinylpyridine and vinylimidazole; N-methylol (meth) acrylamide , N-butoxymethyl (meth) acrylamide and other cross-linkability (Meth) acrylamide monomers; hydrolyzable groups such as vinyltrimethoxysilane, vinyltriethoxysilane, γ- (meth) acryloylpropyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, allyltriethoxysilane A silane monomer in which is directly bonded to a silicon atom; a monomer having an epoxy group such as glycidyl (meth) acrylate, glycidyl ether (meth) acrylate; 2-isopropenyl-2-oxazoline, 2-vinyl-2 -Monomers having an oxazoline group such as oxazoline; monomers having an aziridin group such as 2-aziridinylethyl (meth) acrylate and (meth) acryloylaziridine; vinyl fluoride, vinylidene fluoride, vinyl chloride, chloride A monomer having a halogen group such as vinylidene; E) Esters of acrylic acid and polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, 1,3-butylene glycol, neopentyl glycol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol Polyfunctional (meth) acrylic acid ester having a plurality of unsaturated groups in the molecule such as fluoride; polyfunctional (meth) acrylamide having a plurality of unsaturated groups in the molecule such as methylenebis (meth) acrylamide; diallyl phthalate, diallyl maleate Polyfunctional allyl compounds having a plurality of unsaturated groups in the molecule, such as diallyl fumarate; allyl (meth) acrylate; divinylbenzene.

When (co) polymerizing the monomer, a chain transfer agent may be used for the purpose of adjusting the molecular weight. Examples of chain transfer agents include compounds having a mercapto group such as mercaptoethanol, mercaptopropionic acid, t-dodecyl mercaptan; carbon tetrachloride; isopropyl alcohol; toluene; hypophosphorous acid, sodium hypophosphite, sodium bisulfite, etc. A compound having a high chain transfer coefficient is preferred. These may be used alone or in combination of two or more. The amount of the chain transfer agent used is preferably 0.005 to 0.15 mol with respect to 1 mol of the total monomer composition.

Methods for (co) polymerizing the above monomers include various conventionally known polymerization methods such as oil-in-water emulsion polymerization, water-in-oil emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation weight. A combination method, a solution polymerization method, an aqueous solution polymerization method, a bulk polymerization method and the like can be employed. Among these, the aqueous solution polymerization method is preferable from the viewpoint of reduction in polymerization cost (production cost) and safety.

The polymerization initiator used for the polymerization may be a compound that decomposes by heat or a redox reaction to generate radical molecules. Moreover, when performing superposition | polymerization by aqueous solution polymerization method, it is preferable to use the polymerization initiator provided with water solubility. Examples of the polymerization initiator include persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; 2,2′-azobis- (2-amidinopropane) dihydrochloride, 4,4′-azobis- (4-cyano Water-soluble azo compounds such as pentanoic acid; thermal decomposable initiators such as hydrogen peroxide; hydrogen peroxide and ascorbic acid, t-butyl hydroperoxide and Rongalite, potassium persulfate and metal salts, ammonium persulfate and sodium bisulfite A redox polymerization initiator comprising a combination of the above is preferred. These may be used alone or in combination of two or more. What is necessary is just to set suitably as the usage-amount of a polymerization initiator according to a monomer composition, polymerization conditions, etc.

The polymerization conditions such as the reaction temperature and reaction time in the above polymerization may be appropriately set according to the monomer composition, the type of polymerization initiator, etc., but the reaction temperature may be 0 to 150 ° C. Preferably, it is 40-105 degreeC. The reaction time is preferably about 3 to 15 hours. As a method for supplying the monomer composition to the reaction system in the case of performing polymerization by an aqueous solution polymerization method, a batch addition method, a divided addition method, a component dropping method, a power feed method, or a multistage dropping method can be used. The polymerization may be performed under normal pressure, reduced pressure, or increased pressure.

In the production of the polymer compound, the concentration of the non-volatile component containing the polymer compound contained in the polymer compound aqueous solution obtained when the aqueous solution polymerization method is adopted is preferably 70% by mass or less. When it exceeds 70 mass%, there exists a possibility that a viscosity may become high too much.

The one or more polymer compounds selected from the polymer compound group A in the present invention preferably have a weight average molecular weight of 1,000 to 1,000,000. If the weight average molecular weight is less than 1000, the action as a dispersant may be reduced. If it exceeds 1,000,000, the viscosity of the polymer compound becomes too high, and it may be difficult to add so that the action as a dispersant is sufficiently exhibited. More preferably, it is 2000 or more and 200000 or less. In the present specification, the weight average molecular weight is a value measured under the following measurement conditions.

(Weight average molecular weight measurement conditions)
Column: Aqueous GPC column “GF-7MHQ” (trade name, manufactured by Showa Denko KK) One carrier liquid: 34.5 g of disodium hydrogen phosphate dodecahydrate and 46.2 g of sodium dihydrogen phosphate dihydrate Ultrapure water is added to make the total amount 5000 g.
Aqueous solution flow rate: 0.5 ml / min
Pump: “L-7110” (trade name, manufactured by Hitachi, Ltd.)
Detector: Ultraviolet (UV) detector “L-7400” (trade name, manufactured by Hitachi, Ltd.), wavelength 214 nm
Molecular weight standard sample: sodium polyacrylate (sodium polyacrylate having a weight average molecular weight of 1300 to 1360000 available from Soka Kagaku)
The analysis sample is prepared by diluting with the carrier liquid so that the polymer compound is 0.1% by mass in solid content.
However, the following measurement conditions are applied to polymer compounds that cannot be measured under the above measurement conditions.
Model: Waters LCM1
Carrier solution: 115.6 g of sodium acetate trihydrate dissolved in a mixture of 10999 g of water and 6001 g of acetonitrile, and further adjusted to pH 6.0 with 30% aqueous sodium hydroxide solution Flow rate: 0.8 ml / min
Column: Water-based GPC column “TSKgel GuardColumnSWXL + G4000SWXL + G3000SWXL + G2000SWXL” (manufactured by Tosoh Corporation)
Column temperature: 35 ° C
Detector: Waters 410 Differential refraction detector Molecular weight standard sample: Polyethylene glycol The analytical sample is prepared by diluting with the carrier solution so that the polymer compound is 0.1% in solid content.

The polymer compound preferably has a dispersity of 12 or less. If the degree of dispersion exceeds 12, the action of dispersing fine iron ore tends to be small, and the action of making pseudo particles tends to decrease. More preferably, it is 10 or less. The dispersity is a ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn), and represents the molecular weight distribution. The number average molecular weight is measured by the same method as the weight average molecular weight.
These polymer compounds may be added in a solid form, but are preferably added in the form of an aqueous solution having a solid content concentration of 0.1 to 70%.

The manufacturing method of the sintered ore of the present invention has the above-described configuration, improves the granulation property of the sintered raw material, and at the same time maintains the ignition of the sintered raw material layer, and further improves the productivity and improves the productivity. Can be manufactured. In addition, the sintered ore of the present invention can effectively use the polymer compound and the fuel by adding the fuel later, so that the granulation property of the sintering raw material is improved and the sintered ore is efficiently made. It is useful to be produced by the method for producing a sintered ore of the present invention.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by weight” and “%” means “mass%”.

The sintered raw materials and pellet raw materials in the examples and comparative examples described below were all in an absolutely dry state. The weight average molecular weight of the polymer in the polymer aqueous solution was measured by polyethylene glycol conversion by GPC (gel permeation chromatography).
The average particle diameter and GI index, product yield, production rate, and carbon content in the pseudo particles in Examples and Comparative Examples were measured by the following methods.
(Average particle size of pseudo particles, GI index)
The pseudo particles obtained by the granulation operation were dried at 80 ° C. for 1 hour and classified using a sieve to obtain the particle size (pseudo particle size). The GI index of the granulated pseudo particles is one of the evaluation methods disclosed in Steel Manufacturing Research No. 288 (1976), page 9, and indicates the ratio of fine particles adhering around the core particles. The GI index was measured according to the method described in Steel Manufacturing Research No. 288 (1976), page 9.
In the measurement of each of the following Examples and Comparative Examples, the GI index of pseudo particles having a particle diameter after granulation of 0.25 mm or less was determined.
Moreover, the GI index (pseudo graining index) of pseudo particles of 0.25 mm or less was calculated by the following formula.
GI index = {(ratio of raw material of 0.25 mm or less before granulation−ratio of raw material of 0.25 mm or less after granulation) / (ratio of raw material of 0.25 mm or less before granulation)} × 100

(Product yield, production rate)
In the product yield, in the sintering pot test, 50 kg of sintered ore after sintering (sinter cake) was dropped 5 times on a steel plate from a height of 2 m. The ratio was evaluated by measuring. The production rate was calculated by the following formula.
Production rate (t / day / m ² ) = total mass of particles having a particle size of 5 mm or more after product yield evaluation (t) / sintering time (day) / surface area of sintering machine (pan) (m ² )

(Quantification of carbon content in pseudo particles)
The sifted portion of 1 mm or less of the pseudo particles after the GI index measurement is mixed, and the whole amount is pulverized by a pulverizer such as a mill. At this time, the average particle size after pulverization is set to 50 μm or less. If there are many sieving parts and it cannot be pulverized at once, pulverize in two or more times and mix so as to be uniform after pulverization.
About 1 g of pseudo particles after pulverization are collected in a commercially available PP (polypropylene) container having a capacity of 120 ml, and the mass is accurately measured (assumed to be Ag). Add 10 g of distilled water and let it blend lightly. In order to remove carbon contained in limestone out of the system as carbon dioxide, about 1.2 to 1.3 g of phosphoric acid is added, and after foaming is observed, the container is shaken by hand, and then 135 ° C. Dry thoroughly in the oven set to. Remove the contents from the PP container, transfer to a mortar, grind and dry in an oven at 135 ° C. At this time, when the content does not become powder, it is pulverized and dried again after drying in an oven at 135 ° C. The mass of the content after drying (referred to as composition 1) is measured (referred to as Bg). The amount of C in the composition 1 is determined by elemental analysis (C%). The amount of coke contained in a pseudo-ladder of 1 mm or less is calculated as follows.
Amount of coke contained in pseudo particles of 1 mm or less (%) = B (g) × C (%) / A (g)

Example 1
Among the sintering raw materials (raw materials for iron making) having the composition shown in Formulation 1 in Table 1, 68824 parts of sintering raw materials to be pretreated were prepared except for 1176 parts of coke added after granulation.
The above-mentioned sintered raw material 68824 parts was put into a drum mixer and pre-stirred for 1 minute at a rotational speed of 24 min ⁻¹ . Thereafter, while stirring the composition at the same rotational speed, a polyacrylic acid having a weight average molecular weight of 6000, which was prepared in advance with a non-volatile content of 0.4% as a granulating agent for iron making, to the composition (sintering raw material). 5250 parts of an aqueous sodium solution was sprayed (added) using a spray bottle over about 1.5 minutes. After spraying, the above-mentioned composition to which the dispersant was added (final composition for granulation treatment) was further stirred at the same rotational speed for 3 minutes to perform granulation treatment (pseudo granulation). Furthermore, after stopping the drum mixer and adding 1176 parts of coke, the mixture was stirred for 3 minutes at a rotational speed of 24 min ⁻¹ . The ratio of sodium polyacrylate to the sintering raw material was 0.03%.
The obtained pseudo particles were sintered in a 50 kg scale pan test to obtain sintered ore. The test conditions were as follows: the sintering pot had a diameter of 300 mm, a height of 600 mm, a layer thickness of 550 mm, and a suction negative pressure of 9.8 kPa (constant). The productivity of the obtained sintered ore was measured. These results are summarized in Table 2.

Example 2
Among the sintering raw materials (raw materials for iron making) having the composition shown in Formulation 2 of Table 1, 67647 parts of sintering raw materials to be pretreated were prepared except for 2353 parts of coke added after granulation.
67647 parts of the above-mentioned sintered raw material was put into a drum mixer and pre-stirred for 1 minute at a rotation speed of 24 min ⁻¹ . Thereafter, while stirring the composition at the same rotational speed, a polyacrylic acid having a weight average molecular weight of 6000, which was prepared in advance with a non-volatile content of 0.4% as a granulating agent for iron making, to the composition (sintering raw material). 5250 parts of an aqueous sodium solution was sprayed (added) using a spray bottle over about 1.5 minutes. After spraying, the above-mentioned composition to which the dispersant was added (final composition for granulation treatment) was further stirred at the same rotational speed for 3 minutes to perform granulation treatment (pseudo granulation). Further, the drum mixer was stopped, 2353 parts of coke were added, and the mixture was stirred for 3 minutes at a rotation speed of 24 min ⁻¹ . The ratio of sodium polyacrylate to the sintering raw material was 0.03%. Further, in the same manner as in Example 1, the productivity of the obtained sintered ore was measured. These results are summarized in Table 2.

Example 3
Among sintering raw materials (raw materials for iron making) having the composition shown in Formulation 3 of Table 1, 69647 parts of sintering raw materials to be pretreated were prepared except for 353 parts of coke added after granulation.
69647 parts of the above sintered raw material was put into a drum mixer, and pre-stirred at a rotational speed of 24 min ⁻¹ for 1 minute. Thereafter, while stirring the composition at the same rotational speed, a polyacrylic acid having a weight average molecular weight of 6000, which was prepared in advance with a non-volatile content of 0.4% as a granulating agent for iron making, to the composition (sintering raw material). 5250 parts of an aqueous sodium solution was sprayed (added) using a spray bottle over about 1.5 minutes. After spraying, the above-mentioned composition to which the dispersant was added (final composition for granulation treatment) was further stirred at the same rotational speed for 3 minutes to perform granulation treatment (pseudo granulation). The ratio of sodium polyacrylate to the sintering raw material was 0.03%. Thereafter, 74897 parts of the composition (sintering raw material) was charged into a sintering pan, and 353 parts of coke was added from above using a 16 mesh sieve.
The obtained pseudo particles were sintered in a 50 kg scale pan test to obtain sintered ore. The test conditions were as follows: the sintering pot had a diameter of 300 mm, a height of 600 mm, a layer thickness of 550 mm, and a suction negative pressure of 9.8 kPa (constant). The productivity of the obtained sintered ore was measured. These results are summarized in Table 2.

Example 4
By the method described in WO 02/066688, a sodium acrylate / methyl acrylate copolymer having a weight average molecular weight of 33000 (composition ratio of sodium acrylate is 78.7 mol%, copolymer 1) is obtained. It was. In Example 1, 5250 parts of the aqueous copolymer 1 solution previously adjusted to a non-volatile content of 0.27% was replaced with 5250 parts of an aqueous sodium polyacrylate solution having a weight average molecular weight of 6000 previously adjusted to a non-volatile content of 0.4%. The productivity of the sintered ore was measured in the same manner as in Example 1 except that it was used. The addition amount of the copolymer with respect to the sintering raw material was 0.02%. The results are shown in Table 2.

Example 5
In Example 1, instead of 5250 parts of a sodium polyacrylate aqueous solution having a weight average molecular weight of 6000 adjusted to 0.4% nonvolatile content in advance, a β-naphthalenesulfonic acid formalin condensate previously adjusted to 1.32% nonvolatile content was used. The productivity of sintered ore was measured in the same manner as in Example 1 except that 5320 parts of an aqueous solution of certain mighty 150 (trade name: manufactured by Kao Corporation) was used. The amount of β-naphthalenesulfonic acid formalin condensate added to the sintering raw material was 0.1%. The results are shown in Table 2.

Comparative Example 1
A sintered raw material (raw material for iron making) having the composition shown in Formulation 4 of Table 1 was prepared.
70000 parts of the above sintered raw material was put into a drum mixer and pre-stirred for 1 minute at a rotation speed of 24 min ⁻¹ . Then, while stirring the composition at the same rotational speed, a polyacrylic acid having a quantitative average molecular weight of 6000, which was prepared in advance with a non-volatile content of 0.4% as a granulating agent for iron making in the composition (sintering raw material). 5250 parts of an aqueous sodium solution was sprayed (added) using a spray bottle over about 1.5 minutes. After spraying, the above-mentioned composition to which the dispersant was added (final composition for granulation treatment) was further stirred at the same rotational speed for 3 minutes to perform granulation treatment (pseudo granulation). Furthermore, it stirred for 3 minutes at the same rotational speed. The ratio of sodium polyacrylate to the sintering raw material was 0.03%. Further, in the same manner as in Example 1, the productivity of the obtained sintered ore was measured. These results are summarized in Table 2.

Comparative Example 2
In Comparative Example 1, in place of 5250 parts of a sodium polyacrylate aqueous solution having a weight average molecular weight of 6000 adjusted to 0.4% nonvolatile content in advance, a β-naphthalenesulfonic acid formalin condensate previously adjusted to 14.7% nonvolatile content was used. The productivity of sintered ore was measured in the same manner as Comparative Example 1 except that 5250 parts of an aqueous solution of a certain mighty 150 (trade name: manufactured by Kao Corporation) was used. The amount of β-naphthalenesulfonic acid formalin condensate added to the sintering raw material was 1.1%. Firing was impossible due to poor ignition of the sintered raw material.

Example 6
In Example 2, instead of 5250 parts of an aqueous sodium polyacrylate solution having a weight average molecular weight of 6000 adjusted to 0.4% nonvolatile content in advance, a β-naphthalenesulfonic acid formalin condensate previously adjusted to 14.7% nonvolatile content was used. The productivity of sintered ore was measured in the same manner as Comparative Example 1 except that 5250 parts of an aqueous solution of a certain mighty 150 (trade name: manufactured by Kao Corporation) was used. The amount of β-naphthalenesulfonic acid formalin condensate added to the sintering raw material was 1.1%. The results are shown in Table 2.

Example 7
The same operation as in Example 3 was performed to obtain pseudo particles, and then approximately 1 kg was sampled uniformly, and the pseudo particles were dried in an oven at 80 ° C. for 1 hour, and then 1 mm or less of pseudo particles were sieved. The total amount of pseudo particles of 1 mm or less was pulverized using a hammer mill so as to have an average particle size of 50 μm or less. The amount of coke contained in pseudo particles of 1 mm or less was calculated by the above method. The results are shown in Table 3.

Comparative Example 3
After the same operation as in Comparative Example 1 was performed to obtain pseudo particles, about 1 kg was uniformly sampled, and the pseudo particles were dried in an oven at 80 ° C. for 1 hour, and then 1 mm or less of pseudo particles were sieved. The total amount of pseudo particles of 1 mm or less was pulverized using a hammer mill so as to have an average particle size of 50 μm or less. The amount of coke contained in pseudo particles of 1 mm or less was calculated by the above method. The results are shown in Table 3.

Comparative Example 4
After the same operation as in Comparative Example 2 was performed to obtain pseudo particles, about 1 kg was sampled uniformly, and the pseudo particles were dried in an oven at 80 ° C. for 1 hour, and then 1 mm or less of pseudo particles were sieved. The total amount of pseudo particles of 1 mm or less was pulverized using a hammer mill so as to have an average particle size of 50 μm or less. The amount of coke contained in pseudo particles of 1 mm or less was calculated by the above method. The results are shown in Table 3.

From Table 2, after the sintering raw material is granulated in the presence of one or more polymer compounds selected from the group consisting of (1), (2), (3) and (4) above, It turns out that productivity of a sintered ore improves by adding a part or all compared with the past. Moreover, it can be seen from Table 3 that since the coke content (mass%) of pseudo particles of 1 mm or less is increased, the ignitability of the sintering material layer in the sintering bed is improved.

Comparative Example 5
In Comparative Example 1, in addition to 70000 parts of the sintering raw material, 840 parts of quick lime was added, and 5600 parts of water was replaced with 5250 parts of a sodium polyacrylate aqueous solution having a weight average molecular weight of 6000, which was adjusted in advance to a nonvolatile content of 0.4%. The productivity of the sintered ore was measured in the same manner as in Comparative Example 1 except that it was added. As a result, the productivity was 26.5 t / day / m ² .

FIG. 1 is a specific example (flow) of the method of adding the remaining fuel in the present invention. FIG. 2 is a specific example (schematic diagram) of the method (1) in the present invention. FIG. 3 is a specific example (schematic diagram) of the method (2) in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Primary drum mixer 2 Secondary drum mixer 3 Floor hopper 4, 17 Feeder 5 Surge hopper 6 Drum feeder 7 Hopper 8, 9 Charging device 10 Ignition 11 Sintering machine 12 Sintering raw material layer 13 Main duct 14 Dust collector 15 Blower 16 Chimney 18 Wind box 19 Spray nozzle

Claims (4)

A method for producing sintered ore by using a sintered raw material for iron making containing fine iron ore,
The method for producing the sintered ore is a step of granulating a sintering raw material in the presence of one or more polymer compounds selected from the group consisting of (1), (2), (3) and (4). After that, there is a step of adding part or all of the fuel.
(1) A polymer derived from, as an essential component, a monomer having one or two at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group, and a salt thereof per monomer molecule A polymer compound, wherein the monomer is 10 to 100 mol% of the total amount of monomers that are raw materials of the polymer compound.
(2) β-naphthalene sulfonate formalin condensate.
(3) Melamine sulfonate formalin condensate.
(4) Aromatic aminosulfonic acid polymer. The fuel is one or more kinds selected from the group consisting of coke, anthracite, and dust having a combustible carbon content of 5% by mass or more generated from a steel mill and / or a factory other than a steel mill. The method for producing a sintered ore according to claim 1. 3. The method according to claim 1, wherein the method for producing the sintered ore comprises a step of adding fuel and a step of mixing the fuel after the step of granulating with a drum mixer. Production method of ore. The ratio of the fuel added in the step of adding a part or all of the fuel is 5 to 100% by mass with respect to the total amount of the fuel. Production method.

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