JP2003073749A - Granulation method for raw material for iron manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a granulation method preferably used for granulating a raw material for iron manufacture. SOLUTION: This granulation method comprises granulating a part of a raw material for iron manufacture, while using a part of the whole added water to be used for granulation treatment, as a granulation agent, and further granulating a mixture of the obtained granulated substance, the remaining raw material for iron manufacture, and a granulation agent for iron manufacture, which contains a high molecular compound and the remaining water in the whole added water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for granulating a raw material for iron making, and more particularly to a method for producing a sinter ore as a raw material for iron making, which comprises granulating a raw material for iron making. In this case, the present invention relates to a method particularly suitable for adjusting the water content of the iron-making raw material to granulate to form pseudo-granulate.

[0002]

2. Description of the Related Art In the production of sinter, first, iron ore, which is a sintering raw material, auxiliary raw materials, fuel, etc. are mixed, and the water content is adjusted with a granulator such as a drum mixer, a pelletizer or an Erich mixer. Granulate to create pseudo particles. Pseudo particles are generally particles in which fine particles of 0.5 mm or less are attached to core particles of 1 to 3 mm. At this time, the action required for granulation is to improve the pseudo-granulation property in which fine powder particles adhere around the core particles, and the pseudo-particles are hard to disintegrate in the wet zone, dry zone, etc. in the firing process. . By making the sintering raw material pseudo particles in this way, it is possible to improve the air permeability in the sintering raw material packed layer (sintering bed) on the sintering machine and improve the productivity of the sintering machine. .

The sintering machine for sintering the sintering raw material adopts a downward suction type, and the air necessary for sintering is circulated by sucking from the lower side of the sintering raw material and at the upper side of the sintering raw material. The fuel is burned from the bottom to the bottom to sinter the sintering raw material. For this reason, when the sintering raw material contains a large amount of fine powder, the air permeability is lowered due to clogging or the like, and the combustion speed of coke, which is a fuel, is slowed down, so that the production efficiency of the sintering machine is lowered.

Therefore, in order to improve air permeability, pretreatment such as granulating (pseudo-granulating) the sintering raw material is performed. As the pretreatment, for example, a granulation operation such as adding a small amount of water to the sintering raw material and stirring is performed.

However, when the sintering raw material contains a large amount of fine iron ore or when the sintering raw material contains a large amount of sintering raw material having poor granulation properties, the raw material is sufficiently granulated. There is a problem that you cannot do it.

Therefore, as a conventional measure for improving the pseudo-granularity, for example, the sintering raw material is divided into a main raw material group such as iron ore and coke and the other group such as return ore and fine iron ore. Prior to mixing and granulating the main raw material group and the other group, a nuclear granule is formed by granulating the sintered powder contained in the return ore as a nucleus, and this nuclear granule is mainly used. A method of mixing and granulating main raw material groups has been proposed.

Further, the granulation operation using only water has a poor effect of improving the pseudo-granulation property, and the amount of fine powder contained in the sintering raw material cannot be reduced so much that the pseudo-granulation property is improved. As a countermeasure, a method of adding various granulating additives as a binder to the sintering raw material has been proposed.
Many are known as granulating additives. For example, bentonite, lignin sulfite (pulp waste liquor), starch, sugar, molasses, water glass, cement, gelatin, carboxymethyl cellulose and the like have been studied for use as binders or thickeners. In the production of sinter, these are not industrially used because they have a problem that the amount added is relatively large and the cost is high, and it is difficult to secure the amount used.

[0008] As a granulating additive that is currently put into practical use, for example, quick lime disclosed in Iron Making Research No. 288 (1976) page 9 is widely used. According to this, the effect of quick lime is shown as follows. First, it is possible to promote pseudo-granulation in the mixer. Secondly, the pseudo-particles should be collapsed during the drying and heating process in the sintering process after filling the sintering raw material consisting of pseudo-particles to a specific height and igniting the surface layer after forming the sintering bed. It is said that the above can be prevented and a uniform wind flow in the sintered layer can be maintained.

Therefore, for example, as a conventional pretreatment method for a sintering raw material, the sintering raw material is divided into a main raw material group such as iron ore and coke and another group such as return ore and fine iron ore. Prior to mixing and granulating the raw material group and the other group, a method has been proposed in which the other group is granulated using quicklime as a binder, and this is further mixed with the main raw material group and granulated (see Japanese Laid-Open Patent Application No. 3-64422 and Japanese Patent Laid-Open No. 4-74829.
No.

[0010]

However, the use of binders such as quicklime and molasses is generally expensive, which causes an increase in manufacturing cost. Also, although granulation using quick lime has been put to practical use, quick lime easily absorbs moisture,
Since heat is generated at this time, there is a problem in that handling is required. Further, the quick lime currently used cannot be sufficiently effective unless the amount of it is used is relatively large, resulting in high cost. Therefore, it is the present situation that the amount used is reduced as much as possible. Even if 2% by weight or more of quick lime is added, the effect of improving the pseudo-granularity tends to reach the ceiling. Furthermore, recently, with the depletion of fine lump ores, the inferiority of powdered ores has become severe, and there is a problem that the granulation properties of sintering raw materials are worse than before. For this reason, even if granulation is performed by adding quick lime, the effect is smaller than before. Furthermore, binders other than quicklime have an insufficient effect of reducing the amount of fine powder contained in the sintering raw material, have a small effect of improving the air permeability of the sintering bed and shortening the sintering time, and The strength of the sintered ore is weak. Sintered ore with weak strength
For example, since fine powder is likely to be generated at the time of crushing after sintering, the return ore is increased, the product yield is reduced, and the production efficiency is reduced. Therefore, granulation using a binder other than quicklime has not been put to practical use.

Further, the effect of reducing the amount of fine powder contained in the sintering raw material by the granulation processing method for iron making using quick lime is not yet sufficient.

The present invention has been made in view of the above conventional problems, and an object thereof is to provide a granulation treatment method of a raw material for iron making, which is suitably used for granulating a raw material for iron making. Especially.

[0013]

In order to solve the above problems, a method for granulating a raw material for iron making according to the present invention is a method for granulating a raw material for iron making containing fine iron ore. Part of the raw material for granulation is granulated by using part of the total added water used for granulation as a granulation agent for ironmaking, and then the resulting granulated product and the rest It is characterized in that the raw material is mixed with the polymer compound and the granulation treatment agent for iron making containing the remaining water of the total added water used for the granulation treatment, and the granulation treatment is carried out.

In order to solve the above problems, the method for granulating a raw material for iron making according to the present invention is characterized in that the polymer compound is obtained by polymerizing or copolymerizing an acid group-containing monomer. .

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The method for granulating a raw material for iron manufacturing according to the present invention is a method for granulating a raw material for iron manufacturing (sintering raw material) containing fine iron ore, which contains an auxiliary raw material, a fuel and the like. Depending on the particle size distribution, granulation property, composition, etc. of each brand of raw material for
After mixing, kneading, and granulating a part of the iron-making raw material, the remaining iron-making raw material is mixed and kneaded for granulation, or the remaining iron-making raw material is mixed and kneaded for granulation. In the treatment method (selective granulation), part of the iron-making raw material, part of the total added water used in the granulation treatment, is used as the first iron-making granulation treatment agent (iron-making granulation treatment agent ( After the granulation treatment using A)), the resulting granulated product, the remaining iron-making raw material, the polymer compound, and the residual water of the total added water used for the granulation treatment This is a method in which the granulation treatment agent for ironmaking (No. 2 granulation treatment agent for ironmaking (B)) is mixed and further granulated.

In the present invention, the polymer compound means an organic or inorganic compound having a weight average molecular weight of more than 1000. As the polymer compound used in the present invention, an organic or inorganic compound having water solubility or hydrophilicity is used, and a polymer compound having high water solubility or hydrophilicity has a high effect of improving the pseudo-granulation property. It is good.

The polymer compound used in the present invention is preferably a water-soluble or alkali-soluble polymer, and specifically, for example, polyacrylic acid, polymethacrylic acid, a copolymer of acrylic acid and acrylamide. Anionic synthetic polymers obtained by polymerizing or copolymerizing acid group-containing monomers, such as copolymers of styrene and maleic acid, copolymers of (meth) acrylic acid and (meth) acrylic acid esters; polyethylene glycol , Polypropylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, nonionic synthetic polymers such as poly (meth) acrylic acid hydroxyethyl; cationic monomers such as polyethyleneimine, dimethylaminoethyl poly (meth) acrylate, diallyldimethylammonium chloride Polymerized or copolymerized cationic synthetic polymers; graft or block polymers of these polymers; starch, cellulose, chitin, gelatin, lignin, natural rubber and other natural polymers carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, lignin sulfonic acid, etc. Polymers and the like can be mentioned, but the invention is not particularly limited.
These polymer compounds may be used alone or in combination of two or more, as required.

Among them, as the above-mentioned polymer compound, an anionic polymer compound obtained by polymerizing or copolymerizing an acid group-containing monomer has a high effect of improving the pseudo-granulation property,
It is more suitable. Among them, anionic polymers containing an acid group are particularly preferable because they have high granulation property.

The acid group-containing monomer that can be used in the present invention is not limited to the above-exemplified compounds, and specific examples include (meth) acrylic acid,
Carboxyl group-containing monomers such as maleic acid, maleic anhydride, itaconic acid and crotonic acid; sulfo group-containing monomers such as vinyl sulfonic acid, styrene sulfonic acid and sulfoethyl (meth) acrylate; 2- (meth) acryloyloxy Acidic phosphate ester group-containing unit amount such as ethyl acid phosphate, 2- (meth) acryloyloxypropyl acid phosphate, 2- (meth) acryloyloxy-3-chloropropyl acid phosphate, 2- (meth) acryloyloxyethyl phenyl phosphate Body; carboxylic acid monomers such as vinylphenol; and salts thereof. The acid group-containing monomer may be used alone or in combination of two or more, if necessary.

Of the acid groups derived from the acid group-containing monomers exemplified above, a carboxyl group and / or a salt thereof is preferable, and at least one acid selected from the group consisting of (meth) acrylic acid, maleic acid, and salts thereof. Those introduced by polymerizing or copolymerizing a group-containing monomer are more preferable.

When a salt of an acid group-containing monomer is used as the acid group-containing monomer, its neutralizing base is not particularly limited, but alkali metal ions such as potassium ion and sodium ion; calcium ion and the like. Alkaline earth metal ions; ammonium, nitrogen-containing bases such as primary to quaternary amines; and the like.

In the present invention, polymerizing or copolymerizing the acid group-containing monomer means polymerizing a monomer component (monomer composition) containing the acid group-containing monomer, and the acid group-containing monomer alone or in the acid group It shows that it is (co) polymerized with another monomer (copolymerization component) that is copolymerizable with the contained monomer.

The other monomer copolymerizable with the acid group-containing monomer is, for example, (meth)
(Meth) acrylic acid alkyl ester, which is an esterified product of (meth) acrylic acid and a monohydric alcohol having 1 to 18 carbon atoms, such as methyl acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate; cyclohexyl (Meth) acrylic acid cycloalkyl ester such as (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, monoester product of (meth) acrylic acid and polypropylene glycol, hydroxyl such as Group containing (meta)
Acrylic acid ester; Polyalkylene glycol (meth) acrylic acid ester such as polyethylene glycol monomethacrylic acid ester, methoxypolyethylene glycol monomethacrylic acid ester, methoxypolyethylene glycol monoacrylic acid ester; 3-methyl-3-
Polyalkylene glycol monoalkenyl ether monomer obtained by adding ethylene oxide to buten-1-ol; polyethylene glycol monoethenyl ether monomer obtained by adding ethylene oxide to allyl alcohol; polyethylene glycol added to maleic anhydride Maleic acid polyethylene glycol half ester; styrene, vinyltoluene, α-methylstyrene,
Styrene and its derivatives such as ethyl vinyl benzene and chloromethyl styrene; (meth) acrylamide, N
-Methyl (meth) acrylamide, N-ethyl (meth)
(Meth) acrylamide and its derivatives such as acrylamide, N, N-dimethyl (meth) acrylamide;
Vinyl acetate; (meth) acrylonitrile; N-vinyl-
2-pyrrolidone; dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide,
Base-containing monomers such as vinylpyridine and vinylimidazole; cross-linkable (meth) acrylamide monomers such as N-methylol (meth) acrylamide and N-butoxymethyl (meth) acrylamide; vinyltrimethoxysilane, A silane-based monomer such as vinyltriethoxysilane, γ- (meth) acryloylpropyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, and allyltriethoxysilane in which a hydrolyzable group is directly bonded to a silicon atom. Body; epoxy group-containing monomers such as glycidyl (meth) acrylate and glycidyl ether (meth) acrylate; oxazoline group-containing monomers such as 2-isopropenyl-2-oxazoline and 2-vinyl-2-oxazoline; Aziridinylethyl (meth) acrylate, (meth Acrylate aziridine group-containing monomers such as acryloyl aziridine; vinyl fluoride, vinylidene fluoride,
Halogen group-containing monomers such as vinyl chloride and vinylidene chloride: (meth) acrylic acid and ethylene glycol, diethylene glycol, propylene glycol, 1,3-butylene glycol, neopentyl glycol, 1,6-
Polyfunctional (meth) acrylic acid esters having a plurality of unsaturated groups in the molecule such as esterified products with polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, and dipentaerythritol; methylenebis (meth) acrylamide, etc. , Polyfunctional (meth) acrylamide having a plurality of unsaturated groups in the molecule; diallyl phthalate, diallyl maleate, diallyl fumarate, etc.,
Examples thereof include polyfunctional allyl compounds having a plurality of unsaturated groups in the molecule; allyl (meth) acrylate; divinylbenzene; etc., but are not particularly limited. These monomers may be used alone if necessary, and
You may use 2 or more types.

In addition to these monomers, a chain transfer agent may be used for the purpose of adjusting the molecular weight. Specific examples of the chain transfer agent include mercapto group-containing compounds such as mercaptoethanol, mercaptopropionic acid, and t-dodecylmercaptan; carbon tetrachloride;
Compounds having a high chain transfer coefficient such as isopropyl alcohol; toluene;

The proportion of the units derived from the acid group-containing monomer in the polymer compound (polymer) is not particularly limited, but the lower limit is preferably 10 mol%, more preferably 20 mol%. And the upper limit is preferably 100 mol%.

The method for producing the polymer compound according to the present invention, that is, the method for polymerizing the monomer component containing at least the acid group-containing monomer is not particularly limited, and various conventionally known polymerization methods, for example, Oil-in-water emulsion polymerization method, water-in-oil emulsion polymerization method, suspension polymerization method, dispersion polymerization method,
A precipitation polymerization method, a solution polymerization method, an aqueous solution polymerization method, a bulk polymerization method and the like can be adopted. Among the above-exemplified polymerization methods, it is preferable to employ the aqueous solution polymerization method or the emulsion polymerization method because the safety is high and the production cost (polymerization cost) can be reduced.

The polymerization initiator used in the above polymerization method is
Any compound that decomposes by heat or a redox reaction to generate radical molecules may be used. Further, when the aqueous solution polymerization method is adopted, a water-soluble polymerization initiator is preferable. Specific 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
-Cyanopentanoic acid) and other water-soluble azo compounds; thermal decomposition initiators such as hydrogen peroxide; hydrogen peroxide and ascorbic acid, t-butyl hydroperoxide and rongalite, potassium persulfate and metal salts, ammonium persulfate and sulfite. Examples thereof include a redox polymerization initiator composed of a combination of sodium hydrogen and the like, but are not particularly limited. These polymerization initiators may be used alone or in combination of two or more. The amount of the polymerization initiator used may be appropriately set according to the composition of the monomer components, the polymerization conditions and the like.

The emulsifier used in the case of employing the emulsion polymerization method is, for example, an anionic surfactant,
Examples thereof include nonionic surfactants, cationic surfactants, amphoteric surfactants, polymeric surfactants, and reactive surfactants thereof, but are not particularly limited. These emulsifiers may be used alone or in combination of two or more, if necessary.
Emulsion polymerization can also be performed without using an emulsifier.

Specific examples of the anionic surfactant include alkylsulfate salts such as sodium dodecyl sulfate, potassium dodecyl sulfate and ammonium alkyl sulfate; sodium dodecyl polyglycol ether sulfate; sodium sulforicinoate; sulfonation. Alkyl sulfonates such as paraffin salts, sodium dodecylbenzene sulfonate, alkali metal sulfates of alkali phenol hydroxyethylene, long-chain alkylnaphthalene sulfonates, condensates of naphthalene sulfonic acid and formaldehyde, sodium laurate, triethanolamine oleate, Unsaturated fatty acid salts such as abietic acid triethanolamine; polyoxyalkyl ether sulfate salts; polyoxy Chirenkarubon ester sulfates, polyoxyethylene phenyl ether sulfate; dialkyl succinate sulfonate, and polyoxyethylene alkylaryl sulfate salts, reactive anionic emulsifiers having an unsaturated group; and the like. These anionic surfactants may be used alone or in combination of two or more.

Specific examples of the nonionic surfactants include polyoxyethylene alkyl ether; polyoxyethylene alkylaryl ether; sorbitan aliphatic ester, polyoxyethylene sorbitan aliphatic ester; glycerin monolaurate and the like. , An aliphatic monoglyceride; a polyoxyethylene-polyoxypropylene copolymer; a condensate of ethylene oxide with an aliphatic amine, amide or acid; and the like. These nonionic surfactants may be used alone or in combination of two or more.

Specific examples of the polymeric surfactant include:
For example, polyvinyl alcohol and its modified products; (meth) acrylic acid-based water-soluble polymer, hydroxyethyl (meth) acrylate-based water-soluble polymer, hydroxypropyl (meth) acrylate-based water-soluble polymer (however, according to the present invention Polymers different from copolymers); polyvinylpyrrolidone; and the like. These polymeric surfactants may be used alone or in combination of two or more.

The polymerization conditions such as the reaction temperature and the reaction time may be appropriately set according to the composition of the monomer components and the type of the polymerization initiator, but the reaction temperature is more preferably in the range of 0 to 100 ° C. It is more preferably within the range of 40 to 95 ° C. The reaction time is preferably about 3 to 15 hours. Examples of the method for supplying the monomer component (monomer composition) to the reaction system when employing the emulsion polymerization method or the aqueous solution polymerization method include, for example, batch addition method, divided addition method, component dropping method, pre-emulsion method, power feed method. The seed method, the multi-stage dropping method, and the like can be performed, but are not particularly limited.

The weight average molecular weight of the polymer compound used in the present invention, particularly the weight average molecular weight of the above-mentioned polymer, is preferably more than 1,000 and 5,000,000 or less. The lower limit (weight average molecular weight) is 150.
It is more preferably 0, and particularly preferably 2000. The upper limit (weight average molecular weight) is 300.
It is more preferable that it is 10,000, and it is particularly preferable that it is 2 million.

The concentration of the non-volatile component containing the above polymer contained in the emulsion obtained when the emulsion polymerization method is used or in the polymer aqueous solution obtained when the aqueous solution polymerization method is used is 60% by weight or less. More preferably. An emulsion or polymer aqueous solution having a non-volatile content of more than 60% by weight may have too high a viscosity and may not be able to maintain dispersion stability, resulting in aggregation.

The average particle size of the particles contained in the emulsion obtained when the emulsion polymerization method is adopted is 30 nm.
Is more preferably in the range of
More preferably, it is in the range of nm to 50 μm.
An emulsion in which the average particle size of the particles is less than 30 nm is
When the viscosity becomes too high, dispersion stability may not be maintained and aggregation may occur.

The polymer used in the present invention is dissolved or swelled in water by neutralizing at least a part thereof with a basic neutralizing agent or as it is (without neutralization). .

Specific examples of the above-mentioned neutralizing agent include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; basic compounds such as sodium carbonate, sodium hydrogen carbonate, ammonium carbonate and ammonium hydrogen carbonate. Examples thereof include carbonates; nitrogen-containing bases such as aqueous ammonia and monoethanolamine; however, they are not particularly limited.

The method for granulating a raw material for iron making according to the present invention is a method for granulating a part of a raw material for iron making according to the particle size distribution, granulating property, composition, etc. of each brand of raw material for iron making including auxiliary raw materials and fuel. After mixing, kneading and granulating, mix the rest of the raw materials for iron making
A so-called selective granulation method in which an iron-making raw material (sintering raw material) containing fine iron ore is granulated in two stages by kneading or by mixing and kneading this with the rest of the iron-making raw material. In the first step, in the first step, a part of the iron-making raw material is granulated by using a part of the total added water used for the granulation treatment as the iron-making granulating agent (A). Of the granulation treatment step, the second step, the granulation treatment product obtained by the first granulation treatment step, the remaining iron-making raw material, the polymer compound, and the total added water used for the granulation treatment. A second granulation treatment step of mixing the iron-containing granulation treatment agent (B) containing the remaining water of
When a part of the iron-making raw material exhibits the difficult granulation property, the above-mentioned iron-making granulating agent (A) is added to the difficult-to-granulate iron-making raw material in the first granulation treatment step. After moisturizing and granulating the difficult-to-granulate iron-making raw material, the remaining iron-making material is produced by using the iron-making granulating agent (B) containing the polymer compound as an active ingredient in the second granulating treatment step. Pseudo-granulation can be achieved by further granulating with the raw material.

More specifically, for example, of all the iron-making raw materials to be granulated, the iron-making raw material containing a relatively large amount of fine iron ore is selected, and the selected iron-making raw material is used for granulation. After a part of the total added water is added and the iron-making raw material is granulated with water (iron-making granulation treatment agent (A)), the granulated product is mixed with the remaining iron-making raw material and Pseudo-granulation can be achieved by adding the molecular compound and the granulating agent (B) for iron making containing the remaining water of the total added water used for granulation and further granulating.

By using the above-mentioned granulation treatment method according to the present invention, not only high pseudo-granulation property can be obtained as compared with the case where only water or quick lime is used as the granulation treatment agent, The pseudo-granulation property can be further improved as compared with the case where granulation is performed using the above-described polymer compound without humidifying and granulating a part of the iron-making raw material.

The part of the iron-making raw material selected in the first stage (first granulation treatment step) means that a plurality of iron-making raw materials are used as the iron-making raw material to be granulated. When doing, at least one of the raw materials for iron making containing a relatively large amount of relatively fine iron ore, in other words, at least one specific brand containing a large amount of relatively fine iron ore, among the plurality of types of iron making raw materials. The iron-making raw material or a part thereof may be fine particles obtained by separating the whole iron-making raw material to be granulated into fine particles (average particle diameter of less than 0.25 mm) and other particles with a sieve or the like. However, from the viewpoint of workability, at least one specific brand of iron-making raw material containing a relatively large amount of fine iron ore is preferable.

The iron-making raw material selected in the first stage is, more specifically, a raw material containing limonite containing a large amount of fine powder (iron ore containing a large amount of water of crystallization), and generally contains a large amount of fine powder. However, an ore that is difficult to granulate is used. Specific examples of such ores include maramanba ore. In the first stage, a raw material having a larger amount of fine powder than the raw material for iron making selected in the second stage is used.

The total amount of added water in the raw material for iron making depends on the water content (water brought in) in the raw material for iron making, which is generally the ratio of water to the raw material for iron making, in other words, in the obtained pseudo particles. Is finally added so that the proportion of water contained therein is 6% by weight or more and 8% by weight or less, and preferably 7% by weight. Therefore, if there is a large amount of water brought in by the iron-making raw material, the amount of added water that can be added later will be correspondingly smaller.

In the present embodiment, the amount of water added in the first stage, that is, the amount of the iron-forming granulating agent (A) used, is the amount of water used in the first stage in the production of sinter. The ratio of water to binding raw materials (iron ore, auxiliary raw materials, fuel, etc.)
The amount is preferably in the range of 5% by weight or more and 12% by weight or less, and the lower limit value thereof is more preferably 6% by weight, and particularly preferably 7% by weight. The upper limit is more preferably 11% by weight and particularly preferably 10% by weight. 12% by weight
If the granulating agent (A) for iron making, that is, water is added in excess of the above range, the pseudo-granulating property may be rather deteriorated. Further, if the addition amount of the granulating agent (A) for iron making is less than 5% by weight, the sintering raw materials (iron ore, auxiliary raw materials, fuel, etc.) cannot be sufficiently humidified, and the first stage There is a possibility that the effect obtained by performing granulation using only water and performing granulation using water and the polymer compound in the second stage may not be sufficiently obtained.

As a result of intensive studies by the inventors of the present invention, according to the present invention, when the selective granulation is performed as described above, the iron-making process is performed before adding the polymer compound to the iron-making raw material in a dry state. It was found that a high granulation effect can be obtained by moistening the raw material for ironing, adding the remaining iron-making raw material and the polymer compound, and granulating again.

A granulating agent for iron making (B) added in the second step (second granulating step) to the granulated product obtained in the first step (first granulating step). The amount of water used in step 1) depends on the total amount of added water used in the granulation process,
The remaining water excluding the water used in the granulation treatment step of 1.
Add the raw materials used in the second step and adjust the water added in the second step to
The ratio of water to the raw material for iron making, that is, the ratio of water to the raw material for iron making after the end of the granulation treatment step of the stage is 6% by weight or more and 8% by weight at the end.
Hereinafter, it is preferably added so as to be 7% by weight.

The iron-making granulation treatment agent (B) contains at least the polymer compound as an active ingredient in addition to water. The polymer compound (ratio) in the granulation treatment agent (B) for ironmaking is an ore (iron ore) as a raw material for ironmaking.
It may be appropriately set depending on the granulation property (type), the type of compound used, the granulator used, and the like, and is not particularly limited, but is 0.01 wt% or more and 90 wt% or less. It is preferable that the lower limit value is 0.05% by weight, more preferably 0.07% by weight. The upper limit thereof is more preferably 85% by weight, particularly preferably 80% by weight. If the content of the polymer compound in the iron-making granulation treatment agent (B) is less than 0.01% by weight, a sufficient amount of the polymer compound may not be added to the iron-making raw material. On the other hand, when the content of the polymer compound in the iron-making granulation treatment agent (B) exceeds 90% by weight, the viscosity of the iron-making granulation treatment agent (B) becomes too high and the iron-making granulation treatment agent is used during granulation. The granulation treatment agent (B) may not be sufficiently diffused in the raw material for iron making.

Further, the above-mentioned granulation treatment agent (B) for iron making, if necessary, within the range not impairing the performance of the above-mentioned polymer compound, in particular, the effect of improving the pseudo-granulation property, other components may be added. For example, other conventionally known granulating additives such as quick lime may be used in combination.

In the present embodiment, the iron-making granulating agent (B) added in the second stage is contained in the iron-making granulating agent (B) in the production of sinter. Sintering raw material (iron ore, auxiliary raw material,
(Fuel, etc.) is preferably added so as to be in the range of 0.001% by weight or more and 10% by weight or less, and more preferably the lower limit value thereof is 0.003% by weight. It is particularly preferable to add 0.005% by weight. Further, it is more preferably added so that the upper limit value is 5% by weight, and particularly preferably added so as to be 2% by weight. If the addition amount of the polymer compound contained in the iron-making granulation treatment agent (B) to the sintering raw material exceeds 10% by weight, granulation becomes excessive and solidification of the sintering raw material occurs. There is an adverse effect such that the inside of the mass of the sintering raw material is not sintered. The lower limit of the addition amount of the above-described iron-making granulation treatment agent (B) depends on the granulation property of the ore as the sintering raw material, the amount of water added, the granulator used, etc. It is desirable to design so that

The iron-making granulation treatment agent (B) is a component of the iron-making granulation treatment agent (B) containing the above-described polymer compound, other than water, mixed with water added to the granulator. Alternatively, the iron-making material which is stirred in a state of being dissolved or dispersed (emulsified) in the remaining water except the water used in the first granulation processing step from the total added water used in the granulation processing It is particularly preferable to spray the raw material for use because it can be added easily and uniformly.

The first step (first granulation processing step)
Different granulators may be used for the second step (second granulation treatment step), and the second step granulation may be performed using the granulator used in the first step. Good. According to the present invention, it is possible to freely select the combination of the raw material for iron making, the granulator, the timing and the place where each component is added, and therefore the combination is not particularly limited.

According to the present invention, the G of the granulated pseudo particles is
It is possible to provide a method of granulating a raw material for iron making, which has a high I index and is excellent in pseudo-granulation. The GI index of the granulated pseudo particles is a value indicating the ratio of fine powder particles adhering around the core particles. The larger the value, the better the granulation property and the air permeability during sintering. , The air permeability of the sinter is improved, and the production efficiency of the sinter is increased. The measurement of the GI index is described in the examples below.

[0053]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these. The average particle size and GI index in the examples and comparative examples were measured by the following methods.
In the examples and comparative examples, "part" means "part by weight" and "%" means "% by weight".

(Average Particle Size, GI Index) The particle size (pseudo particle size) and the average particle size were obtained by classifying the pseudo particles obtained by performing the granulation operation using a sieve. The GI index of the granulated pseudo particles is one of the evaluation methods disclosed in Iron Making Research No. 288 (1976), page 9, and as described above, the ratio of fine powder particles attached around the core particles. Indicates.

All of the sintering raw materials used in the following Examples and Comparative Examples were in an absolutely dry state.

Example 1 A flask equipped with a dropping funnel, a stirrer, a nitrogen gas introducing tube, a thermometer, and a reflux condenser was charged with 199.1 parts of ion-exchanged water and an emulsifier (manufactured by Nippon Emulsifier Co., Ltd. (Name; New Call 707SF)
9.8 parts and 11.7 parts of sodium styrene sulfonate as an acid group-containing monomer were charged. Then 75
By stirring at 0 ° C., the emulsifier was completely dissolved, and the inside of the flask was replaced with nitrogen gas. On the other hand, 164.3 parts of methacrylic acid as an acid group-containing monomer and methyl acrylate 11 as a (meth) acrylic acid ester
Monomer composition consisting of 7.4 parts (monomer component)
9.8 parts of emulsifier (same as above) and ion-exchanged water 46
A pre-emulsion was prepared by adding to 0.5 part and stirring vigorously. Then, the pre-emulsion was placed in a dropping funnel.

Next, 52.6 parts of the pre-emulsion was dropped into the aqueous solution in the flask from the dropping funnel, and
The mixture was stirred at 0 ° C for 5 minutes. Subsequently, 13.7 parts of a 5% aqueous solution of ammonium persulfate as a polymerization initiator was placed in the flask and stirred at 75 ° C. for 20 minutes to carry out initial polymerization. Thereafter, while maintaining the reaction temperature at 75 ° C., 699.3 parts of the remaining pre-emulsion was added dropwise from the dropping funnel over 2 hours. After 30 minutes from the end of the dropping, 13.8 parts of a 0.5% sodium hydrogen sulfite aqueous solution as a reducing agent was added to the aqueous solution in the flask, and the mixture was further polymerized for 1 hour, and then the obtained reaction solution was cooled. Then, the copolymerization was completed.

As a result, an alkaline water-soluble emulsion having a nonvolatile content of 29.9% containing an anionic synthetic polymer (acrylic acid type polymer) as a copolymer was obtained. The weight average molecular weight of the above copolymer measured by GPC (gel permeation chromatography) was about 1.4 million. Then, 96.9 parts of the obtained emulsion was added to 4895.8 parts of water, and then 7.3 parts of sodium carbonate was added and well stirred to give a granulation treatment agent (B) for iron making according to the present invention. As a result, 5500 parts of an aqueous polymer solution (1) was obtained. On the other hand, a sintering raw material (raw material for iron making) having the composition shown in Table 1 was prepared.

[0059]

[Table 1]

10500 parts of a sintering raw material (raw material for iron making) having the composition shown in Table 1 was put into a drum mixer and preliminarily stirred at a rotation speed of 24 min ^-1 for 1 minute. Then, while stirring at the same rotation speed, 420 parts of water was sprayed onto the sintering raw material for about 1.5 minutes by means of a sprayer. After spraying, a granulation operation was performed by further stirring for 3 minutes at the same rotation speed (first granulation treatment step). Then, to this,
59500 parts of the above-mentioned sintering raw material shown in (1) were further added and pre-stirred for 1 minute at a rotation speed of 24 min ⁻¹ . afterwards,
While stirring at the same rotation speed, 4830 parts of the polymer aqueous solution (1) prepared in advance was sprayed onto this sintering raw material for about 1.5 minutes using a sprayer. The ratio of the copolymer in the aqueous polymer solution (1) to all the sintering raw materials is 0.0
It was 4%. After spraying, a granulation operation was performed by further stirring for 3 minutes at the same rotation speed (second granulation treatment step).

By measuring the water content in the obtained pseudo particles and classifying the pseudo particles using a sieve, the average particle size and the particle size after granulation are 0.25 mm.
The GI index of the following pseudo particles was determined. The results are shown in Table 2 together with the amount of the above-mentioned copolymer added to the total amount of the raw materials for iron making.

Comparative Example 1 10500 parts of the sintering raw material having the same composition as shown in Table 1 as in Example 1 was charged into a drum mixer and preliminarily stirred at a rotation speed of 24 min ⁻¹ for 1 minute. Then, while stirring at the same rotation speed, water 4 was added to the sintering raw material.
Twenty parts were sprayed using a spray gun for about 1.5 minutes.
After spraying, a granulation operation was performed by further stirring for 3 minutes at the same rotation speed (first granulation treatment step). Then, the same sintering raw material 595 shown in Table 1 as in Example 1
Further, 00 parts was added and pre-stirred at a rotation speed of 24 min ⁻¹ for 1 minute. Then, while stirring at the same rotation speed, 4830 parts of water was sprayed onto this sintering raw material for about 1.5 minutes using a sprayer. After spraying, the granulation operation was performed by further stirring for 3 minutes at the same rotation speed (second
Granulation treatment step). By measuring the water content in the obtained pseudo particles and classifying the pseudo particles using a sieve, the average particle size and the particle size after granulation are 0.2.
The GI index of pseudo particles of 5 mm or less was obtained. The results are shown in Table 2 together with the amount of the above-mentioned copolymer added to the total amount of the raw materials for iron making.

Reference Example 1 By adding 98.2 parts of the emulsion obtained in Example 1 to 5384.4 parts of water, and then adding 7.4 parts of sodium carbonate and stirring well, the present invention was carried out. 5500 parts of an aqueous polymer solution (2) as the granulation treatment agent (B) for iron making was obtained.

The same as in Example 1, 10500 parts of the sintering raw material having the composition shown in Table 1 was put into a drum mixer, and preliminarily stirred at a rotation speed of 24 min ^-1 for 1 minute. Then, while stirring at the same rotation speed, 787 parts of the polymer aqueous solution (2) was sprayed onto the sintering raw material using a sprayer for about 1.5 minutes. After spraying, a granulation operation was performed by further stirring for 3 minutes at the same rotation speed (first granulation treatment step). Then, 59500 parts of the sintering raw material shown in Table 1, which is the same as that in Example 1, is further charged into this, and the rotation speed is 24 min.
Pre-stirred at ^-1 for 1 minute. Then, while stirring at the same rotation speed, the above-mentioned polymer aqueous solution (2) was added to this sintering raw material.
4460 parts were sprayed using a spray gun for about 1.5 minutes. After spraying, a granulation operation was performed by further stirring for 3 minutes at the same rotation speed (second granulation treatment step). By measuring the water content in the obtained pseudo particles, by classifying the pseudo particles using a sieve, the average particle size,
In addition, the GI index of pseudo particles having a particle size after granulation of 0.25 mm or less was obtained. The results are shown in Table 2 together with the amount of the above-mentioned copolymer added to the total amount of the raw materials for iron making.

Reference Example 2 By adding 98.1 parts of the emulsion obtained in Example 1 to 5394.5 parts of water, and then adding 7.4 parts of sodium carbonate and stirring well, the present invention was added. 5500 parts of an aqueous polymer solution (3) as the granulation treatment agent (B) for iron making was obtained.

[0066] The same as in Example 1, was charged with raw material to be sintered 10500 parts of formulation shown in Table 1, in Example 1 the same, and a sintering material 59,500 parts shown in Table 1 in a drum mixer, rotational speed 24Min ^- Pre-stirred at ¹ for 1 minute. Then, while stirring at the same rotation speed, 5250 parts of the polymer aqueous solution (3) was sprayed onto the sintering raw material for about 1.5 minutes using a sprayer. After spraying, granulation operation was performed by further stirring for 3 minutes at the same rotation speed (granulation treatment step).
By measuring the water content of the obtained pseudo particles and classifying the pseudo particles using a sieve, the average particle size and the GI index of the pseudo particles having a particle size after granulation of 0.25 mm or less. I asked. The results are shown in Table 2 together with the amount of the above-mentioned copolymer added to the total amount of the raw materials for iron making.

[0067]

[Table 2]

As is clear from the results shown in Table 2, it was found that by using the iron-making raw material granulation treatment method according to the present invention, the average particle size of the pseudo particles and the GI index can be greatly increased. . From these results, it can be seen that the granulation treatment method of the iron-making raw material according to the present invention exerts an excellent effect in pseudo-granulating the iron-making raw material, and the granulation treatment method of the iron-making raw material according to the present invention. It can be seen that the production rate of the sintered ore obtained by sintering the pseudo particles can be improved by using.

[0069]

INDUSTRIAL APPLICABILITY As described above, the method of granulating a raw material for iron making according to the present invention is such that a part of the raw material for iron making is part of the total added water used for the granulating treatment for iron making. After the granulation treatment using the granulation agent, the obtained granulation product, the remaining iron-making raw material, the high-molecular compound and iron-making containing the remaining water of the total added water used for the granulation treatment This is a method of performing a granulation treatment by mixing with a granulation treatment agent for use.

Further, the method for granulating the raw material for iron making according to the present invention is a method in which the polymer compound is obtained by polymerizing or copolymerizing an acid group-containing monomer as described above.

This makes it possible to provide a granulation treatment method suitable for granulating (pseudo-granulating) a raw material for iron making (sintering raw material) containing fine iron ore to obtain a sintered ore. Has the effect. According to the above granulation treatment method,
When granulating (pseudo-granulating) a raw material for iron making (sintering raw material) containing fine iron ore, it has an excellent effect of adhering fine powder particles around the core particles and improves the production efficiency of the sintering machine. be able to.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuyuki Shinagawa             1-1 Tobata-cho, Tobata-ku, Kitakyushu, Fukuoka             Within Honetsu Steel Co., Ltd. (72) Inventor Katsuyuki Kono             5-8 Nishiomitabicho, Suita City, Osaka Prefecture             Within Nippon Shokubai (72) Inventor Keiichi Nakamoto             5-8 Nishiomitabicho, Suita City, Osaka Prefecture             Within Nippon Shokubai F-term (reference) 4K001 AA10 CA39

Claims (2)

[Claims] 1. A method for granulating an iron-making raw material containing fine iron ore, wherein a part of the iron-making raw material is part of the total added water used for the granulating treatment. After the granulation process using as an agent, the obtained granulated product, the remaining iron-making raw material, the high-molecular compound and the iron-containing granulation product containing the remaining water of the total added water used for the granulation process. A method for granulating a raw material for iron making, which comprises mixing the granulating agent with a granulating agent. 2. A method for granulating a raw material for iron making, wherein the polymer compound is obtained by polymerizing or copolymerizing an acid group-containing monomer.