JP5066352B2 - Granulating agent for iron making - Google Patents

Description

  The present invention relates to a granulating agent for iron making. More specifically, the present invention relates to a granulation treatment agent used when granulating a sintered raw material, a pellet raw material, or the like in the manufacture of a raw material for iron making such as a sintered ore or a pellet.

  The iron making process is generally performed by charging a raw material for iron making mainly composed of iron ore into a blast furnace. Iron ores include massive iron ores and fine iron ores. About 60% of the iron ore produced in the world is fine iron ore with a particle size of about 5 mm or less. If such a powdered iron ore is charged into an iron blast furnace as it is, it causes poor ventilation, non-uniformity, an increase in the amount of gas ash generated, and adversely affects blast furnace operation. Therefore, a sintered ore obtained by agglomerating fine iron ore is preferably used as a raw material for iron making in the iron making process.

  In a typical manufacturing process of sintered ore, a sintering machine is filled with sintering raw materials containing fine iron ore, auxiliary materials, fuel, etc., a sintering bed is formed, and the surface layer is ignited for sintering. . In a sintering machine, a downward suction type is usually employed. In the lower suction type sintering machine, air necessary for sintering is circulated by suction from the lower side of the sintering raw material, and fuel is burned from the upper side to the lower side of the sintering raw material, The sintering raw material is sintered. For this reason, if the sintered raw material contains a large amount of fine powder, the air permeability decreases due to clogging and the like, the combustion rate of coke as a fuel becomes slow, and the productivity of the sintered ore decreases.

  In order to improve the air permeability in a sintering machine when sintering a sintering raw material, the sintering raw material is granulated into pseudo particles. For example, granulation is performed by mixing powdered iron ore as a raw material for sintering, auxiliary raw materials, fuel, and the like, adding a small amount of water, and stirring with a granulator. The pseudo particles generally mean particles in which fine particles having a particle size of 0.5 mm or less are attached to core particles having a particle size of 1 to 3 mm. By performing granulation, for example, the pseudo-particle formation property in which fine particles adhere to the periphery of the core particles is improved, or the obtained pseudo particles are less likely to collapse during sintering. By granulating the sintered raw material into pseudo particles, the air permeability in the sintered raw material packed layer (sintered bed) on the sintering machine is improved, and the productivity of the sintered ore is improved.

  In granulation of a sintering raw material, granulation using only water has a poor effect of improving the pseudo-particle property, and the amount of fine powder contained in the sintering raw material cannot be sufficiently reduced. Therefore, a method of adding a granulating additive having an action as a binder to the sintered raw material has been proposed in order to improve pseudo-particle formation. Examples of the granulating additive include bentonite, lignin sulfite (pulp waste liquid), starch, sugar, molasses, water glass, cement, gelatin, and corn starch. At present, quicklime is widely used as a granulating additive. The quicklime can promote the formation of pseudo particles and can prevent the pseudo particles from collapsing during sintering, thereby improving the air permeability in the sintering bed.

  However, binders such as molasses are generally relatively expensive. In addition, quicklime is easy to absorb moisture and generates heat during moisture absorption, so it is difficult to handle. Furthermore, since quick lime cannot obtain a sufficient effect unless the usage amount is increased, the cost increases.

  In the granulation of a sintering raw material, a technique using a granulating agent for iron making obtained by copolymerizing a monomer component containing a monomer having a carboxyl group and / or a salt thereof has been reported (Patent Literature). 1-5). However, in recent years, with the depletion of excellent agglomerates, the deterioration of powdered iron ore is severe, and the granulation properties of the sintered raw material are worse than before. It may be difficult to sufficiently reduce the amount of fine powder contained in the raw material, and air permeability may be reduced due to clogging of the sintering machine, and the productivity of sintered ore may be reduced. .

On the other hand, in the manufacture of pellets as a raw material for iron making, after mixing raw iron ore, dust, carbonaceous materials, etc., granulation is performed while adjusting moisture with a granulator such as a pelletizer. A pellet generally refers to a particle having particles of 1.0 mm or less solidified into a spherical shape of 6.0 to 50 mm. Under the present circumstances, the effect | action calculated | required by granulation is that the intensity | strength in the state of the raw pellet before drying is high, it is destroyed during a drying process or a transport process, and is not pulverized. In order to improve the strength of the pellets, there is a method for producing pellets by adding 1% by weight or more of bentonite as a granulating additive to a finely powdered raw material and kneading and performing a granulating operation while spraying an appropriate amount of water. . In addition, the pellet as a raw material for iron manufacture referred to in the present invention is a blast furnace raw material, a sintered raw material, a converter raw material, or the like.
Japanese Patent No. 3792583 JP 2004-76126 A JP 2004-76131 A JP 2004-76132 A JP 2004-76133 A

  An object of the present invention is to sufficiently reduce the amount of fine powder contained in a sintered raw material or pellet raw material when granulating the sintered raw material or pellet raw material in the production of raw materials for iron making such as sintered ore and pellets. Providing a granulating agent for iron making that can improve the air permeability of a sintering machine, and thus improve the productivity of raw materials for iron making such as sintered ore and pellets There is to do.

  As a result of intensive studies to solve the above problems, the inventors of the present invention are a granulating agent for iron making containing a (meth) acrylic acid polymer, and the (meth) acrylic acid polymer is constituted. The ratio of the total amount of (meth) acrylic acid and / or salt thereof in all monomers to be within the specified range, and a sulfonic acid group is introduced at the terminal of the (meth) acrylic acid polymer It has been found that the above-mentioned problems can be solved by using what has been made. Furthermore, as an index indicating that a sulfonic acid group has been introduced at the end of the (meth) acrylic acid polymer, a sulfur element introduction amount S defined by a specific formula is adopted, and the sulfur element introduction amount S is It was found that a sulfonic acid group was introduced at the end of the (meth) acrylic acid polymer when it was within a specific range. Further, it is a granulating agent for iron making containing a (meth) acrylic acid polymer, and the (meth) acrylic acid polymer is (meth) acrylic acid and / or a salt thereof in the presence of sulfite. It has been found that the above-mentioned problems can be solved if the polymer is obtained by polymerizing a monomer containing. The present invention has been completed in this way.

The granulating agent for iron making of the present invention is
A granulating agent for iron making containing a (meth) acrylic acid polymer,
The ratio of the total amount of (meth) acrylic acid and / or a salt thereof in all monomers for constituting the (meth) acrylic acid polymer is 80 to 100 mol%,
The sulfur element introduction amount S defined by the formula (1) is 25-50.
S = [(S amount contained in (meth) acrylic acid polymer) / (total S amount in the granulating agent for iron making)] × 100 (1)

Another granulating agent for iron making according to the present invention is:
A granulating agent for iron making containing a (meth) acrylic acid polymer,
The (meth) acrylic acid polymer is a polymer obtained by polymerizing a monomer containing (meth) acrylic acid and / or a salt thereof in the presence of a sulfite.

  In a preferred embodiment, the sulfite is sodium bisulfite.

  According to the present invention, in the production of raw materials for iron making such as sintered ore and pellets, the amount of fine powder contained in the sintered raw materials and pellet raw materials is sufficiently reduced when granulating the sintered raw materials and pellet raw materials. Providing a granulating agent for iron making that can improve the air permeability of a sintering machine, and thus improve the productivity of raw materials for iron making such as sintered ore and pellets can do.

  The effect as described above is a granulation treatment agent for iron making containing a (meth) acrylic acid polymer, and the (meth) acrylic acid based polymer in all monomers for constituting the (meth) acrylic acid polymer. ) The ratio of the total amount of acrylic acid and / or salt thereof is within a specific range, and can be expressed by using a sulfonic acid group introduced at the terminal of the (meth) acrylic acid polymer. . The introduction of a sulfonic acid group at the terminal of the (meth) acrylic acid polymer can be confirmed by the sulfur element introduction amount S defined by a specific formula being within a specific range.

  The effect as described above is a granulating agent for iron making containing a (meth) acrylic acid polymer, and the (meth) acrylic acid polymer is (meth) acrylic acid in the presence of sulfite. And / or a polymer obtained by polymerizing a monomer containing a salt thereof can be expressed.

  The granulating agent for iron making of the present invention contains a (meth) acrylic acid polymer. In the present invention, the “(meth) acrylic acid polymer” refers to a polymer obtained by polymerizing a monomer containing (meth) acrylic acid and / or a salt thereof. In the present invention, “(meth) acrylic acid” refers to acrylic acid and / or methacrylic acid. As the “salt”, any appropriate salt can be adopted as long as it is a neutralized salt of (meth) acrylic acid. For example, alkali metal salts such as potassium salts and sodium salts; alkaline earth metal salts such as calcium salts; nitrogen-containing salts such as ammonium salts and primary to quaternary amine salts; The amount ratio of the (meth) acrylic acid-based polymer contained in the granulation treatment agent for iron making of the present invention is any appropriate amount proportion depending on the performance desired for the granulation treatment agent for iron making of the present invention. Can be adopted. Preferably, when the granulating agent for iron making of the present invention contains water, it is preferably 0.1 to 300 parts by weight, more preferably 5 to 250 parts by weight with respect to 100 parts by weight of the water. It is.

  The (meth) acrylic acid polymer preferably has a ratio of the total amount of (meth) acrylic acid and / or a salt thereof in all monomers for constituting the (meth) acrylic acid polymer. 80 to 100 mol%, more preferably 85 to 100 mol%, still more preferably 90 to 100 mol%, particularly preferably 95 to 100 mol%, most preferably 98 to 100 mol%. is there. By making the ratio of the total amount of (meth) acrylic acid and / or a salt thereof in all monomers for constituting the (meth) acrylic acid polymer within the above range, other techniques of the present invention When combined with the specific characteristics, the granulation treatment agent for iron making containing the (meth) acrylic acid polymer is a fine powder contained in the sintering raw material or pellet raw material when granulating the sintering raw material or pellet raw material. Therefore, the air permeability of a sintering machine or the like can be improved. Therefore, the productivity of iron-making raw materials such as sintered ores and pellets can be improved.

  Monomers other than (meth) acrylic acid or a salt thereof in all monomers for constituting the (meth) acrylic acid polymer (hereinafter sometimes referred to as “other monomers”) Any suitable monomer may be employed as long as the effects of the present invention are not impaired.

Other monomers include, for example,
Carboxyl group-containing monomers such as maleic acid, maleic anhydride, itaconic acid, fumaric acid, crotonic acid, acrylamide glycolic acid and salts thereof;
Sulfo group-containing monomers such as vinyl sulfonic acid, styrene sulfonic acid, sulfoethyl (meth) acrylate, isoprene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and salts thereof;
2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxypropyl acid phosphate, 2- (meth) acryloyloxy-3-chloropropyl acid phosphate, 2- (meth) acryloyloxyethyl phenyl phosphate and their Acidic phosphate group-containing monomers such as salts;
Carboxylic acid monomers such as vinylphenol and salts thereof;
Polyalkylene glycol (meth) acrylates such as polyethylene glycol mono (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, butoxypolyethylene mono (meth) acrylate;
Polyalkylene glycol monoalkenyl ether monomer obtained by adding ethylene oxide to 3-methyl-3-buten-1-ol, polyethylene glycol monoethenyl ether monomer obtained by adding ethylene oxide to allyl alcohol, anhydrous maleic A polyalkylene glycol chain-containing monomer such as maleic acid polyethylene glycol half ester obtained by adding polyethylene glycol to acid;
Methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylic acid (N, N-dimethylaminoethyl), (meth) acrylic acid (N, N-diethylaminoethyl) , (Meth) acrylic acid alkyl esters having 1 to 18 carbon atoms, such as aminoethyl (meth) acrylate;
(Meth) acrylamide and derivatives thereof such as (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide;
Vinyl acetate;
(Meth) acrylonitrile; base-containing monomers such as N-vinyl-2-pyrrolidone, vinylpyridine, vinylimidazole;
(Meth) acrylamide monomers having crosslinkability, such as N-methylol (meth) acrylamide and N-butoxymethyl (meth) acrylamide;
Hydrolyzable groups such as vinyltrimethoxysilane, vinyltriethoxysilane, γ- (meth) acryloylpropyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, allyltriethoxysilane are directly connected to the silicon atom. Silane monomer;
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;
Aziridine group-containing monomers such as 2-aziridinylethyl (meth) acrylate and (meth) acryloylaziridine;
Halogen group-containing monomers such as vinyl fluoride, vinylidene fluoride, vinyl chloride, vinylidene chloride;
(Meth) 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 esterified product;
Polyfunctional (meth) acrylamide having a plurality of unsaturated groups in the molecule, such as methylenebis (meth) acrylamide;
Polyfunctional allyl compounds having a plurality of unsaturated groups in the molecule, such as diallyl phthalate, diallyl maleate, diallyl fumarate;
Allyl (meth) acrylate;
Divinylbenzene;
Etc. Only one type of other monomer may be used, or two or more types may be used in combination.

  The (meth) acrylic acid polymer contained in the granulating agent for iron making according to the present invention includes those having a sulfonic acid group introduced at the end thereof. By incorporating a sulfonic acid group at the terminal of the (meth) acrylic acid polymer, in combination with the other technical features of the present invention, the steel for containing iron-containing polymer containing the (meth) acrylic acid polymer The granulation treatment agent can sufficiently reduce the amount of fine powder contained in the sintering raw material and pellet raw material when granulating the sintering raw material and pellet raw material, and improves the air permeability of the sintering machine and the like. Therefore, the productivity of ironmaking raw materials such as sintered ore and pellets can be improved.

The introduction of a sulfonic acid group at the terminal of the (meth) acrylic acid polymer so that the object of the present invention can be achieved is that the sulfur element introduction amount S defined by the formula (1) is 25-50. It can be confirmed by being within the range. The upper limit value of the sulfur element introduction amount S defined by the formula (1) is a value calculated when a sulfonic acid group is introduced at substantially all terminals of the (meth) acrylic acid polymer. Theoretically 50. When the sulfur element introduction amount S is less than 25, a sulfonic acid group is not introduced at the terminal of the (meth) acrylic acid polymer to the extent that the effects of the present invention can be sufficiently exhibited. The amount of fine powder remaining after the grain increases.
S = [(S amount contained in (meth) acrylic acid polymer) / (total S amount in the granulating agent for iron making)] × 100 (1)

  In order to further exert the effect of the present invention, particularly the effect of reducing the amount of fine powder remaining after granulation, the sulfur element introduction amount S is preferably in the range of 30 to 50, more preferably. Is in the range of 35-50.

  The weight average molecular weight (Mw) of the (meth) acrylic acid polymer is preferably 500 to 100,000, more preferably 500 to 50,000, still more preferably 1,000 to 20,000, and particularly preferably 1500 to 10,000. The number average molecular weight (Mn) of the (meth) acrylic acid polymer is preferably 500 to 50000, more preferably 500 to 30000, still more preferably 800 to 10000, and particularly preferably 1000 to 5000. If the weight average molecular weight (Mw) or number average molecular weight (Mn) of the (meth) acrylic acid polymer is within the above range, the effects of the present invention can be further exhibited.

  The (meth) acrylic acid polymer can be produced by any appropriate method. Preferably, it is produced by polymerizing a monomer containing (meth) acrylic acid and / or a salt thereof in the presence of sulfite. At this time, the sulfite is introduced into the polymer terminal as a chain transfer agent or a polymerization initiator.

  As a monomer containing the said (meth) acrylic acid and / or its salt, all the monomers for comprising the (meth) acrylic acid type polymer mentioned above correspond.

  When manufacturing the said (meth) acrylic-acid type polymer, it is preferable to use a sulfite. This is because a sulfonic acid group is introduced at the end of the (meth) acrylic acid polymer so that the object of the present invention can be achieved. Arbitrary appropriate sulfites can be employ | adopted as said sulfite. Examples thereof include sodium bisulfite, potassium bisulfite, and ammonium bisulfite. In order to further exhibit the effects of the present invention, sodium bisulfite is preferable. Moreover, only one type of sulfite may be used, or two or more types may be used in combination. The sulfite can preferably act as a chain transfer agent.

  You may use together the said sulfite and 1 or more types of chain transfer agents (When the said sulfite is a chain transfer agent, other chain transfer agents). Any appropriate chain transfer agent can be adopted as such a chain transfer agent. For example, mercapto group-containing compounds such as mercaptoethanol, mercaptopropionic acid, t-dodecyl mercaptan; hydrogen peroxide; sodium hypophosphite; carbon tetrachloride; isopropyl alcohol; toluene; .

  Any appropriate amount can be adopted as the amount of the sulfite used. Preferably, the amount is preferably 1 to 50 g, more preferably 1 to 20 g, and still more preferably 2 to 20 g with respect to 1 mol of the monomer containing the (meth) acrylic acid and / or salt thereof. Particularly preferred is 3 to 10 g. By setting the amount of sulfite used within the above range, a sulfonic acid group can be introduced at the end of the (meth) acrylic acid polymer so that the object of the present invention can be achieved.

  The sulfite may be preferably dissolved in water and added in the form of an aqueous solution. The concentration when used as a sulfite aqueous solution is preferably 10 to 50% by weight, more preferably 20 to 40% by weight, and still more preferably 30 to 40% by weight. Here, when the concentration of the aqueous sulfite solution is less than 10% by weight, the concentration of the product may decrease. When the concentration of the sulfite aqueous solution exceeds 40% by weight, sulfite may be precipitated.

  Any appropriate polymerization method can be adopted as the polymerization. For example, a polymerization method for producing a (meth) acrylic acid polymer described in JP-B-60-24806, and a (meth) acrylic acid polymer described in JP-A-11-315115. And a polymerization method for producing a (meth) acrylic acid polymer described in JP-A-2004-75971 can be preferably employed.

  Examples of the polymerization method include an oil-in-water emulsion polymerization method, a water-in-oil emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method, a precipitation polymerization method, a solution polymerization method, an aqueous solution polymerization method, and a bulk polymerization method. . Among these, the aqueous solution polymerization method is preferable. This is because the polymerization cost (production cost) can be reduced and the safety is high. The aqueous solution used in the aqueous solution polymerization method may contain a solvent, a polymerization initiator, and other additives.

  In the above polymerization, a polymerization initiator is preferably used. As the polymerization initiator, any appropriate polymerization initiator can be adopted as long as it is a compound that decomposes by heat or a redox reaction to generate radical molecules. In the case of employing an aqueous solution polymerization method, a polymerization initiator having water solubility is preferable. Only one type of polymerization initiator may be used, or two or more types may be used in combination. What is necessary is just to set the usage-amount of a polymerization initiator suitably according to a monomer composition, polymerization conditions, etc.

  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 Water-soluble azo compounds such as -cyanopentanoic 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 sulfurous acid A redox polymerization initiator comprising a combination of sodium hydride and the like; a combination of sulfite and air or oxygen; and the like. Among these, persulfate is preferable in order to efficiently produce the (meth) acrylic acid polymer in the present invention.

  The polymerization initiator is preferably dissolved in water and added in the form of an aqueous solution. The concentration when used as a polymerization initiator aqueous solution is preferably 1 to 35% by weight, more preferably 5 to 35% by weight, and still more preferably 10 to 30% by weight. Here, when the concentration of the polymerization initiator aqueous solution is less than 1% by weight, the concentration of the product may be lowered. When the concentration of the polymerization initiator aqueous solution exceeds 35% by weight, the polymerization initiator may be precipitated.

  The polymerization reaction temperature can be set to any appropriate temperature depending on the composition of the monomer, the type of the polymerization initiator, and the like. Preferably it is 0-100 degreeC, More preferably, it is 10-100 degreeC, More preferably, it is 15-100 degreeC, Most preferably, it is 20-99 degreeC, Most preferably, it is 25-99 degreeC. The polymerization temperature need not always be kept substantially constant during the polymerization.

  When the aqueous solution polymerization method is employed as the polymerization method, the solvent used is preferably an aqueous solvent such as water, alcohol, glycol, glycerin, polyethylene glycol, and particularly preferably water. These may be used alone or in combination of two or more. The solvent used may be partially or wholly charged into the reaction vessel at the beginning of polymerization. In addition, in order to improve the solubility of the monomer in the solvent, any appropriate organic solvent may be appropriately added as long as it does not adversely affect the polymerization of each monomer.

  Examples of the organic solvent include lower alcohols such as methanol and ethanol; amides such as dimethylformaldehyde; ethers such as diethyl ether and dioxane; These may use only 1 type and may use 2 or more types together.

  In the polymerization, it is preferable to use the sulfite and the persulfate in combination. In this case, the addition ratio is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, and further preferably 1 to 3 parts by weight with respect to 1 part by weight of the persulfate. It is. If the sulfite is less than 0.1 part by weight per part by weight of the persulfate, the effect of the sulfite may not be sufficiently exhibited. For this reason, there is a possibility that a sulfonic acid group sufficient to satisfy the sulfur element introduction amount S value defined above may not be introduced into the terminal of the (meth) acrylic acid polymer. If the sulfite exceeds 10 parts by weight with respect to 1 part by weight of the persulfate, the sulfite is excessively supplied in the polymerization reaction system in a state in which the effect of the sulfite is not expressed as much as the addition ratio (consumed wastefully). ) For this reason, excess sulfite is decomposed in the polymerization reaction system, and a large amount of sulfurous acid gas is generated.

  In the polymerization, any appropriate pressure can be adopted as the pressure in the reaction system. For example, the pressure may be any of normal pressure (atmospheric pressure), reduced pressure, and increased pressure. Preferably it is under a normal pressure or pressurization, More preferably, it is under a normal pressure. When polymerization is carried out under normal pressure, there is no need to provide a pressurizing device or a decompressing device, and there is no need to use a pressure-resistant reaction vessel or piping. For this reason, the manufacturing cost can be reduced.

  In the polymerization, the atmosphere in the reaction system may be an air atmosphere or an inert atmosphere. As a method for polymerizing in an inert atmosphere, specifically, for example, the inside of the system is replaced with an inert gas such as nitrogen before the polymerization is started. Thereby, atmospheric gas (for example, oxygen gas etc.) in the reaction system dissolves in the liquid phase and acts as a polymerization inhibitor. As a result, the polymerization initiator is prevented from being deactivated and reduced.

  The polymerization is preferably performed under acidic conditions. By carrying out under acidic conditions, an increase in the viscosity of the polymerization reaction system can be suppressed, and a (meth) acrylic acid polymer can be produced satisfactorily. Furthermore, since the polymerization reaction can proceed under high concentration conditions, the production efficiency can be significantly increased. By carrying out the polymerization reaction under such acidic conditions, it is possible to carry out the polymerization at a high concentration and in one stage, and the concentration step can be omitted. Therefore, the productivity of the (meth) acrylic acid polymer is greatly improved, and an increase in production cost can be suppressed. As said acidic conditions, pH at 25 degreeC of the reaction solution in superposition | polymerization becomes like this. Preferably it is 1-6, More preferably, it is 1-5, More preferably, it is 1-4.

  In order to adjust the pH, a pH adjusting agent may be used. Examples of pH adjusters include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide; ammonia, monoethanolamine, and triethanol. And salts of organic amines such as amines. These may be used alone or in combination of two or more. Among these, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are preferable, and sodium hydroxide is particularly preferable.

  The degree of neutralization during the polymerization is preferably 0 to 40 mol%, more preferably 1 to 40 mol%, still more preferably 1 to 30 mol%, and particularly preferably 1 to 25 mol%. . If the degree of neutralization during the polymerization is within the above range, the polymerization or copolymerization can be best performed. In addition, it is possible to suppress an increase in the viscosity of the polymerization reaction system. Furthermore, since the polymerization reaction can proceed under high concentration conditions, the production efficiency can be significantly increased.

  As a neutralization method for adjusting to the neutralization degree, a neutralization method using any appropriate neutralizing agent can be adopted. Examples of the neutralizing agent include alkaline monomers such as sodium (meth) acrylate and alkali metal hydroxides such as sodium hydroxide. Only one type of neutralizing agent may be used, or two or more types may be used in combination. The addition form of the neutralizing agent may be a solid or an aqueous solution dissolved in an appropriate solvent, preferably water. When the aqueous solution is used, the concentration of the aqueous solution is 10 to 60% by weight, preferably 20 to 55% by weight, more preferably 30 to 50% by weight.

  In the above polymerization, an aqueous monomer solution, an aqueous solution of sulfite, an aqueous solution of a chain transfer agent, an aqueous solution of a polymerization initiator, and the like are placed in a reaction vessel charged with a solvent (preferably water) from a separate dropping nozzle. It is preferable to carry out by dripping. When the polymerization is carried out batchwise, the total dropping time is preferably 180 to 600 minutes, more preferably 210 to 480 minutes, and further preferably 240 to 420 minutes. When the total dropping time is less than 180 minutes, for example, the effect of the chain transfer agent may be difficult to be exhibited, and the sulfone is added to the end of the (meth) acrylic acid polymer to the extent that the effects of the present invention can be sufficiently exerted. There is a risk that acid groups will not be introduced. When the total dropping time exceeds 600 minutes, the productivity of the (meth) acrylic acid polymer may be lowered. The total dropping time here means the time from the start of dropping the first dropping component (not necessarily one component) to the completion of dropping the last dropping component (not necessarily one component).

  In the above polymerization, ripening may be performed for a predetermined time after all of the dropping components have been dropped. The aging time is preferably 1 to 120 minutes, more preferably 5 to 60 minutes, and still more preferably 10 to 50 minutes. When the aging time is less than 1 minute, the monomer component may remain due to insufficient aging, which may cause impurities due to the residual monomer, resulting in performance degradation. On the other hand, when the aging time exceeds 120 minutes, the polymer solution may be colored.

  The temperature during aging may be maintained at a constant temperature (preferably the temperature at the end of dropping), or the temperature may be changed over time during aging.

  The solid content concentration in the reaction solution when the polymerization is completed (that is, the polymerization solid content concentration of the monomer) is preferably 35 to 80% by weight, more preferably 40 to 70% by weight, and still more preferably 40 to 70% by weight. 60% by weight. If the solid content concentration at the end of the polymerization reaction is 35% by weight or more, the polymerization can be carried out at a high concentration and in one stage, and a (meth) acrylic acid polymer can be obtained efficiently. For example, the concentration step can be omitted and the production efficiency can be greatly increased. As a result, the productivity of the (meth) acrylic acid polymer can be greatly improved, and the increase in production cost can be suppressed. It becomes. If the solid content concentration at the end of the polymerization reaction is less than 35% by weight, the productivity of the (meth) acrylic acid polymer may not be significantly improved. For example, it may be difficult to omit the concentration step.

  The polymerization is performed under the acidic conditions. Therefore, the degree of neutralization (final neutralization degree) of the (meth) acrylic acid polymer to be obtained is determined by appropriately adding an appropriate alkaline component as a post-treatment as needed after the polymerization is completed. Can be set to a range. The degree of final neutralization varies depending on the intended use and can be set in a very wide range of 1 to 100 mol%.

  Examples of the alkali component include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide; ammonia, monoethanolamine, diethanolamine, Organic amines such as triethanolamine; and the like. Only one type of alkali component may be used, or two or more types may be used in combination.

  The polymerization may be performed in a batch manner or a continuous manner.

  The granulating agent for iron making according to the present invention only needs to contain a (meth) acrylic acid polymer as described above, and is in a solution state (preferably an aqueous solution state) obtained by the above-described production method. ) Acrylic polymer may be used as a granulating agent for iron making. Furthermore, any suitable additive or solvent may be added. Examples of the additive include granulating additives such as quick lime; anti-collapse agents such as calcium carbonate, fly ash, bentonite, kaolin clay, dolomite, silica fume, and anhydrous gypsum; An example of the solvent is water. In particular, by diluting with water, the viscosity of the granulating agent for iron making can be suppressed and the dispersion stability can be maintained.

  In the production of raw materials for iron making such as sintered ore and pellets, if the raw material for granulation for iron making of the present invention is used to granulate the raw material for sintering, the raw material for pellets is used for granulation. The amount of fine powder contained in the steel can be sufficiently reduced, the air permeability in a sintering machine or the like can be improved, and therefore the productivity of raw materials for iron making such as sintered ores and pellets can be improved. .

  The ratio of the (meth) acrylic acid polymer in the granulation treatment agent for iron making relative to 100 parts by weight of the sintering raw material when granulating the sintering raw material using the granulation treatment agent for iron making of the present invention is preferably Is 0.001 to 5 parts by weight, more preferably 0.001 to 2 parts by weight. The effect of this invention can fully be expressed by making the ratio of the (meth) acrylic-acid type polymer in the granulation processing agent for iron manufacture with respect to 100 weight part of sintering raw materials in the said range.

  The ratio of the (meth) acrylic acid-based polymer in the granulating agent for iron making to 100 parts by weight of the pellet raw material when the pellet raw material is granulated using the granulating agent for iron making of the present invention is preferably 0. 0.005 to 5 parts by weight, more preferably 0.01 to 1 part by weight. The effect of this invention can fully be expressed by making the ratio of the (meth) acrylic acid-type polymer in the granulation processing agent for iron manufacture with respect to 100 weight part of pellet raw materials in the said range.

  The ratio of the granulation treatment agent for iron making relative to 100 parts by weight of the sintering raw material when granulating the sintering raw material using the granulation treatment agent for iron making of the present invention is preferably 0.001 to 15 parts by weight. More preferably, it is 0.005 to 10 parts by weight. The effect of this invention can fully be expressed by making the ratio of the granulation processing agent for iron manufacture with respect to 100 weight part of sintering raw materials into the said range.

  The ratio of the granulating agent for iron making to 100 parts by weight of the pellet raw material when the pellet raw material is granulated using the granulating agent for iron making of the present invention is preferably 0.01 to 50 parts by weight, more Preferably it is 0.05-10 weight part. The effect of this invention can fully be expressed by making the ratio of the (meth) acrylic acid-type polymer in the granulation processing agent for iron manufacture with respect to 100 weight part of pellet raw materials in the said range.

  Arbitrary appropriate addition methods may be employ | adopted for the addition method of the granulation processing agent for iron manufacture of this invention. Preferably, a method of mixing the granulating agent for iron making into an aqueous solution and mixing it with the added water of the granulator, or a method of spraying on the iron making raw material being stirred may be employed. By adopting these methods, the granulating agent for iron making can be added easily and uniformly, and since it is pseudo-granulated without spots, fine powder can be further reduced.

  Depending on the particle size distribution, granulation properties, composition, etc. of each brand of ironmaking raw material, a part of the ironmaking raw material is mixed, kneaded and granulated, and then mixed with the remaining ironmaking raw material for granulation. Also in the processing method, the granulating agent for iron making of the present invention can be used. For example, when a part of the raw material for iron making shows difficult granulation property, it can be made into pseudo particles by adding a granulating agent for iron making to this hardly granulated raw material for iron making. Therefore, the raw material for iron making can be efficiently granulated with a small amount of the granulating agent for iron making.

  In the present invention, for example, a part of the raw material for iron making, such as a difficult-to-granulate sintered raw material, is selectively mixed and / or granulated in advance, and then added to the remaining sintered raw material for granulation. A processing method may be used. At this time, the granulating agent for iron making according to the present invention may be added before or during the selective mixing / granulating process in advance, or added before or during the granulating treatment with the remaining sintered raw materials. May be.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited by these Examples. In the examples, “parts” and “%” are based on weight.

<Measurement of S content and total S content contained in (meth) acrylic acid polymer>
The amount of S before and after the dialysis treatment of the (meth) acrylic acid polymer obtained by the polymerization was quantified by inductively coupled plasma (ICP) emission spectrometry. Here, the amount of S of the (meth) acrylic acid polymer before dialysis was defined as “total amount of S”. Further, the S amount of the (meth) acrylic acid polymer after dialysis treatment was defined as “the S amount contained in the (meth) acrylic acid polymer”. The dialysis method here will be described below.

≪Dialysis method≫
(1) A suitable amount of water was added to the (meth) acrylic acid polymer obtained by polymerization to prepare a (meth) acrylic acid polymer aqueous solution having a solid content concentration of 30% by weight. 20 g of this was put into a dialysis membrane 40 cm (length) and sealed. For the dialysis membrane, Spectra / Por Membrane MWCO: 1000 fractional molecular weight 1000 (manufactured by SPECTRUM LABORATORIES INC) was used. In the present invention, any material having a fractional molecular weight comparable to that of the dialysis membrane may be used.
(2) This was immersed in 2000 g of water in a 2 liter beaker and stirred with a stirrer.
(3) After 6 hours, the dialysis membrane was taken out of the beaker and the outside of the dialysis membrane was thoroughly washed with water, and then the contents of the dialysis membrane were taken out.
(4) What concentrated this with the evaporator was used as the (meth) acrylic-acid-type polymer sample after a dialysis process.
(5) In addition, as the (meth) acrylic acid polymer sample before dialysis treatment, the (meth) acrylic acid polymer obtained by polymerization in the above (1) is the same as the above (4). What was concentrated with the evaporator was used.

<Measurement of weight average molecular weight (Mw) and number average molecular weight (Mn)>
The weight average molecular weight (Mw) and number average molecular weight (Mn) of the (meth) acrylic acid polymer were both measured by GPC (gel permeation chromatography). In addition, the (meth) acrylic acid type polymer obtained by the polymerization of the above << dialysis method >> (1) was used for the sample here as it was. The measurement conditions and apparatus are as follows.
As a GPC column, G-3000PWXL (trade name) manufactured by Tosoh Corporation was used.
As a mobile phase, pure water was added to 34.5 g of disodium hydrogen phosphate 12 hydrate and 46.2 g of sodium dihydrogen phosphate dihydrate (both of which are reagent-grade) to make a total amount of 5000 g, and then 0. An aqueous solution filtered through a 45 μm membrane filter was used.
As the detector, Model 481 manufactured by Waters was used, and the detection wavelength was UV: 214 nm.
As a pump, L-7110 (trade name) manufactured by Hitachi, Ltd. was used.
The mobile phase flow rate was 0.5 ml / min and the temperature was 35 ° C. The calibration curve was prepared using a sodium polyacrylate standard sample manufactured by Sowa Kagaku.

<Measurement of average particle size>
The average particle diameter of the ironmaking raw material was calculated as follows.
Using a sieve with openings of 9.5 mm, 4.75 mm, 2.8 mm, 1.0 mm, 0.5 mm, and 0.25 mm, sieving is performed to obtain a particle size of 9.5 to 4.75 mm and 4.75 to 2 Calculate the weight ratio (% by weight) of .8 mm particle size, 2.8 to 1.0 mm particle size, 1.0 to 0.5 mm particle size, 0.5 to 0.25 mm particle size, and 0.25 mm or less particle size. did. Since a raw material of 9.5 mm or more was not used, it was excluded from the above calculation. The sieving was performed by shaking for 30 seconds using MIC-113-0-02 (manufactured by MARUIN & Co., LTD) as a sieve shaker.
The average particle size was calculated from the following formula.
Average particle diameter (mm) = (weight ratio of particle size of 9.5 to 4.75 mm × 7.125) + (weight ratio of particle size of 4.75 to 2.8 mm × 3.775) + (2.8− 1.0 mm weight ratio × 1.9) + (1.0-0.5 mm weight ratio × 0.75) + (0.5-0.25 mm weight ratio × 0.375) + (0.25 mm The following weight ratio x 0.125)

<Classification of granulated product>
Sieving was performed using sieves having a mesh opening of 9.5 mm, 4.75 mm, 2.8 mm, 1.0 mm, 0.5 mm, and 0.25 mm. The sieving was performed by shaking for 30 seconds using MIC-113-0-02 (manufactured by MARUIN & Co., LTD) as a sieve shaker.

[Example 1]
A 2.5-liter SUS separable flask equipped with a reflux condenser and a stirrer was charged with 156.5 g of pure water (initial charge), and heated to 90 ° C. with stirring.
Next, in a polymerization reaction system in a constant state at about 90 ° C. with stirring, 427.5 g (4.75 mol) of an 80% aqueous acrylic acid solution (hereinafter abbreviated as 80% AA) and an aqueous 37% sodium acrylate solution (hereinafter referred to as “80% AA”) , 37% SA) 63.5 g (0.25 mol), 15% sodium persulfate aqueous solution (hereinafter abbreviated as 15% NaPS) 66.7 g (monomer input to the monomer (here, monomer) The input amount refers to the total input amount of the monomer. The same shall apply hereinafter.) 2.0 g / mol.), 35% sodium bisulfite aqueous solution (hereinafter abbreviated as 35% SBS) 71 .4 g (5.0 g / mol when converted to monomer charge) was dropped from separate dropping nozzles. Each dropping time was 80% AA, 37% SA, 35% SBS for 300 minutes and 15% NaPS for 310 minutes. Further, during each dropping time, the dropping rate of each component was kept constant, and dropping was continuously performed.
After completion of the dropwise addition, the reaction solution was aged while maintaining at 90 ° C. for another 30 minutes to complete the polymerization. After completion of the polymerization, the reaction solution was allowed to cool, and 366.7 g (4.40 mol) of a 48% aqueous sodium hydroxide solution (hereinafter abbreviated as 48% NaOH) was gradually added dropwise to the reaction solution while stirring. It was summed up. Thus, an aqueous solution (hereinafter referred to as polymer (1)) containing sodium polyacrylate having a solid content concentration of 45% by weight and a final neutralization degree of 93 mol% was obtained. The polymerization recipe is summarized in Table 1.
Table 3 shows the results of measuring the molecular weight and S value of the obtained polymer (1).
1000 parts of a sintering raw material for iron making having an average particle diameter of 1.8 mm (iron ore 84%, limestone 13%, coke 3%) was previously conditioned to a moisture content of 5%. The raw material was put into a cylindrical container having an outer diameter of 550 mm, and pre-stirred for 1 minute at a rotational speed of 24 min ⁻¹ . Thereafter, 23 parts of a 1.3% aqueous solution of the polymer (1) was sprayed on the raw material over 1 minute using a spray bottle while stirring the raw material at the same rotational speed. Furthermore, the granulation process was performed by stirring for 3 minutes at the same rotational speed. The granulated product was dried in an oven at 80 ° C. for 1 hour and classified, and the amount of fine powder of 0.5 mm or less after granulation was examined. It can be judged that the smaller the amount of fine powder, the better the granulation. Table 3 shows the amount of fine powder of 0.5 mm or less after granulation.

[Examples 2 to 4]
Except having set it as the polymerization prescription shown in Table 1, it superposed | polymerized similarly to Example 1 and obtained polymer (2)-(4).
Table 3 shows the results of measuring the molecular weight and S value of the obtained polymers (2) to (4).
Table 3 shows the results of examining the amount of fine powder of 0.5 mm or less after granulation in the same manner as in Example 1.

Example 5
In Example 4, the same procedure as in Example 4 was conducted except that 80% AA was changed to 405.0 parts, and 80% AA 315.0 parts and 80% methacrylic acid aqueous solution (hereinafter abbreviated as 80% MAA) 107.5 parts were added. Polymerization was conducted in the same manner to obtain a polymer (5). The polymerization recipe is summarized in Table 1.
Table 3 shows the results of measuring the molecular weight and S value of the polymer (5) obtained.
Table 3 shows the results of examining the amount of fine powder of 0.5 mm or less after granulation in the same manner as in Example 1.

Example 6
In a 5-liter SUS separable flask equipped with a reflux condenser and a stirrer, 350 g of pure water was charged (initial charge), and the temperature was raised to the boiling point under stirring.
Next, under stirring, in a polymerization reaction system in a boiling point reflux state, 900 g (10 mol) of 80% AA, 266.7 g of 15% NaPS (4.0 g / mol when converted to monomer input amount), 228.6 g of 35% SBS (vs. In terms of monomer charge, 8.0 g / mol) and 83.3 g (1 mol) of 48% NaOH were added dropwise from separate dropping nozzles. The dropping time was 80% AA, 48% NaOH for 180 minutes, and 15% NaPS, 35% SBS for 190 minutes. During each dropping time, the dropping speed of each component was kept constant, and the dropping was continuously performed.
After completion of the dropwise addition, the reaction solution was kept at the boiling point for aging for another 30 minutes to complete the polymerization. After completion of the polymerization, the reaction solution was allowed to cool, and 666.7 g (8.0 mol) of 48% NaOH was gradually added dropwise to the reaction solution while stirring to neutralize it. In this way, an aqueous solution (hereinafter referred to as polymer (6)) containing sodium polyacrylate having a solid content concentration of 45 wt% and a final neutralization degree of 90 mol% was obtained. The polymerization recipe is summarized in Table 1.
Table 3 shows the results of measuring the molecular weight and S value of the polymer (6) obtained.
Table 3 shows the results of examining the amount of fine powder of 0.5 mm or less after granulation in the same manner as in Example 1.

Example 7
A 5-liter SUS separable flask equipped with a reflux condenser and a stirrer was charged with 150 g of pure water (initial charge) and heated to the boiling point under stirring.
Next, under stirring, in a polymerization reaction system in a boiling point reflux state, 900 g (10 mol) of 80% AA, 266.7 g of 15% NaPS (4.0 g / mol when converted to monomer input amount), 228.6 g of 35% SBS (vs. In terms of monomer charge, 8.0 g / mol) and 11.4 g of pure water were both dropped from separate dropping nozzles over 120 minutes. During each dropping time, the dropping speed of each component was kept constant, and the dropping was continuously performed.
After completion of the dropwise addition, the reaction solution was kept at the boiling point for aging for another 30 minutes to complete the polymerization. After the completion of the polymerization, the reaction solution was allowed to cool, and 750 g (9.0 mol) of 48% NaOH was gradually added dropwise to the reaction solution while stirring to neutralize it. Thus, an aqueous solution (hereinafter referred to as polymer (7)) containing sodium polyacrylate having a solid content concentration of 45% by weight and a final neutralization degree of 90 mol% was obtained. The polymerization recipe is summarized in Table 1.
Table 3 shows the results of measuring the molecular weight and S value of the polymer (7) obtained.
Table 3 shows the results of examining the amount of fine powder of 0.5 mm or less after granulation in the same manner as in Example 1.

[Comparative Example 1]
In a 5 liter SUS separable flask equipped with a reflux condenser and a stirrer, 666.5 g of pure water was charged (initial charge), and the temperature was raised to the boiling point with stirring.
Next, under stirring, 80% AA 1324.7 g (14.7 mol) and 15% NaPS 38.3 g (0.3 g / mol in terms of monomer charge) were separately added to the polymerization reaction system in a boiling point reflux state. It dripped from the dripping nozzle. Each dropping time was 80% AA for 120 minutes and 15% NaPS for 130 minutes.
After completion of the dropwise addition, the reaction solution was kept at the boiling point for aging for another 30 minutes to complete the polymerization. After completion of the polymerization, the reaction solution was allowed to cool. After the completion of the polymerization, the reaction solution was allowed to cool, and 1163.8 g (14.0 mol) of 48% NaOH was gradually added dropwise to the reaction solution while stirring to neutralize it. Thus, an aqueous solution containing sodium polyacrylate having a solid content concentration of 43% by weight and a final neutralization degree of 95 mol% (hereinafter referred to as comparative polymer (1)) was obtained. The polymerization recipe is summarized in Table 2.
Table 3 shows the results of measuring the molecular weight and S value of the obtained comparative polymer (1).
Table 3 shows the results of examining the amount of fine powder of 0.5 mm or less after granulation in the same manner as in Example 1.

[Comparative Example 2]
A 2.5-liter SUS separable flask equipped with a reflux condenser and a stirrer was charged with 635.3 g of pure water (initial charge), and heated to the boiling point with stirring.
Next, 762.5 g (3.0 mol) of 37% SA, 24.0 g of 15% NaPS (1.2 g / mol in terms of monomer input), and pure water 82 in a polymerization reaction system in a boiling point reflux state with stirring. .3 g was dropped from separate dropping nozzles. Each dropping time was 37% SA for 200 minutes, 15% NaPS, and pure water for 205 minutes.
After completion of the dropwise addition, the reaction solution was kept at the boiling point for aging for another 30 minutes to complete the polymerization. After completion of the polymerization, the reaction solution was allowed to cool. Thus, an aqueous solution containing sodium polyacrylate having a solid content concentration of 20% by weight and a final neutralization degree of 100 mol% (hereinafter referred to as comparative polymer (2)) was obtained. The polymerization recipe is summarized in Table 2.
Table 3 shows the results of measuring the molecular weight and S value of the obtained comparative polymer (2).
Table 3 shows the results of examining the amount of fine powder of 0.5 mm or less after granulation in the same manner as in Example 1.

Table 3 shows the amount of residual fine powder after granulation (5.7%) when granulated using the comparative polymer (1) and granulation using the comparative polymer (2). The amount of fine powder remaining after granulation (5.4%) is clearly larger than the amount of fine powder remaining after granulation when the polymers (1) to (7) are used for granulation. . In general, in the production of raw materials for iron making such as sintered ore and pellets, even if the amount of fine powder remaining after granulation is increased by 1% when granulating sintered raw materials and pellet raw materials, Significantly adversely affect the productivity of raw materials.

Claims (3)

A granulating agent for iron making containing a (meth) acrylic acid polymer,
The ratio of the total amount of (meth) acrylic acid and / or a salt thereof in all monomers for constituting the (meth) acrylic acid polymer is 80 to 100 mol%,
The sulfur element introduction amount S defined by the formula (1) is 25-50.
Granulating agent for iron making.
S = [(S amount contained in (meth) acrylic acid polymer) / (total S amount in the granulating agent for iron making)] × 100 (1) The (meth) acrylic acid polymer is a polymer obtained by polymerizing a monomer containing (meth) acrylic acid and / or a salt thereof in the presence of a sulfite.
The granulating agent for iron making according to claim 1 . The granulating agent for iron making according to claim 2, wherein the sulfite is sodium hydrogen sulfite.