JP7516065B2 - Granulated steel sludge and/or steel dust - Google Patents

Description

The present invention relates to a granulated product of steel sludge and/or steel dust, a method for producing the same, and a granulation treatment agent for the granulated product.

In the steelmaking process, waste liquid is generated from the elution of metals during the pickling process of steel surfaces, and the metal components in this waste liquid are recovered as steelmaking sludge, such as pickling sludge and neutralization sludge. In addition, in various steps of the steelmaking process, ironmaking dust with a high water content is generated by dehydrating the dust that has been wet collected. Such ironmaking dust and ironmaking sludge often contain iron and other useful metals (e.g., Ni, Cr, etc.), and it is very useful to reuse the ironmaking dust and ironmaking sludge as raw materials for furnaces, etc.

In order to reuse steelmaking sludge and steelmaking dust as raw materials for furnaces (e.g., shaft furnaces, converters, electric furnaces, smelting reduction furnaces, etc.), it is desirable to agglomerate them into briquettes, pellets, etc.

Patent Document 1 discloses a method for producing granulated material using steel sludge as the main raw material, which includes a process of crushing cake-like steel sludge using a specific raw material processing device, adding steel dust and a solidifying agent to the crushed steel sludge and mixing it, and a process of feeding the raw material that has undergone this process into a tumbling granulator, granulating the raw material, and performing a sizing process to smooth the surface of the granulated material.

Patent Document 2 discloses a treatment agent used to granulate raw materials for ironmaking, including fine iron ore, which contains at least one polymer compound selected from the group consisting of a polymer compound having an acid group and a polyalkylene glycol chain, a β-naphthalenesulfonate-formaldehyde condensate, a melamine sulfonate-formaldehyde condensate, an aromatic aminosulfonic acid polymer, and a modified ligninsulfonic acid.

Patent Document 3 discloses a method for treating iron-making dust, which comprises filling a reaction vessel with at least one of iron-making dust and iron-making sludge containing metal oxides and carbon, and reducing and agglomerating the metal oxides, in which the iron concentration in the space surrounding the metal oxides when filled into the reaction vessel is set to 800 kg/ ^m3 or more.

JP 2012-97294 A JP 2002-322514 A JP 2017-179560 A

The present invention provides granulated steel sludge and/or steel dust with excellent strength.

The present invention relates to a granulated material containing steelmaking sludge and/or steelmaking dust, hydraulic powder, and a dispersant for hydraulic powder.

The present invention also relates to a method for producing a granulated product, which comprises mixing steel sludge and/or steel dust (hereinafter referred to as the main raw material), hydraulic powder, and a dispersant for hydraulic powder, followed by granulation.

The present invention also relates to a granulation treatment agent for granulated materials made from steel sludge and/or steel dust, which contains a hydraulic powder and a dispersant for the hydraulic powder.

The present invention provides granulated steel sludge and/or steel dust with excellent strength.

<Granulated material>
Examples of the main raw material, iron-making sludge, include rolling sludge, plating sludge, pickling sludge, etc. In general, the moisture content of iron-making sludge is about 40% by mass or more and 70% by mass or less.
Examples of the iron dust as the main raw material include blast furnace dust, sintering dust, converter dust, and pre-processing dust. Wet-collected iron dust contains a considerable amount of moisture, and the moisture content is generally about 5% by mass to 35% by mass. In addition, iron dust containing a considerable amount of moisture may be mixed with dry powder iron dust (dry-collected) for the purpose of adjusting the moisture content.

From the viewpoint of suitability as a raw material for iron making, the proportion of iron in the solid content of the main raw material is preferably 0.1 mass% or more, more preferably 10 mass% or more, even more preferably 20 mass% or more, and preferably 60 mass% or less, more preferably 55 mass% or less. Here, the solid content of the main raw material may be the components other than water in the main raw material.

The main raw material is preferably sludge recovered from the steel manufacturing process and/or dust recovered from the steel manufacturing process, in terms of the content of useful metals such as Ni and Cr.

From the viewpoint of suppressing slag, the total proportion of silica and alumina in the solid content of the main raw material is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, even more preferably 1 mass% or more, and preferably 50 mass% or less, more preferably 40 mass% or less, even more preferably 30 mass% or less.
From the viewpoint of suppressing slag, the proportion of calcium in the solid content of the main raw material is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, even more preferably 1 mass% or more, and preferably 50 mass% or less, more preferably 40 mass% or less, even more preferably 30 mass% or less.
It is preferable that the main raw material has a total content of silica and alumina within the above range, and a calcium content within the above range.

In addition, the total proportion of chromium and nickel in the solid content of the main raw material is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, even more preferably 1 mass% or more, and preferably 50 mass% or less, more preferably 40 mass% or less, even more preferably 30 mass% or less, from the viewpoint of efficiently utilizing useful metals.

From the viewpoint of forming granules, the ratio of carbon components in the solid content of the main raw material is preferably 50 mass % or less, more preferably 40 mass % or less, and even more preferably 30 mass % or less.
Furthermore, even if the solid matter of the main raw material does not contain carbon components, there is no problem from the viewpoint of effective utilization of the granulated material produced. However, considering that the granulated material will be used for recovering metals, the carbon components can be utilized as a heat source. Therefore, the proportion of carbon components in the solid matter of the main raw material is preferably 5 mass% or more, more preferably 7 mass% or more, and even more preferably 10 mass% or more.
Here, the proportion of carbon components in the solid content of the main raw material can be measured by a method conforming to the "Method of Determination of Carbon" specified in JIS R 1603.

Examples of hydraulic powders include powders that have the physical property of hardening through a hydration reaction. Specific examples include cement, gypsum, and the like. Preferred are ordinary Portland cement, belite cement, moderate heat cement, high-early strength cement, ultra-high-early strength cement, and sulfate-resistant cement. Powders having posolan action and/or latent hydraulic properties, such as blast furnace slag, fly ash, and silica fume, and powdered stone (calcium carbonate powder) may also be added to these, such as blast furnace slag cement, fly ash cement, and silica fume cement. From the viewpoints of strength development and availability, the hydraulic powder is more preferably ordinary Portland cement, high-early strength cement, or blast furnace slag cement, and even more preferably blast furnace slag cement from the viewpoint of reducing the environmental load.

In the present invention, when the hydraulic powder includes powders selected from powders having pozzolanic properties, powders having latent hydraulic properties, and stone powder (calcium carbonate powder) in addition to powders such as cement that have the property of hardening through a hydration reaction, the amounts of these powders are also included in the amount of hydraulic powder. In addition, when the powders having the property of hardening through a hydration reaction contain high-strength admixtures, the amount of the high-strength admixture is also included in the amount of hydraulic powder. This also applies to parts by mass and mass ratios that involve the mass of the hydraulic powder.

The dispersant for hydraulic powder may be one or more types of dispersant for hydraulic powder selected from naphthalene-based dispersants, polycarboxylic acid-based dispersants, melamine-based dispersants, lignin-based dispersants, and phenol-based dispersants.

From the viewpoint of improving dispersibility, the dispersant for hydraulic powder is preferably one or more types of dispersant for hydraulic powder selected from naphthalene-based dispersants and polycarboxylic acid-based dispersants.

As the naphthalene-based dispersant, a naphthalene sulfonic acid formaldehyde condensate or a salt thereof is preferably used. The naphthalene sulfonic acid formaldehyde condensate or a salt thereof is a condensate of naphthalene sulfonic acid and formaldehyde or a salt thereof. The naphthalene sulfonic acid formaldehyde condensate may be co-condensed with an aromatic compound capable of co-condensing with naphthalene sulfonic acid, such as, for example, methylnaphthalene, ethylnaphthalene, butylnaphthalene, hydroxynaphthalene, naphthalenecarboxylic acid, anthracene, phenol, cresol, creosote oil, tar, melamine, urea, sulfanilic acid and/or derivatives thereof, as a monomer, as long as the performance is not impaired.

Naphthalenesulfonic acid formaldehyde condensate or its salt may be a commercially available product such as Scorol PD-315M, Mighty 150, Demol N, Demol RN, Demol MS, Demol SN-B, Demol SS-L (all manufactured by Kao Corporation), Celluflow 120, Labelin FD-40, Labelin FM-45 (all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), etc.

From the viewpoint of low viscosity, the naphthalenesulfonic acid formaldehyde condensate or its salt has a weight average molecular weight of preferably 200,000 or less, more preferably 100,000 or less, even more preferably 80,000 or less, even more preferably 50,000 or less, and even more preferably 30,000 or less. From the viewpoint of dispersibility, the naphthalenesulfonic acid formaldehyde condensate or its salt has a weight average molecular weight of preferably 1,000 or more, more preferably 3,000 or more, even more preferably 4,000 or more, and even more preferably 5,000 or more. The naphthalenesulfonic acid formaldehyde condensate may be in an acid state or a neutralized product.

The molecular weight of the naphthalenesulfonic acid-formaldehyde condensate or its salt can be measured by gel permeation chromatography under the following conditions.
[GPC conditions]
Column: G4000SWXL + G2000SWXL (Tosoh Corporation)
Eluent: 30mM _CH3COONa / _CH3CN =6/4
Flow rate: 0.7ml/min
Detection: UV 280 nm
Sample size: 0.2 mg/ml
Standard substance: Polystyrenesulfonate sodium salt (monodisperse polystyrenesulfonate sodium: molecular weight: 206, 1,800, 4,000, 8,000, 18,000, 35,000, 88,000, 780,000) manufactured by Nishio Kogyo Co., Ltd.
Detector: Tosoh Corporation UV-8020

For example, a method for producing a naphthalenesulfonic acid formaldehyde condensate or a salt thereof includes a method of obtaining a condensate by a condensation reaction of naphthalenesulfonic acid and formaldehyde. The condensate may be neutralized. In addition, water-insoluble substances produced as by-products in the neutralization may be removed. Specifically, in order to obtain naphthalenesulfonic acid, 1.2 to 1.4 moles of sulfuric acid are used per mole of naphthalene, and the mixture is reacted at 150 to 165°C for 2 to 5 hours to obtain a sulfonated product. Next, formalin is dropped at 85 to 95°C over 3 to 6 hours so that 1 mole of the sulfonated product has 0.95 to 0.99 moles of formaldehyde, and after the dropwise addition, a condensation reaction is performed at 95 to 105°C. Furthermore, since the aqueous solution of the obtained condensate is highly acidic, from the viewpoint of suppressing metal corrosion of storage tanks, etc., water and a neutralizing agent can be added to the obtained condensate, and a neutralization process can be performed at 80 to 95°C. The neutralizing agent is preferably added in an amount of 1.0 to 1.1 times the molar amount of naphthalenesulfonic acid and unreacted sulfuric acid. In addition, water-insoluble matters resulting from neutralization can be removed, and a preferred method for this is separation by filtration. These steps provide an aqueous solution of a water-soluble salt of a naphthalenesulfonic acid formaldehyde condensate. This aqueous solution can be used as a naphthalenesulfonic acid formaldehyde condensate or its salt as is. If necessary, the aqueous solution can be dried and powdered to obtain a powdered salt of a naphthalenesulfonic acid formaldehyde condensate, which can be used as a powdered dispersant. Drying and powdering can be performed by spray drying, drum drying, freeze drying, etc.

From the viewpoint of dispersibility, the polycarboxylic acid-based dispersant is preferably a copolymer containing, as a constituent monomer, a monomer (1) represented by the following general formula (1).
The polycarboxylic acid-based dispersant is more preferably a copolymer containing, as constituent monomers, a monomer (1) represented by the following general formula (1) and a monomer (2) represented by the following general formula (2):

[Wherein,
R ¹ and R ² may be the same or different and are a hydrogen atom or a methyl group. R ³ : a hydrogen atom or -COO(AO) _n X ^1
X1 : a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; AO: a group selected from an ethyleneoxy group and a propyleneoxy group; n: the average number of moles of AO added, which is a number of 1 to 300; q: a number of 0 to 2; p: a number of 0 or 1.

[Wherein,
R ⁴ , R ⁵ , and R ⁶ may be the same or different and are a hydrogen atom, a methyl group, or (CH ₂ ) _r COOM ² , and (CH ₂ ) _r COOM ² may form an anhydride with COOM ¹ or another (CH ₂ ) _r COOM ² , in which case M ¹ and M ² of those groups do not exist.
M ¹ and M ² may be the same or different and each represents a hydrogen atom, an alkali metal, an alkaline earth metal (1/2 atom), an ammonium group, an alkylammonium group, a substituted alkylammonium group, an alkyl group, a hydroalkyl group, or an alkenyl group; r represents a number of 0 to 2.

In the general formula (1), R ¹ is preferably a hydrogen atom from the viewpoint of polymerizability.
In general formula (1), R ² is preferably a methyl group from the viewpoint of storage stability.
In general formula (1), R ³ is preferably a hydrogen atom from the viewpoint of polymerizability.
In general formula (1), X ¹ is preferably a hydrogen atom or a methyl group, more preferably a methyl group, from the viewpoint of hydrophilicity.
In the general formula (1), AO is preferably an ethyleneoxy group from the viewpoint of hydrophilicity. AO preferably contains an ethyleneoxy group.
In general formula (1), n is the average number of moles of AO added, and from the viewpoint of dispersibility, n is preferably 5 or more, more preferably 10 or more, even more preferably 15 or more, still more preferably 20 or more, and preferably 300 or less, more preferably 200 or less, even more preferably 150 or less, and still more preferably 130 or less.
In the general formula (1), p is preferably 1 from the viewpoint of storage stability.
In formula (1), q is preferably 0.

In general formula (2), from the viewpoint of polymerizability, R ⁴ is preferably a hydrogen atom.
In the general formula (2), from the viewpoint of storage stability, R ⁵ is preferably a methyl group.
In general formula (2), from the viewpoint of polymerizability, R ⁶ is preferably a hydrogen atom.
(CH ₂ ) _r COOM ² may form an anhydride with COOM ¹ or another (CH ₂ ) _r COOM ² , and in that case, M ¹ and M ² of those groups do not exist.
^M1 and ^M2 may be the same or different and each represents a hydrogen atom, an alkali metal, an alkaline earth metal (1/2 atom), an ammonium group, an alkylammonium group, a substituted alkylammonium group, an alkyl group, a hydroalkyl group, or an alkenyl group.
The alkyl group, hydroalkyl group and alkenyl group of M ¹ and M ² each preferably have 1 to 4 carbon atoms.
^M1 and ^M2 may be the same or different and are preferably a hydrogen atom, an alkali metal, an alkaline earth metal (1/2 atom), an ammonium group, or an alkylammonium group, more preferably a hydrogen atom, an alkali metal, an alkaline earth metal (1/2 atom), or an ammonium group, still more preferably a hydrogen atom, an alkali metal, or an alkaline earth metal (1/2 atom), and still more preferably a hydrogen atom or an alkali metal.
From the viewpoint of availability, r in (CH ₂ ) _r COOM ² in the general formula (2) is preferably 1.

In the copolymer containing the monomer (1) as a constituent monomer, from the viewpoint of dispersibility, the total amount of the monomer (1) in the constituent monomers is preferably 70 mass% or more, more preferably 75 mass% or more, even more preferably 80 mass% or more, and preferably 100 mass% or less.
In the copolymer containing the monomer (1) and the monomer (2) as constituent monomers, the total amount of the monomer (1) and the monomer (2) in the constituent monomers is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, and preferably 100% by mass or less, from the viewpoint of dispersibility and adsorptive property. This total amount may be 100% by mass.

In a copolymer containing monomer (1) and monomer (2) as constituent monomers, the proportion of monomer (2) in the total of monomer (1) and monomer (2) is preferably 40 mol% or more, and preferably 99 mol% or less, more preferably 97 mol% or less, and even more preferably 95 mol% or less, from the viewpoint of dispersibility.

The weight average molecular weight of the polycarboxylic acid dispersant, the copolymer further containing monomer (1) as a constituent monomer, and the copolymer further containing monomer (1) and monomer (2) as constituent monomers is preferably 20,000 or more, more preferably 30,000 or more, even more preferably 40,000 or more, and preferably 100,000 or less, more preferably less than 100,000, even more preferably 80,000 or less, from the viewpoint of dispersibility.

The weight average molecular weight and number average molecular weight of the polycarboxylic acid dispersant, the copolymer further containing the monomer (1) as a constituent monomer, and the copolymer further containing the monomer (1) and the monomer (2) as constituent monomers were measured by gel permeation chromatography (GPC) under the following conditions.
*GPC conditions: Apparatus: GPC (HLC-8320GPC) manufactured by Tosoh Corporation Column: G4000PWXL + G2500PWXL (manufactured by Tosoh Corporation)
Eluent: 0.2M phosphate buffer/ _CH3CN =9/1
Flow rate: 1.0mL/min
Column temperature: 40°C
Detection: RI
Sample size: 0.2 mg/mL
Standard substance: Polyethylene glycol equivalent (monodisperse polyethylene glycol with known molecular weight, molecular weight 87,500, 250,000, 145,000, 46,000, 24,000)

Two or more polycarboxylic acid dispersants with different average number of moles of AO added or different ratios of monomer (1) and monomer (2) can also be used.

From the viewpoint of suitability as a raw material for iron making, the content of the main raw material in the granulated material of the present invention is preferably 30% by mass or more, more preferably 35% by mass or more, even more preferably 40% by mass or more, and preferably 90% by mass or less, more preferably 88% by mass or less, even more preferably 85% by mass or less, calculated as solid content.

From the viewpoint of the crushing strength of the granules of the present invention, the content of hydraulic powder in the granules is preferably 0.5% by mass or more, more preferably 1% by mass or more, and from the viewpoint of slag suppression, it is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

From the viewpoint of improving the dispersibility of the raw materials, the content of the hydraulic powder dispersant in the granules of the present invention is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, even more preferably 0.05% by mass or more, and preferably 5% by mass or less.

From the viewpoints of preventing deposition and workability, the granulated product of the present invention has an average particle size of preferably 0.1 mm or more, more preferably 0.5 mm or more, and even more preferably 1 mm or more, and from the viewpoint of meltability, it is preferably 100 mm or less, more preferably 50 mm or less, and even more preferably 10 mm or less. This average particle size is measured by a sieving test (JIS 8815-1994).

The granules of the present invention are suitable as raw materials for ironmaking, and further suitable as raw materials for converters in steelmaking.

<Method of manufacturing granules>
The present invention provides a method for producing a granulated material, which comprises mixing iron sludge and/or iron dust (main raw material), hydraulic powder, and a dispersant for hydraulic powder, followed by granulation. The granulated material of the present invention can be produced by the production method of the present invention.
Specific examples and preferred aspects of the steel sludge, the steel dust, the hydraulic powder, and the dispersant for hydraulic powder are the same as those of the granulated product of the present invention. The matters described for the granulated product of the present invention can be appropriately applied to the manufacturing method of the present invention. In addition, for example, the contents of the main raw material, the hydraulic powder, and the dispersant for hydraulic powder in the granulated product can be read as the mixed amount and applied.

In the method for producing a granulated product of the present invention, it is preferable to granulate the mixture obtained by mixing the main raw material, hydraulic powder, and a dispersant for hydraulic powder.

The main raw material is, for example, sludge or dust recovered from the steel manufacturing process. It is preferable that the main raw material has a minimal surface irregularity.

In the method for producing a granulated product of the present invention, it is preferable to mix the main raw material, the hydraulic powder, and the dispersant for the hydraulic powder using a drum pelletizer.
Drum pelletizers include those that include a drum into which the material to be processed is placed and an agitating rotor.
An example of a drum pelletizer is one that includes a drum in which the raw material to be processed is placed, an agitating blade that revolves within the drum, and an agitating rotor that rotates while revolving within the drum together with the agitating blade.
These drum pelletizers can also be combined with a tumbling granulator into which the raw materials processed by the drum pelletizer are fed and which performs granulation of the raw materials and sizing to smooth the surface of the granulated material.

In the method for producing a granulated product of the present invention, the following treatments (A) and (B) can be carried out in this order.
(A): Cake-like steelmaking sludge and/or steelmaking dust is crushed.
(B): The hydraulic powder and a dispersant for the hydraulic powder are added to the raw material disintegrated in the process (A), and mixed.

In the method for producing a granulated product of the present invention, the following steps (A), (B), and (C) can be carried out in this order.
(A): Cake-like steelmaking sludge and/or steelmaking dust is crushed.
(B): The hydraulic powder and a dispersant for the hydraulic powder are added to the raw material disintegrated in the process (A), and mixed.
(C): A preliminary granulation process is carried out on the raw materials mixed in process (B).

In the method for producing a granulated product of the present invention, the drum pelletizer includes a drum in which a raw material to be processed is placed, an agitating blade that revolves within the drum, and an agitating rotor that revolves within the drum together with the agitating blade and rotates about its own axis,
The revolution direction and revolution speed of the stirring blade and the rotation speed of the stirring rotor are variable,
When the stirring blade revolves in one revolution direction, the upper surface side of the stirring blade stirs up the raw material, and when the stirring blade revolves in the other revolution direction, the lower surface side of the stirring blade compresses the raw material.
When the agitator blade revolves in a direction that scrapes up the raw material on the upper side, this is called "forward rotation," and when the agitator blade revolves in a direction that compresses the raw material on the lower side, this is called "reverse rotation." When the agitator rotor rotates in the same rotational direction as the agitator blade's "forward rotation," this is called "forward rotation." By selecting the revolution direction and revolution speed of the agitator blade and the rotation speed of the agitator rotor, the following processes (A), (B1), and (B2) can be carried out sequentially.
(A): Cake-like iron sludge is crushed by alternately performing one or more cycles of a crushing process in which the stirring rotor is rotated forward at high speed while the stirring impeller is rotated in the reverse direction at low speed, and a crushing process in which the stirring rotor is rotated forward at high speed while the stirring impeller is rotated forward at low speed.
(B1): The iron-making dust is added to the iron-making sludge disintegrated in the process (A) and mixed. At this time, the mixing process is performed by rotating the stirring blade in the forward direction at a low speed while rotating the stirring rotor in the forward direction at a low speed.
(B2): Add hydraulic powder and a dispersant for hydraulic powder to the raw material mixed in the process (B1) and mix them together. At this time, the mixing process is performed by rotating the stirring blade in the reverse direction at a low speed while rotating the stirring rotor in the forward direction at a high speed.

In the method for producing a granulated product of the present invention, the drum pelletizer includes a drum in which a raw material to be processed is placed, an agitating blade that revolves within the drum, and an agitating rotor that revolves within the drum together with the agitating blade and rotates about its own axis,
The revolution direction and revolution speed of the stirring blade and the rotation speed of the stirring rotor are variable,
When the stirring blade revolves in one revolution direction, the upper surface side of the stirring blade stirs up the raw material, and when the stirring blade revolves in the other revolution direction, the lower surface side of the stirring blade compresses the raw material.
When the agitator blade revolves in a direction that scrapes up the raw material on the upper side, this is called "forward rotation," and when the agitator blade revolves in a direction that compresses the raw material on the lower side, this is called "reverse rotation." When the agitator rotor rotates in the same rotational direction as the agitator blade's "forward rotation," this is called "forward rotation." By selecting the revolution direction and revolution speed of the agitator blade and the rotation speed of the agitator rotor, the following processes (A), (B1), (B2), and (C) can be carried out in sequence.
(A): Cake-like iron sludge is crushed by alternately performing one or more cycles of a crushing process in which the stirring rotor is rotated forward at high speed while the stirring impeller is rotated in the reverse direction at low speed, and a crushing process in which the stirring rotor is rotated forward at high speed while the stirring impeller is rotated forward at low speed.
(B1): The iron-making dust is added to the iron-making sludge disintegrated in the process (A) and mixed. At this time, the mixing process is performed by rotating the stirring blade in the forward direction at a low speed while rotating the stirring rotor in the forward direction at a low speed.
(B2): Add hydraulic powder and a dispersant for hydraulic powder to the raw material mixed in the process (B1) and mix them together. At this time, the mixing process is performed by rotating the stirring blade in the reverse direction at a low speed while rotating the stirring rotor in the forward direction at a high speed.
(C): A preliminary granulation process is performed on the raw material mixed in the process (B2). At this time, the preliminary granulation process is performed by rotating the stirring rotor in the normal direction at a medium speed while rotating the stirring blade in the normal direction at a medium speed.

In the method for producing granulated material of the present invention, the mixture obtained by mixing the main raw material, hydraulic powder, and dispersant for hydraulic powder is fed into a tumbling granulator, where the raw material is granulated and the surface of the granulated material is smoothed by a sizing process.

For the drum pelletizer, refer to the raw material processing device in JP 2012-97294 A. For the rolling granulator, refer to JP 2012-97294 A.

In the method for producing a granulated material of the present invention, it is not necessary to sinter the granulated material. In other words, the method for producing a granulated material of the present invention includes a method for producing a granulated material in which a main raw material, a hydraulic powder, and a dispersant for hydraulic powder are mixed and granulated to produce a granulated material, and then the granulated material is not sintered.

<Granulation treatment agent>
The present invention provides a granulation treatment agent for granulated products using ironworks sludge and/or ironworks dust, which contains a hydraulic powder and a dispersant for the hydraulic powder. Specific examples and preferred aspects of the ironworks sludge, ironworks dust, hydraulic powder, and dispersant for the hydraulic powder are the same as those of the granulated product of the present invention. The matters described for the granulated product of the present invention can be appropriately applied to the granulation treatment agent of the present invention. The granulation treatment agent of the present invention is used by mixing with the ironworks sludge and/or ironworks dust when producing a granulated product of the ironworks sludge and/or ironworks dust.

<Raw materials for granulated materials>
*Main raw material: Steel sludge: Moisture content 36% by mass, iron content 30% by mass in solid content, total content of silica and alumina 15% by mass or less, calcium content 8% by mass, carbon content 10% by mass
Iron dust: Moisture content 8% by mass, iron content 50% by mass in the solid content, silica and alumina total content 3% by mass or less, calcium content 2% by mass, carbon content mainly including coal dust that has been thermally decomposed and turned into powder under high temperatures 10% by mass.
* Hydraulic powder/blast furnace cement: The total ratio of silica and alumina is 35% by mass, calcium is 60% by mass, and other elements are 5% by mass.
* Dispersant for hydraulic powders Dispersant (1): Sodium neutralized salt of copolymer of methacrylic acid and ester of methacrylic acid and polyethylene glycol monomethyl ether (weight average molecular weight of polyethylene glycol portion: 5300) (copolymerization ratio: methacrylic acid/ester of methacrylic acid and polyethylene glycol monomethyl ether=90/10 (mol%)) Dispersant (2): Scoroll PD-315M, Kao Corporation, sodium salt of naphthalenesulfonic acid-formaldehyde condensate

<Production of Granules>
A granulated product was produced using a drum pelletizer equipped with a drum in which the raw material to be processed is placed, an agitating blade that revolves within the drum, and an agitating rotor that rotates within the drum while revolving together with the agitating blade, and a rolling granulator into which the raw material processed by the drum pelletizer is placed and which performs a granulation process for the raw material and a granulation process for smoothing the surface of the granulated product. Specifically, the raw material processing device shown in Figures 1 to 3 of JP 2012-97294 A was used as the drum pelletizer, and the rolling granulator shown in Figures 5 and 6 of JP 2012-97294 A was used as the rolling granulator.

The main raw material and hydraulic powder were mixed in the drum pelletizer in the amounts shown in Table 1. To this mixed powder, a dispersant for hydraulic powder and water were added in that order in the amounts shown in Table 1. After 30 seconds of mixing (the stirring blade and the stirring rotor rotate in opposite directions) and 40 seconds of preliminary granulation mixing (the stirring blade and the stirring rotor rotate in the same direction), the mixture was placed in the tumbling granulator and subjected to 60 seconds of granulation processing to obtain a granulated product.

<Crushing strength of granules>
The crushing strength of the granules was measured according to the method of JIS Z 8841-1993, and the results are shown in Table 1.

*1 The numbers in parentheses for the mixed amounts of the main ingredients are the amounts converted into solid content. The mixed amounts in Table 1 are approximately the same as the content of each ingredient in the granulated product.

Claims (25)

A granulated material containing iron sludge and/or iron dust (hereinafter referred to as a main raw material), a hydraulic powder, and a dispersant for the hydraulic powder ,
the hydraulic powder dispersant is one or more types of hydraulic powder dispersant selected from a naphthalene-based dispersant and a polycarboxylic acid-based dispersant;
Used as a raw material for steelmaking without sintering.
Granulated material . The granules according to claim 1, in which the proportion of iron in the solid content of the main raw material is 0.1% by mass or more and 60% by mass or less. The granules according to claim 1 or 2, in which the total proportion of silica and alumina in the solid content of the main raw material is 50% by mass or less, and the proportion of calcium is 50% by mass or less. The granules according to any one of claims 1 to 3, in which the proportion of carbon components in the solid content of the main raw material is 50 mass% or less. The granule according to any one of claims 1 to 4, wherein the content of the main raw material in the granule is 30% by mass or more and 90% by mass or less, calculated as solid content. The granule according to any one of claims 1 to 5, wherein the content of the hydraulic powder dispersant in the granule is 0.01% by mass or more and 1% by mass or less. The granule according to any one of claims 1 to 6 , which contains water . A method for producing a granulated product, comprising mixing and granulating steel sludge and/or steel dust (hereinafter referred to as a main raw material), hydraulic powder, and a dispersant for hydraulic powder,
the hydraulic powder dispersant is one or more types of hydraulic powder dispersant selected from a naphthalene-based dispersant and a polycarboxylic acid-based dispersant;
The granules are used as a raw material for iron making without being sintered.
A method for producing granulated material . The method for producing a granulated material according to claim 8, which comprises granulating the mixture obtained by mixing the main raw material, hydraulic powder, and a dispersant for hydraulic powder. The method for producing a granulated material according to claim 8 or 9, wherein the iron content in the solid content of the main raw material is 0.1% by mass or more and 60% by mass or less. The method for producing a granulated material according to any one of claims 8 to 10, wherein the total ratio of silica and alumina in the solid content of the main raw material is 5% by mass or more and 50% by mass or less, and the ratio of calcium is 2% by mass or more and 50% by mass or less. The method for producing a granulated material according to any one of claims 8 to 11, wherein the proportion of carbon components in the solid content of the main raw material is 50 mass% or less. The method for producing a granulated product according to any one of claims 8 to 12, wherein the content of the main raw material in the granulated product is 30% by mass or more and 85% by mass or less, calculated as solid content. The method for producing a granulated material according to any one of claims 8 to 13, wherein the content of the hydraulic powder dispersant in the granulated material is 0.01% by mass or more and 1% by mass or less. The method for producing a granulated product according to any one of claims 8 to 14 , wherein the granulated product contains water .
The method for producing a granulated material according to any one of claims 8 to 15, in which the main raw material, hydraulic powder, and dispersant for hydraulic powder are mixed using a drum pelletizer. The method for producing granulated material according to claim 16, wherein the drum pelletizer comprises a drum in which the raw material to be processed is placed and a stirring rotor. The method for producing granulated material according to claim 16 or 17, wherein the drum pelletizer comprises a drum in which the raw material to be processed is placed, an agitator blade that revolves within the drum, and an agitator rotor that rotates within the drum while revolving together with the agitator blade. The method for producing a granulated product according to any one of claims 8 to 18, comprising sequentially carrying out the following treatments (A) and (B):
(A): Cake-like steelmaking sludge and/or steelmaking dust is crushed.
(B): The hydraulic powder and a dispersant for the hydraulic powder are added to the raw material disintegrated in the process (A), and mixed. The method for producing a granulated product according to any one of claims 8 to 19, comprising sequentially carrying out the following treatments (A), (B), and (C):
(A): Cake-like steelmaking sludge and/or steelmaking dust is crushed.
(B): The hydraulic powder and a dispersant for the hydraulic powder are added to the raw material disintegrated in the process (A), and mixed.
(C): A preliminary granulation process is carried out on the raw materials mixed in process (B). The drum pelletizer includes a drum in which the raw material to be processed is placed, an agitating blade that revolves within the drum, and an agitating rotor that revolves within the drum together with the agitating blade and rotates about its own axis.
The revolution direction and revolution speed of the stirring blade and the rotation speed of the stirring rotor are variable,
When the stirring blade revolves in one revolution direction, the upper surface side of the stirring blade stirs up the raw material, and when the stirring blade revolves in the other revolution direction, the lower surface side of the stirring blade compresses the raw material.
The method for producing a granulated material according to claim 16 or any one of claims 17 to 20 that cite claim 16, in which the revolution direction and revolution speed of the agitating blade and the rotation speed of the agitating rotor are selected, where "forward rotation" is defined as the revolution direction of the agitating blade that acts to scrape up the raw material on the upper surface side, and "reverse rotation" is defined as the revolution direction of the agitating blade that acts to compress the raw material on the lower surface side, and "forward rotation" is defined as the rotation direction of the agitating rotor that rotates in the same rotation direction as the revolution of the agitating blade in the "forward rotation", and the following processes (A), (B1), and (B2) are sequentially performed by selecting the revolution direction and revolution speed of the agitating blade and the rotation speed of the agitating rotor.
(A): Cake-like iron sludge is crushed by alternately performing one or more cycles of a crushing process in which the stirring rotor is rotated forward at high speed while the stirring impeller is rotated in the reverse direction at low speed, and a crushing process in which the stirring rotor is rotated forward at high speed while the stirring impeller is rotated forward at low speed.
(B1): The iron-making dust is added to the iron-making sludge disintegrated in the process (A) and mixed. At this time, the mixing process is performed by rotating the stirring blade in the forward direction at a low speed while rotating the stirring rotor in the forward direction at a low speed.
(B2): Add hydraulic powder and a dispersant for hydraulic powder to the raw material mixed in the process (B1) and mix them together. At this time, the mixing process is performed by rotating the stirring blade in the reverse direction at a low speed while rotating the stirring rotor in the forward direction at a high speed. The drum pelletizer includes a drum in which the raw material to be processed is placed, an agitating blade that revolves within the drum, and an agitating rotor that revolves within the drum together with the agitating blade and rotates about its own axis.
The revolution direction and revolution speed of the stirring blade and the rotation speed of the stirring rotor are variable,
When the stirring blade revolves in one revolution direction, the upper surface side of the stirring blade stirs up the raw material, and when the stirring blade revolves in the other revolution direction, the lower surface side of the stirring blade compresses the raw material.
The method for producing a granulated material according to claim 16 or any one of claims 17 to 20 that cite claim 16, in which the revolution direction and revolution speed of the agitating blade and the rotation speed of the agitating rotor are selected, where "forward rotation" is defined as the revolution direction of the agitating blade that acts to scrape up the raw material on the upper surface side, and "reverse rotation" is defined as the revolution direction of the agitating blade that acts to compress the raw material on the lower surface side, and "forward rotation" is defined as the rotation direction of the agitating rotor that rotates in the same rotation direction as the revolution of the agitating blade in the "forward rotation", and the following processes (A), (B1), (B2), and (C) are sequentially performed by selecting the revolution direction and revolution speed of the agitating blade and the rotation speed of the agitating rotor.
(A): Cake-like iron sludge is crushed by alternately performing one or more cycles of a crushing process in which the stirring rotor is rotated forward at high speed while the stirring impeller is rotated in the reverse direction at low speed, and a crushing process in which the stirring rotor is rotated forward at high speed while the stirring impeller is rotated forward at low speed.
(B1): The iron-making dust is added to the iron-making sludge disintegrated in the process (A) and mixed. At this time, the mixing process is performed by rotating the stirring blade in the forward direction at a low speed while rotating the stirring rotor in the forward direction at a low speed.
(B2): Add hydraulic powder and a dispersant for hydraulic powder to the raw material mixed in the process (B1) and mix them together. At this time, the mixing process is performed by rotating the stirring blade in the reverse direction at a low speed while rotating the stirring rotor in the forward direction at a high speed.
(C): A preliminary granulation process is performed on the raw material mixed in the process (B2). At this time, the preliminary granulation process is performed by rotating the stirring rotor in the normal direction at a medium speed while rotating the stirring blade in the normal direction at a medium speed. The method for producing a granulated material according to any one of claims 8 to 22, comprising: feeding a mixture obtained by mixing a main raw material, a hydraulic powder, and a dispersant for hydraulic powder into a tumbling granulator; granulating the raw material; and performing a sizing process to smooth the surface of the granulated material. A granulation treatment agent for granulated materials using steel sludge and/or steel dust, comprising a hydraulic powder and a dispersant for the hydraulic powder ,
the hydraulic powder dispersant is one or more types of hydraulic powder dispersant selected from a naphthalene-based dispersant and a polycarboxylic acid-based dispersant;
The granules are used as a raw material for iron making without being sintered.
A granulation processing agent for granulated materials . The granulation processing agent according to claim 24 , wherein the granulated material contains water.