KR102306415B1 - Fe-containing briquette, organic binder included therein and manufacturing method of Fe-containing briquette - Google Patents

Abstract

The present invention relates to a high steel-containing briquette, an organic binder included therein, and a manufacturing method of the high steel-containing briquette. The high steel-containing briquette comprises about 2-5 parts by weight of organic binder and about more than 0 part by weight and equal to or less than 6 parts by weight of inorganic binder, for 100 parts by weight of a steel-containing mixture comprising about 30-60 wt% of mill scale, about 30-50 wt% of fine steel sludge, and about 10-20 wt% of [C] material. The high steel-containing briquette has excellent compressive strength, warm strength, and molding ratio and contributes to environment by reusing steel sludge.

Description

TECHNICAL FIELD [0002] Fe-containing briquette, organic binder included therein and manufacturing method of Fe-containing briquette

The present invention relates to a high iron content briquette, an organic binder contained therein, and a method for manufacturing the high iron content briquette, and more particularly, to a high iron content briquette composed of mill scale, finely divided iron-containing by-product, [C] material, an organic binder and an inorganic binder. It relates to a briquette and a method for manufacturing the same.

In general, a large-scale steel manufacturing process adopts the manufacturing process shown in FIG. 1 in order to lower the production cost. In this process, the iron ore contained in the coal is melted by heating the coal to a high temperature to produce molten iron, that is, molten iron. It consists of a steelmaking process and a rolling process in which the solid iron obtained through the steelmaking process is molded into the form of a plate or wire.

Among them, the steelmaking process is a process of changing the carbon content of the molten iron produced in the blast furnace to a desired component. In the steelmaking process, as shown in FIG. A converter facility that goes through the process steps of measurement), tapping, and discharging is used.

In the steelmaking process, various types of by-products are generated for each process, and in general, in the steelmaking process, steelmaking dust, steelmaking sludge, hot-rolled oil sludge, mill scale, basemetal, etc. this is created

Among the ironmaking by-products, steelmaking dust and steelmaking sludge are complex compounds composed of iron oxides and non-metallic compounds, and as iron-containing byproducts containing a large amount of iron (Fe), they can be recycled as a substitute for scrap iron or a coolant.

In the conventional case, molasses, starch, pitch (petroleum residue, asphalt, etc.), high molecular compound (polymer), bentonite, water glass, etc. have been used as binders to recover by-products, and among them, petroleum pitch and high molecular compound (polymer) ), harmful gases are generated during combustion, and it is difficult to handle as well as uneconomical.

Among the by-products of ironmaking, fine powder by-products having very fine particles are difficult to form, so that the amount of binder used increases, and thus recycling costs increase.

Conventional techniques using finely divided iron-containing by-products have problems such as low dry strength or hot strength of the product, difficult mixing of the raw material and binder, or weakening of the strength of the product as the content of the iron-containing by-product increases. there was

Registered Patent No. 10-1008694 (Registered on Jan. 10, 2011) Registered Patent No. 10-1927710 (Registered on Dec. 5, 2018)

An object of the present invention is to provide a high-iron briquette recycled using an iron-containing by-product generated in the steelmaking process, an organic binder included in the high-iron briquette, and a method for manufacturing the high-iron briquette.

An embodiment of the present invention for achieving the above object is an iron-containing mixture 100 containing 30 to 60 wt% of mill scale, 30 to 50 wt% of iron-containing by-products of fine powder, and 10 to 20 wt% of [C] material Based on parts by weight, it relates to a high iron briquette comprising 2 to 5 parts by weight of an organic binder and 6 parts by weight or less of an inorganic binder and more than 0 parts by weight.

The organic binder is characterized in that it includes at least one selected from the group consisting of molasses and starch. At this time, with respect to 100 parts by weight of molasses, it is preferable that 10 to 30 parts by weight of silica fume is further included.

The inorganic binder is characterized in that at least one or more selected from the group consisting of cement, slaked lime, bentonite and blast furnace slag.

The [C] material may be at least one selected from the group consisting of anthracite and CDQ (Coke Dry Quenching) dust.

Another embodiment of the present invention is an organic binder, including at least one selected from the group consisting of molasses and starch, and 10 to 30 parts by weight of silica fume is included with respect to 100 parts by weight of the molasses.

Another embodiment of the present invention relates to a method for manufacturing high iron briquettes, prepared by mixing 30 to 60 wt% of mill scale, 30 to 50 wt% of fine iron-containing by-products and 10 to 20 wt% of [C] material 1 A first mixing step of preparing a mixture; a second mixing step of preparing a second mixture by additionally mixing 2-5 parts by weight of an organic binder and 6 parts by weight or less of an inorganic binder exceeding 0 parts by weight with respect to 100 parts by weight of the first mixture; a molding step of press-molding the second mixture; and a drying and curing step of drying and curing the press-molded mixed raw material.

In this case, it is preferable that the organic binder according to the present invention is used as the organic binder in the second mixing step.

After the drying and curing step, a film forming step of spraying the boron compound aqueous solution with a spray device may be further performed, and the boric compound aqueous solution is boric acid, borax, and metaboric acid. It is characterized in that it comprises at least one selected from the group consisting of.

The high-iron briquette of the present invention has excellent compressive strength, hot strength, and molding rate, and has an effect of contributing to the environment because the iron-containing by-product is recycled.

The organic binder of the present invention has an advantage in that it has excellent bonding strength with a raw material despite a decrease in viscosity.

In addition, when the organic binder and raw materials of the present invention are mixed, wettability and moldability of briquettes are improved, so that it is easy to recycle fine iron-containing by-products that are difficult to form.

In addition, it is economical because the recovery amount of Fe can be improved even when a small amount of the inorganic binder is used.

In addition, the high-iron briquette manufactured through the manufacturing method of the present invention has the advantage that a film is formed on the surface of the briquette, and the amount of dust generated in the process of storage, transport or field use of the briquette is minimized.

In addition, the high-iron briquettes may be suppressed from low-temperature differentiation due to oxidation at low temperatures, thereby increasing the use effect of briquettes.

1 is a schematic diagram schematically showing a general steel manufacturing process.
2 is a diagram schematically illustrating a steelmaking process sequence.
3 is a photograph of the high-content iron briquette according to the present invention.
4 is a flowchart illustrating a method for manufacturing high iron briquettes.

Before describing in detail through preferred embodiments of the present invention, terms or words used in the claims of the present specification should not be construed as being limited to conventional or dictionary meanings, but meanings consistent with the technical spirit of the present invention. and should be interpreted as a concept.

Throughout this specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

The present invention relates to high-iron briquettes recycled using iron-containing by-products generated in a steelmaking process, an organic binder included in the high-iron briquettes, and a method for manufacturing high iron-containing briquettes.

First, referring to FIG. 3 , the high-iron briquette according to an embodiment of the present invention includes about 30-60 wt% of mill scale, about 30-50 wt% of finely divided iron-containing by-products, and about 10-20 wt% of [C] material Based on 100 parts by weight of the iron-containing mixture containing the organic binder, about 2 to 5 parts by weight of the organic binder and more than about 0 parts by weight of the inorganic binder 6 parts by weight or less.

Mill scale is an iron oxide film formed on the surface of a steel in a steelmaking process or a rolling process, and generally has a high iron content of 70 wt% or more, but has a small particle size and a high iron oxide content.

The mill scale is preferably included in an amount of about 30 to 60% by weight, and when it is included in an amount of less than 30% by weight, the content of the iron-containing by-products of the relatively fine powder may be excessive, thereby weakening the strength of the briquettes. On the other hand, when it exceeds 60% by weight, the content of iron-containing by-products of fine powder is lowered, thereby reducing recycling efficiency, and there are disadvantages in that the strength of the briquettes produced is not constant.

The iron-containing by-products of the fine powder include steelmaking sludge or steelmaking dust that is difficult to form into briquettes due to the extremely fine particles, and the steelmaking sludge or steelmaking dust includes blast furnace sludge, steelmaking sludge, steelmaking dust, dust collection dust, etc. The present invention is not limited thereto, and it can be used without any limitation on the type as long as it occurs in the steel process.

The iron-containing by-product of such fine powder is preferably included in an amount of about 30-50 wt%, and when it is included in an amount of less than 30 wt%, there is a disadvantage of being uneconomical, and when it exceeds 50 wt%, the formability may be deteriorated. have.

Meanwhile, the [C] material is a carbon component, and at least one selected from the group consisting of anthracite and CDQ (Coke Dry Quenching) dust may be used.

[C] The material is preferably included in about 10-20% by weight, and in the case of less than 10% by weight, it may not have a sufficient heating effect when the temperature of molten iron is lowered due to the use of iron-containing briquettes, and 20% by weight If it exceeds, there is a disadvantage that the carbon content in the molten steel may increase.

An organic binder according to another embodiment of the present invention is for molding the iron-containing by-product of fine powder into a shape of a predetermined size or more.

It is preferable that about 2 to 5 parts by weight of the organic binder is included based on 100 parts by weight of the iron-containing mixture. When the organic binder is included in an amount of less than 2 parts by weight, the absolute amount of the binder is insufficient, so fine iron-containing by-products are not combined, so that the high iron content briquettes are not easily manufactured, or the dry strength and hot strength of the manufactured briquettes are low due to the low dust generation rate This can increase. On the other hand, when the organic binder is included in excess of 5 parts by weight, the process may be uneconomical and the strength of the briquette may be weakened.

The organic binder includes at least one selected from the group consisting of molasses and starch, and in this case, about 10 to 30 parts by weight of silica fume may be further included with respect to 100 parts by weight of the molasses.

When the briquette is to be formed using the iron-containing by-product of the fine powder, it is difficult to mix the molasses with the fine powder raw material due to the high viscosity of the molasses, thereby reducing the formability and mechanical strength of the manufactured briquette.

To solve this problem, molasses and water are mixed and used, but when water is added, the bonding force between the molasses and the pulverized raw material is reduced, and thus the strength of the briquette is lowered.

Accordingly, in the present invention, silica fume is added to and mixed with molasses to maintain the binding force of the molasses, but there is an advantage in that it is easy to mix with the fine powder by lowering the viscosity. In addition, the wettability of the pulverized raw material is improved to increase the formability of the briquette, and the mechanical strength of the briquette is maintained constant, so that the utilization of the high iron briquette can be improved.

Accordingly, even though the organic binder having a low viscosity is used, the overall bonding strength through the organic binder is maintained, so that the total amount of the binder is reduced, thereby reducing the manufacturing cost of high iron briquettes.

When the silica fume is included in an amount of less than 10 parts by weight, the high viscosity of the molasses is not alleviated, so that it is difficult to mix with the pulverized raw material. On the other hand, when the silica fume is included in excess of 30 parts by weight, the decrease in viscosity, increase in the formability of briquettes, or improvement in mechanical strength is insignificant, but the amount of silica fume is increased, so that the process is uneconomical.

The silica fume is an admixture obtained by using an electrostatic precipitator from ultrafine silicon by-products generated during silicon manufacturing, and is a pozzolan reactant. Specifically, the [CSH] composite material is produced by the pozzolan reaction in which CaO and silica fume contained in the iron-containing by-products of mill scale or fine powder combine at room temperature, so that the dry strength and hot strength at room temperature of the manufactured high iron briquettes can be improved. have.

On the other hand, the inorganic binder forms a hydrated product having the form of needles and rods of a network structure through the reaction of inorganic substances with water. It is possible to increase the degree of recycling of finely divided iron-containing by-products.

In the present invention, it is possible to increase the recovery amount of Fe at low cost by minimizing the amount of the inorganic binder.

The inorganic cement is preferably at least one selected from the group consisting of slaked lime, bentonite and blast furnace slag, and more preferably cement may be used. At this time, it is preferable that the inorganic binder is included in an amount of more than 0 parts by weight and not more than 6 parts by weight based on 100 parts by weight of the iron-containing mixture in consideration of bonding strength and manufacturing cost.

If the inorganic binder is not included at all, the strength and molding rate of the briquettes to be manufactured are lowered, and when it exceeds 6 parts by weight, there is a problem in that the amount of Fe recovery is lowered.

On the other hand, another embodiment of the present invention relates to a method for manufacturing the high-iron briquette, and since the high-iron briquette of the embodiment can be manufactured according to the manufacturing method, the overlapping description will be omitted here.

Referring to FIG. 4 , in the method of manufacturing high iron briquettes according to the present invention, about 30 to 60% by weight of mill scale, about 30 to 50% by weight of fine iron-containing by-products and about 10 to 20% by weight of [C] material are mixed. a first mixing step of preparing a first mixture; a second mixing step of preparing a second mixture by further mixing about 2 to 5 parts by weight of an organic binder and about 0 parts by weight to 6 parts by weight or less of an inorganic binder with respect to 100 parts by weight of the first mixture; a molding step of press-molding the second mixture; and a drying and curing step of drying and curing the press-molded mixed raw material. In this case, as the organic binder in the second mixing step, the organic binder according to the present invention is preferably used.

The first mixing step is a step of mixing mill scale, finely divided iron-containing by-product and [C] material, and the second mixing step is a step of mixing the organic binder and the inorganic binder according to the above-described weight ratio, respectively.

At this time, stirring may be performed in the first mixing step or the second mixing step for uniform mixing of each component. Adhesion can be developed.

The forming step is a step of press-molding the second mixture to form a predetermined shape.

The drying and curing step is a step of drying and curing the press-molded mixed raw material, and this step may be performed in a manner in which warm air is supplied for about 16 to 36 hours at a temperature range of about 40 to 80 °C. Under these conditions, as the drying and curing steps progress, the strength of high-iron briquettes is expressed, and the fine powder production rate is lowered. Problems such as lowering of input efficiency and lowering of steelmaking efficiency can be minimized.

On the other hand, after the drying and curing step, a film forming step of spraying the boron compound aqueous solution with a spray device may be further included. The film forming step is a step of forming a film on the dried and cured high-iron briquettes, wherein the aqueous boric compound solution is at least one selected from the group consisting of boric acid, borax and metaboric acid. may include.

The high-iron briquettes produced through the film forming step have a film formed on the surface, thereby reducing the amount of dust generated from the surface of the briquettes, and suppressing the low-temperature differentiation phenomenon caused by oxidation in the furnace.

Hereinafter, it will be described focusing on specific embodiments of the present invention. However, the scope of the present invention is not limited only to the following examples, and these examples are merely presented by way of example to describe the present invention in more detail, and those of ordinary skill in the art may It is intended to disclose that various modified forms of the described content can be implemented.

[Production Example]

40% by weight of mill scale, 50% by weight of iron-containing by-product of fine powder [C] A first mixture is prepared by mixing 10% by weight of anthracite, and each component according to the mixing ratio of Table 1 with respect to 100 parts by weight of the first mixture was mixed to prepare a second mixture. Molasses (sil) is a mixture of 15 parts by weight of silica fume with respect to 100 parts by weight of molasses.

The second mixture was press-molded into Brecat briquettes at a pressure of 340 psi, dried and cured by supplying hot air at 60° C. for 24 hours to obtain high iron briquettes. At this time, the obtained high-containing iron briquette was photographed and shown in FIG. 3 . The high iron briquette was dried and an aqueous boron compound solution was applied to the surface.

first mixture
(parts by weight) Binder composition (parts by weight) organic binder inorganic binder
(cement) molasses starch Molasses (thread) Comparative Example 1 100 5 - - - Comparative Example 2 100 - 3 - - Comparative Example 3 100 4 2 - - Comparative Example 4 100 4 2 - 4 Example 1 100 - - 5 - Example 2 100 - 2 4 - Example 3 100 - 2 3 3

[Experimental example]

For the briquette briquettes prepared according to the Comparative Examples and Experimental Examples of Preparation Example Table 1, the compressive strength and hot strength were measured after drying at room temperature, and the deviation of the measured compressive strength was analyzed, and the results are shown in Table 2 below. It was.

Regarding the evaluation of compressive strength, if the compressive strength exceeded 300 kgf/cm2, it was judged as excellent, if it was 200 to 300 kgf/cm2, it was good, and if it was less than 200 kgf/cm2, it was judged as bad.

Regarding the evaluation of hot strength, as a contrast ratio, measure the hot strength as a ratio of Char with a particle size of 10 mm or more. did.

In addition, the molding rate (%) of the prepared briquettes was measured, and the molding rate (%) was calculated according to Equation 1 below.

Forming rate (%) = (O/P) x 100 (Equation 1)

(O; the weight of the briquettes molded into an intact shape, P; the weight of the second mixture put into the molding machine)

compressive strength Hot strength (%) Molding rate (%) Measured value (kg _f /cm ² ) strength deviation Comparative Example 1 117 ±57 53 63 Comparative Example 2 198 ±36 64 77 Comparative Example 3 256 ±41 68 82 Comparative Example 4 281 ±44 77 83 Example 1 163 ±31 73 74 Example 2 326 ±23 88 94 Example 3 366 ±24 92 96

As can be seen in Table 2, the high iron briquettes according to Examples 2 and 3 were excellent in compressive strength and hot strength, had a higher forming rate than Comparative Examples 1 to 4, and had a low strength deviation of about 23 to 24. confirmed that.

Compressive strength, hot strength, and molding rate were all higher in Comparative Examples 3 and 4 in which molasses and starch were mixed than in Comparative Examples 1 and 2 in which molasses or starch was used alone, and Example 2 and 3, the compressive strength, hot strength and formability were further increased. Accordingly, it was confirmed that the high iron briquettes prepared according to Examples 2 and 3 were excellent, and in particular, the high iron briquettes according to Example 3 were the most excellent.

Claims (10)

delete delete delete delete delete delete A first mixing step of preparing a first mixture by mixing 30 to 60% by weight of mill scale, 30 to 50% by weight of iron-containing by-products of fine powder, and 10 to 20% by weight of [C] material;
a second mixing step of preparing a second mixture by additionally mixing 2-5 parts by weight of an organic binder and 6 parts by weight or less of an inorganic binder exceeding 0 parts by weight with respect to 100 parts by weight of the first mixture;
a molding step of press-molding the second mixture;
Dry curing step of drying and curing the press-molded mixed raw material; and
After the drying and curing step, a film forming step of spraying the boron compound aqueous solution with a spray device;
The organic binder includes molasses and starch, and further comprises 10 to 30 parts by weight of silica fume with respect to 100 parts by weight of the molasses,
The inorganic binder is at least one selected from the group consisting of cement, slaked lime, bentonite and blast furnace slag,
The [C] material is, characterized in that at least any one or more selected from the group consisting of anthracite and CDQ (Coke Dry Quenching) dust, a method of manufacturing high iron briquettes. delete 8. The method of claim 7,
The boron compound aqueous solution,
Boric acid (Boric acid), borax (Borax) and metaboric acid (Metaboric acid), characterized in that it comprises at least any one selected from the group consisting of, the method of manufacturing high iron briquettes.
delete

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