Auxiliary material for steelmaking and production method thereof

Abstract

To provide an auxiliary material for steelmaking capable of easily adjusting the bulk specific gravity, generating little CO2 during use, and contributing to the effective utilization of rock wool waste material.SOLUTION: An auxiliary material for steelmaking comprises 1-95 mass% of rock wool as a main raw material, 1-95% of granules and 1-50% of a binder as auxiliary raw materials. A first form of the auxiliary material comprises granules of at least one of fired ash, fly ash, silica sand and brick waste, and papermaking sludge. A second form of the auxiliary material comprises granules of at least one of calcined ash and silica powder. A third form of the auxiliary material comprises granules of at least one of silica dust, fly ash, silica sand, brick waste, coke, bentonite, glass powder, clay, magnesia, magnesia clinker and magnesia carbon, and papermaking sludge. The binder comprises at least one of vinyl acetate, lignin, molasses, sodium silicate, alpha starch, corn starch, carboxymethyl cellulose, thermosetting resin and thermoplastic resin.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to secondary steelmaking materials such as heat-insulating materials and inhibitors, and to a method for producing the same. [Background technology]

[0002] In the iron and steelmaking industries, various steelmaking auxiliary materials are used, such as thermal insulation materials that are added to the surface of molten metal in hot metal ladles or ladles to cover the surface of the molten metal and prevent the temperature of the molten metal from dropping, and inhibitors that are added to the slag that forms on the surface of molten steel in converters to create an escape route for gas and suppress the foaming and expansion of the slag to prevent it from boiling over.

[0003] Currently, the most common insulation materials are rice husks left over after threshing rice, and sludge-burned products made by burning sludge generated in paper mills in a rotary kiln. Rice husks are not cheap these days, but they are cheap because of the carbon dioxide (CO 2 ), and there are problems with unstable deliveries and the securing of stock levels. Sludge calcined products have problems with high analytical values ​​for the chemical components sulfur and phosphorus, limited deliveries, and a higher bulk density than rice husks, making them more expensive.

[0004] Currently, the mainstream inhibitor is a synthetic product made by extruding a mixture of raw sludge from paper mills and industrial waste from converters and electric furnaces into a briquette or cylindrical shape. Since synthetic products are made from raw sludge as the main raw material, they emit an ammonia odor during production. In addition, synthetic products contain carbonaceous matter, and this carbon reacts with FeO contained in the slag of molten steel to produce CO. 2 This CO 2The gas increases the gas pressure in the slag, causing the slag to expand. From the viewpoint of suppressing slag foaming, it is preferable to keep the carbon content in the chemical composition of the suppressor low, as this has the opposite effect. This is because a vigorous reaction is observed when the T-Fe content in the slag is high, but conversely, when the T-Fe content in the slag is low, the carbon content has an exothermic effect, contributing to the fluidity of the slag, and improving the gas release, which helps to calm the reaction. However, synthetic products have a low bulk density, so they do not break down the foam in the slag sufficiently, and a large amount of CO 2 is discharged.

[0005] In this way, conventional steelmaking sub-materials emit little CO during use. 2 Global warming caused by solar panels is becoming a problem.

[0006] In recent years, industrial waste has been utilized as secondary materials for steelmaking. For example, Patent Document 1 describes a foaming inhibitor using construction waste and automobile waste, Patent Document 2 describes a secondary material for steelmaking using shredder dust, Patent Document 3 describes a slag foaming inhibitor by the present applicant using biomass combustion ash, Patent Document 4 describes a foaming inhibitor for steelmaking using shredder dust, fine silicon and / or fine silicon carbide, and combustion ash, and Patent Document 5 describes a heat-insulating material using used MgO-C bricks from converters. Patent Document 6 describes secondary materials for steelmaking using fibrous waste such as asbestos, glass fiber, rock wool, slag wool, and FRP resin.

[0007] Rock wool and slag wool are produced by melting rocks, blast furnace slag, and silica at high temperatures, blowing them away with centrifugal force, and processing them into fibers, and are used as heat insulation, sound absorption, and fireproofing materials, but a large amount of waste material is generated during production.Waste rock wool is either disposed of in landfills or used as a bulking agent for cement, but there is a demand for its effective use and recycling. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 5749386 specification [Patent Document 2] JP 2018-178171 A [Patent Document 3] JP 2016-196686 A [Patent Document 4] JP 2015-57506 A [Patent Document 5] JP 2009-132951 A [Patent Document 6] JP 2007-253031 A Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of the above-mentioned problems of the conventional art, and is capable of easily adjusting the bulk density and reducing the amount of CO 2 The objective of the present invention is to provide a steelmaking auxiliary material that completely eliminates the generation of waste rock wool and contributes to the effective use of waste rock wool, and a method for producing the same. [Means for solving the problem]

[0010] The means for solving the above problems are as follows. (1) Steelmaking auxiliary materials are: The main raw material is 1-95% by mass of rock wool, the secondary raw materials are 1-95% powder material, and 1-50% binder. (2) In the above-mentioned means 1, The auxiliary materials include at least one of powdered materials selected from the group consisting of burnt ash, fly ash, silica sand, and brick waste, and papermaking sludge. The papermaking sludge may be used in small amounts or may not be used at all as long as it does not cause any problems in terms of strength. (3) In the above-mentioned means 1, The auxiliary raw materials include at least one powder of calcined ash and silica powder. (4) In the above-mentioned means 1, The auxiliary raw materials include at least any one of powdered materials selected from the group consisting of silica powder, fly ash, silica sand, brick waste, coke, bentonite, glass powder, clay, magnesia, magnesia clinker, and magnesia carbon, and papermaking sludge. (5) In any one of the above means 1 to 4, The binder includes at least one of vinyl acetate, lignin, molasses, sodium silicate, alpha starch, corn starch, carboxymethyl cellulose, a thermosetting resin, and a thermoplastic resin.

[0011] The manufacturing method of steelmaking auxiliary materials is as follows: A wetting process in which 1 to 95% by mass of rock wool as a main raw material is wetted with water; A gelatinization step of adding a mixture of a thickener and water to the wet rock wool to gelatinize it; A kneading step of mixing and kneading the gelatinized rock wool with 1 to 95% powder material and 1 to 50% binder as auxiliary raw materials; an extrusion process for extruding the kneaded raw material into a predetermined shape and cutting it; Includes. It is preferable that the method further comprises a drying step of drying the extruded product. Effect of the Invention

[0012] According to the present invention, the bulk density can be easily adjusted by changing the mixing ratio of the auxiliary raw materials. In addition, since rock wool is used as the main raw material, the CO 2 This will eliminate the generation of waste rock wool, which will greatly contribute to the realization of a carbon-free society, while at the same time contributing to the effective use of waste rock wool. By reusing rock wool that is discarded in large quantities as a raw material again, the disposal costs for rock wool manufacturers will be reduced to zero, which will enable significant cost reductions. [Brief description of the drawings]

[0013] [Figure 1] 1 is a flowchart showing a manufacturing process of a steelmaking secondary material according to an embodiment of the present invention. [Diagram 2]FIG. 1 is a block diagram showing a manufacturing apparatus for steel-making secondary materials according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described.

[0015] Steelmaking secondary materials that can be used as heat-insulating materials or inhibitors contain 1 to 95 mass %, preferably 5 to 20%, of rock wool as a main raw material, 1 to 95% by mass, preferably 20 to 80% by mass of powder as an auxiliary raw material, and 1 to 50% by mass, preferably 0.5 to 20% by mass of a binder.

[0016] The main raw material, rock wool, is made from recycled rock wool waste generated during the rock wool manufacturing process.

[0017] The first type of powdered auxiliary material contains at least one of powdered waste materials from paper mills, such as burnt ash, fly ash, silica sand, and brick waste, and paper sludge, in order to create a mixture suitable for thermal insulation materials with low bulk density. If there is no problem with strength, the amount of paper sludge may be small, or it may not be used at all.

[0018] The second type of powdered auxiliary material contains at least one of powdered calcined ash and silica powder in order to obtain a blend suitable for a thermal insulation material having a bulk density greater than that of the first type.

[0019] The third type of powdered auxiliary raw material has a bulk density greater than that of the second type, making it suitable for use with an inhibitor, and contains at least one of powdered silica stone, fly ash, silica sand, brick waste, coke, bentonite, glass powder, clay, magnesia, magnesia clinker, and magnesium carbon, as well as paper sludge to maintain green strength.

[0020] The binder includes at least one of vinyl acetate, lignin, molasses, sodium silicate, alpha starch, corn starch, carboxymethyl cellulose, a thermosetting resin, and a thermoplastic resin.

[0021] Next, a method for producing the steelmaking secondary material of the embodiment will be described.

[0022] As shown in Figs. 1 and 2, the method for producing steelmaking secondary materials includes a rock wool wetting step, a rock wool gelatinization step, a rock wool kneading step, an extrusion step, and a drying step.

[0023] In the rock wool wetting process, a predetermined amount of rock wool is weighed as the main raw material and wetted with water. Rock wool waste stored in a raw material yard in a loose state is fed into a main raw material storage device 11, and a constant amount is continuously fed to a mixer 13 by a constant feeder 12, and water is added to wet the rock wool.

[0024] In the rock wool gelatinization process, a mixture of thickener and water is added to the rock wool moistened in the rock wool wetting process and kneaded and gelatinized in the mixer 13. As the mixer 13, a ribbon mixer with double ribbon-shaped blades arranged horizontally, or a mortar mixer with vertical stirring blades for making mortar can be used. As the thickener, alpha starch, corn starch, lignin, carboxymethyl cellulose, poval, bentonite, clay, etc. can be used.

[0025] In the rock wool kneading process, rock wool gelatinized in the mixer 13 is introduced into the kneader 14, while a constant amount of powdered material stored in the auxiliary raw material storage device 11a is continuously fed by the constant-volume feeder 12a and, together with the binder contained in the binder tank 11b, is fed into the kneader 14 and kneaded. As the kneader 14, a mix muller, a tire-type, or a roller-type kneader can be used.

[0026] The specific gravity can be adjusted by changing the type and composition of the binder mixed in the rock wool kneading process.

[0027] In the extrusion process, the raw material kneaded in the rock wool kneading process is extruded and cut into a predetermined shape using an extrusion molding machine 15. A pelletizer can be used as the extrusion molding machine 15. The shape after extrusion and cutting is preferably 5 to 10 mm in diameter and 10 to 15 mm in length for a heat insulating material, and 50 to 60 mm in diameter and 50 to 60 mm in length for a suppressing material.

[0028] In the drying process, the extruded molded product is dried in a light drying oven 16. As the light drying oven 16, a propane burner, a net type dryer, a cart insertion type drying oven, a rotary kiln, or the like can be used.

[0029] <Example 1 (Thermal insulation material)> Table 1 shows the heat insulation material of the present invention, which is manufactured by the above-mentioned method using a mixture of 30% by mass of rock wool as the main raw material, 60% by mass of calcined ash as a powdered secondary raw material, and 2% by mass of a binder, in comparison with conventional heat insulation materials (calcined sludge products and rice husks). [Table 1]

[0030] Table 2 shows a comparison between a conventional heat insulating material (sludge carbonized material) and the heat insulating material of the present invention. [Table 2] As shown in Table 2, the thermal insulation material of the present invention does not emit any CO2, produces no smoke or dust, and greatly improves the working environment. Its specific gravity is also smaller than that of conventional products, so its unit cost is smaller and its price is cheaper.

[0031] Example 2 (Inhibitor) Table 3 shows a comparison of the inhibitor of the present invention, which is manufactured by the above-mentioned method using a mixture of 10% by mass of rock wool as the main raw material, 70% by mass of calcined ash as a powdered secondary raw material, and 2% by mass of binder, with conventional inhibitors (those used 50 to 60 years ago, 30 to 40 years ago, and those currently in use). [Table 3]

[0032] Table 4 shows a comparison between the conventional inhibitor (sludge char) and the inhibitor of the present invention. [Table 4] As shown in Table 4, the suppressor of the present invention 2 There is no generation of dust or smoke, which greatly improves the working environment and also makes the price cheaper.

[0033] The steelmaking secondary material according to the embodiment of the present invention can easily adjust the bulk density by changing the mixing ratio of the secondary raw materials. In addition, since rock wool is used as the main raw material, it is possible to reduce CO 2 This will reduce the amount of waste rock wool generated, which will contribute greatly to the realization of a carbon-free society, while also contributing to the effective use of waste rock wool. In other words, by reusing rock wool that is discarded in large quantities as a raw material again, the cost of disposal will become zero for rock wool manufacturers, enabling significant cost reductions. [Explanation of symbols]

[0034] 11...Raw material storage device 11a…Auxiliary raw material storage device 11b…Binder tank 12,12a…Quantitative supply device 13,13a…Mixing device 14...Kneading device 15...Extrusion device 16...Drying device

Claims

1. A steelmaking auxiliary material containing 1-95% by mass of rock wool as the main raw material, 1-95% powder material as auxiliary raw materials, and 1-50% binder.

2. 2. The steelmaking secondary material according to claim 1, wherein the secondary raw materials include at least one of powdered material selected from the group consisting of burnt ash, fly ash, silica sand, and brick waste, and papermaking sludge.

3. 2. The steelmaking auxiliary material according to claim 1, wherein the auxiliary raw material contains at least one powder of calcined ash and silica powder.

4. 2. The steelmaking auxiliary material according to claim 1, comprising, as the auxiliary raw materials, at least one powder of silica powder, fly ash, silica sand, brick waste, coke, bentonite, glass powder, clay, magnesia, magnesia clinker, and magnesia carbon, and papermaking sludge.

5. 2. The steelmaking auxiliary material according to claim 1, wherein the binder comprises at least one of vinyl acetate, lignin, molasses, sodium silicate, alpha starch, corn starch, carboxymethyl cellulose, a thermosetting resin, and a thermoplastic resin.

6. A wetting step of wetting 1 to 95% by mass of rock wool as a main raw material with water; A gelatinization process in which a mixture of a thickener and water is added to the wet rock wool to gelatinize it; A kneading step of mixing and kneading the gelatinized rock wool with 1 to 95% powder material and 1 to 50% binder as auxiliary materials; an extrusion process for extruding the kneaded raw material into a predetermined shape and cutting it; A method for producing steelmaking auxiliary materials comprising the steps of:

7. The method for producing a steelmaking secondary material according to claim 6, further comprising a drying step of drying the extruded product.

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