Debris

Abstract

This product provides a waste removal material that can reduce the amount of natural resources used, such as obsidian and pumice, as raw materials. [Solution] A slag remover was produced by mixing a first pulverized material, which is made by crushing obsidian or pumice as the raw material, with a second pulverized material, which is made by crushing cuporus lag discharged in the molten metal production process using a cupola. Since a portion of the first pulverized material, which consists of obsidian or pumice, is replaced by the second pulverized material, which consists of cuporus lag, the amount of natural resources used, such as obsidian or pumice, can be reduced. In addition, since cuporus lag, which was previously discarded, can be reused, it can also contribute to reducing waste.

Description

Technical Field

[0001] The present invention relates to a dross removing material used for removing impurities from molten cast iron.

Background Art

[0002] In the manufacturing process of castings, when pouring molten cast iron from an electric furnace (including a holding furnace, etc.) or a ladle into a mold, before pouring, impurities (slag) floating on the surface of the molten cast iron in the ladle are removed. The slag is casting sand or the like adhering to recycled materials such as metal oxides and dams generated during casting. For removing the slag, commercially available dross removing materials obtained by crushing obsidian or pumice as raw stones are used (see Patent Document 1). When the dross removing material is put into the molten metal in the ladle, the slag floating on the surface of the molten metal is removed by a slag removal rod or the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, obsidian and pumice, which are the raw materials of the dross removing material, are natural resources, and in view of recent demands for a circular economy, it is preferable to reduce the consumption of such natural resources as much as possible.

[0005] Therefore, an object of the present invention is to provide a dross removing material capable of reducing the usage amount of natural resources such as obsidian and pumice as raw materials.

Means for Solving the Problems

[0006] To achieve the above object, the dross removing material of the present invention is a first pulverized body obtained by pulverizing obsidian or pumice as a raw stone, and A second pulverized body is obtained by pulverizing the cupola lag discharged in the molten metal generation process using a cupola, It is made by mixing these together. [Effects of the Invention]

[0007] According to the present invention, a portion of the first pulverized material, which consists of obsidian or pumice, is replaced by a second pulverized material, which consists of cuporus lag. This reduces the amount of natural resources used, such as obsidian and pumice. Furthermore, the cuporus lag removed during the process of producing molten cast iron using a cupola is not discarded as industrial waste, but is reused as a slag remover. Therefore, by reducing the amount of natural resources used and thus lowering casting costs, while simultaneously achieving waste reuse, this invention contributes to a circular economy. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram illustrating the molten metal production process; (a) shows the dissolution process, and (b) shows the impurity removal process. [Figure 2] This figure shows the mixing ratio and evaluation of the slag removal agent in Example 1. [Figure 3] This figure shows the mixing ratio and evaluation of the slag removal agent in Example 2. [Figure 4] This figure shows the mixing ratio and evaluation of the slag removal agent in Example 3. [Modes for carrying out the invention]

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] First, let's explain cuporus lag, which is used as a slag remover. Cuporus lag is discharged during the melting process in the production process of molten cast iron for casting, in which melting materials such as pig iron and iron scraps are melted and turned into molten metal.

[0011] As shown in Figure 1(a), a cupola 10 is used as a melting furnace in the melting process. The cupola 10 has a main body 11, combustion means such as hot air from tuyeres (air outlets) 12, a molten metal storage section 13, and a molten metal outlet 14. Coke 21, which is the combustion material, and the melting material 22 are sequentially fed into the main body 11 from the top. By burning the coke 21 with hot air from the tuyeres 12 located at the bottom of the main body 11, molten metal 23 is generated at the bottom of the main body 11 in which the melting material 22 has melted.

[0012] The molten metal storage section 13 is located in the middle of the flow path from the lower part of the main body 11 to the tapping section 14. The molten metal 23 generated in the main body 11 flows into the molten metal storage section 13 and is stored there. In the molten metal storage section 13, the cuporus lag 24 separated by specific gravity is removed from the molten metal 23. The molten metal 23 from which the cuporus lag 24 has been removed flows out from the tapping section 14 and is stored in the holding furnace 15.

[0013] Here, the cuporus lag 24 is a glassy substance mainly composed of silica (silicon dioxide), with alumina (aluminum oxide) and calcia (calcium oxide) also present. Furthermore, after being removed from the molten metal 23, the cuporus lag 24 is either rapidly cooled by being placed in a cooling pool, or naturally cooled (slowly cooled) by air without being placed in a cooling pool. The former is called water-cooled cuporus lag, and the latter is called air-cooled cuporus lag (slowly cooled cuporus lag). Whether water-cooled or air-cooled cuporus lag is discharged depends on the differences in the molten metal production equipment.

[0014] Before proceeding to the casting process (not shown) in which the molten metal 23 produced in the melting process is poured into a mold, an impurity removal process is performed. In the impurity removal process, as shown in Figure 1(b), a slag remover 25 is added to the holding furnace 15, and impurities (slag) floating on the surface of the molten metal 23 are removed. Slag is metal oxides that are formed when the surface of the molten metal 23 oxidizes while the molten metal 23 is stored in the holding furnace 15 or ladle, and foundry sand and other materials that adhere to the reused materials when weirs and other materials generated during casting are reused in the production of the molten metal 23. A slag removal rod 31 is used to remove the slag. While stirring the molten metal 23 to which the slag remover 25 has been added with the slag removal rod 31, the viscous slag adheres to the slag removal rod 31, and the slag removal rod 31 is removed from the molten metal 23 to scrape the slag out of the molten metal 23. Subsequently, the slag-removing rod 31, to which the slag has adhered, is placed on a slag collection cart (not shown) to knock off the slag and remove it from the slag-removing rod 31.

[0015] The slag remover 25 in this disclosure is used in the impurity removal process. The slag remover 25 is a mixture of a first pulverized material obtained by crushing obsidian or pumice as the raw material and a second pulverized material obtained by crushing cuporus lag 24 discharged in the dissolution process.

[0016] The first pulverized material is obtained by crushing obsidian or pumice as raw material, and commercially available pulverized material used as a slag remover is used. From the viewpoint of improving dispersibility in the molten metal 23 and increasing the contact area with the molten metal 23, it is preferable that the first pulverized material be as fine as possible. On the other hand, if it is made too fine, the heat resistance will be poor. For this reason, the average particle size of the first pulverized material is preferably 0.3 mm or more and 10 mm or less. Furthermore, from this viewpoint, the average particle size of the first pulverized material is more preferably 1 mm or more and 5 mm or less. In this specification, the average particle size is a value measured by laser diffraction.

[0017] Like the first pulverized material, from the perspective of improving the dispersibility in the molten metal 23 and increasing the contact area with the molten metal 23, and from the perspective of ensuring heat resistance, it is preferable that the average particle size of the second pulverized material is 0.3 mm or more and 10 mm or less. Further, from this perspective, it is more preferable that the average particle size of the second pulverized material is 1 mm or more and 5 mm or less. Also, from the point of improving handling properties, it is preferable that the average particle size of the second pulverized material is equivalent to that of the first pulverized material. Specifically, the ratio (D2 / D1) of the average particle size D2 of the second pulverized material to the average particle size D1 of the first pulverized material is preferably 0.9 to 1.1, and more preferably 0.95 to 1.05.

[0018] The pulverization treatment method of the cupola slag 24 when manufacturing the second pulverized material is not particularly limited, and it can be carried out using a known pulverizer or crusher. For example, it is carried out by pulverizing the cupola slag 24 with various pulverizing media such as iron rods, iron balls, and aluminum balls.

[0019] By mixing the first pulverized material and the second pulverized material to form the dross removal material 25, the cupola slag 24 is not discarded as industrial waste but reused, thus contributing to circular economy. Also, to reuse the cupola slag 24 as the dross removal material 25, it is sufficient to simply pulverize the cupola slag 24 discharged from the melting process, and the cost for reuse is relatively low. Therefore, the amount of natural resources such as obsidian and pumice used in the dross removal material 25 can be reduced, and the casting cost can be reduced compared to the case of using only the conventional commercially available dross removal material.

[0020] The method of mixing the first pulverized material and the second pulverized material is not particularly limited. Examples of the mixing method of the first pulverized material and the second pulverized material include a drum rotation method, a blade rotation method, and the like.

[0021] The mixing ratio of the second pulverized material to the first pulverized material is preferably 5% by mass or more and 50% by mass or less. By setting the mixing ratio of the second pulverized material to the first pulverized material within the above range, when using the slag removal material 25 mixed with the cupola slag 24, the slag removal property (ease of removing slag from the molten metal 23) and the slag knocking-off property (ease of slag peeling when knocking off the slag from the slag removal rod 31) can be improved. From this perspective, the mixing ratio of the second pulverized material to the first pulverized material is more preferably 10% by mass or more and 30% by mass or less.

[0022] When mixing the second pulverized material with the first pulverized material to form the slag removal material 25, the pulverized body of the cupola slag 24 used as the second pulverized material may be either the pulverized body of water-cooled cupola slag or the pulverized body of air-cooled cupola slag, or both may be mixed and used. Also in this case, the average particle size of the pulverized body of water-cooled cupola slag and the average particle size of the pulverized body of air-cooled cupola slag are each made equivalent to the average particle size of the second pulverized material described above. When these two pulverized bodies are mixed to form the second pulverized material, in the case of having different facilities for water cooling and air cooling for the cooling of the cupola slag 24, the cupola slag 24 discharged from both facilities can be reused as the slag removal material 25.

[0023] From the perspective of improving the slag removal property, within the range of the mixing ratio of the second pulverized material to the first pulverized material described above, it is preferable to use more of the pulverized body of water-cooled cupola slag than the pulverized body of air-cooled cupola slag. Specifically, when the mixing ratio of the second pulverized material to the first pulverized material is 10% by mass or more and 30% by mass or less, the ratio (W2 / W1) of the mass% (W2) of the second pulverized material to the mass% (W1) of the pulverized body of water-cooled cupola slag is preferably 0.04 to 1.0, and more preferably 0.099 to 0.111.

Examples

[0024] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. In the following, “%” is based on mass unless otherwise specified.

[0025] [Example 1] 1. Manufacturing of slag removal material containing crushed cuporus lag As the first pulverized material, a commercially available slag remover made from obsidian (product name: Nice Catch, manufactured by Kinsei Matec Co., Ltd.) was used, and as the second pulverized material, a slag remover was manufactured using water-cooled cuporus lag or air-cooled cuporus lag discharged from the molten metal generation equipment installed at the applicant's factory. The main physical properties of the water-cooled cuporus lag and air-cooled cuporus lag are shown in the following table. [Table 1]

[0026] The first pulverized material had an average particle size D1 of 1 mm. Water-cooled or air-cooled cuporus lag was pulverized using a pulverizer (vibration mill manufactured by Chuo Kakoki Co., Ltd., pulverizing medium: iron rod) to achieve an average particle size D2 of 1 mm. The average particle size D2 of the second pulverized material after pulverization was measured using a laser diffraction particle size distribution analyzer.

[0027] Next, the first and second pulverized materials were put into a mixer (manufactured by Tombo Industries Co., Ltd., type: blade rotation type) in a mixing ratio of 90% by mass of the first pulverized material and 10% by mass of the second pulverized material, as shown in Figure 2, and thoroughly mixed to obtain a sludge removal material containing cuporus lag pulverized material. The following was used as the second pulverized material. (a) Crushed material of water-cooled cuporus lag (average particle size D2: 1 mm) (b) Crushed material of air-cooled cuporus lag (average particle size D2: 1 mm)

[0028] 2. Evaluation The slag removal properties of the slag remover in Example 1 were evaluated. Slag removal properties were evaluated by comparing the ease of removing slag from the molten cast iron with the case where only commercially available slag removers made from obsidian or pumice were used, by comparing the ease of removing slag with the case where only commercially available slag removers made from obsidian or pumice were used, by comparing the ease of removing slag with the case where only commercially available slag removers made from obsidian or pumice were used, by comparing the ease of removing slag with the case where only commercially available slag removers made from obsidian or pumice were used. Both evaluations were subjective evaluations by workers engaged in slag removal work and were evaluated on a four-point scale: better than commercially available slag removers (◎), equivalent to commercially available slag removers (○), inferior to commercially available slag removers but usable (△), and not usable at all (×).

[0029] As a result, as shown in Figure 2, it was confirmed that in both cases where air-cooled cuporus lag and water-cooled cuporus lag were used as the second pulverized material, the evaluation was at least that of being usable (△), although inferior to commercially available sludge removers. Furthermore, in Example 1a, where water-cooled cuporus lag was used as the second pulverized material, it was confirmed that the sludge removal performance was equivalent to that of commercially available sludge removers. On the other hand, in Example 1b, where air-cooled cuporus lag was used as the second pulverized material, it was confirmed that the sludge removal performance was better than that of commercially available sludge removers.

[0030] [Example 2] 1. Manufacturing of slag removal material containing crushed cuporus lag In contrast to Example 1, the first and second pulverized materials were mixed in a ratio of 90% by mass for the first pulverized material and 10% by mass for the second pulverized material. Then, as shown in Figure 3, a sludge remover was obtained by mixing a water-cooled cuporus lag pulverized material (average particle size D2: 1 mm) and an air-cooled cuporus lag pulverized material (average particle size D2: 1 mm) in the following mixing ratio. (a) Water-cooled cuporus lug: 9.7% by mass, air-cooled cuporus lug: 0.3% by mass (b) Water-cooled cuporus lug: 9.6% by mass, air-cooled cuporus lug: 0.4% by mass (c) Water-cooled cuporus lug: 9.1% by mass, air-cooled cuporus lug: 0.9% by mass (d) Water-cooled cuporus lug: 9% by mass, air-cooled cuporus lug: 1% by mass (e) Water-cooled cuporus lug: 5% by mass, air-cooled cuporus lug: 5% by mass

[0031] 2. Evaluation As shown in Figure 3, in all of Examples 2a to 2e, it was confirmed that the slag removal and slag cleanup performance was at least as good as (△), although inferior to commercially available slag removers. Furthermore, in Example 2a, it was confirmed that the slag cleanup performance was equivalent to that of commercially available slag removers. In Example 2b, it was confirmed that the slag removal performance was equivalent to that of commercially available slag removers, and the slag cleanup performance was better than that of commercially available slag removers. In Example 2c, it was confirmed that both the slag removal and slag cleanup performance were better than that of commercially available slag removers. In Example 2d, it was confirmed that the slag removal performance was better than that of commercially available slag removers, and the slag cleanup performance was equivalent to that of commercially available slag removers. In Example 2e, it was confirmed that the slag removal performance was better than that of commercially available slag removers.

[0032] (Example 3) 1. Manufacturing of slag removal material containing crushed cuporus lag Unlike Examples 1 and 2, the second pulverized material was prepared using the same mixing ratio as in Example 2d, which consisted of water-cooled cuporus lag pulverized material (average particle size D2: 1 mm) and air-cooled cuporus lag pulverized material (average particle size D2: 1 mm). Then, as shown in Figure 4, the first and second pulverized materials were mixed in the following ratio to obtain a sludge removal material. (a) First pulverized material: 80% by mass, Second pulverized material: 20% by mass (b) First pulverized material: 70% by mass, Second pulverized material: 30% by mass

[0033] 2. Evaluation As shown in Figure 4, both Example 3a and Example 3b were confirmed to be superior to commercially available sludge removal materials in terms of sludge removal and sludge removal properties. [Explanation of Symbols]

[0034] 10...Cupola, 23...Molten metal, 24...Cupola slag, 25...Slag removal material.

Claims

1. A first pulverized body obtained by crushing obsidian or pumice as the raw material, A second pulverized body is obtained by pulverizing the cupola lag discharged in the molten metal generation process using a cupola, A slag remover made by mixing these materials.

2. The slag remover according to claim 1, wherein the mixing ratio of the second pulverized material to the first pulverized material is 5% by mass or more and 50% by mass or less.

3. The slag remover according to claim 1, wherein the average particle size of the first pulverized material and the average particle size of the second pulverized material are equivalent.

4. The sludge remover according to any one of claims 1 to 3, wherein the second pulverized material is a mixture of a water-cooled cuporus lag pulverized material obtained by water-cooling the cuporus lag and an air-cooled cuporus lag pulverized material obtained by air-cooling the cuporus lag, and the amount of water-cooled cuporus lag mixed is greater than the amount of air-cooled cuporus lag pulverized material.

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