Blast furnace taphole plugging mud material

Abstract

To provide a mud material that shows excellent slipperiness and shape retention even when the amount of a clay component is reduced, and has excellent corrosion resistance.SOLUTION: A mud material prepared by blending a refractory raw material and an organic binder, is made to include organic modified clay mineral. Organic bentonite is preferably used as the organic modified clay mineral. The mud material has a composition including 8 mass% or less (excluding zero) of the organic modified clay mineral in 100 mass% of the refractory raw material. Thereby, a mud material showing excellent slipperiness and shape retention and having excellent corrosion resistance, can be obtained even when the amount of a conventional common clay component is reduced.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a mud material used for plugging a blast furnace taphole or the like. [Background technology]

[0002] As a mud material for plugging blast furnace tapholes and the like, for example, compositions are used which are made by blending refractory aggregates such as rosestone, chamotte, alumina, silicon carbide, and carbon, sintered materials such as clay components (fire clay), silicon metal, and silicon nitride, and organic binders such as tar and phenol resin.

[0003] The clay component contributes to the slipperiness and shape retention of the mud material during filling. However, the clay component reacts with blast furnace slag to form low-melting compounds. Therefore, using a large amount of clay component can rapidly increase the taphole diameter during tapping. On the other hand, reducing the clay component ratio can make it difficult or impossible to push the material out of the filler and fill the taphole.

[0004] Patent Document 1 discloses a mud material containing 3% by weight or less of a clay component and 2 to 20% by weight of carbon black, with the aim of providing a mud material that has excellent corrosion resistance and good filling and opening properties. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-119754 [Non-patent literature]

[0006] [Non-Patent Document 1] Minase, Shin: Oleoscience, Vol. 14, No. 5 (2014) Summary of the Invention [Problem to be solved by the invention]

[0007] Patent Document 1 claims that adding carbon black makes it possible to obtain a mud material with excellent lubricity and shape retention, even when the clay content is reduced. However, carbon black is easily dissolved in molten iron, which reduces corrosion resistance. Furthermore, even when carbon black is added, there is still the problem of poor lubricity and shape retention when the clay content is reduced to 3% by mass or less.

[0008] The present invention has been proposed in view of the above-mentioned conventional circumstances, and provides a rubber composition that exhibits good slip properties and shape retention even with a reduced clay content, and also has excellent corrosion resistance. For blocking blast furnace tap hole The object is to provide a mud material. [Means for solving the problem]

[0009] The present invention is a refractory material comprising a refractory raw material and an organic binder. For blocking blast furnace tap hole This mud material contains organically modified clay minerals.

[0010] The organically modified clay mineral is preferably organic bentonite.

[0011] The organically modified clay mineral is contained in an amount of 8% by mass or less (excluding zero) in 100% by mass of the refractory raw material. [Effects of the Invention]

[0012] The above composition allows for good slip properties and shape retention, and also excellent corrosion resistance, even with a reduced amount of conventional clay content. For blocking blast furnace tap hole Mud material is obtained. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 shows a sample holder for measuring extrusion resistance. [Figure 2] FIG. 1 is a schematic diagram of an apparatus for measuring extrusion resistance. [Figure 3] FIG. 1 is a diagram showing the relationship between the consistency of a mud material and the extrusion resistance value. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the present invention will be described in detail below. Note that the embodiments described below do not unduly limit the content of the present disclosure described in the claims, and not all of the configurations described in the present embodiments are necessarily essential as means for solving the problems of the present disclosure.

[0015] The present invention relates to a mud material containing an organically modified clay mineral, which is prepared by blending a refractory raw material with an organic binder, such as tar or phenol resin.

[0016] <Organically modified clay minerals> An example of the organically modified clay mineral is organic bentonite, which is an organically modified clay mineral in which the layer surface of montmorillonite is reacted with quaternary ammonium ions (see Non-Patent Document 1).

[0017] Unlike unmodified bentonite, the organic bentonite swells in organic solvents. Adding organic bentonite to mud improves shape retention and slipperiness with less amount than conventional unmodified bentonite or general clay components. This improves the corrosion resistance of the mud.

[0018] The amount of organic bentonite added is preferably 8% by mass or less, more preferably 3% by mass or less. There is no lower limit, but 0.1% by mass or more is preferred, and 0.3% by mass or more is more preferred. By adding organic bentonite in this range, shape retention and slipperiness are improved, and corrosion resistance is also improved, without the need to add conventional clay components. Here, conventional clay components refer to kibushi clay, gairome clay, ball clay, unmodified bentonite, etc.

[0019] <Clay raw materials (other than organically modified clay minerals)> The clayey raw material other than the organically modified clay mineral of the present invention is preferably contained in an amount of 10% by mass or less of the refractory raw material, more preferably 3% by mass or less, and even more preferably no added. By reducing the amount of the clayey raw material, the corrosion resistance of the mud material is improved.

[0020] <Refractory raw materials> The types of refractory raw materials used in the mud material according to the present invention are the same as those used in conventional mud materials, and examples of the main raw materials that can be used include alumina raw materials, clay raw materials, silicon carbide raw materials, silicon nitride raw materials, and carbonaceous raw materials.

[0021] In addition, carbon black, silica fume, clayey raw materials, etc. can be added to further impart plasticity during plugging, so long as the desired properties are obtained. In the present invention, as will be described later, the amount of binder added is specified as an outer percentage of the other raw materials excluding the binder, and therefore, for convenience, the binder is not included in the refractory raw material.

[0022] <Alumina raw materials> Examples of alumina raw materials that can be used include bauxite and alumina shale with an Al2O3 content of 80% by mass or more, and fused alumina, sintered alumina, and calcined alumina with an Al2O3 content of 95% by mass or more. If the alumina raw material is contained in an amount of 35% by mass or less in the refractory raw material, corrosion resistance against slag is improved. A particularly preferred range is 20 to 30% by mass.

[0023] Although it is preferable to use an alumina-based raw material as the refractory raw material to ensure corrosion resistance, it is also possible to adopt a refractory raw material formulation in which no alumina-based raw material is added. In this case, a siliceous raw material such as rosewood or silica stone can be used instead of the alumina-based raw material. Furthermore, the siliceous raw material may be added to the refractory raw material in addition to the alumina-based raw material within the above-mentioned range.

[0024] <Silicon carbide raw materials> Silicon carbide raw materials can be used as needed. The use of silicon carbide raw materials is particularly effective for improving corrosion resistance against slag. It is preferable to add silicon carbide raw materials in an amount of 30 mass% or less to the refractory raw materials. If the amount is 30 mass% or less, corrosion resistance against molten iron is improved.

[0025] <Silicon nitride raw materials> Silicon nitride raw materials include silicon nitride and silicon iron nitride, and either one alone or a mixture of both can be used. It is preferable to add 10% by mass or more of silicon nitride raw materials to the refractory raw materials. When the silicon nitride raw materials are 10% by mass or more, SiC bonds are formed during use, improving strength.

[0026] <Carbonaceous raw material> As the carbonaceous raw material, one or more of petroleum coke, coal coke, anthracite, natural graphite, artificial graphite, carbon black, etc., each having a carbon content of 80 mass % or more, can be used as needed.

[0027] <Metal powder> Furthermore, various metal powders may be added as needed to enhance the strength. Examples of metal sources that can be used include aluminum, silicon, ferrosilicon, titanium, Al-Si alloys, and magnesium diboride (MgB2). The examples in Table 1 below show examples in which no metal powder is used.

[0028] <Binder> The binder (organic binding agent) can be tar, pitch, phenolic resin, etc. The amount of binder added is preferably in the range of 5 to 30 mass % based on the total mass of the refractory raw material. If necessary, a solvent such as creosote can be added to these binders. [Example]

[0029] The mud material of the present invention will be described in detail below with reference to examples and comparative examples.

[0030] <Test sample> Refractory raw material formulations were prepared according to Table 1. In Table 1, formulations A and B (comparison products) are outside the scope of the present invention and contain conventional clay components but no organic bentonite. Formulations C to H (present invention products) are within the scope of the present invention and contain organic bentonite. Formulation I (comparison product) is outside the scope of the present invention and contains neither conventional clay components nor organic bentonite. Formulations J to L (present invention products) are based on formulation E and have different amounts of refractory raw materials, and all are within the scope of the present invention.

[0031] The above refractory raw material mixture was mixed in a universal mixer for 3 minutes, and then a binder kept at 60°C was added and mixed for 20 minutes to obtain test samples. The test samples were kept at 60°C, and the shape retention and slip properties of compounds A to I were investigated as described below. Compounds A, E, J, K, and L were also subjected to a corrosion resistance test, which is represented by the corrosion index in Table 1.

[0032] <Shape retention> Shape retention was evaluated using a needle penetration tester as specified in JIS R2506 "Consistency test method for fire-resistant mortar." The consistency value is the length of penetration of a needle in 5 seconds, measured in 0.1 mm increments, multiplied by 10 (absolute number). The smaller the consistency value, the better the shape retention was judged to be.

[0033] <Slipperiness> The slipperiness was evaluated based on the extrusion load value by a test method commonly known as the "Marshall test" by those skilled in the art. The test equipment and test method are as follows.

[0034] Figure 1 shows the stainless steel sample holder 1 used in the push-out load measuring device shown in Figure 2. The tip of the cavity is nozzle-shaped, and the dimensions of each part of the stainless steel sample holder 1 used here are (L1 = 9 cm, L2 = 6 cm, L3 = 26 cm, L4 = 12 cm, L5 = 2 cm).

[0035] Figure 2 shows a push-out load measuring device that uses the stainless steel sample holder. Sample holder 1, filled with a sample placed on pedestal 3, is set on sample push-out face plate 4. A cylinder head 2 is inserted into the rear end of sample holder 1, and the cylinder head 2 is moved at a predetermined speed to evaluate the push-out load value of the sample from the tip of sample holder 1.

[0036] First, the sample holder 1 is filled with a test sample kept at 60°C, and the extrusion speed of the cylinder head 2 is set to 10 mm / sec. At this time, the load applied to the sample extrusion face plate 4 is continuously measured while the mud material is flowing out from the bottom, and the maximum load is taken as the extrusion load value. The smaller the extrusion load value, the better the slipperiness is judged to be.

[0037] Next, we investigated the changes in shape retention and slipperiness as the amount of binder added increased. After kneading the test sample, a small amount of binder was further added, and the consistency and extrusion load values ​​were measured after 5 minutes of kneading. The above procedure was repeated until the extrusion load value decreased to about 2 kN, and the relationship between the consistency value and the extrusion load value was measured. The results are shown in Figure 3.

[0038] In Figure 3, the comparative compound, Compound A, contains 10% by mass of conventional clay components, and although it has low consistency and push-out load values, it has poor corrosion resistance, as will be described later. Compound B, also a comparative compound, has the conventional clay component reduced to 1% by mass, but the push-out load value changes significantly with changes in consistency, making it difficult to optimize the consistency and push-out load value by adjusting the binder amount.

[0039] The present invention's compounds C to G have small changes in the extrusion load value in response to changes in consistency, making it easy to optimize the consistency and extrusion load value by adjusting the binder amount. The present invention's compound H has a slightly larger change in the extrusion load value in response to changes in consistency, but it is still possible to optimize the consistency and extrusion load value.

[0040] In the case of the comparative compound I, if the organically modified clay mineral or the conventional viscosity component is not added in an attempt to reduce the extrusion load value, the consistency value becomes too high and shape retention is lost.

[0041] From the above, it can be seen that the product of the present invention has a small change in extrusion load value in response to a change in consistency. In addition, since the extrusion load value and consistency are both small, it can be evaluated as having excellent slip properties and shape retention.

[0042] <Corrosion resistance> The test specimens were pressed into the specified shape using an Amsler testing machine and subjected to a corrosion resistance test using the rotating drum method. Blast furnace slag was used as the corrosion agent. The test temperature and time were 1550°C x 2 hours. After the test, the specimens were cut and the corrosion depth was measured. The corrosion depth of the comparative specimen, specimen A, was set at 100, and the corrosion index was calculated.

[0043] As can be seen from Table 1, in order to equalize the shape retention and extrusion load values, the amount of organic bentonite added was 1% compared to the 10% ball clay added to the comparative sample A, with the difference being replaced with alumina stone, alumina shale, fine alumina powder, and coke powder. All of the products of the present invention showed excellent shape retention, slipperiness, and corrosion resistance.

[0044] Although the present embodiment has been described in detail above, it will be readily apparent to those skilled in the art that many modifications are possible without substantially departing from the novel features and advantages of the present disclosure. Therefore, all such modifications are included within the scope of the present disclosure. For example, a term described at least once in the specification together with a different term having a broader or equivalent meaning may be replaced with that different term anywhere in the specification. Furthermore, the configuration of the present embodiment is not limited to that described in the present embodiment, and various modifications are possible.

[0045] [Table 1] [Explanation of symbols]

[0046] 1. Sample holder 2 cylinder heads 3. Pedestal 4 Face plate for sample extrusion 5. Push-out load measuring device

Claims

1. A blast furnace taphole plugging mud material comprising a refractory raw material and tar or phenol resin, A mud material for plugging blast furnace tapholes, characterized by containing an organically modified clay mineral.

2. 2. The blast furnace taphole plugging mud material according to claim 1, wherein the organically modified clay mineral is organic bentonite.

3. 3. The blast furnace taphole plugging mud material according to claim 1, wherein the organically modified clay mineral is contained in an amount of 3% by mass or less (excluding zero) based on 100% by mass of the refractory raw material.

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