Technical field
[0001]
　The present invention relates to a chromium-free patching refractory material applied to the lining of a waste treatment furnace or a coal gasification furnace. The waste treatment furnace is a concept including a waste melting furnace and a waste incinerator.
Background technology
[0002]
　An amorphous refractory containing a chromium oxide raw material having a high melting point and excellent corrosion resistance is generally used for the lining of a waste treatment furnace or a coal gasification furnace (see, for example, Patent Document 1). However, amorphous refractories containing chromic oxide raw materials have problems such as hexavalent chromium being feared to be generated at the time of disposal after use, and a strict management system is required. Amorphous refractories that do not contain, that is, chrome-free amorphous refractory are also used. As a chromium-free amorphous refractory, for example, an amorphous refractory using an alumina raw material, a yttria raw material, and a zirconia raw material is known (see, for example, Patent Document 2).
[0003]
　By the way, regardless of whether or not it is chromium-free, the amorphous refractory applied to the lining of the waste treatment furnace or the coal gasification furnace is a castable refractory, that is, castable refractory (for example, patent See Paragraph 0002 of Document 1 and Paragraph 0043 of Patent Document 2). However, when the castable refractory is applied to the lining, there is a problem that the construction period becomes long because it takes time to install and remove the formwork for the pouring construction. Also, in castable refractories, it is common to use alumina cement as a binder, but when alumina cement is used, a drying step is required to dry the cement hydrate for strength development, and the construction period is further increased. There is the problem of becoming longer. In recent years, especially in the operation of waste melting furnaces and coal gasification furnaces, there has been a demand for shortening the construction period, so there is a strong demand for shortening the lining construction period.
Prior art documents
Patent literature
[0004]
Patent Document 1: Japanese Patent Laid-Open No. 2016-199449
Patent Document 2: Japanese Patent Laid-Open No. 2009-227508
Summary of the invention
Problems to be Solved by the Invention
[0005]
　The problem to be solved by the present invention is to shorten the construction period in an amorphous refractory applied to the lining of a waste treatment furnace or a coal gasification furnace,
Means for solving the problems
[0006]
　The present inventors have an idea to use a patching refractory instead of a castable refractory as the irregular refractory in order to shorten the construction period of the lining with the irregular refractory. That is, conventionally, the patching refractory has been used for partial repair of the lining, but the present inventors have obtained a new idea of ​​applying the patching refractory to the entire target area of ​​the lining or for new construction. Of. According to the patching construction using the patching refractory, the construction period can be shortened because it is not necessary to install or remove the formwork.
[0007]
　Further, the present inventors have aimed to partially repair the lining of the conventional patching refractory, and since the corrosion resistance was not so important, to improve the corrosion resistance of the patching refractory in order to realize the above idea. I wanted it. At that time, chrome-free was premised from the viewpoint of avoiding the above-mentioned problem of hexavalent chromium generation, and on this premise, attention was paid to a zirconia-based raw material for improving corrosion resistance.
[0008]
　Furthermore, the present inventors have focused on aluminum phosphate as a binder for shortening the construction period and improving corrosion resistance.By using aluminum phosphate, the drying step required when alumina cement is used is Since it is unnecessary, the construction period can be shortened. In addition, aluminum phosphate has the highest melting point among binders other than alumina cement, so it improves corrosion resistance under the high temperature environment (for example, about 1400 to 2000 ° C) of the lining of waste treatment furnaces or coal gasification furnaces. It is valid.
[0009]
　That is, according to one aspect of the present invention, the following patching refractory material is provided.
"A chrome-free patching refractory applied to the lining of a waste treatment furnace or a coal gasification furnace, containing a
　refractory raw material and a binder,
　and 80 mass% of an alumina raw material in 100 mass% of the refractory raw material. Or more and 95 mass% or less and 3 mass% or more and 10 mass% or less of zirconia-based raw materials having a particle size of less than 75 μm, respectively, and
　aluminum phosphate as the binder is externally applied to the refractory raw material in an amount of 2 mass% or more and 8 mass% or more. % Refractory containing less than or equal to%. "
The invention's effect
[0010]
　According to the patching refractory of the present invention, the construction period of the lining of the waste treatment furnace or the coal gasification furnace can be shortened, and the corrosion resistance can be improved as compared with the construction using the conventional patching refractory. .
MODE FOR CARRYING OUT THE INVENTION
[0011]
　The patching refractory material of the present invention is a chromium-free patching refractory material applied to the lining of a waste treatment furnace or a coal gasification furnace, and contains a refractory raw material and a binder. As the refractory raw material, 80 mass% to 95 mass% of an alumina raw material and 3 mass% to 10 mass% of a zirconia raw material having a particle diameter of less than 75 μm are contained in 100 mass% of the refractory raw material.
[0012]
　In the present invention, the alumina raw material is a raw material containing 70% by mass or more of Al 2 O 3 , and examples thereof include fused alumina, sintered alumina, bauxite, and calcined alumina. In the present invention, the zirconia-based raw material is a raw material containing 20% ​​by mass or more of ZrO 3 , and examples thereof include electrofused zirconia, zirconia mullite raw material, and alumina zirconia raw material. In the present invention, in order to improve the dispersibility of the zirconia-based raw material and the corrosion resistance, a fine-grained zirconia-based raw material, specifically, a zirconia-based raw material having a particle size of less than 75 μm is used. That is, in the patching refractory material of the present invention, 80% by mass or more and 95% by mass or less of the alumina-based material and 3% by mass or more and 10% by mass or less of the zirconia-based material having a particle diameter of less than 75 μm are contained in 100% by mass of the refractory material. 5% by mass or more and 8% by mass or less), the corrosion resistance can be improved as compared with the conventional patching refractory. If an unstabilized zirconia-based raw material is used as the zirconia-based raw material, microcracks can be introduced, so that heat resistant spalling property can be secured. Clay, starch, dextrin, carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), sorbitol, glycerin and the like can be appropriately used as the refractory raw material other than the alumina raw material and the zirconia raw material.
[0013]
　Aluminum phosphate is used as the binder. By using aluminum phosphate as the binder, it is possible to shorten the construction period because the drying step that is necessary when using alumina cement is unnecessary. In addition, aluminum phosphate has the highest melting point among binders other than alumina cement, so it improves corrosion resistance under the high temperature environment (for example, about 1400 to 2000 ° C) of the lining of waste treatment furnaces or coal gasification furnaces. It is valid. The amount of aluminum phosphate added is 2% by mass or more and 8% by mass or less (preferably 4% by mass or more and 7% by mass or less) by externally applied to the refractory material. If the amount of aluminum phosphate added is less than 2% by mass, the bond function as a binder will be insufficient. On the other hand, when the addition amount of aluminum phosphate exceeds 8% by mass, a large amount of low-melting point substances are generated, so that the corrosion resistance decreases. Although aluminum phosphate can be added as an aqueous solution, in this case, the addition amount of aluminum phosphate is the addition amount of aluminum phosphate itself excluding the solvent (water).
[0014]
　The patching refractory of the present invention can be applied to a partial repair of the lining of a waste treatment furnace or a coal gasification furnace, but it is effective to apply it to the repair or new construction of the entire target part of the lining. is there. In this way, when applied to repairing the entire target area of ​​the lining or applying to new construction, it is preferable to install a reinforcing bar frame or the like as an anchor material before construction.
Example
[0015]
　Corrosion resistance, compressive strength and drying time were evaluated for the amorphous refractories of each example shown in Table 1. In Table 1, Examples 1 to 8 and Comparative Examples 1 to 5 are patching refractories, and Comparative Example 6 is castable refractories.
[0016]
[table 1]

[0017]
　The corrosion resistance was evaluated by the melt loss index measured according to the crucible erosion test (former JISR2214). As the erosion agent for the erosion test, a waste slag having a CaO / SiO 2 mass ratio of 0.8 and heated to 1500 ° C. was used, and after the erosion test, the maximum erosion size of the test piece was measured. A value obtained by dividing the maximum erosion dimension of the test piece of each example by the maximum erosion dimension of the test piece of Comparative Example 1 and multiplying by 100 is the erosion index. The smaller the melt loss index, the better the corrosion resistance. In Table 1, when the melt loss index is less than 90, it is indicated as ⊚ (excellent), when it is 90 or more and less than 100, it is indicated as ◯ (good), and when it is 100 or more, it is indicated as × (defective).　
[0018]
　The compressive strength was measured at 1400 ° C. according to JIS R2213. In Table 1, the case where the compressive strength is 70 MPa or more is indicated by ⊚ (excellent), the case of 30 MPa or more and less than 70 MPa is indicated by O (good), and the case of less than 30 MPa is indicated by X (defective).　
[0019]
　The drying time was measured as the time required until the internal water vapor pressure of the construction body became 2 MPa or less after curing in the construction with 30 tons of irregular-shaped refractory assuming actual lining construction. The present inventors have confirmed that if the internal water vapor pressure is 2 MPa or less, no explosion will occur during operation. The internal water vapor pressure was directly measured by embedding the tip of the pressure transmission pipe in the construction body.
[0020]
　As shown in Table 1, Examples 1 to 8, which are patching refractories within the scope of the present invention, have good corrosion resistance and compressive strength, and particularly, the amounts of the zirconia-based raw material and aluminum phosphate are within the preferred ranges. Examples 1, 4, 5, and 8 in Table 1 were excellent in both corrosion resistance and compressive strength. Further, the drying time in each of Examples 1 to 8 was zero (0).
[0021]
　Comparative Example 1 is an example in which the amount of zirconia-based raw material was small, and sufficient corrosion resistance was not obtained.
　Comparative Example 2 is an example in which the amount of the zirconia-based raw material is large, the generation of microcracks was excessive, and as a result, the corrosion resistance was lowered.
　Comparative Example 3 is an example in which the particle size of the zirconia-based raw material is large, the dispersibility of the zirconia-based raw material deteriorates, and as a result, the corrosion resistance decreases.
　Comparative Example 4 is an example in which the amount of aluminum phosphate was small, the bond function became insufficient, and as a result, the corrosion resistance and compressive strength decreased.
　Comparative Example 5 is an example in which the amount of aluminum phosphate is large, and a large amount of low-melting point substance is generated, so that the corrosion resistance is deteriorated.
　Comparative Example 6 is a castable refractory using alumina cement as a binder and required a drying time of 4 days.
The scope of the claims
[Claim 1]
　A chromium-free patching refractory applied to the lining of a waste treatment furnace or a coal gasification furnace, containing a
　refractory raw material and a binder,
　and 80 mass% or more of an alumina raw material in 100 mass% of the refractory raw material. 95 mass% or less, 3 mass% or more and 10 mass% or less of the zirconia-based raw material having a particle size of less than 75 μm, respectively, and
　aluminum phosphate as the binder is externally applied to the refractory raw material in an amount of 2 mass% or more and 8 mass% or less. A patching refractory characterized by including:
[Claim 2]
　The patching refractory material according to claim 1, wherein the zirconia-based raw material is an unstabilized zirconia-based raw material.