​Technical field

[0001]
​The present invention relates to monolithic refractory, especially adiabatic amorphous refractory
​Background

[0002]
​Refractory is indispensable in the field of handling high-temperature substances including steel production, the high service life is important to stabilize production and to reduce costs. The monolithic refractory, which is a kind of refractory, is provided, so that it is widely used because of improvement in workability and easiness of repair
[0003]
​In the production of monolithic refractory, high pressure pressing as seen in the production of the monolithic refractory is not performed. Therefore, the importance of the characteristics of the fire-resistant raw material and the binder is high. SOLUTION: a calcium aluminate cement (hereinafter, alumina cement) (main constituent compound: cao. Al2 o3, cao. 2 Al2 o3, 12 cao. 7 (L2o3) is used as a binder in a wide range of applications
[0004]
​However, when the alumina cement coexists with al2 o3, the alumina cement contains ca 2 (cao) at a temperature around 1,200° c. When 2 Al2 o3 is generated, an expansion tendency is shown. In particular, a large amount of alumina cement is added, the expansion at a high temperature is further increased, and the generation of cracks is caused
[0005]
​Also, in the heat insulating amorphous refractory, a heat insulating aggregate (lightweight aggregate) is used) water absorption is higher than that of a normal fire-resistant aggregate, it is necessary to add a large amount of water in comparison with an ordinary monolithic refractory. If so, the curing strength is lowered, and there is a possibility that the curing strength may be peeled off at the time of demolding
[0006]
​Binder for monolithic refractory, strontium aluminate cement (hereinafter, strontium cement) is known in addition to the # T alumina cement. For example, patent document 1 discloses a chemical composition of sral2o4 and sro. Al2 o3, sro. SOLUTION: there is provided a method for producing a sro. To provide a chemical composition such as 6Al2 o3 and the like (3); and a strontium cement composed of a chemical composition such as caxsr1-x al2 o4
[0007]
​Using these strontium cement, an expansion problem at high temperature due to generation of ca2 generated when alumina cement is used is solved. The strontium cement is excellent in strength expression compared with alumina cement, the problem of lowering of the curing strength is also expected
​Prior art literature

​Patent document

[0008]
​Patent document 1: japanese patent application laid-open no. 2010 -120843
​Patent document 2: japanese patent application laid-open no. 58 -26079
​Patent document 3: japanese patent application laid-open no. 2008 -290934
​Summary of the invention

​Problem to be solved by the invention

[0009]
​However, since strontium cement contains sr, excellent strength expression is obtained, but aggregation is likely to occur quickly. For this reason, a sufficient pot life is sometimes difficult to be secured for execution
[0010]
​In addition, the strontium cement is intended to be applied to the heat insulating amorphous refractory, it is necessary to add a large amount of water as described above in the heat insulating monolithic refractory, in order to obtain sufficient curing strength, it is necessary to add a large amount of strontium cement. On the other hand, the problem of strontium cement in which a sufficient pot life is difficult to be secured appears more remarkably
[0011]
​For example, japanese laid-open patent publication no. 2002 -35879 discloses a method in which strontium cement is not a heat insulating amorphous refractory but also a furnace of the present invention is applied to an amorphous refractory used for lining, and the addition amount of water is set to 6.8 mass % (paragraph 0037). However, in the case of a heat insulating amorphous refractory, an amount of water added at 20 mass % or more is required. When the amount of water added is increased, the curing strength is secured, it is necessary to increase the addition amount of strontium cement ​In patent document 3, the addition amount of strontium cement is set to 8 mass % (paragraph 0037), when the amount of addition is 8 mass %, sufficient curing strength cannot be obtained in the heat insulating amorphous refractory. In order to obtain sufficient curing strength, a large amount of strontium cement is added, aggregation is accelerated, and a sufficient pot life cannot be secured
[0012]
​Thus, in the heat insulating monolithic refractory, strontium cement can be simply applied as a binder, the curing strength cannot be obtained, a problem arises in that a sufficient pot life is difficult to be secured for execution
[0013]
​As disclosed in patent document 1, the iron oxide and the low melt in the molten iron and the slag are easily formed, there is a problem that wear and infiltration are advanced from a part of the alumina cement (1) of paragraph [ 0011 ]), a strontium cement is applied as a binder. Therefore, when strontium cement and alumina cement are to be used together as a binder for a heat insulating amorphous refractory, there is a fear that the above problem of alumina cement becomes remarkable, there is no conventional idea of using strontium cement and alumina cement
[0014]
​PROBLEM TO BE SOLVED: to ensure sufficient curing strength and pot life, and excellent in stability at high temperatures
​Means for solving the problem

[0015]
​In order to solve the above problems, it is possible to obtain the idea that sufficient curing strength and stability at a high temperature can be achieved when the alumina cement and the strontium cement are used in combination as a binder for the heat insulating amorphous refractory, the present invention has been completed
[0016]
​According to one aspect of the present invention, a binder and a refractory raw material are mixed together, and the kneaded material of the heat insulating amorphous refractory and water is cured at room temperature for 24 hours and dried at 110°c for 24 hours in a heat insulating amorphous refractory having a bulk specific gravity of 0.8 or more and 1.8 or less, the binder includes: alumina cement containing cao and al2 o3 as chemical components; and sro, and strontium cement containing al2 o3 as a chemical component, and when the amount of the binder and the refractory raw material is 100 mass %, ​And 2 mass % or more and 10 mass % or less of the strontium cement, and the amount of cao caused by the alumina cement is 1 mass % or more and 12 mass % or less
​Effects of the invention

[0017]
​The heat insulating monolithic refractory contains alumina cement and strontium cement in the binder. Therefore, sufficient curing strength can be obtained, and a sufficient pot life can be secured. Further, the amount of cao can be reduced while maintaining the curing strength, expansion at high temperatures can be suppressed, and stability at high temperatures can be improved
​System for carrying out the invention

[0018]
​SOLUTION: a heat-insulating amorphous refractory according to the present invention comprises, a binder and a refractory raw material are mixed together, and the kneaded material of the heat insulating amorphous refractory and water is cured at room temperature for 24 hours and dried at 110°c for 24 hours, the bulk specific gravity is in the range of 0.8 to 1.8. Thus, in the heat insulating monolithic refractory of the present invention, the heat insulation characteristic which is a prerequisite is specified with a "bulk specific gravity"
[0019]
​SOLUTION: a heat-insulating amorphous refractory according to the present invention comprises, it is assumed that the bulk specific gravity is low as in the above range, a so-called lightweight aggregate is mainly used as the refractory raw material. SOLUTION: a lightweight aggregate includes: a lightweight aggregate (hollow alumina, hollow spinel) a porous lightweight aggregate (porous alumina, porous spinel, ca6 lightweight aggregate) and the like. In addition to these lightweight aggregates, sintered alumina, electrofused alumina, and calcined alumina, an ordinary refractory raw material such as an electrofusion spinel or a siliceous raw material can be used in combination
[0020]
​The binder uses alumina cement and strontium cement. As the alumina cement, cao. Al2 o3, cao. 2 Al2 o3 and 12 cao. Alumina cement may be used which includes any of the minerals of 7 (l2o3). The alumina cement has a cao content of less than 22% in alumina cement, the cao content in the alumina cement is 22% or more and less than 30%, the cao content in the alumina cement is 30% or more and less than 40%, they may be used alone or in combination. It is preferable that the alumina cement has a cao component of 30% or less
[0021]
​The strontium cement includes sral2o4 and sro described in the above-mentioned patent documents 1 to 3. Al2 o3, sro. SOLUTION: there is provided a method for producing a sro. A mineral such as 6 Al2 o3, caxsr1-x Al2 o4 or the like is provided has one or more combinations of strontium cement can be used
[0022]
​The amount of strontium cement is added, and when the amount of the binder and the refractory raw material is 100 mass %, it is set to 2 mass % or more and 10 mass % or less. When the strontium cement is less than 2 mass %, the curing strength cannot be secured. When the content exceeds 10 mass %, a pot life cannot be secured. The amount of the strontium cement is preferably 3 mass % or more and 7 mass % or less
[0023]
​In the present invention, the amount of the binder and the refractory raw material is 100 mass %, the amount of cao caused by the alumina cement is set to 1 mass % or more and 12 mass % or less. When the cao content caused by the alumina cement is less than 1 mass %, the curing strength cannot be secured. To ensure a curing strength, and it is necessary to blend strontium cement in excess of 10 mass % of the upper limit, in this case, the pot life cannot be secured. On the other hand, when the cao content caused by the alumina cement exceeds 12 mass %, the expansion at a high temperature becomes large. The amount of cao caused by the alumina cement is preferably 4 mass % or more and 9 mass % or less
[0024]
​In addition to the binder and the refractory raw material, other raw materials are used, sodium tripolyphosphate, sodium hexametaphosphate, and polyacrylic acid, sodium polyacrylate, sodium polyacrylate, polycarboxylic acid, and polyether, dispersant such as sodium naphthalene sulfonate and sodium lignin sulfonate, boric acid, citric acid, slaked lime, sodium carbonate, lithium carbonate, lithium phosphate, etc. and foaming agent, an air bubble agent, a thickener, an organic fiber, a fluidity adjusting agent and the like can be appropriately added
[0025]
​The amount of water to be used in kneading may be determined according to the construction method. Specifically, when the amount of the binder and the refractory raw material is 100 mass %, 20 mass % or more and 70 mass % or less in the outer hook. In the case of less than 20 mass %, the possibility that the bulk specific gravity becomes 1.8 or more is high, there is a possibility that a sufficient fluidity cannot be obtained and the execution failure may be caused. On the other hand, when the content exceeds 70% by mass, sufficient curing strength cannot be secured
[0026]
​The content of the sio2 component in the heat-insulating amorphous refractory of the present invention is determined by the content of the sio2 component in the heat-insulating amorphous refractory according to the present invention, sufficient feo resistance is secured, when the amount of the binder and the refractory raw material is 100 mass %, it is preferably 1 mass % or less
​Embodiment
[0027]
​The heat insulating monolithic refractory of each example shown in table 1 has a pot life, bulk specific gravity, and cured bending strength, the maximum value of the expansion rate up to 1,500°c and the feo resistance are evaluated, and the total evaluation is performed
[0028] ​[ TABLE-US -00001 ]. TABLE 1
[0029]
​The heat insulating monolithic refractory in each example is shown in table (1) and the mixture amount of the fire-resistant raw material and the binder shown in # T is 100 mass %, a polycarboxylic acid is used as the # T dispersant, and water is added to the polycarboxylic acid, the amount described in each example is added to the mixture with the mixture of the # T refractory material and the binder with respect to 100 mass %, and each evaluation is performed for each evaluation, in each example, the lightweight aggregate is a ca6 lightweight aggregate or a hollow spinel, silica fume and alumina raw material are used as the siliceous raw material, the alumina cement has a cao content of 18% in the alumina cement, or a cement b having a cao content of 27% in the alumina cement is used
[0030]
​The pot life is set at 20°c by putting the kneaded material into a vinyl bag, and a time required until the free flow value is less than 150 mm, compared to normal casting monolithic refractory, and 90 minutes or more is taken as a pass criterion from the point of time required for the execution
[0031]
​The bulk specific gravity is an atmospheric temperature of 20°c (room temperature)) for 24 hours and dried at 110°c for 24 hours (2205) and the bulk specific gravity measured according to the method is an index of heat insulating property, the present invention is based on the assumption that it is in the range of 0.8 or more and 1.8 or less
[0032]
​When the bulk specific gravity is less than 0.8, the lightweight aggregate is increased, even when 10% of strontium cement is added, the amount of added water becomes large, the curing strength cannot be secured at 1.0 mpa. In addition, (1.8) the heat insulating function is not sufficient
[0033]
​The cured bending strength is obtained by curing the kneaded material at an ambient temperature of 20°c for 24 hours, with respect to the curing bending strength obtained by measuring the # T bending strength, and when it is less than 1.0 mpa, it is peeled off at the time of removal, so that 1.0 mpa or more is used as a pass criterion
[0034]
​The maximum value of the expansion rate to 1500°c is, the kneaded material is cured for 24 hours at an atmospheric temperature of 20°c and dried at 350°c for 24 hours, an expansion rate of up to 1,500°c is measured, and when the maximum value of the expansion rate up to 1,500°c where the maximum value of the measured expansion rate is evaluated exceeds 1.3%, and the maximum value of the expansion rate is set to 1.3% or less as a pass criterion
[0035]
​Feo is 85 mm × 85 mm × (80mm) in a crucible shape in which a hole with a diameter of 35 mm × 35 mm is opened at a central part of the upper part of the crucible, a sample cast in a crucible shape is cured at an atmospheric temperature of 20°c for 24 hours to be removed, 110°c for 24 hours, 40 g of iron oxide and calcined at 1,500°c for 5 hours, by measuring the dimension of the sample eroded by the iron oxide, the erosion dimension is less than 1 mm (◯) of 1 mm or more and less than 1.5 mm is acceptable (delta), and 1.5 mm or more is set to be impossible (×)
[0036]
​The comprehensive evaluation satisfies each pass criterion in each of the above-mentioned evaluation, and when the feo resistance is superior, and when the feo resistance is good, and when the acceptance criteria is not satisfied, x is obtained
[0037]
​The chemical components in table 1 are the same as those in table 1, and the content of the binder and the refractory raw material is represented by the content of 100 mass %
[0038]
​Examples 1 -7 of table 1, (9~14) and each of # T is a heat insulating amorphous refractory within the scope of the present invention, and the total evaluation is "◯". In example 8, the sio2 component is contained in 2.0 mass %, the content of the sio2 component is 1.0 mass % or less, the feo resistance is slightly poor, and the total evaluation is delta. Thus, in order to secure sufficient feo resistance, the content of the sio2 component is preferably 1.0 mass % or less
[0039]
​Comparative example 1 is an example in which the content of strontium cement exceeds the upper limit of the present invention, and no sufficient pot life is obtained (2) # T is an example in which the content of strontium cement falls below the lower limit of the present invention, and the curing strength does not exceed 1.0 mpa
[0040]
​The comparative example 3 is an example in which the cao amount caused by the alumina cement falls below the lower limit of the present invention. PROBLEM TO BE SOLVED: to provide a comparative (4) is an example in which the amount of cao caused by the alumina cement exceeds the upper limit of the present invention. The maximum value of the expansion rate up to 1,500°c exceeds 1.3%
[0041]
​Comparative example 5 is an example in which alumina cement is used alone as a binder. PROBLEM TO BE SOLVED: to provide a comparative (6) is an example in which strontium cement is used alone as a binder. The pot life is remarkably shortened
​Claim

​[ Claim 1 ]
​SOLUTION: there is provided a heat insulating amorphous refractory comprising a binder and a refractory raw material, and the kneaded material of the heat insulating amorphous refractory and water is cured at room temperature for 24 hours and dried at 110°c for 24 hours in a heat insulating amorphous refractory having a bulk specific gravity of 0.8 or more and 1.8 or less,
​The binder includes calcium aluminate cement containing cao and al2 o3 as chemical components, sro and strontium aluminate cement containing al2o3 as a chemical component,
​When the amount of the binder and the refractory raw material is 100 mass %, and 2 mass % or more and 10 mass % or less of the strontium aluminate cement, and the amount of cao caused by the calcium aluminate cement is 1 mass % or more and 12 mass % or less
​[ Claim 2 ]
​When the amount of the binder and the refractory raw material is 100 mass %, the content of the sio2 component is 1 mass % or less
​[ Claim 3 ]
​When the amount of the binder and the refractory raw material is 100 mass %, 20 mass % or more and 70 mass % or less of water is added (1) or (2)