Spraying construction method of amorphous refractory and spraying material used for it
Technical field
[0001]
　The present invention relates to various molten metal containers and kilns such as blast furnaces, hives, brazing mills, converters, pans, secondary smelting furnaces, tundish, cement rotary kilns, waste melting furnaces, incinerators, and non-iron molten metal containers. Regarding the spraying construction method of irregular fireproof materials for the construction or repair of the furnace, and the spraying material used for it.
Background technology
[0002]
　The spraying construction method for amorphous refractories can be roughly divided into the wet construction method and the dry construction method.
　The wet construction method is a construction method in which construction water is added to the material in advance and kneaded to form a slurry of the sprayed material, which is then pressure-fed and sprayed by adding a quick-setting agent or the like at the tip spraying nozzle portion. On the other hand, the dry construction method is a construction method in which the sprayed material is gas-conveyed in a dry state, and the construction water is injected and sprayed at the tip spray nozzle portion.
[0003]
　The wet construction method can form a dense refractory sprayed construction body having excellent adhesion as compared with the dry construction method, and has the effect of reducing the amount of dust generated during construction. On the other hand, a kneading device and a slurry pumping device are required for spraying, and the structure of the device is complicated and expensive, and the slurry-like spraying material adheres to the kneading device and the transport hose after the spraying work. However, there is a drawback that the cleaning work takes time.
[0004]
　On the other hand, in the dry construction method, basically, the construction water is simply injected into the spray material that has been gas-conveyed in a dry state with the tip spray nozzle, so the spray device is simple and workable. However, since the spraying material is not sufficiently mixed with water (construction water), a large amount of dust is generated during spraying, and the refractory structure of the sprayed construction body is also uneven. The adhesion rate, adhesion strength and corrosion resistance are also inferior. Compared with the wet construction method, the kneading effect is low and the amount of construction water is large, so there is a drawback that it is difficult to obtain a dense sprayed construction body.
[0005]
　Therefore, as an improvement of the dry construction method, two water injectors are provided in the material transport pipe from the material feeder to the tip spray nozzle, and atomized water of 100 μm or less on average is injected from each water injector together with compressed air. The construction method is known (see, for example, Patent Document 1).
　However, when the present inventors carried out many spraying works by this spraying work method, the phenomenon that the discharge amount of the sprayed material fluctuated and the sprayed material and the construction water were separated was occasionally found. It was found that there is room for improvement in the stability of spraying work.
Advanced technical literature
Patent documents
[0006]
Patent Document 1: Japanese Patent No. 4377913
Outline of the invention
Problems to be solved by the invention
[0007]
　The problem to be solved by the present invention is that a water injector is provided in the material transfer pipe from the material feeder to the tip spray nozzle, and construction water is injected into the spray material conveyed from the water injector in the material transfer pipe. The purpose is to improve the stability of the spraying work in the spraying work method of the standard refractory.
Means to solve problems
[0008]
　The present inventors considered that it is important to improve the mixing of the construction water with the spray material and the transportability of the spray material in order to improve the stability of the spray construction, and repeated tests on the water injector. The ratio of the flow rate of the construction water transport gas for transporting the introduced construction water (Nm 3 / min) to the flow rate of the spray material transport gas for transporting the spray material (Nm 3 / min). And, it was found that the degree of compression of the sprayed material is an important parameter for improving the above-mentioned water mixing and transportability and, by extension, the stability of the spraying work, and completed one embodiment of the present invention. I came to do it.
[0009]
　Further, the present inventors have described the ratio of the flow rate of the construction water transport gas (Nm 3 / min) for transporting the construction water introduced into the water injector to the construction water amount (m 3 / min) as described above. It has been found that it is an important parameter for improving water mixing and transportability, and eventually for improving the stability of spraying work, and has completed other forms of the present invention.
[0010]
　That is, according to one embodiment of the present invention, the following spraying construction method is provided.
　It is a method of spraying an amorphous fireproof material by installing a water injector on the material transfer pipe from the material feeder to the tip spray nozzle and injecting construction water into the spray material transported from this water injector in the material transfer pipe. Te,
　the flow of the construction water carrier gas for transporting the construction water introduced into the water injector (Nm 3 and / min), the spraying material conveying gas for conveying the spraying material flow (Nm 3 The ratio to (/ min) (flow rate of construction water transport gas / flow rate of spray material transport gas) is 0.07 or more and 2 or less, and the degree of compression of the spray material is 32% or less. Spraying construction method for irregular fireproof materials.
[0011]
　Further, according to another embodiment of the present invention, the following spraying construction method is provided.
　This is a method of spraying an amorphous fireproof material by installing a water injector on the material transfer pipe from the material feeder to the tip spray nozzle and injecting construction water into the spray material transported from this water injector in the material transfer pipe. Te,
　the water injector flow construction water carrier gas for transporting the construction water introduced into (Nm 3 / min) and construction water (m 3 in / min) ratio of (construction water carrier gas flow rate / A method of spraying an amorphous fireproof material with a construction water volume of 100 or more and 1000 or less.
[0012]
　Further, according to another aspect of the present invention, there is provided a spraying material used in the method for spraying an amorphous refractory of the present invention, which has a degree of compression of 32% or less.
Effect of the invention
[0013]
　According to the present invention, at the time of spraying construction, the mixing water of the construction water with respect to the spraying material and the transportability of the spraying material are improved, and as a result, the stability of the spraying construction is improved.
A brief description of the drawing
[0014]
FIG. 1 is a conceptual diagram showing an example of a spraying device for carrying out the spraying construction method of the present invention.
FIG. 2 is a conceptual diagram showing another example of a spraying device for carrying out the spraying construction method of the present invention.
Mode for carrying out the invention
[0015]
　First, an example of a spraying device for carrying out the spraying construction method of the present invention will be described with reference to FIG.
[0016]
　In FIG. 1, reference numeral 1 denotes a material feeder in which the spray material 2 is housed. The material feeder 1 can be used without any problem with any type of rotor gun, lead gun, Nogami cement gun, etc. as long as it is generally used for spraying equipment for amorphous refractories and can be discharged in a fixed quantity. it can.
[0017]
　The internal pressure of the sprayed material 2 in the material feeder 1 is adjusted by a gas such as compressed air supplied into the material feeder 1, and the material is supplied by a table feeder 3 driven by a motor M provided at the lower end. It is supplied to the material transfer pipe 5 from the machine 1 to the tip spray nozzle 4.
[0018]
　The sprayed material transfer gas is supplied to the material transfer pipe 5 through the spray material transfer gas introduction pipe 6 of the table feeder 3, and the spray material 2 from the material supply machine 1 is sprayed from the material transfer pipe 5 to the tip spray nozzle. Spray construction is performed on the spray target body A from 4.
[0019]
　The material transfer pipe 5 is provided with a water injection device 7 in the vicinity of the tip spray nozzle 4.
　From the water injector 7, construction water is supplied together with the construction water transport gas to the spray material 2 transported in the material transport pipe 5. The configuration of the water injector 7 is not particularly limited as long as it can supply (inject) construction water into the material transport pipe 5 together with the construction water transport gas. Since the construction water is injected from the water injector 7 together with the construction water transporting gas, the construction water becomes so-called spray water (atomized water).
　The position where the water injection device 7 is provided is preferably in the range of 0.5 m or more and less than 5 m from the tip of the tip spray nozzle 4, and more preferably 0.5 m or more and less than 3 m. The length of the tip spray nozzle 4 is approximately 1 m or more and 10 m or less.
[0020]
　The gas such as the spray material transport gas and the construction water transport gas used in the present invention is typically air (compressed air), but other gases such as nitrogen (compressed nitrogen) may be used. You can also. The pressure of the gas used can be generally in the range of 0.2 MPa or more and 0.5 MPa or less.
[0021]
　Next, the spraying construction method of the present invention will be described by using the spraying device of FIG.
　The first feature in one form of the spraying construction method of the present invention is the flow rate (Nm 3 / min) of the construction water transport gas for transporting the construction water introduced into the water injector 7 and the spraying material. The ratio to the flow rate of the spray material transport gas for transport (Nm 3 / min) (flow rate of the construction water transport gas / flow rate of the spray material transport gas) (hereinafter referred to as "transport gas flow rate ratio". ) Is 0.07 or more and 2 or less. By setting the transport gas flow rate ratio to 0.07 or more and 2 or less, the mixing water of the construction water and the transportability of the sprayed material are improved, and the stability of the sprayed construction is improved.
　On the other hand, if the transport gas flow rate ratio is less than 0.07, the flow rate of the spray material transport gas is large, so that the construction water does not reach the center of the material transport pipe 5 that transports the spray material. Poor water mixing.
　On the other hand, when the transport gas flow rate ratio exceeds 2, a large flow rate of the construction water transport gas causes a turbulent flow with the spray material transport gas, and as a result, spraying in the vicinity of the water injector 7. Adhesion of the material and further, adhesion of the sprayed material to the material transport pipe 5 on the upstream side thereof occurs, and the transportability of the sprayed material is lowered.
　The transport gas flow rate ratio is preferably 0.1 or more and 1 or less.
[0022]
　The second feature in one form of the spraying construction method of the present invention is that a material having a degree of compression of 32% or less is used as the spraying material. In other words, a spray material whose particle size composition and the like are adjusted so that the degree of compression is 32% or less is used. Here, the degree of compression is obtained by the following equation.
　Compressibility (%) = (Densely packed bulk density-Sparsely filled bulk density) / Densely packed bulk density x 100 Although
　details will be described later, the spray material used in the present invention contains fibers in addition to the fireproof raw material powder. However, when fibers are contained, the evaluation of the degree of compression (measurement of densely packed bulk density and sparsely packed bulk density) shall be carried out with the fibers removed. That is, when the spraying material contains fibers, the degree of compression in the present invention means an evaluation of the spraying material excluding the fibers.
[0023]
　When construction water is added to the spray material, the powder that comes into contact with the construction water tends to become a slurry and become more viscous. Since it is contained, it is likely to aggregate due to the external force of the construction water transport gas. Furthermore, since the partial viscosity of the slurry is increased by the addition of the construction water, the aggregation is further accelerated, the construction water is not uniformly wetted, and the water mixture is lowered. If the agglomeration is significant, the sprayed material sticks to the material transport pipe 5 and causes clogging, resulting in a decrease in transportability.
　This degree of compression is preferably 25% or less.
[0024]
　In order to reduce the compressibility of the sprayed material to 32% or less, the content of particles having a particle size of more than 2 mm in 100% by mass of the sprayed material should be 30% by mass or less (including 0% by mass) and a particle size of 45 μm or less. The content of the particles is preferably 3% by mass or more and 30% by mass or less.
　That is, when the content of particles having a particle size of more than 2 mm exceeds 30% by mass, the number of particles having a particle size of more than 2 mm increases, so that the gap in the spraying material becomes large, and fine powder flows into the gap due to an external force. Since the structure becomes dense, the degree of compression may exceed 32%.
　Further, when the content of particles having a particle size of 45 μm or less exceeds 30% by mass, many particles have a particle size of less than 45 μm, so that the spraying material contains a large amount of air and is easily aggregated by an external force and compressed. The degree may exceed 32%. If the content of particles having a particle size of less than 45 μm is less than 3% by mass, it becomes difficult to form a good sprayed body.
　Here, in the present invention, when the particle size of the particles exceeds d, it means that the particles remain on the sieve of the opening d, and when the particle size of the particles is d or less, the particles are eyes. It means that the particle size passes through the sieve of the opening d.
[0025]
　Another feature of the spraying construction method of the present invention is the ratio of the flow rate of the construction water transport gas (Nm 3 / min) to the construction water amount (m 3 / min) (flow rate of the construction water transport gas / construction). The amount of water) (hereinafter referred to as "gas / construction water amount ratio") is 100 or more and 1000 or less. By setting the gas-construction water amount ratio to 100 or more and 1000 or less, the mixing water of the construction water, the transportability of the sprayed material, and the stability of the spraying construction are improved. The gas / construction water amount ratio is preferably 250 or more and 800 or less.
[0026]
　In the spraying construction method of the present invention, the ratio of the discharge amount of the spray material (kg / min) to the total flow rate of the transport gas (Nm 3 / min) (discharge amount of the spray material / total flow rate of the transport gas). ) (Hereinafter referred to as "solid-gas ratio") is preferably 1 or more and 20 or less. By setting the solid-air ratio to 1 or more and 20 or less, the mixing water of the construction water, the transportability of the sprayed material, and the stability of the spraying construction are improved.
[0027]
　The spraying material used in the spraying construction method of the present invention may appropriately contain and mix additives such as a binder, a dispersant, and a quick-setting agent in addition to the refractory powder. Fibers can also be included with the agent.
[0028]
　As the refractory powder, any refractory powder used for general amorphous refractories can be used without any problem. For example, metal oxides, metal carbides, metal nitrides, carbons, metals and the like can be appropriately selected and combined according to the material of the sprayed object, temperature conditions and the like.
[0029]
　Examples of the binder include slaked lime, alumina cement, magnesia cement, phosphate, silicate and the like, and one or a combination of two or more of these can be used.
[0030]
　The dispersant is also called a dispersant and has the effect of imparting fluidity to the spray material. As this dispersant, any dispersant used in a general amorphous refractory can be used without any problem. Specific examples include sodium tripolyphosphate, sodium hexametaphosphate, sodium ultrapolyphosphate, sodium acid hexamethaphosphate, sodium borate, sodium carbonate, polymethaphosphate, silicate, inorganic salts such as phosphate, sodium citrate, etc. Sodium tartrate, sodium polyacrylic acid, sodium sulfonate, polycarboxylic acid salt, β-naphthalene sulfonates, naphthaline sulfonic acid, carboxyl group-containing polyether dispersant and the like.
[0031]
　The quick-setting agent reacts with the binder in the presence of construction water to rapidly cure the spray material and impart adhesion to the spray material. The quick-setting agent may be mixed into the spraying material in a powder state from the beginning, or the quick-setting agent may be added from the tip spray nozzle 4 or the water injector 7. When the quick-setting admixture is added from the tip spray nozzle 4 or the water injector 7, if necessary, the quick-setting admixture is used in a liquid diluted with water.
　Specific examples of the quick-setting admixture include silicates such as sodium silicate and potassium silicate, aluminate such as sodium aluminate, potassium aluminate and calcium aluminate, sodium carbonate, potassium carbonate, sodium hydrogen carbonate and the like. carbonates, sodium sulfate, potassium sulfate, sulfates such as magnesium sulfate, CaO · Al 2 O 3 , 12CaO · 7Al 2 O 3 , CaO · 2Al 2 O 3 , 3CaO · Al 2 O 3 , 3CaO · 3Al 2 O 3・ CaF 2 , 11CaO ・ 7Al 2 O 3・ CaF 2Calcium aluminates such as calcium oxide, calcium hydroxide, calcium salts such as calcium chloride and the like.
[0032]
　As the fiber, a fiber used for the purpose of preventing explosion in an ordinary amorphous refractory can be used, and for example, vinylon, nylon, PVA, polyvinyl, polystyrene, polypropylene, carbon and the like.
[0033]
　The spraying construction method of the present invention can be carried out under any of cold, warm and hot temperature conditions. Then, the material composition of the spraying material used in the spraying construction method of the present invention can be appropriately determined according to these temperature conditions, the material of the sprayed object, and the like.
[0034]
　FIG. 2 shows another example of a spraying device for carrying out the spraying construction method of the present invention. In the spraying device of FIG. 2, the blowing means 8 is provided on the upstream side of the water injector 7.
[0035]
　In the spraying construction method of the present invention, when a spraying device provided with the blowing means 8 on the upstream side of the water injection device 7 is used as shown in FIG. 2, the amount of construction water from the blowing means 8 is 20% by mass of the total amount of construction water. It is preferable that the following (including 0% by mass) is applied, and the remaining construction water of the total construction water amount is injected from the water injector 7. By balancing the injection amount of the construction water in this way, when the blowing means 8 is used, the mixing water of the construction water, the transportability of the spraying material, and the stability of the spraying construction are improved.
[0036]
　Here, when the construction water is blown from the blowing means 8 together with the gas or gas, the flow rate (Nm 3 / min) of the gas blown from the blowing means 8 is the calculation of the above-mentioned transport gas flow rate ratio and the gas / construction water amount ratio. In the above, it shall be added up as " flow rate of gas for transporting construction water (Nm 3 / min)".
　Similarly, the construction water amount (Nm 3 / min) from the blowing means 8 shall be added up as "construction water amount (m 3 / min)" in the above-mentioned calculation of the gas / construction water amount ratio .
[0037]
　As described above, in the spraying construction method of the present invention, the ratio of the discharge amount of the spray material (kg / min) to the total flow rate of the transport gas (Nm 3 / min) (discharge amount of the spray material / transport gas). The total flow rate of the solid air ratio), that is, the solid air ratio is preferably 1 or more and 20 or less. However, the “total flow rate of the transport gas (Nm 3 / min)” used in the calculation of the solid air ratio is the spray material transportation. When the flow rate of the sprayed material transfer gas from the gas introduction pipe 6 (Nm 3 / min), the flow rate of the construction water transfer gas from the water injector 7 (Nm 3 / min), and the blowing means 8 are used. It refers to the total flow rate (Nm 3 / min) of the gas flow rate (Nm 3 / min) from the blowing means 8 .
Example
[0038]

　Table 1 shows the first embodiment of the present invention. In this embodiment, the spraying work was carried out using the spraying device shown in FIG. That is, in this embodiment, the construction water and the gas for transporting the construction water were supplied only from the water injector 7. The pressure of the construction water transport gas and the spray material transport gas was in the range of 0.2 MPa or more and 0.5 MPa or less.
　The spraying material was a mixture of alumina-silica powder as a refractory powder, slaked lime as a binder, and silicate as a dispersant in a predetermined ratio, and this spraying material was used in the spraying apparatus shown in FIG. After spraying, the water mixing and transportability at that time were evaluated. Then, a comprehensive evaluation was performed based on these evaluation results.
[0039]
　The water mixture was evaluated by visually observing the state of spraying from the tip spray nozzle 4 and evaluating the degree of separation between the construction water and the spray material. The smaller the degree of separation, the better the water mixing property. Specifically, the case where there was no separation was evaluated as ◯ (excellent), the case where the separation was small was evaluated as Δ (good), and the case where the separation was large was evaluated as × (bad).
[0040]
　The transportability was evaluated by visually observing the state of spraying from the tip spray nozzle 4 and evaluating the degree of fluctuation in the discharge amount of the spray material. The smaller the degree of fluctuation in the discharge amount, the better the transportability. Specifically, the case where the discharge amount does not fluctuate is evaluated as ◯ (excellent), the case where the discharge amount fluctuates slightly is evaluated as Δ (good), and the case where the discharge amount fluctuates greatly is evaluated as × (bad).
[0041]
　The comprehensive evaluation was made in the following three stages based on the evaluation results of water mixing and transportability.
　○ (excellent): Both evaluation results are ○ (excellent).
　Δ (good): At least one of the evaluation results is Δ (good) and there is no evaluation result of × (bad).
　× (defective): At least one of the evaluation results is × (defective).
[0042]
[Table 1]

[0043]
　In each of Examples 1 to 12 in Table 1, the transport gas flow rate ratio is 0.07 or more and 2 or less, and the compressibility of the sprayed material is 32% or less, which are within the range of the present invention, and have water mixing properties and transportability. Was good with no evaluation of × (defective), and the overall evaluation was also good.
[0044]

　Table 2 shows a second embodiment of the present invention. In this embodiment, the spraying work was carried out using the spraying device of FIG. The pressures of the construction water transport gas, the spray material transport gas, and the gas blown from the blowing means 8 were set in the same range of 0.2 MPa or more and 0.5 MPa or less as in the first embodiment.
　As the spray material, a material having the same material composition as that of the first example was used, and the evaluation method of water mixing and transportability and the standard of comprehensive evaluation were the same as those of the first example.
[0045]
[Table 2]

[0046]
　In Table 2, Example 13 is an example in which construction water is blown from the blowing means 8 together with gas (gas for transporting construction water), and Example 14 is an example in which only gas is blown from the blowing means 8. In each case, the transport gas flow rate ratio is 0.07 or more and 2 or less, and the compressibility of the sprayed material is 32% or less, which is within the range of the present invention. The overall evaluation was also good.
Description of the sign
[0047]
　1 Material feeder
　2 Spraying material
　3 Table feeder
　4 Tip spraying nozzle
　5 Material transport pipe
　6 Spraying material transporting gas introduction pipe
　7 Water injection device
　8
　Blowing means A Spraying object
The scope of the claims
[Request item 1]
　It is a method of spraying an amorphous fireproof material by installing a water injector on the material transfer pipe from the material feeder to the tip spray nozzle and injecting construction water into the spray material transported from this water injector in the material transfer pipe. Te,
　the flow of the construction water carrier gas for transporting the construction water introduced into the water injector (Nm 3 and / min), the spraying material conveying gas for conveying the spraying material flow (Nm 3 The ratio to (/ min) (flow rate of construction water transport gas / flow rate of spray material transport gas) is 0.07 or more and 2 or less, and the degree of compression of the spray material is 32% or less. Spraying construction method for irregular fireproof materials.
[Request item 2]
　This is a method of spraying an amorphous fireproof material by installing a water injector on the material transfer pipe from the material feeder to the tip spray nozzle and injecting construction water into the spray material transported from this water injector in the material transfer pipe. Te,
　the water injector flow construction water carrier gas for transporting the construction water introduced into (Nm 3 / min) and construction water (m 3 in / min) ratio of (construction water carrier gas flow rate / A method of spraying an amorphous fireproof material with a construction water volume of 100 or more and 1000 or less.
[Request item 3]
　A blowing means for blowing construction water together with gas into the spraying material is provided on the upstream side of the water injector,
　and the amount of construction water from the blowing means is 20% by mass or less (including 0% by mass) of the total amount of construction water. The method for spraying an amorphous fireproof material according to claim 1 or 2, wherein there is, and the remaining construction water of the total construction water amount is injected from the water injector.
[Request item 4]
The ratio 　of the discharge amount of the sprayed material (kg / min) to the total flow rate of the transport gas (Nm 3 / min) (discharge amount of the spray material / total flow rate of the transport gas) is 1 or more and 20 or less. The method for spraying an amorphous refractory according to any one of claims 1 to 3.
[Request 5]
　The content of particles having a particle size of more than 2 mm in the spray material is 30% by mass or less (including 0% by mass), and the content of particles having a particle size of 45 μm or less is 3% by mass or more and 30% by mass or less. , The method for spraying an amorphous refractory according to any one of claims 1 to 4.
[Request 6]
　A spraying material used in the method for spraying an amorphous refractory according to any one of claims 1 to 5, wherein the degree of compression is 32% or less.
[Request 7]
　According to claim 6, the content of particles having a particle size of more than 2 mm is 30% by mass or less (including 0% by mass), and the content of particles having a particle size of 45 μm or less is 3% by mass or more and 30% by mass or less. The spray material described.