JPH0427190B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is a novel fire-resistant material for use in so-called slurry addition spraying construction, in which coarse particles and fine particles are separately supplied to a spray nozzle, mixed within the nozzle, and sprayed. Regarding the composition. [Conventional technology] Molten metal containers (ladles, tie-dishes, pails, etc.)
In recent years, the construction of interior linings has changed from brickwork to pouring with monolithic refractories, but due to the complexity of on-site kneading and framing work, there is a shift to spraying. However, the spraying method has the drawback of low corrosion resistance, especially in the slag line part, and short lifespan due to the low packing density of the construction body. In order to improve the above-mentioned drawbacks, the present inventors completed the "Construction Method for Fireproof Composition for Spraying Construction" described in Japanese Patent Publication No. 62-21754, thereby creating a construction material with high packing density. Now you can get
It has become quite widely adopted. According to this method, ``a curing agent is added to the particle size-adjusted refractory aggregate of 74 μm or more, a deflocculant is added to the fine powder portion of 74 μm or less, and the fine powder portion of 74 μm or less is mixed separately. A method for applying fireproof compositions for spraying, which consists of making slurry with a binder, supplying each slurry separately to a spray nozzle, mixing them at the nozzle, and spraying. By using less so-called alumina-free spray material, it has become possible to perform spray construction with quality (characteristics) equal to or better than vibration molding or pouring construction even with a low moisture content. [Problems to be Solved by the Invention] However, when the packing density of the sprayed material becomes high, when drying or heating up, the moisture of the construction object does not evaporate from the surface, and water vapor stays inside, eventually damaging the surface of the construction object. It breaks and protrudes, causing what is called an explosion, so if you continue to use it as is, it will cause local damage during operation and significantly shorten its life, or if the explosion is large, you will have to stop raising the temperature and spray it again (repair). This has led to problems such as the need for On the other hand, there has been a technique in the past to add inorganic fibers or organic fibers to the spray material, but this was only for reducing ribbon loss and was ineffective in preventing explosions. In addition, as a similar technique, ``vinylon, There is a refractory for pouring construction that contains 0.01 to 1.0% by weight of organic fibers selected from nylon, polyvinyl, polyester, polyethylene, polypropylene, etc. that melt or decompose at temperatures below 200°C. It melts or decomposes, and the objective of the present invention, which is to prevent the sprayed body from exploding during drying and heating, is a completely different technical idea. [Means for Solving the Problems] In order to prevent the above-mentioned explosion, the present inventors
We discovered that it is sufficient to create ventilation gaps that serve as a path for moisture evaporation before drying begins, and after conducting various research, we found that fibrous substances that dissolve in the added water whose temperature rose during drying of the construction body and temperature rise were found to be effective. We have completed a blended fire-resistant composition for spraying. That is, the present invention provides a fire-resistant composition for spraying, in which a coarse particle part and a fine powder part are separately supplied to a spray nozzle, and mixed at a predetermined ratio in the nozzle for spray construction. Particle size of raw material: 3mm to 74μ
100 parts by weight of coarse particles, diameter 0.1~20μ, length 1~5mm,
Consisting of 0.05 to 1.0 parts by weight of a hot water-soluble fibrous substance with a dissolution temperature of 50°C or higher in water, and 0.1 to 1.5 parts by weight of a hardening agent; and the fine powder part is 100 parts by weight of fine powder with a particle size of 74μ or less of refractory raw material, solid content 20 This invention relates to a fire-resistant composition for spraying, characterized in that it is a slurry consisting of ~30% by weight of colloidal silica liquid and water. [Function] The fireproof composition for spraying of the present invention (hereinafter simply referred to as spraying material) will be explained below. The refractory raw materials used in the present invention include silica sand,
Construction objects intended for use with siliceous raw materials such as silica stone and low stone, high alumina raw materials such as fused alumina, calcined alumina, bauxite, and clay shale, and conventional raw materials such as silicon carbide, magnesia raw materials, zirconia and zircon. It can be used accordingly. Coarse particles of refractory raw materials are obtained by crushing and sifting raw materials selected from the above raw materials by a conventional method, and generally refer to particles in the particle size range of 3 mm to 74μ, but the As an unavoidable component, fine powder of 74 μm or less may also be included in an amount of about 20% by weight of the entire coarse particle portion. The fine powder of the refractory raw material generally refers to those with a particle size range of 74μ or less, but for the same reason as the coarse particle portion, coarse particles of 74μ or more can be contained up to about 20% by weight of the entire fine powder portion. The coarse particles and fine particles of the refractory raw material may be used in combination of two or more of the above raw materials whose particle sizes are adjusted within the above range depending on the use and purpose of the construction body. The coarse particle portion of the spray material of the present invention further contains a fibrous substance soluble in hot water. The fibrous material has a diameter
It needs to have a diameter of 0.1 to 20 μm, a length of 1 to 5 mm, and a dissolution temperature in water of 50° C. or higher. When the diameter of the fibrous material is less than 0.1 μm, the ventilation voids formed as described below are too small to allow water vapor to move or diffuse during drying and heating. Moreover, if it exceeds 20μ, the ventilation voids become too large and the structure of the constructed body becomes porous, resulting in a decrease in corrosion resistance. Furthermore, if the length of the fibrous material is less than 1 mm, ventilation voids cannot be continuously formed, and movement and dispersion of water vapor are difficult to occur. Furthermore, if the thickness exceeds 5 mm, the added fibrous substances will become entangled with each other, making it difficult to disperse them evenly during spraying. Furthermore, if the dissolution temperature of the hot water-soluble fibrous material in water is less than 50°C, it will dissolve in water immediately after spraying, so the portion occupied by the fibrous material will become fine powder of the refractory raw material. The ventilation gap cannot be formed as desired. As the above-mentioned hot water-soluble fibrous material, organic or inorganic materials such as commercially available polyvinyl alcohol fibers for paper making or cellulose fibers can be blended. The amount of the fibrous material added is 0.05 to 0.5 parts by weight per 100 parts by weight of coarse particles of the refractory raw material. If the amount added is less than 0.05 part by weight, there will be few ventilation gaps formed in the construction body, and the explosion prevention effect will be low. Moreover, if it exceeds 0.5 part by weight, the structure of the construction body becomes too porous and corrosion resistance decreases. Further, a curing agent is added to the coarse grain portion. As a hardening agent, commercially available sodium silicate (powder), potassium silicate,
Slaked lime powder, magnesium chloride, etc. are added in an amount of 0.1 to 1.5 parts by weight per 100 parts by weight of coarse particles of the refractory raw material.
When the amount of curing agent added is less than 0.1 part by weight,
The curing speed of the spray material is slow and the adhesion rate decreases. Moreover, if it exceeds 1.5 parts by weight, the curing speed is too fast and the nozzle may become clogged, making spraying impossible. As described above, the coarse grain portion of the spray material of the present invention is composed of the coarse grains of the refractory raw material, the hot water soluble fibrous material, and the hardening agent. Next, colloidal silica liquid is added to the fine powder portion of the spray material of the present invention. Colloidal silica liquid is commercially available with a solid content of 20 to 30% by weight, and is a fine powder of refractory raw material.
Add 10 to 30 parts by weight per 100 parts by weight. When the amount of colloidal silica liquid is less than 10 parts by weight,
The solid content decreases and the strength of the construction body decreases. Moreover, if it exceeds 30 parts by weight, the water content will be too large as a whole, and the construction body will become porous and its strength will decrease. During construction, about 0 to 10 parts by weight of water is added to the fine powder part prepared as described above as a remainder of the construction water content, and the powder is mixed with colloidal silica and refractory raw material fine powder with a moisture content of 15 to 25% by weight. It is provided as a slurry. Note that if the amount of water in the colloidal silica liquid alone can cover the amount of water in the application, there is no need to add additional water. When applying the spray material of the present invention, the coarse particles are prepared in advance at a predetermined ratio. The coarse particles are put into a spray device equipped with a feeder motor, called a spray gun, and supplied to a nozzle through a material hose. On the other hand, at the construction site, the fine powder part is made into a slurry by putting fine powder of refractory raw materials, colloidal silica liquid, and water into a slurry unit at a predetermined ratio, and the slurry is fed under pressure to the nozzle through the slurry hose. A desired construction body can be formed by uniformly mixing the powder and the fine powder part at a predetermined ratio, and the resulting mixture is ejected from a nozzle. The ratio of coarse particles to fine particles can be varied depending on the size and shape of the construction object, but is usually 50:50 to 75:25, preferably 70:30.
That's about it. Further, in order to adjust the curing speed of the construction body, the blending ratio of the curing agent and the colloidal silica liquid can be changed as appropriate. When the construction body obtained from the sprayed material of the present invention as described above is heated at a rate of temperature increase of about 1°C per minute according to a conventional method, a fibrous material with a temperature of 50°C or higher is formed from the heated surface of the construction body. The fibrous material dissolves and disappears into the water and/or colloidal silica liquid from the portion that reaches a temperature equal to or higher than the dissolution temperature of the fibrous material, after which fine ventilation voids are formed. As the portion of the fibrous portion within the construction object reaches the melting temperature moves, ventilation voids are sequentially formed within the construction object, and eventually are formed over the entire construction object. Since the water vapor generated inside the construction body passes through the formed ventilation gap and is released to the outside, an explosion phenomenon can be prevented. [Example] The spray material of the present invention will be further explained by giving examples below. Example A coarse particle part and a fine powder part are mixed in the proportions shown in Table 1 below, and the coarse particle part is supplied to the spray nozzle at a rate of about 20 kg/min, while the fine powder part is supplied at a rate of 8 to 10 kg/min. The material was supplied to the nozzle at a speed of Obtained. In addition, the test specimens for the explosion resistance test were 12
After being left for a period of time, it was placed in an electric furnace maintained at the specified temperature listed in Table 1, and exploded in 30 minutes.
Items that did not explode were marked as ○. The characteristics of the specimen are also listed in Table 1.

[Table] [Effects of the Invention] As detailed above, the spray material of the present invention is used in construction by supplying separately prepared coarse grain portions and fine powder portions to the same nozzle. By adding a hot water-soluble fibrous substance that dissolves in hot water of 50℃ or higher to the coarse grain part, extremely small ventilation gaps are formed when drying the construction object, resulting in rapid drying.
It is possible to prevent the construction object from exploding even if the temperature rises,
Particularly in new furnaces, drying and preheating periods can be reduced compared to conventional methods.
It can be shortened by up to 30%, which is very useful for energy saving and does not reduce corrosion resistance during use. Further, the spray material of the present invention can be used for repairing various refractories as well as conventional spray materials.

Claims (1)

[Claims] 1. In a fire-resistant composition for spraying, in which a coarse particle part and a fine powder part are separately supplied to a spray nozzle and mixed at a predetermined ratio in the nozzle for spray construction, the coarse particle part has a particle size of 3 mm of the refractory raw material. 100 parts by weight of coarse particles of ~74μ, diameter 0.1~20μ, length 1~5mm, warm water soluble fibrous material with a water dissolution temperature of 50℃ or higher 0.05~
1.0 parts by weight, and 0.1 to 1.5 parts by weight of a curing agent;
In addition, the fine powder part is a fine powder with a particle size of 74μ or less of refractory raw material.
A fireproofing composition for spraying construction, characterized in that it is a slurry consisting of 100 parts by weight, a colloidal silica liquid and water having a solid content of 20 to 30% by weight.