JPH057355B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel lightweight fireproof insulation block and its manufacturing method. Fireproof insulation materials used in heating furnaces, etc. utilize the insulating properties of air by creating pores and air layers within their structure to reduce thermal conductivity.
Generally, fireproof insulation bricks, ceramic fiber insulation materials, lightweight castable refractories, etc. are used. Among these, fireproof insulation bricks do not have sufficient strength. There are drawbacks such as the low maximum operating temperature, which is usually around 1600℃. In addition, insulation materials made of ceramic fiber processed into wet felt shapes, etc.
Although it is lightweight and has great heat insulating properties, the fiber used is amorphous, so as time passes and temperature rises, crystals precipitate and become coarser, causing it to lose its flexibility and become powdered or shrink. The major drawback is that it cannot withstand long-term use at high temperatures. In addition, lightweight castable refractories contain lightweight aggregate and lime (CaO), so they cannot withstand long-term use at high temperatures, are complicated to construct, and contain a large amount of water, so It has drawbacks such as requiring a large amount of time and a heat source for drying. The purpose of the present inventor is to develop a fire-resistant insulation material that does not have the above-mentioned drawbacks, that is, a fire-resistant insulation material that is lightweight, has a high maximum operating temperature, has sufficient strength, has little deterioration during use, and is stable for a long period of time. As a result of intensive research,
The inventors have discovered that the object can be achieved by firing a rod-shaped or (and) string-shaped molded body containing a refractory raw material and a binder, and have completed the present invention. That is, the present invention provides a rod-shaped or (and) string-shaped molded article containing a refractory raw material and a binder and having a cross-sectional diameter of 0.3 to 5 mm, which is irregularly or (and)
A lightweight fireproof insulation block that is regularly arranged, sintered and integrated, and has a bulk specific gravity of 0.7 or more, and a rod-shaped or (and ) The string-like molded body material or its dried or calcined material is filled into a molding frame in an irregular or (and) regularly arranged arrangement, and then fired so that the bulk specific gravity becomes 0.7 or more. This invention relates to a method of manufacturing a lightweight fireproof insulation block characterized by being integrated. The lightweight fireproof insulation block of the present invention is made by sintering and integrating the above-mentioned specific rod-shaped or (and) string-shaped molded bodies arranged irregularly or (and) regularly. Since it has a large number of voids, it is lightweight, has excellent heat insulation properties, and has sufficient strength. Here, sintering of rod-shaped or (and) string-shaped molded bodies arranged irregularly or (and) regularly means, for example, (1) a fixed or various shape (length, cross-sectional shape); and diameter, etc.)
(2) A layer in which rod-shaped molded bodies of a certain shape are irregularly entangled and sintered, or (2) a layer in which rod-shaped molded bodies of a certain shape are irregularly entangled and a rod-shaped molded body of a certain shape that is different from that layer. One or more layers in which bodies are irregularly intertwined may be sintered by overlapping alternately or continuously or discontinuously in the order of the shape (e.g. length) of the rod-shaped compact, or ( 3) Layers in which rod-shaped compacts of a certain or various shapes are arranged in a certain direction and layers in which they are arranged in a different direction (for example, at right angles) may be alternately overlapped and sintered, or ( 4) A rod-shaped molded body of a constant or various shapes and a string-shaped molded body of a constant or various shapes may be irregularly entangled and sintered, and (5) A rod-shaped molded body of a constant or various shapes may be sintered. (6) String-like molded bodies of fixed or various shapes may be folded irregularly or regularly and sintered. This shows that layers and layers in which rod-shaped molded bodies of fixed or various shapes are irregularly intertwined or regularly arranged may be alternately overlapped and sintered. The lightweight fireproof insulation block of the present invention is manufactured, for example, as follows. That is, by kneading refractory raw materials, binder, water, etc.
It is extruded and molded into a rod or string shape using an extrusion molding machine or the like. The rod-shaped molded body may be obtained by appropriately cutting a string-shaped molded body base material or a product obtained by drying or calcining the same, or may be obtained by cutting a regular molded body into a rod shape. The cross section of the rod-shaped molded body or string-shaped molded body may be any shape such as circular, elliptical, square, rectangular, polygonal, etc., and may be solid or hollow, but the diameter is about 0.3 to 5 mm. It's good.
Incidentally, the diameter as used in the present invention is of course a direct line when the cross section is circular, but when the cross section is not circular, the diameter D is determined by the following formula.

[Formula] (S indicates the cross-sectional area). If the diameter is smaller than 0.3 mm, it is difficult to manufacture, and the structure of the block after firing tends to become dense and the insulation effect decreases.If the diameter exceeds 5 mm, the structure of the block after firing becomes sparse. This is not preferable because it tends to reduce strength. Further, the rod-shaped molded body or string-shaped molded body may be linear or curved, or may be twisted. Rod-shaped and string-shaped are originally continuous concepts, so in the present invention, the length of the rod-shaped molded product is not limited at all, but for convenience of handling, the length is usually about 3 to 300 mm. There are many things to do. The refractory raw materials used above are not particularly limited, and may be acidic, neutral, or basic, such as alumina, mullite, aluminum shale, zircon, zirconia, spinel, magnesia, clay, dolomite, silica, and silica. ,chromium,
One type or a combination of two or more of these can be used to determine the required usage conditions (for example, maximum usage temperature, required strength, reactivity with heated objects such as furnace walls, etc.). Select and use the appropriate one. Carbon, silicon carbide, nitride, etc. may be used in combination as a refractory raw material. These refractory raw materials are used after adjusting the particle size appropriately according to a conventional method. The binder is not particularly limited, and examples include organic binders such as methyl cellulose, polyvinyl alcohol, dextrin, sodium lignin sulfonate, pitch, tar, and resin, sodium silicate, potassium silicate, aluminum phosphate, and phosphoric acid. Examples include inorganic materials such as magnesium, and at least one of these is used. The above-mentioned refractory raw material and binder are kneaded according to a conventional method, adding water or the like if necessary, and then formed into a rod or string shape as described above. Next, the obtained rod-shaped molded body or (and) string-shaped molded body is used as it is, or after being dried or calcined, it is filled into a molding frame made of refractory material or the like.
They are integrated by firing at a temperature of about 1000 to 2000°C, preferably 1350 to 1900°C. Rod-shaped molded body or (and)
When filling the molding frame with string-like molded bodies, the string-like molded bodies are filled in an irregular or/and regular arrangement depending on the structure of the block of the present invention as described above. At this time, if necessary, vibration may be applied, or it may be pressed with an appropriate pressure after filling. Further, the firing may be performed while the mold is filled in the mold, or the mold may be removed from the mold. The firing temperature is
Considering the composition of the raw materials used and various properties such as the strength required for the block after firing, and in order to ensure that it is stable without changes in quality or shrinkage of structure during use as a heat insulating block, it is within the above range. in,
Select a temperature that is approximately the same as or higher than the operating temperature. The firing time may also be determined as appropriate. Furthermore, the molding frame used above can be of any shape, so for example, rectangular parallelepipeds, cubes, rectangular shapes, prismatic shapes, cylinder shapes, cylindrical shapes, spherical shapes, etc., or irregular shapes that are a combination of these. Any block can be manufactured depending on the purpose of use. The lightweight fireproof heat insulating block of the present invention can be produced by selecting and combining various refractory raw materials, lengths of rod-shaped molded bodies and/or string-shaped molded bodies, cross-sectional shape and diameter, arrangement method, firing temperature, etc. The strength, amount of voids (bulk specific gravity), density, maximum operating temperature, etc. of the product can be adjusted as appropriate depending on the purpose of use. The lightweight fireproof insulation block of the present invention has a novel structure not previously known, is lightweight, has sufficient strength, can have a high maximum operating temperature, is easy to construct, and is durable during use. It is stable for a long time with little deterioration. Therefore, the lightweight fireproof insulation block of the present invention can be suitably used as a fireproof insulation material for, for example, tundish covers, various melt container covers such as ladles, various gutter covers, heating furnaces, soaking furnaces, electric furnaces, etc. . EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 After kneading a particle size-adjusted refractory raw material consisting of 97 parts by weight of Shamotsu containing 71% by weight of alumina and 29% by weight of silica and 3 parts by weight of kaolin clay with 30 parts by weight of a liquid binder (15% by weight aqueous solution of methyl cellulose). Using an extrusion molding machine, a rod-shaped molded body having a circular cross section of 1 mm in diameter and a length of 10 to 120 mm was obtained. A molding frame (400 x 400 x 150 (mm) made of high alumina bricks) assembled on a baking cart.
temperature) in a tunnel kiln.
After firing at 1600° C. for 6 hours, the individual rod-shaped compacts were irregularly intertwined and sintered to obtain a lightweight and sufficiently strong block with many voids. Example 2 A base of a rod-shaped molded body having the same composition as in Example 1 and a diameter of 3 mm was prepared, and the rod-shaped molded body with a diameter of 1 mm was first filled to a thickness of about 20 mm into the same molding frame as in Example 1, and then the rod-shaped molded body with a diameter of 3 mm was filled. A 3 mm rod-shaped molded body is filled to a thickness of about 3 mm, and then a 1 mm diameter rod-shaped molded body is placed on top of this, followed by 3 mm diameter rod-shaped molded bodies.
Repeating the method of filling mm rod-shaped molded bodies,
The two types of rod-shaped compacts filled in layers were fired in a tunnel kiln at 1600°C for 6 hours.
In this way, as in Example 1, a block in which the rod-shaped molded bodies were irregularly entangled and sintered into one piece was obtained. The physical properties of each block obtained in Examples 1 and 2 are shown in Table 1. Table 1 shows that the lightweight fireproof insulation block of the present invention is lightweight and has sufficient strength. For comparison, commercially available product examples (Company A:
Alumina-silica-based ultra-light fireproof and insulating bricks) are also listed in Table 1.

【table】

Claims (1)

[Claims] 1. Rod-shaped or (and) string-shaped molded bodies containing a refractory raw material and a binder and having a cross-sectional diameter of 0.3 to 5 mm are arranged irregularly or (and) regularly. A lightweight fireproof insulation block that is sintered and integrated with bulk specific gravity of 0.7 or more. 2. A rod-shaped or (and) string-shaped molded body containing a refractory raw material and a binder and having a cross-sectional diameter of 0.3 to 5 mm, or a dried or calcined product thereof, is placed in an irregular or ( and) A method for manufacturing a lightweight fireproof and heat-insulating block, characterized by filling the blocks in a regular array, and then baking and integrating them so that the bulk specific gravity is 0.7 or more.