JPS6051671A - Castable refractories - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a castable refractory having high mechanical strength and excellent spalling resistance and erosion resistance.

Castable refractories have the advantage of being easy to construct and producing a uniform construction body, and are used in a wide range of applications such as various industrial kilns and blast furnace tap troughs. However, conventional castable refractories have the disadvantage that they tend to peel off due to cracking when used for a long period of time.

Metal fibers have been added to solve the above drawbacks, but it is difficult to mix them uniformly because the metal fibers tend to get tangled during mixing or kneading, and the metal fibers become more susceptible to oxidation as they are used. It also has the disadvantage that it hardens, softens and melts, and diffuses into the matrix of the refractory, reducing its fire resistance.

In addition, a rod-shaped reinforcing material containing 40 to 60% by weight of 11209 for improving the spalling resistance and mechanical strength of monolithic refractories is known (Japanese Patent Application Laid-Open No. 129208/1983); Even when using the above, the mechanical strength, erosion resistance and spalling resistance, especially at high temperatures, are still insufficient.

Furthermore, recently, non-oxide materials such as carbon, silicon carbide, and silicon nitride are often blended as refractory raw materials for castable refractories, and in this case, oxide reinforcing materials such as alumina are not compatible with the matrix. Since it is not sufficient, there is a drawback that the mechanical strength is rather reduced.

In view of the above-mentioned current situation, the present inventor conducted extensive research to improve the mechanical strength, erosion resistance, and spalling resistance of castable refractories, and as a result, found that a remarkable reinforcing effect can be obtained in a specific stable refractory. The present inventors have discovered that the objective can be achieved by obtaining a sufficient reinforcing effect even with ordinary castable refractories, and have completed the present invention.

That is, the present invention has a diameter of 0.3 to 1Q mm and a length of 5 to 5 mm.
The present invention relates to a castable refractory characterized by containing 1 to 50% by weight of a rod-shaped non-oxide having a diameter of 0.0 and a length/diameter ratio of 2 to 100.

The rod-shaped non-oxide compounded in the present invention is, for example, carbon, graphite,
8iC! %B40 %Carbide such as WO, 818N4,
A/N.

Nitride such as BN, boride such as ZrB4, TiB2, M
It can be produced by firing one batch of non-oxide raw materials such as silicides such as o8i□ in a non-oxidizing or reducing atmosphere such as nitrogen gas, argon gas, or coke please. As the binder in the above, resin binders such as phenol resin, epoxy resin, and Fura/Il resin are preferable, but
Polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, lignin derivatives, etc. may be used alone or in combination with a resin binder. Further, the rod-shaped non-oxide may be manufactured by a fine ceramic sintering method such as pot press, HIP, reaction sintering, OVD, or the like.

The cross sections of rod-shaped non-oxides are circular, oval, square, rectangular,
Any shape such as a polygon may be used, but the diameter should be 0.3~
It is preferable that it is about 10 tones.

Incidentally, the diameter in the present invention is of course the diameter when the cross section is circular, but the diameter when the cross section is other than circular is expressed by the product of the following formula).

If the diameter is smaller than Q, 3 mnl, it will break during crosstalk, and if it is thicker than lQl1m, the reinforcing effect will not be sufficient. Also, the rod-shaped non-oxide may be linear or curved, but
The length is preferably about 5 to 5 Qn1m. If the length is less than 5 or 2 m, high mechanical strength cannot be obtained, and if it is longer than 50 m, crosstalk becomes difficult. Further, the length/diameter ratio of the rod-shaped non-oxide is preferably about 2 to 100, more preferably 6 to 50. The ratio is 2
If it is smaller, the reinforcing effect will not be sufficient, and if it is larger than 100, it will be difficult to knead uniformly.

The amount of rod-shaped non-oxide compounded is usually 1 to 50% by weight. 1
If the amount is less than heavy violet, there will be no reinforcing effect, and if it exceeds 50% by weight, it will be difficult to cross wires uniformly.

The refractory raw materials for the castable refractories of the present invention include:
Any known material can be used, such as alumina, mullite, bauxite, chamotte, waxite, silica, zircon, silicon carbide, silicon nitride, carbon, metallic silicon, clay, magnesia, chromium, etc. Use one type or two or more types. Further, any known binder can be used, such as alumina cement, phosphate, silicate, pitch, etc., and at least one of these can be used.

The Φ Yastapur refractory of the present invention has significantly improved mechanical strength, erosion resistance, and spalling resistance due to the combination of rod-shaped non-oxide materials with a specific shape, and is significantly improved compared to conventional ones. Lifespan is extended. In addition, when conventionally manufacturing castable refractories with metal fibers added, there were problems such as the metal fibers inserting into the hose and causing the hose to clog or burst when the material was being pumped into the hose, but the castable refractory of the present invention Construction work can be easily carried out with materials without such obstacles.

The castable refractory of the present invention may be constructed by any known method, and in addition to vibration casting and pouring construction, spraying construction and prepact construction can also be employed.

The castable refractories of the present invention can be suitably used, for example, in blast furnace tap troughs, various trough covers, and the like.

Hereinafter, the present invention will be explained in more detail by giving production examples, examples, and comparative examples.

Production Example 1 5 parts by weight of phenol resin powder, 1 part by weight of polyvinyl alcohol, and 15 parts by weight of water were added to 8i0100 parts by weight with a particle size of 0.044 ynyn or less, mixed, and then put into an extruder with a 3 mm diameter nozzle. was attached, extrusion molded, and fired at 1700°C in a nitrogen atmosphere in an electric furnace. Thereafter, it was cut into a length of 30 mm to obtain a rod-shaped SiO.

Example 1 A castable large-sized product of the present invention having the composition shown in Table 1 below was cast. The shape of the molded product is 4 Qmm x 40
It was set to mm x 160 mm. However, the shape of the one for spalling test is 230t)m x 114fmn
×65wn.

Table 1 Comparative Example 1 Castable refractories having the same composition as in Example 1 except that the rod 810 was not used were cast in the same manner.

Comparative Example 2 In Example 1, stainless steel fiber (diameter Q, 5 twn, length 30t) was used instead of the rod 810.
Castable refractories having the same composition except for using 3 parts by weight of 3 parts by weight of 50 nm ) were similarly cast and molded.

Comparative Example 3 In Example 1, rod-shaped alumina (
Castable refractories having the same composition except that the same amount of castable refractories (32 mm in diameter and 3 Q mm in length) were used were cast in the same manner.

The castable refractory molded product of the present invention or comparison obtained above was dried at 110°C for 20 hours, and then dried at 800°C for 3 hours.
Various tests wI after firing for 1 hour or 3 hours at 1400°C
LllC was provided. The test results are shown in Tables 2 and 3. Note that the hot bending strength was determined by drying the sample at 110°C for 20 hours. It's Subo again. In addition, the slag test is 1
Pig iron samples were dried at 10°C for 20 hours:
The difference in sample thickness before and after the test when tested using a rotary slag tester at 1560°C for 2 hours using blast furnace slag = 1 = 1 sbg' is defined as melting loss x <ntm>, and Comparative Example 1 It is expressed as the erosion loss ratio when the amount of erosion loss is taken as 100.

Claims (1)

[Claims] ■ A rod-shaped non-oxide with a diameter of 0.3 to 10 mm, a length of 5 to 50 mm, and a length/diameter ratio of 2 to 100 is
A castable refractory characterized by containing ~50% by weight.