JPH09150408A - Manufacture of fireproof block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of fireproof block excellent in durability and reliability. SOLUTION: This manufacturing method of a fireproof block comprises the steps of charging fireproof aggregate 1 having the particle diameter of 3mm or more in a form 2; forming a formed body by charging slurry 5, which is made of hardener-containing fireproof raw material having the particle diameter of 0.3mm or less and deaerated, among the fireproof aggregate particles 1 charged in the form 2; and drying and solidifying the resultant formed body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a refractory block that is structurally dense and has high bending strength.

[0002]

2. Description of the Related Art As is well known, for example, a slide gate of molten metal in a steelmaking process or a casting process, or a porous plug guide sleeve for preparing a molten metal composition by blowing an inert gas, etc.
A dense refractory block that does not contain coarse porosity is used. And, this kind of refractory block and refractory material layer are generally marketed as so-called irregular shaped refractory and molded (standardized) at the time of use, but for easy handling and quick response. It is also commercially available in the fireproof block state, which is molded with consideration.

By the way, a conventional refractory amorphous block is a slurry-like substance prepared by kneading an amorphous refractory having a particle size of 5 mm or less and having a continuous particle size distribution (grain size mixture) with water. The block is poured (filled) into a mold of a specified shape, cured for 24 hours at room temperature, demolded, and then dried at 110 ° C for 24 hours, for example. ), And is put to practical use in the form of a molded body. In addition, in pouring (filling) into the above mold, while imparting sufficient fluidity to the slurry-like material, defoaming is performed. Therefore, generally, the frame mold is placed on a vibrating table, or A rod-shaped vibrator is inserted into the frame mold to vibrate the filled slurry material.

[0004]

With respect to the refractory block, it is desired to improve corrosion resistance and mechanical strength.
In response to these demands, a large reduction in coarse pores on the surface and inside (or no coarse pores) has been achieved. That is, attempts have been made to improve fluidity and facilitate defoaming by vigorous shaking and increasing the amount of kneading water. However, applying the strong vibration,
By increasing the amount of kneading water and the fluidity and defoaming property of the slurry-like material, on the other hand, separation or breathing easily occurs in the amorphous refractory due to the size of the particle size, etc. However, there is a problem that the amorphous refractory and water are easily separated or breathed even in the slurry-like material, and as a result, a refractory block or a refractory layer having a uniform composition cannot be obtained. In other words, the manufactured or formed refractory block or refractory material layer is likely to have a deviation in quality, which is not a practically satisfactory means.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for easily manufacturing a refractory block having excellent durability and reliability.

[0006]

According to the present invention, a step of filling a refractory aggregate having a particle diameter of 3 mm or more in a mold, and a curing agent between the refractory aggregate particles filled in the mold. Including particle size 0.3mm
A refractory block consisting of the following refractory raw material, and having a step of filling a defoamed slurry to form a molded body, and a step of drying and solidifying the molded body It is a manufacturing method.

That is, according to the present invention, the refractory material constituting the refractory block is a mixed system (or a hybrid system) of discontinuous grain size blends having a grain size of 3 mm or more and a grain size of 0.3 mm or less. In addition, the main point is to perform defoaming treatment on the slurry-like material during casting.

In the present invention, examples of the refractory aggregate include natural materials such as bauxite, kaolin, magnesite, chromite, sintered alumina, fused alumina, synthetic mullite, spinel, sintered magnesia, fused magnesia, Artificial raw materials such as electro-fused magkuro are mentioned. However, it is necessary to select those refractory aggregates having a particle size of 3 mm or more, more preferably 5 mm or more. That is,
If the particle size is less than 3 mm, the gap between the aggregates is too narrow, making it difficult to densely fill the slurry-like material,
As a result, a dense refractory block may not be obtained. When the particle size is selected to be 5 mm or more, dense filling by pouring the slurry-like material is more easily performed. The fire-resistant aggregate may be added with, for example, metal fibers to reinforce the peel resistance or the bondability.

In the present invention, examples of the refractory raw material in the form of a slurry include natural raw materials such as bauxite, kaolin, magnesite, chromite, sintered alumina, fused alumina, synthetic mullite, spinel, sintered magnesia, Examples include artificial raw materials such as electrofused magnesia and electrofused magcro, zircon flour, silicon carbide, earth-like graphite, and carbon black. However, these refractory raw materials have a particle size of 0.3 mm or less, more preferably 0.074 mm (2
(00 mesh) The following must be selected. That is, if it exceeds 0.3 mm, it is easy to form a bridge when poured as a slurry, it is practically impossible to sufficiently fill the gap between the aggregates, and as a result, a dense refractory block etc. I can't get it. The particle size is 0.074 mm (2
(00 mesh) If selected below, it exhibits even better fluidity. When a basic material such as spinel, magnesia, or magnesite is used as the refractory material, it is preferable to use a hydration inhibitor having a chelating effect together.

In the present invention, examples of the curing agent contained in the refractory raw material include alumina cement, sodium silicate, and the like. Further, in order to improve the fluidity of the slurry-like material, ultrafine silica powder or The ultrafine alumina powder may be further added and mixed with sodium phosphate, polycarboxylic acid or the like as a dispersant.

In the present invention, in pouring and filling the slurry-like material in the region filled with the refractory aggregate, the slurry-like material needs to be defoamed in advance. That is, prior to pouring and filling, for example, vacuum or reduced pressure treatment must be performed to remove or reduce air bubbles in the slurry as much as possible, resulting in the formation of a dense refractory fixed block. There is a problem.

In the present invention, the combination of the refractory raw material having a particle diameter of 3 mm or more and the refractory raw material containing a hardening agent and having a particle diameter of 0.3 mm or less enables the refractory raw material to be easily and densely packed between the refractory aggregate particles. Since it becomes easy to adopt the constitution filled in, it becomes unnecessary to perform strong vibration and increase of kneading water, and it is possible to form a highly reliable and durable refractory block with a high yield while simplifying the process.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIG.

Sintered alumina having a particle size of 20 to 5 mm (refractory aggregate A), sintered alumina having a particle size of 5 to 3 mm (refractory aggregate B),
Fused alumina (refractory aggregate C) with a particle size of 5 to 3 mm, particle size
Sintered alumina of 0.3 mm or less (refractory raw material a), particle size 0.07
4mm or less of fused alumina (refractory raw material b), particle size 0.074m
Magnesia (refractory raw material c) of m or less, hydration inhibitor, curing agent (alumina cement), and kneading water (added water:
As shown in Table 1, the external ratio (%) was selected and combined with the refractory aggregate and the slurry. First, a mold of 40 × 40 × 160 mm was prepared, and the refractory aggregates A, B or C were filled in the mold.

Next, as schematically shown in FIG. 1, the mold 2 filled with the refractory aggregate 1 was placed on a vibrating table 3 which moves forward and backward or left and right to give a gentle vibration. Into the mold 2 to which this gentle vibration was given, the corresponding slurry-like material 5 which had been separately put into the defoaming device 4 of the vacuum defoaming system and defoamed was poured by pressure supply while stirring. The degassed slurry-like material 5 was filled in the gap between the refractory aggregates 1.

After the filling of the slurry-like material, after curing and molding at room temperature for 24 hours, the molded body is removed from the mold 2 (demolded), dried at 110 ° C. for 24 hours, and fireproofed. Sex block pieces (test pieces) were obtained.

For each of the above test pieces, the surface condition and the cut surface condition were observed, bulk specific gravity, apparent porosity%,
Bending strength MPa was measured, while bulk specific gravity, apparent porosity%, and heat treatment were performed at 1500 ℃ for 3 hours.
The results of the measurements of the bending strength MPa are also shown in Table 1.

[0018]

[Table 1] For comparison, sintered alumina with a particle size of 20 to 5 mm (refractory aggregate A), sintered alumina with a particle size of 5 to 3 mm (refractory aggregate B),
Sintered alumina with a grain size of 3 to 1 mm (refractory aggregate D), grain size 5
~ 3 mm fused alumina (refractory aggregate C), particle size 1 mm or more sintered alumina (refractory material d), particle size 0.3 mm or less sintered alumina (refractory material a), particle size 0.074 mm or less As shown in Table 2, the fused alumina (refractory raw material b), the curing agent (alumina cement), and the kneading water (added water: external ratio%) were selected and combined with the refractory aggregate and slurry. First, a mold of 40 × 40 × 160 mm was prepared, and the refractory aggregates A, B, C or D were filled in the mold.

Next, the mold filled with the refractory aggregate was placed on a vibrating table which moves forward and backward or left and right, and strong vibration was applied as compared with the above embodiment. The corresponding slurry-like material was defoamed and poured under pressure into the mold to which vibration was applied, and the slurry-like material was filled in the gaps between the refractory aggregates. In the case of Comparative Example 3, the defoaming treatment of the slurry-like material was omitted, and in the case of Comparative Example 4, the refractory aggregate and the slurry-like material were previously mixed and kneaded, and this mixed and kneaded material was molded. It was poured and filled into the frame. After the slurry is filled, it is cured and molded at room temperature for 24 hours, and then the molded body is removed from the mold (demolded) at 110 ° C.
The pieces were dried for 24 hours to obtain fireproof block pieces (test pieces).

For each of the above test pieces, the surface condition and the state of the cut surface were observed, the bulk specific gravity, the apparent porosity%,
Bending strength MPa was measured, while bulk specific gravity, apparent porosity%, and heat treatment were performed at 1500 ℃ for 3 hours.
Table 2 also shows the results obtained by measuring the bending strength MPa.

[0021]

[Table 2] As can be seen from Table 1 and Table 2 above, each of the refractory blocks of the examples has substantially the same bulk specific gravity as compared with each of the refractory blocks of the comparative examples, but has significantly higher porosity and bending strength. It has improved properties. That is, the apparent porosity after drying treatment is about 18 to 20% and the apparent porosity after heating treatment is about 21 to 24%, and the apparent porosity after drying treatment is about 13 to 14%. The rate is significantly reduced to around 15 to 17%. Also, from the bending strength of 3.5 to 10 MPa after drying and the bending strength of 12 to 16.5 MPa after heating, the bending strength after drying is 10.4 to 12 MPa and the bending strength after heating is 24 to 24 MPa. 32
It has greatly improved to about MPa.

As described above, the bulk specific gravity itself does not change so much, the reduction of the apparent porosity (densification of the structure) and the improvement of the bending strength contribute to the durability of the refractory block or the refractory material layer, It provides a highly reliable refractory block or refractory layer. The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention. For example, in the above, the slurry-like material was poured into the mold filled with the refractory aggregate from above, but the pressure inside the mold filled with the refractory aggregate was reduced if necessary, and the slurry was poured from the bottom wall surface side of the form. A refractory block having the same characteristics can be formed by adopting a method of press-fitting a material.

[0023]

According to the present invention, it is possible to provide a high-quality refractory block suitable for the slide gate, the porous plug, etc. with a high yield while avoiding the complication of the manufacturing process.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing an embodiment of a step of pouring and filling a slurry-like material in a method for manufacturing a refractory block.

[Explanation of symbols]

 1 ... Fire-resistant aggregate 2 ... Formwork 3 ... Shaking table 4 ... Defoaming device 5 ... Slurry material

Claims (1)

[Claims] 1. A step of filling a mold with a refractory aggregate having a particle size of 3 mm or more, and a fireproof particle having a particle size of 0.3 mm or less containing a curing agent between the refractory aggregate particles filled in the mold. A method for manufacturing a refractory block, comprising: a step of filling a defoaming-treated slurry made of a conductive raw material to form a molded body; and a step of drying and solidifying the formed molded body.