JPH04312801A - Manufacture of refractory block - Google Patents

Abstract

PURPOSE:To enable refractory blocks with denseness to be manufactured by applying vibration force and press force to a monolithic refractory substance poured into a mold. CONSTITUTION:In a manufacture of refractory blocks through pressure dehydration vibration molding characterized such that a mold 2 having a film 8 with a plurality of drainage ports 7 and a filtration paper or a hole is provided on a vibration table 1, and a monolithic refractory substance 3 is poured therein so as to be pressure-dehydrated by a pressure plate 4, vibration is simultaneously applied thereon in order that pressure sufficiently spreads in the inner part thereof during pressurization. Such time is limited to be in the range of from 30min. to the time when the monolithic refractory substance material cures. By keeping the continuous vibration during pressurization, frictional forces and cohesive forces are weakened, with the result that pressure can sufficiently be spread in the inner part thereof.

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 refractory blocks for uses such as gutter blocks, gutter tip blocks, ladle hot water blocks, ladle tuyere blocks, TD weir blocks, and TD tuyere blocks.

0002

[Prior Art] Conventionally, as a method for densifying refractory blocks manufactured from monolithic refractories, the Japanese Patent Publication No. 56-43
There is a ``method for producing a refractory block by reduced pressure vibration'' disclosed in Japanese Patent No. 009, and a ``method for producing a refractory block'' disclosed in JP-A-55-137900.

0003

[Problem to be Solved by the Invention] However, regarding the former, it is possible to evacuate the air drawn in during mixing, kneading, and casting to the outside of the system by reducing pressure; Only about 2% of the trapped air remains after normal vibration molding, and the amount of air removed by depressurization is at most less than this amount, so it cannot be said to be an adequate method for densification. I don't get it. Moreover, most of this air is sealed pores, and it is considered that the effect is small from the point of view of the original purpose of densification, that is, improving corrosion resistance and suppressing slag infiltration resistance. Regarding the latter, it is true that this method achieves dehydration and deaeration, resulting in densification, but under the exemplified conditions, the inventor's experiments showed that the effect was insufficient. The problem to be solved by the present invention is to find a method for producing a refractory block with even higher density.

0004

[Means for Solving the Problems] The method for manufacturing a refractory block of the present invention includes applying vibration force and pressurizing force to a monolithic refractory poured into a formwork for 30 minutes until the material hardens. The feature is that the time is added.

[0005]

[Operation] In order to describe the method of densifying a refractory block made of monolithic refractories, it is first necessary to discuss the state of its structure. Normally, when manufacturing fireproof blocks, water-based monolithic refractories are used and vibration-molded using a rod-shaped vibrator or Uras vibrator, so the structure immediately after forming is composed of material, water, and entrained air. Needless to say, the amount of entrained air introduced during mixing, kneading, and casting is calculated to be about 2%, so the main reason for inhibiting densification is the air added during kneading to impart fluidity. It can be said that this is nothing but essential surplus water. Considering that excess water remains as open pores after drying of the refractory block, promoting slag infiltration during use and contributing to a significant deterioration of corrosion resistance and structural spall resistance, it is necessary to reduce the amount of excess water. It is self-evident that this is the most effective method for densification. Therefore, the above-mentioned JP-A-55-13
"Method for manufacturing refractories" disclosed in Publication No. 7906,
In other words, simply speaking, the manufacturing method of refractory blocks by pressurized dehydration vibration molding is based on Pascal's principle (the pressure at one point of a fluid at rest in a sealed container) because the monolithic refractory contains excess water. This is considered to be a very effective method in view of the law that states that if the pressure is increased by a certain amount, the pressure at all points within the fluid increases by the same amount. For this reason, as a result of various studies based on the example (pressurization + vibration) time exemplified in this publication of 3 minutes, we found that there was variation in quality in the uniaxial direction of pressurization, that is, the fact that it was difficult to tighten the middle part. It became clear. According to Pascal's principle, the compressibility of water as a pressure medium is approximately 4
．． Because it is extremely small at 23 x 10-5 cm2/kg,
The pressure within the system instantly became equal, so there should be virtually no variation in quality, but the actual results were different. This is considered to suggest that Pascal's principle does not hold in subsequent stages because when a certain amount of water flows out of the system, some of the grain boundaries come into contact with other particles. Therefore, this fact means that as water flows out of the system, the pressure propagation to the inside is further reduced.Based on this knowledge, the methods of further densification are to reduce the internal frictional force, Furthermore, it would be better to reduce the cohesive force, and as a result of various studies based on this idea,
This has led to the completion of the present invention.

In a specific embodiment, as shown in FIG. 1, a formwork 2 having a plurality of drainage holes 7 and a filter paper or a film 8 having holes as shown in FIG. 2 is provided on a vibrating table 1. In a method for manufacturing a refractory block by pressurized dehydration vibration molding, which is characterized by pouring an unshaped refractory 3 inside and dehydrating it under pressure with a pressure plate 4, the pressure during the pressurization is sufficiently propagated inside. Vibration should be applied at the same time as the refractory material, and the duration should be between 30 minutes and until the monolithic refractory material hardens. By continuing to vibrate during this period of pressurization, the frictional force and cohesive force are weakened, making it possible to sufficiently propagate the pressure inside. However, if the time is less than 30 minutes, dehydration will occur but the effect will be small, and vibration after curing will have no further effect since the material has already lost its rocking force, and furthermore, the vibration may destroy the tissue. It's possible, so I don't like it. Regarding the monolithic refractories used,
There are no other restrictions as long as the pot life is long enough to require dehydration. The vibration conditions are as follows:
There are no restrictions other than the vibration time mentioned above, but the frequency is 1.
The range is generally from 000 to 30,000 rpm, and it may be determined as appropriate within this range depending on the material properties.

[0007]

[Example] In this example, two materials, a high alumina material and an alumina-magnesia material shown in Table 1, were used for testing. The sample in Table 1 is shown in Figure 1 with a size of 200 x 200 x 200
It was packed into a mold 2 with a diameter of 2 mm and molded under the conditions shown in Table 2. In order to compare with this example, molding was performed under the normal vibration molding conditions shown in the same table using a mold without a pressure plate 4 and without a drainage port, and this was referred to as Comparative Example 1. However, Comparative Example 2 also includes one molded under conditions that do not give sufficient rocking properties (do not give sufficient vibration) as in this example during pressurization.
The refractory blocks of this example and comparative example manufactured under these conditions were dried at 110° C. for 24 hours, and the physical properties of each were investigated. The results are shown in the same table. As is clear from these results, when comparing the apparent porosity of the refractory block obtained by the manufacturing method of the present invention, for example, the decrease in apparent porosity is about 4% compared to Comparative Example 1, but about 2% compared to Comparative Example 2. As a result, it can be said that the manufacturing method according to the present invention makes it possible to manufacture a refractory block with significantly improved compactness.

[0008]

[Table 1A]

[0009]

[Table 1B]

0010

[Table 2]

[0011]

[Effect of the invention] With the present invention, it is possible to manufacture highly dense fireproof blocks, such as gutter blocks,
Suitable for uses such as gutter tip block, ladle hot water block, ladle tuyere block, TD weir block, TD tuyere block, etc.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an overview of the method for manufacturing a manufacturing block disclosed in the present invention,

FIG. 2 is a diagram showing a cut surface of the formwork.

[Explanation of symbols]

1. Vibration table, 2 Formwork, 3. Monolithic refractories, 4 Pressure plate, 5. Eurus vibrator, 6 Spring, 7 Drain port, 8. Filter paper or film with holes.

Claims (1)

[Claims] Claim 1: In a method for producing a refractory block in which a monolithic refractory poured into a mold is molded by vibration, the vibration and pressure applied to the material is controlled from 30 minutes to the time it takes for the material to harden, the vibration force and A method for producing a fireproof block, characterized in that by applying pressure, excess water in the material is discharged through a plurality of holes provided in the formwork to densify it.