JPS60251182A - Manufacture of porous refractory solid - 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 [Industrial Application Field 1] The present invention relates to a method for producing a porous refractory solid used as a solid heat transfer converter, a catalyst carrier, a filter medium, or the like.

[Prior Art] Recently, porous solids having air permeability have been attracting attention as solid heat transfer converters, catalyst carriers, or filter media.

As a method for manufacturing such a porous solid, for example, a flexible polyurethane foam is treated to remove the cell membrane to produce Scott 7 ohm having a regular dodecahedral product structure, and this Scott foam is impregnated with a ceramic slurry. There is a method in which the excess slurry is removed, dried, and then fired to vaporize and remove the Scotto 7 ohm and sinter the ceramic.

The porous solid (ceramic 7 ohm) obtained by this method is lightweight, has a high porosity, has a columnar structure, and has the exclusive advantages of low flow resistance. However, since the porous solid has a columnar structure, it has poor pressure resistance or bending strength, and its flow resistance is too low, so when used as a solid heat transfer converter, sufficient heat storage characteristics cannot be obtained. There was a drawback.

On the other hand, a particle sintered porous body obtained by sintering refractory particles has also been proposed as a method for producing a porous solid having air permeability.

This method produces a porous body with relatively uniform pores manufactured by sintering refractory grains whose particle size has been precisely adjusted.
However, the porosity was about 30% to 50%, and there was a problem that a porosity of 50% or more could not be obtained.

[Object of the invention] This invention was made to solve the above-mentioned problems and the problems of the conventional products, and its purpose is to have high porosity, air permeability, and high bending strength. The object of the present invention is to provide a method for producing a porous refractory solid having high compressive strength.

[Structure 1 of the invention] The present invention impregnates the voids of an organic acid aggregate whose spherical surfaces are in contact with each other with a slurry containing metal powder, refractory raw material powder, or both and a solution, and solidifies the slurry-impregnated organic ring aggregate. The present invention relates to a method for producing a porous refractory solid having air permeability, characterized by eliminating organic rings during treatment or after solidification. According to the present invention, a porous refractory solid having excellent compressive strength and bending strength and turbulent flow can be obtained, and also has various air resistance properties by selecting metal powder and refractory raw material powder.

The organic rings used in the present invention include expanded polystyrene beads, expanded urethane beads of 7 ohm, polyethylene beads, etc., but it is essential that the spherical surfaces are in contact with each other, and the contact is not a point contact. It is desirable that the contact has an area of 172 to 1/20 of the maximum cross-sectional area of the smallest diameter organic ring used; if it exceeds 1/2, the strength of the porous body will decrease, and if it is smaller than 1/20. In some cases, it becomes difficult to obtain sufficient ventilation characteristics.

Examples of methods for bringing the organic rings into contact include filling the impregnating container with the organic rings and then pressing them with a punching plate, or bonding the organic rings together with an adhesive.

The diameter of the organic ring can be appropriately selected depending on the intended use, but when using single-diameter spheres, hexagonal R-close packing is preferred; if hexagonal close-packing is not possible, the porosity decreases.

When using organic rings with two types of particle sizes, it is desirable that the large-diameter spheres are hexagonally close-packed, and the diameter of the small-diameter spheres exists in the void of the large-diameter spheres and is in contact with the four large-diameter spheres. It is desirable that the diameter is the same. If the small-diameter spheres do not come into contact with the large-diameter spheres, the pores of the porous body obtained by the disappearance of the small-diameter spheres become closed pores, impeding air permeability. In addition, since the strength of the porous body decreases,
The use of organic rings with spherical diameters larger than a seed should be avoided.

Examples of the metal powder used in the present invention include ALSi, which exhibits fire resistance through oxidation, carbonization, and nitridation, and examples of the refractory raw material powder include calcia, alumina, silica, magnesia, silicon carbide, silicon nitride, alumina cement, P −
Those used in ordinary refractories such as alumina and Portland cement can be used, but the particle size must be 1710 or less of the pore diameter composed of organic rings, and if it exceeds 1/10. , it becomes difficult to impregnate the slurry.

Moreover, an inorganic binder can be added to the slurry if necessary.

Water, non-aqueous solutions, etc. can be used as the solution for the slurry of the present invention, but if a solution that dissolves organic rings is used, the organic rings will be eluted into the slurry when the slurry is impregnated, resulting in satisfactory porosity. I can't get a body.

The viscosity of the slurry is preferably in the range of 10 to 200 voids; if it exceeds 200 voids, it will be difficult to impregnate the slurry, and if it is less than 10 voids, the separation between the solution and the powder, that is, the solid-liquid separation phenomenon will occur. occurs, making it difficult to obtain slurry with a uniform concentration. In order to obtain the above-mentioned viscosity, the weight ratio of the metal powder, refractory raw material powder, or both solutions should be 7:3 to 7:3.
It is necessary to have a range of 1:10.

In the organic ring elimination process of the present invention, if the slurry is self-hardening at room temperature, after hardening, it is immersed in a solvent that can dissolve the organic spheres to dissolve it, and then fired to sinter the porous solid with air permeability. Let's do it. If the slurry is not self-hardening, a porous solid can be obtained by simultaneously eliminating organic rings and sintering.

FIG. 1 shows a state in which the organic ring 2 of a single-diameter sphere, which is an example of the present invention, is impregnated with the slurry 1, and FIG. 1 is a diagram showing the structure of a porous refractory solid having air permeability, which is composed of a refractory solid 3 having pores 4; FIG.

[Example] The present invention will be further explained with reference to Examples below.

Example 1 After vibrating and filling an impregnation container with single-diameter expanded polystyrene beads with a diameter of 5 Tnu, a punching plate was inserted from above.
Push with Kg/am2, and in this state apply 0.0 kg from above.
A slurry consisting of 60 parts by weight of alumina of 3+al or less than 11, 5 parts by weight of alumina cement, and 35 parts by weight of water is impregnated into the voids of the foamed polystyrene bead aggregate in the impregnating container, and after hardening at room temperature, it is immersed in an ethyl acetate solution to form an organic area was dissolved. The properties of the obtained porous refractory solid are shown in Table 1.
A comparison with the conventional product is shown.

Example 2 After applying self-hardening epoxy resin to the surface of the foamed urethane beads X while mixing foamed urethane beads with a diameter of 1 (laIll) and a diameter of 1 ma+ at a weight ratio of 60:40,
Vibration was filled into a paper impregnated container. Next, a slurry made of metallic silicon and water is impregnated into the voids of the foamed urethane bead aggregate in the container, and after drying, the temperature is 1400°C in a nitrogen atmosphere.
A porous refractory solid made of silicon nitride was produced. The properties of the porous refractory solid obtained are shown in Table 1.

Effects of the Invention] As is clear from Table 1 above, the porous refractory solid obtained by the present invention had excellent characteristics of both porosity (porosity) and strength.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a state in which a single-diameter organic sphere, which is an example of the present invention, is impregnated with slurry, and Fig. 2 shows a state in which the organic sphere is eliminated and has pores after the organic sphere is eliminated. FIG. 2 is a diagram showing the structure of a porous refractory solid having air permeability made of a refractory solid. In the figure: 1. Sludge, 2. Spheroid, 3. Refractory solid, 4.
Hole patent applicant: Shinagawa Shirorenga Co., Ltd. Figure 2

Claims (1)

[Claims] 1. Impregnating the voids of an organic sphere aggregate whose sphere surfaces are in contact with each other with a slurry containing metal powder, refractory raw material powder, or both and a solution, during solidification treatment or after assimilation treatment of the slurry-impregnated organic sphere aggregate. , a method for producing a porous refractory solid having air permeability, characterized in that organic spheres are eliminated.