JPH06211579A - Production of inorganic lightweight fired body - Google Patents

Abstract

(57) [Summary] [Object] To provide a method for producing an inorganic lightweight fired body having a high firing temperature and having desired strength, cosmetic properties and dimensional stability. [Structure] A cement powder, a soft glass powder having a pour point of 800 to 1000 ° C., and an inorganic powder containing a glassy component having a pour point of 1000 ° C. or higher are added with appropriate amounts of a foaming agent, a foaming accelerator and water. A kneaded product is obtained by adding and kneading. Then, the obtained kneaded product in a foamed state is cured and cured to obtain a porous molded body. Further, by firing this porous formed body at the pour point of the inorganic powder or granular material, an inorganic lightweight fired body can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an inorganic lightweight fired body, and more particularly to a method for producing an inorganic lightweight fired body containing cement powder.

[0002]

2. Description of the Related Art Conventionally, as a method for producing an inorganic lightweight fired body containing cement powder, for example, a glazed lightweight inorganic molded body described in JP-A-63-122501 is disclosed. A manufacturing method is disclosed. That is, water is added to and mixed with a mixture of cement powder, frit, aggregate, foaming agent and foaming accelerator for 40 to 6 times.
A glazed lightweight inorganic molded article, characterized in that a kneaded product at 0 ° C. is produced, the kneaded product is poured into a mold, and the raw base material obtained by foaming and curing is glazed.

However, in the above-mentioned conventional example, since the frit which is fused at a relatively low temperature (generally about 800 ° C.) is used as the binder during firing, the firing temperature is low. For this reason, not only high strength is not obtained, but also slaked lime produced from cement becomes quick lime by dehydration reaction during firing, and when this becomes slaked lime by absorbing moisture in the air after firing, the fired body becomes Since it expands, it lacks dimensional stability. As a result, a large amount of cement cannot be added, and the strength of the molded product before firing is low, so thin plates, large plates, and complicated shapes cannot be obtained. Moreover, if the firing temperature is low,
Since ordinary glazes for ceramics cannot be used and the glazes that can be used are limited to low temperature ones, there are few color variations and the manufacturing cost is high.

Therefore, it is conceivable to use a binder that fuses at a high temperature instead of the frit and to fire at a high temperature of 1000 ° C. or higher. However, when the firing temperature becomes 500 ° C. or higher, the strength of the cured curing cement becomes high. Significantly reduced,
There is a problem that the molded body is deformed before the binder is fused and sometimes destroyed.

In view of the above problems, it is an object of the present invention to provide a method for producing an inorganic lightweight fired body having a high firing temperature and having desired strength, cosmetic properties and dimensional stability.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that when a soft glass powder that functions as a binder in the medium temperature range is added, a curing-hardened cement powder is obtained. In order to maintain the shape of the molded body to be fired by melting the soft glass powder particles before the strength is significantly lowered by the increase of the firing temperature, focusing on that it can be fired at a higher temperature than the conventional example, the present invention completed.

That is, according to the present invention, cement powder, soft glass powder having a pour point of 800 to 1000 ° C., and
Mainly composed of inorganic powder or granules containing a glassy component with a pour point of 1000 ° C. or higher, a kneaded product obtained by adding and kneading an appropriate amount of water is cured and cured to obtain a molded product, and then the process of firing It will be.

Cement powder, pour point 800 to 10
00 ° C soft glass powder and pour point 1000 ° C
Mainly composed of the inorganic powder or granules containing the above glassy components, an appropriate amount of a foaming agent and water are added, and a kneaded product in a foamed state obtained by kneading is cured and cured to obtain a porous molded body, According to the method including the step of firing, a lighter weight fired body can be obtained.

The cement powder functions as a binder for maintaining the shape of the compact at low temperature, and for example, Portland cement powder, alumina cement powder, fly ash cement powder and the like can be used.

The soft glass powder and granules function as a binder in the medium temperature range during temperature rise, and for example, window glass, bottle glass crushed products, etc. can be used, and the pour point 8
Those having a temperature of 00 to 1000 ° C. are used. This is because if the pour point is out of the above temperature range, the function as a binder for maintaining the strength of the molded body in the medium temperature range of about 500 to 1000 ° C cannot be sufficiently exhibited.

The particle size of the soft glass powder is not particularly limited, but a particle size of 500 μ or less is preferable. This is because if the particle size exceeds 500 μ, the moldability deteriorates, and particularly extrusion molding becomes difficult. The soft glass powder is added in an amount of 4 to 20 parts by weight to 25 to 50 parts by weight of cement powder. If the amount is less than 4 parts by weight, the strength during firing, especially in the medium temperature range is low,
This is because if the amount exceeds 20 parts by weight, the amount of cement powder or inorganic powder or granules added decreases relatively, and the strength before or after firing becomes low.

The inorganic powdery material containing the vitreous component functions as a binder in a high temperature region during firing, and for example, the pour point of shirasu, fly ash, slag, wollastonite, mine firestone, etc. is 1000 ° C. or more. Those having a glassy component of 30% by weight or more are preferable. When an inorganic powder having a pour point of less than 1000 ° C. is used, it is useful for maintaining the strength of the molded body in the medium temperature range of about 500 to 1000 ° C. as described above, but a general glaze can be used at 1000 ° C. When fired above
This is because the viscosity of the molten glass material is significantly reduced and the molded body is largely deformed. If an inorganic powder having a pour point of 1000 ° C. or higher is used, quick lime produced from slaked lime of cement due to dehydration reaction by high temperature firing does not melt and remains in the binder glass, so after firing, air This is because it does not absorb the water contained therein and expand. Furthermore, the glassy component is set to 30% by weight or more because the glassy component is less than 30% by weight.
This is because it does not substantially function as a binder.

The particle size of the inorganic powder is not particularly limited, but a particle size of 500 μ or less is preferable. This is because if the particle size exceeds 500 μ, the moldability is deteriorated, and extrusion molding is particularly difficult, as described above. And 25 to 50 parts by weight of the inorganic powder is added to 25 to 50 parts by weight of cement powder. If it is less than 25 parts by weight, the strength after firing is low, and if it exceeds 50 parts by weight, the addition amount of cement powder or soft glass powder is relatively reduced, and the strength before or during firing is low. Because it will be transformed.

Further, water is added to the composition and kneaded, and if necessary, appropriate amounts of aggregate, foaming agent and foaming accelerator are added.

The aggregate is added to improve the dimensional stability of the fired body. For example, silica stone, silica sand, chamotte, river sand, etc. can be used, and the addition amount is from the viewpoint of dimensional stability. It is preferable to add a large amount of cement powder, but if too much is added, the amount of cement powder or the like added decreases relatively, and the desired strength cannot be obtained.
A maximum of 40 parts by weight is added to ~ 50 parts by weight.

As the foaming agent, for example, foaming agents such as metallic aluminum and surfactants can be used, and the addition amount is 0.03 to 0.1 part by weight to 25 to 50 parts by weight of cement powder. To be done. The amount of such addition is to ensure a proper expansion ratio while ensuring a predetermined strength.

As the foaming accelerator, for example, sodium hydroxide or the like is added, and the addition amount is almost determined by the addition amount of the foaming agent. Generally, it is 0.05-5. 1 part by weight is added.

Water may be added to such an extent that a kneaded product of the above composition can be poured and molded. Although it is almost determined by the amount of cement powder added, water is 30 with respect to 100 parts by weight of the mixture of the above composition. It is preferable to add -60 parts by weight.

Next, the kneaded product obtained by blending and kneading the above composition in the above blending ratio is poured into a mold, cured and cured at a predetermined temperature to obtain a molded body, or
After foaming and curing to obtain a porous molded body, the porous molded body is taken out from the mold, cut into a desired shape if necessary and dried, and the obtained molded body is fired in an electric furnace. The firing temperature is the pour point of the inorganic powdery material containing the glassy material ± 50 ° C.
The firing is preferably performed within the temperature range of. Pour point +50
When fired at a temperature above ℃, deformation of the fired body can be seen,
This is because if the material is fired at a temperature below the pour point of -50 ° C, the vitreous material is insufficiently melted, the function as a binder is not fully exhibited, and the strength after firing becomes low.

In the foaming and curing step, a kneaded product which is foamed by adding a foaming agent as a foaming agent and mechanically foamed by a mixer may be poured into a mold, cured and cured to obtain a porous molded body. . If necessary, the glaze may be applied by brush, spray or the like after drying and before firing.

In the present invention, the reason why the cement powder, the soft glass powder and the inorganic powder are mainly used is as follows. That is, by using cement, a molded body can be easily obtained at room temperature. When the temperature is raised by heating to heat the molded body, as shown in FIG. 1, the strength of the cement-hardened cement powder decreases as the temperature increases, and the strength at room temperature rises near 500 ° C. It drops to about half.

On the other hand, glass generally has a correlation between temperature and viscosity, and in particular, soft glass powder has a temperature of 60.
It begins to melt from 0 to 800 ° C. and begins to exhibit a binder effect, and contributes to the strength of the molded body. More specifically, just before the softening point at which the viscosity becomes 4.5 × 10 ⁷ poise, a part of the soft glass powder begins to melt and begins to exhibit a binder effect, and the pour point at which the viscosity becomes 10 ⁵ poise ( 800-1
(000 ° C.) maximizes the binder effect. For this reason,
At the pour point at which the viscosity is 10 ⁵ poise, the glass moderately flows while maintaining the binding force, so that the molded article does not lose its shape even in the medium temperature range.

Then, as the temperature rises, the viscosity of the soft glass powder becomes lower than 10 ³ poise and becomes almost completely in a molten state, so that the binding force is lost, and the soft glass powder alone cannot form a molded product. It becomes difficult to maintain the shape. This temperature is approximately 1000 ° C. although it varies depending on the type of glass. However, before it becomes difficult to maintain the shape of the molded body only with soft glass powder,
Part of the vitreous component contained in the inorganic powder and granules begins to melt and begins to exhibit a binder effect, which contributes to the strength of the molded body. Furthermore, when the temperature rises, the soft glass particles become a molten state and the binding force is significantly reduced, but the fluidity of the glassy component of the inorganic particles is improved, and the pour point of the inorganic particles is thereby improved. Since the strength is maximized at, the molded body is fired at a high temperature without causing the shape collapse.

[0024]

Therefore, according to the present invention, the cement powder,
Before the firing, during firing, since the soft glass powder and the inorganic powder containing the glassy component respectively function as binders in the low temperature, medium temperature and high temperature regions.
It will not be deformed after firing and will not lose its shape.

[0025]

【Example】

(Example 1) 40 parts by weight of commercially available Portland cement powder, 10 parts by weight of crushed window glass having an average particle size of 40μ as a soft glass powder, and Shirasu having an average particle size of 40μ as an inorganic powder containing a glassy component 30 parts by weight and 20 parts by weight of silica sand as an aggregate were kneaded with a mixer for several minutes to obtain a mixture in a slurry state. And this kneaded material is 300 × 300
It was poured into a mold of 0 × 100 mm and cured by curing at room temperature for 2 days to obtain a molded body. Then, 300 × 300 molded body
The cut piece obtained by cutting into a size of × 40 mm was dried in a dryer at a temperature of 80 ° C. for 8 hours, and then, an electric furnace (heating rate 40
0 ° C / hr) at a firing temperature of 1180 ° C for 30 minutes,
The fired body was obtained by leaving it in the furnace and cooling it, and this was used as a sample.

This fired body sample had a specific gravity of 1.4 and a bending strength of 98 kg / cm ² , and when the surface thereof was visually observed, cracks and the like were not found. Then, when the sample was cut with a diamond cutter, not only could it be cut easily, but there was no chipping at the edge of the cut surface. Further, it was immersed in water for 1 week, but it did not expand and cracks were not observed.

Example 2 30 parts by weight of commercially available Portland cement powder, and an average particle size of 40 as soft glass powder granules
8.8 parts by weight of crushed window glass, 38 parts by weight of anti-fire stone with an average particle size of 50 μ as an inorganic powder containing glassy components, 23 parts by weight of silica sand as an aggregate, 0.1 parts by weight of metallic aluminum as a foaming agent Parts, 0.1 part by weight of sodium hydroxide as a foaming accelerator is dry-mixed in a mixer for several minutes to obtain a mixture. To 100 parts by weight of this mixture, 55 parts by weight of water is added, and the mixture is kneaded for several minutes to form a slurry state. To obtain a kneaded product. And, this kneaded material is 300 × 3000 × 100 m
It was poured into a m-shaped mold, aged in a thermostatic chamber at a temperature of 60 ° C. for 12 hours, and foam-cured to obtain a porous molded body. Then, the cut piece obtained by cutting the porous molded body into a size of 300 × 300 × 40 mm was dried in a dryer at a temperature of 80 ° C. for 5 hours, and then the cut piece was placed in an electric furnace (heating rate 400 ° C.). ℃ / h
In step r), the material was burnt at a baking temperature of 1180 ° C. for 30 minutes, left in the electric furnace and cooled to obtain a baked body, which was used as a sample.

A sample of this fired body had a specific gravity of 1.0 and a bending strength of 30 kg / cm ² , and the surface thereof was visually observed to be free of cracks and the like. Then, when the sample was cut with a diamond cutter, not only could it be cut easily, but there was no chipping at the edge of the cut surface. Further, it was immersed in water for 1 week, but it did not expand and cracks were not observed.

Example 3 Example 1 was repeated except that the glaze was applied by spraying after the cut pieces were dried and before firing.
A sample of a fired body was obtained by the same treatment as described above. The glaze is composed of 44 parts by weight of quartz, 33 parts by weight of borax, and 15 parts of iron oxide.
It was a mixture of 1 part by weight, 1.5 parts by weight of feldspar, 4 parts by weight of potassium nitrate, 2.5 parts by weight of barium carbonate and 60 parts by weight of water, and the coating amount was 600 g / m ² .

The sample of the fired body had the same specific gravity and strength as in Example 2, and the surface was visually observed.
No bubbles or cracks were found, and it was found that the surface had a smooth and uniform makeup.

(Comparative Example 1) 50 parts by weight of commercially available Portland cement powder, and an average particle size of 40 as soft glass powder granules
30 parts by weight of pulverized window glass and 20 parts by weight of silica sand as an aggregate were used as the raw materials, and the same operation as in Example 1 was performed except that the baking was performed at a baking temperature of 900 ° C. for 30 minutes to obtain a baked body, which was used as a sample. And

This fired body sample had a specific gravity of 1.4 and a bending strength of 75 kg / cm ² , and when the surface thereof was visually observed, cracks and the like were not found. Then, when the sample was cut with a diamond cutter, not only was it easily cut, but no chipping occurred at the edge of the cut surface. However, when immersed in water for 1 week,
% Expansion, and generation of microcracks on the surface was observed.

(Comparative Example 2) Conventional Example (Japanese Patent Laid-Open No. 63-122)
No. 501), Example 25, in which 25 parts by weight of Portland cement powder and borosilicate frit 25 are used.
Parts by weight, 75 parts by weight of alumina powder, 0.1 parts by weight of metallic aluminum powder, 0.2 parts by weight of sodium hydroxide are dry-mixed in a mixer for several minutes, and then 55 parts by weight of water are added and kneaded to obtain a slurry. A kneaded product in a state was obtained. Pour this kneaded product into a mold of 300 × 300 × 100 mm,
It was aged in a thermostatic chamber at a temperature of 60 ° C. for 12 hours, foamed and cured to obtain a molded body. Then, the molded body taken out from the mold was cut into a size of 300 × 300 × 40 mm to obtain a cut piece. Next, this cut piece is dried at a temperature of 80 ° C.
After being dried for 5 hours, the borosilicate glaze is applied by spraying, and after firing in an electric furnace at a temperature of 800 ° C. for 1 hour, the fired body obtained by leaving it in the electric furnace and cooling is used as a sample. did.

The sample thus obtained had a specific gravity of 1.0 and a bending strength of 6 kg / cm ² , and no visual observation of the surface thereof found cracks or the like. And Example 1
When it was cut with a diamond cutter in the same manner as in, the cutting was possible, but chipping occurred at the edge of the cut surface.

A comparison between Example 1 and Comparative Example 1 reveals that Example 1 has not only greater strength, but also the water absorption expansion of the fired body is small even when immersed in water, and cracks do not occur. It was found that Example 1 has better dimensional stability than Comparative Example 1. In addition, Examples 2 and 3 and Comparative Example 2
Comparing with, it was found that Examples 2 and 3 had greater strength, not only had excellent cutter suitability, but also had substantially the same surface shape.

In particular, in Example 1, even though a relatively large amount of cement was added, Example 1 has the dimensional stability of Comparative Example 1 or more when firing in a high temperature range of 1000 ° C. or more. It is considered that the quick lime produced from the slaked lime of the cement by the dehydration reaction due to the high temperature firing does not remain as it is due to the reaction melting in the glass of the binder and does not expand after absorbing the moisture in the air after firing.

[0037]

As is apparent from the above description, according to the method for producing an inorganic lightweight fired body according to the present invention, since the soft glass powder particles functioning as a binder in the medium temperature range are added, Even when the strength of the cement powder is remarkably reduced in the medium temperature range when the temperature is raised to a high temperature, the molded body is not deformed or broken due to the binder function of the soft glass powder granules. Therefore, it can be fired in a temperature range higher than that of the conventional example, and not only an inorganic lightweight fired body having desired strength and dimensional stability can be obtained, but also ordinary glaze can be used, so that cosmetic properties can be improved and production cost can be improved. Is effective.

[Brief description of drawings]

FIG. 1 is a graph showing a correlation between a firing temperature and a strength of a composition which is a main component of the present invention.

Claims (2)

[Claims] 1. Cement powder, pour point 800-1000
℃ soft glass granules, and pour point 1000 ℃ or more mainly inorganic powders containing glassy components, add a suitable amount of water, knead the mixture obtained by kneading, curing and molding A method for producing an inorganic lightweight fired body, which comprises firing after obtaining the body. 2. Cement powder, pour point 800-1000
℃ soft glass granules, and a pour point of 1000 ℃ or more inorganic powders containing a glassy component as a main component, adding a proper amount of a foaming agent and water, kneaded product in a foamed state obtained by kneading, A method for producing an inorganic lightweight fired body, which comprises curing and curing to obtain a porous molded body, and then firing.