JPH06345529A - Production of architectural burnt plate - Google Patents

Abstract

PURPOSE:To provide a production method of an architectural burnt plate with a high productivity, which does not occur cracking at the drying and burning. CONSTITUTION:Siliceous raw material, a calcareous raw material and inorganic powder containing a vitreous component are indispensable constituents and a molding is formed of a mixture obtained with addition of water to these and mixing. An autoclave treatment is carried out so as to produce a calcium silicate hydrate in the obtained molding. Consequently it is burnt at temp. from <=1400 deg.C to >= a softening point of the vitreous component contained in the inorganic powder.

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 fired plate for construction, which is mainly used as a finishing material for interiors and exteriors.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a fired board for construction, there has been used a method for producing a fired board for construction which has improved firing shrinkage and excellent productivity. Technology related to a method for manufacturing a cement-glass ceramic product using the fusion of glass and glass (Japanese Patent Application No.
-199970 and Japanese Patent Application No. 4-339656) have been proposed.

However, in the above-mentioned prior art, a certain strength is required for carrying or processing after molding, so that it is necessary to cure and hydrate it. For this reason, a curing period of several days is required, and further improvement in productivity is desired. Further, in a series of prior art, there is a problem that cracks easily occur due to thermal stress at the time of drying or firing, and the yield in the manufacturing process deteriorates. Furthermore, the unhydrated portion remains after firing. Therefore, it cannot be said that there is no possibility that it will gradually rehydrate over a long period of time, and that cracks will occur due to expansion in the base material and that the white flower phenomenon will occur due to the released alkaline component.

In view of the above problems, it is an object of the present invention to provide a method for manufacturing a fired building plate, which has high productivity and does not cause cracks during drying and firing.

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the inventors of the present invention have conducted extensive studies and, as a result, have carried out an autoclave treatment to form a calcium silicate hydrate after forming a molded body and before firing. It was found that the curing time was shortened and cracks did not occur during drying and firing, and the present invention was completed based on this finding.

That is, the gist of the present invention is that a siliceous raw material, a calcareous raw material, and an inorganic powder containing a vitreous component are essential components, and water is added to and mixed with these to form a molded body. After molding and subjecting the resulting molded body to an autoclave treatment to produce calcium silicate hydrate,
14 above the softening point of the glassy component contained in the inorganic powder
A method for producing a fired plate for construction is characterized by firing at a temperature of 00 ° C. or lower. Further, in the above-described manufacturing method, after the autoclave treatment and before firing, the surface of the molded body may be coated with a glaze raw material, may be subjected to a surface treatment, or may be subjected to a surface treatment to apply the glaze raw material. .

The siliceous raw material is added in order to develop the strength of the green body before firing by hardening by the hydration reaction with the calcareous raw material described later and to reduce the shrinkage that occurs during firing. Examples thereof include diatomaceous earth, silica powder, silica sand, acid clay, and bentonite, and 10 to 50% by weight of the total solid components of the mixture is added. 10
This is because if it is less than wt%, the silicon dioxide component necessary for the calcium silicate formation reaction will be insufficient, and if it exceeds 50 wt%, the calcium oxide component and the vitreous component will be relatively insufficient.

Examples of calcareous raw materials include cement,
Examples include slaked lime and quick lime, and 10 to 30% by weight of the total solid components of the mixture is added. This is because if it is less than 10% by weight, the calcium oxide component necessary for the reaction of forming calcium silicate is insufficient, and if it exceeds 30% by weight, the silicon dioxide component and the vitreous component are relatively insufficient.

In order to efficiently produce the calcium silicate hydrate described below, the mixing ratio of the siliceous raw material and the calcareous raw material is 0.5 to 1.5, preferably CaO / SiO ₂ molar ratio. It is necessary to set it to 0.7 to 1.1. The total addition amount of both is preferably 20 to 70% by weight based on the total solid components of the mixture. This is because if it is less than 20% by weight, the strength of the molded article becomes insufficient and firing shrinkage increases, and if it exceeds 70% by weight, the final strength after firing becomes insufficient due to the lack of vitreous components. .

The inorganic powder containing the vitreous component is added to obtain the strength after firing by melting and fusing the vitreous component by firing.
Fly ash, anti-fire stone, glass powder, slag and the like are included, and 20 to 80% by weight of the total solid components of the mixture is added. This is because if it is less than 20% by weight, the strength after firing is low, and if it exceeds 80% by weight, the addition amount of siliceous raw material and calcareous raw material is relatively reduced, and the strength before firing becomes low. is there.

The amount of water to be added is not particularly limited, but may be appropriately added depending on the needs of the mixing operation and molding operation described later.
In the case of extrusion molding, a thickening agent such as methyl cellulose, carboxymethyl cellulose or poval may be added to maintain the shape immediately after extrusion molding. Further, in the case of papermaking and molding, fibers such as pulp and rockwool and / or a flocculant such as acrylamide may be added to improve drainage during papermaking.

The mixing method is not particularly limited and can be arbitrarily selected from existing mixing methods. For example, a mixture may be obtained by appropriately mixing with a kneader, a mixer or the like.

The molding method can be arbitrarily selected from existing molding methods, and may be, for example, extrusion molding, papermaking molding, press molding or the like.

In the autoclave treatment, stable calcium silicate hydrate is formed in the molded body in a short time, and the liberated alkaline component is eliminated, thereby shortening the curing period and improving the productivity, and at the same time, after firing. It is carried out in order to prevent rehydration at the time of use and to prevent cracks due to expansion in the molded body and the white flower phenomenon due to the released alkaline component. The autoclave treatment is carried out at a temperature of 120 to 250 ° C. and a pressure of 2 to 39 atm for 1 to 20 hours, but at a temperature of 15 at the time efficiency.
It is preferable that the temperature is 0 to 200 ° C. and the pressure is 4.5 to 16 atm for 3 to 10 hours. This is because if the temperature is lower than 120 ° C, the reaction to form tobermorite will be insufficient, and if the temperature exceeds 250 ° C, the crystals of tobermorite will change to zonotolite and the strength will rather decrease. is there. Further, if the treatment time is less than 1 hour, the progress of the reaction for forming calcium silicate hydrate is insufficient, and 2
This is because if it exceeds 0 hours, no further reaction occurs and the productivity decreases.

The reason why calcium silicate hydrate is produced by the autoclave treatment is that the hydrate is less thermally deteriorated. That is, generally, when heated to 400 ° C. after the hydration reaction by room temperature curing, the strength deteriorates to about 45%, and when heated to 800 ° C., the strength deteriorates to about 20%, whereas the hydration reaction by the autoclave treatment deteriorates. This is because if it is heated to 400 ° C. later, the strength deteriorates to about 90%, and if it is heated to 800 ° C., the strength only deteriorates to about 50% and the degree of strength deterioration is improved.

It is preferable to dry the molded product after the autoclave treatment and before the firing, in order to prevent the occurrence of cracks during the baking due to the water remaining in the molded body after the autoclave treatment, and in particular, the water content. Is preferably dried to 3% by weight or less.

The firing operation is performed in order to fuse the glassy components contained in the inorganic powder to develop strength, and the firing temperature is higher than the softening point of the glassy component contained in the inorganic powder, Desirably, the viscosity is within a range of ± 50 ° C. or higher and 1400 ° C. or lower of the viscosity temperature at which the viscosity becomes 10 ⁵ poise (referred to as “Lily point”). Firing temperature 14
The reason why the temperature is set to 00 ° C. or lower is that when the temperature exceeds 1400 ° C., the glassy components and the like are deformed by firing.

The glaze raw material may be applied or surface-treated before firing, or the glaze raw material may be applied after the surface-treatment.
The glaze raw material is not particularly limited, and can be arbitrarily selected from existing glazes for ceramics. Further, the surface processing is not particularly limited, and may be arbitrarily selected from existing methods such as roll embossing, router processing, and sandblasting.

[0019]

Therefore, according to the present invention, calcium silicate hydrate is formed in the molded body by the autoclave treatment before firing.

[0020]

EXAMPLES Next, examples according to the present invention will be described. (Example 1) 10% by weight of acid clay as a siliceous raw material,
18% by weight of silica sand, 30% by weight of ordinary Portland cement as a calcareous raw material, 40% by weight of anti-fire stone as an inorganic powder containing a glassy component, 2% by weight of methylcellulose as a thickening agent, and a total of these powders. Water was added at a ratio of 20 to 100 by weight and mixed with a kneader to obtain a mixture, which was then 300 mm wide and 20 m high by a vacuum extruder.
A hollow molded body having a rectangular cross-section with m, a wall thickness of 8 mm and a length of 1000 mm was obtained. Then, the hollow molded body is heated to a temperature of 180.
After autoclaving for 3 hours at 10 ° C and a pressure of 10 atm, and then drying for 2 hours at 120 ° C, apply a normal glaze for ceramics by spraying at a rate of about 600 g / m ² , and use a roller hearth kiln. 120 minutes, of which
The sample was baked at a maximum temperature of 1130 ° C. for 15 minutes, and the obtained baked product was used as a sample.

The bending strength of this sample is 180 k on average.
It was gf / cm ² , and when the surface of the sample was visually observed, no crack was found.

(Comparative Example 1) 18% by weight of silica sand No. 5 as a siliceous raw material, 40% by weight of ordinary Portland cement as a calcareous raw material, and 40% by weight of anti-firestone as an inorganic powder containing a vitreous component. 2% by weight of methyl cellulose was added as a viscous agent, and the same treatment as in Example 1 was carried out except that the molded body was allowed to cure for 2 days in a sealed room instead of being autoclaved. The fired body thus obtained was used as a sample.

About 10% of the whole sample was cracked by the drying, and about 20% of the whole sample remained after the firing except the cracked sample was cracked. Also, the bending strength of a normal sample without cracks is 170 kg on average.
It was f / cm ² .

(Example 2) As a siliceous raw material, 20% by weight of bentonite, 10% by weight of silica sand No. 5, 30% by weight of slaked lime as a calcareous raw material, and 40% by weight of shirasu as an inorganic powder containing a vitreous component were mixed. To obtain a mixed powder. On the other hand, waste paper pulp and rock wool are mixed in water at a weight ratio of 1: 2 and woven, and then the mixed powder and fibers are mixed at a solid content ratio of 10: 1.
Polyacrylamide as a coagulant is added to 0.5 of the total solid content.
Wt% was added, and then water was appropriately added to obtain a slurry having a concentration of 10%. Then, this slurry was introduced into a gauze machine to make a wet mat having a thickness of 6 mm, and the wet mat was cut into a width of 300 mm and a length of 900 mm to obtain a molded body, and the molded body had a temperature of 180 ° C. Autoclave for 3 hours at a pressure of 10 atm and then a temperature of 12
After drying at 0 ° C for 2 hours, a glaze for ceramics was sprayed on the surface at a rate of about 600 g / m ² , and 90 minutes by a roller hearth kiln, the maximum temperature of which was 11
The sample was baked at 30 ° C. for 15 minutes, and the obtained baked product was used as a sample.

The bending strength of this sample is 105 k on average.
It was gf / cm ² , and when the surface of the sample was visually observed, no crack was found.

(Comparative Example 2) Silica No. 5 was added as a siliceous raw material in an amount of 10% by weight, ordinary Portland cement was added as a calcareous raw material in an amount of 50% by weight, and Shirasu as an inorganic powder containing a vitreous component in an amount of 40% by weight. Instead of the autoclave treatment, a fired body obtained by the same treatment as in Example 2 was used as a sample, except that the molded body was left for 2 days to cure in a sealed chamber.

Approximately 15% of the products were cracked by the drying, and about 15% of the products remaining after the firing except the cracked products were cracked. In addition, the bending strength of a normal sample without cracks is 100 kg on average.
It was f / cm ² .

[0028]

As is apparent from the above description, according to the method for producing a fired plate for construction according to the present invention, most of the molded body is stable in a short time by the autoclave treatment (calcium silicate hydrate ( Since it mainly becomes tobermorite, it is not necessary to carry out curing for a long time after molding as in the conventional example, and it can be fired in a short time after molding, and the productivity is improved. Moreover, by autoclaving, most of the molded body becomes a stable calcium silicate hydrate mainly composed of tobermorite, and even if thermal stress occurs during drying and firing, cracks do not occur and the yield in the manufacturing process is improved. There is an effect of doing.

Claims (4)

[Claims] 1. A siliceous raw material, a calcareous raw material, and an inorganic powder containing a glassy component are essential components, and water is added to and mixed with them to form a molded body, which is obtained. Calcination for construction characterized by calcining at a temperature not lower than 1400 ° C above the softening point of the glassy component contained in the inorganic powder after autoclaving the formed body to produce calcium silicate hydrate Method of manufacturing a plate. 2. A siliceous raw material, a calcareous raw material, and an inorganic powder containing a vitreous component as essential components, and water is added to and mixed with them to form a molded body, which is obtained. After autoclaving the formed body to produce calcium silicate hydrate, apply glaze raw material on the surface and fire at a temperature of 1400 ° C or lower above the softening point of the glassy component contained in the inorganic powder. A method of manufacturing a fired plate for construction, comprising: 3. A molded product was obtained by molding a mixture obtained by adding and mixing water to a siliceous raw material, a calcareous raw material, and an inorganic powder containing a glassy component as essential components. After subjecting the molded body to an autoclave treatment to generate calcium silicate hydrate, the surface is subjected to a surface treatment,
14 above the softening point of the glassy component contained in the inorganic powder
A method for manufacturing a fired board for construction, which comprises firing at a temperature of 00 ° C or lower. 4. A molded body is obtained by molding a mixture obtained by adding and mixing water to these as essential components, a siliceous raw material, a calcareous raw material, and an inorganic powder containing a glassy component. After subjecting the molded body to an autoclave treatment to generate calcium silicate hydrate, surface treatment is applied to the surface and glaze raw material is applied, and the temperature is 1400 ° C or higher at the softening point of the vitreous component contained in the inorganic powder. A method for producing a fired plate for construction, which comprises firing at the following temperature.