JPH0197603A - Manufacture of fly-ash board - Google Patents

Abstract

PURPOSE:To prevent the glaze from falling off a glazed body or darkening by making the body according to the processing steps of putting a kneaded material in a mold having a rod inside; unmolding it, when hardened, together with removal of the rod, glazing the body with a hole after drying; and firing it. CONSTITUTION:Fly ash, alkaline silicate, and water are mixed and stirred to provide a kneaded material. The material is put in a mold with a rod inside, and when hardened it is unmolded with the rod removed at the same time. The rod should be readily separable. The hole formed after the removal of the rod serves as a passage for letting out the CO2 gas which is produced by oxidation of the unburned carbon contained in a fly-ash board when it is fired. This prevents the CO2 gas from flowing over the glazed surface. Thus it is possible to prevent the glaze from falling off or darkening and to burn the board uniformly.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing fly ash boards.

For more details, when firing the fly ash board,
To provide a method for producing a fly ash board capable of effectively preventing glaze flaking, darkening of the glaze, etc. due to CO2 gas generated from the fly ash board by providing a path in the fly ash board for CO2 gas to escape.

[Prior Art and Problems to be Solved by the Invention] Conventionally, clay has been mainly used as a raw material for ceramic products such as tableware, roof tiles, bricks, and tiles. however,
Clay requires a large amount of water for molding, so when drying it is 5 to 8
%, and the product was prone to deformation and cracks. Therefore, relatively small items such as tableware, roof tiles, bricks, tiles, etc. can be fired by controlling the heating conditions, but large items such as panels used for the exterior walls, partition walls, floors, etc. of prefabricated houses cannot be fired. was extremely difficult. In particular, when the wall thickness increases, the drying conditions between the surface layer and the middle layer of the panel become uneven, and deformation and cracks are inevitable, making it impossible to manufacture products that can be supplied to the market in terms of strength and appearance. It was possible.

In addition, large products require reinforcement with reinforcing bars for strength, but when clay is used, cracks occur along the reinforcing bars due to shrinkage during drying, and cracks occur in the base material due to thermal stress during firing. Because of this, it was not possible to provide reinforcement, and in this respect as well, it was considered impossible to manufacture large fired products. Of course, it was possible to manufacture large-scale products to a certain extent if mass production was not taken into account, but since the products produced were small-scale products, they would be extremely expensive.
Moreover, since it cannot be expected to be strong, it can only be used for decorative purposes such as attaching small pieces of ceramic shards to a wall that has been completed like a parapet, and is completely useless as a so-called wall material. It was impossible.

In view of the above-mentioned circumstances, the present inventors have developed a combination of fly ash and alkali silicate to produce a fired product that is free from deformation and cracking, has excellent properties such as strength and durability, and is inexpensive. We attempted to heat and sinter a molded product made from a kneaded product with water, and achieved a sintered product with excellent properties such as strength, as intended.

On the other hand, in order to give J-fired products the desired appearance and durability, an attempt was made to glaze the surface of the molded body and then heat and fire it, but the unburned carbon contained in the fly ash oxidized during firing. This CO2 gas escapes from the glazed surface into the air, causing flaking and darkening of the glaze, making it impossible to walk around the beautiful glazed surface.

In view of the above points, an object of the present invention is to provide a method for manufacturing a fly ash board that can prevent glaze flaking and glaze darkening caused by CO2 gas caused by oxidation of unburned coal in fly ash. shall be.

[Means for Solving the Problems] The method for producing a fly ash board of the present invention involves casting a kneaded mixture of fly ash, alkali silicate, and water into a formwork in which rods are arranged. After the kneaded material has been substantially solidified, the bar is extracted from the kneaded material and demolded, and after drying, the obtained perforated molded product is glazed and heated and fired.

[Example] Hereinafter, a method for manufacturing a fly ash board of the present invention will be described in detail.

In the present invention, alkali silicates are used together with fly ash as raw materials for the fired body. Examples of the alkali silicates include sodium silicate, potassium silicate, and lithium silicate, and these can be used in either liquid or powder form. These alkali silicates are used as a molding and solidifying agent for fly ash and as a firing and sintering agent.

Fly ash boards are manufactured using the following process.

First, all the ingredients are mixed at the same time and stirred with a mixer to obtain a kneaded product. Next, the obtained kneaded product is poured into a mold of an appropriate shape, and the kneaded product is usually removed from the mold after being cured for about 30 to BO.

After demolding, the molded body is dried by hot air, far infrared heating, microwave heating, etc. Drying may be performed at room temperature. The time required for drying varies depending on the thickness of the molded product and the heat dehydration method, but is approximately 30 minutes to 8 hours. In short,
It is preferable to perform rapid drying so that the moisture content is approximately 2% or less.

After drying, the molded body is glazed, then placed in a firing furnace and fired at 980 to 1050°C for about 4 to 6 hours. As the glaze, a suitable glaze such as a frit glaze or a raw glaze can be used, and the amount applied is not particularly limited.

Furthermore, the coating method can be any of the commonly used methods such as spraying, pouring, and brushing.

The heating temperature and heating time during firing may be selected in consideration of the type of raw materials, the proportion of the mixture, the dimensions of the molded body, and the like.

The color tone and gloss of the glaze may be adjusted as required, but it is necessary to mix and adjust the glaze to suit the shrinkage and expansion caused by heating of the flyfish plate to which the glaze is applied. If it is not mixed in this way, defects such as flaking (relatively large glaze flaking) and skipping (relatively small glaze flaking scattered on the glaze surface) may occur when the temperature is raised. There are also disadvantages such as penetration (cracks in the glaze) occurring on the glaze surface after firing.

The blended glaze raw materials are placed in a bot mill or the like, and after adding water, they are ground to a state where the entire amount can pass through a 250-mesh sieve, for example.

In the manufacturing method of the present invention, a bar is placed in the mold in advance before the kneaded material is poured into the mold, and after the kneaded material is substantially solidified, the bar is simultaneously removed from the mold. It is characterized by extracting.

The holes formed by the rod material are removed when the fly ash board is fired.
This serves as a way for CO2 gas produced by oxidation of unburned coal contained in the fly ash plate to escape, and prevents CO2 gas from escaping toward the glaze surface. These holes also play the role of uniformly transmitting heat during firing to the fly ash board, making it possible to fire the entire fly ash board evenly and uniformly, and also to shorten the firing time.

As the rod material, an iron rod, a square rod made of hard vinyl chloride resin, etc. can be used, but it is necessary to use a material with good mold releasability in consideration of extraction from the fly ash board. In addition, in order to improve mold release properties, Pal No. 10 was applied to the surface of the reinforcing bars.
1-A (product name.

A mold release agent (manufactured by Daido Kagaku Kogyo ■) or the like may be applied.

For example, as shown in FIG. 1, the holes may be formed parallel to the longitudinal direction of the plate, or may be formed perpendicular to the longitudinal direction of the plate. It's not a thing.

The hole size and pitch are determined by the thickness of the fly ash board,
It varies depending on the diameter of the iron bar, but for example, 300cm
When forming holes in a fly ash board of 90CII
It is preferable to provide 5ca+pitch.

By forming the holes, it is possible to prevent glaze flaking and darkening of the glaze as mentioned above, and also to allow the board to be fired evenly, as well as to reduce the bulk specific gravity of the fly ash board from a few percent to a maximum of about 30%. becomes.

In addition, in order to use fly ash boards as free-standing walls, it is thought that reinforcement by embedding reinforcing bars and measures to prevent them from falling off are required, but fly ash boards are placed, dried,
If the reinforcing bars are embedded in the holes after firing, cracks will not occur due to the difference in shrinkage between the reinforcing bars and the fly ash board cable base. Furthermore, by burying the reinforcing bars in the holes of the firing board, the reinforcing bars will not rust due to high-temperature firing, and even if the pH value of the base material is low, rust can be prevented by adjusting the pH of the mortar. be.

Next, the manufacturing method of the present invention will be explained based on Examples, but the present invention is not limited to these Examples.

Example 1 A mixture consisting of the following formulation was simultaneously stirred with a mixer for about 3 minutes to obtain a kneaded product.

Mixed raw materials Fly ash 50kg No. 3 water glass 15kg wollastonite powder
lOkgDL powder (trade name. Used to replenish silica content) 10kgB-
1 Fritz (product name)

Sintering aid) 15kg Mesalite (Product name: Foamed shale manufactured by Mitsui Kinzoku ■) 5-7 mm φ 30 f 12.5-5 mm φ 6010.5-2.5 mm φ
90g water
381 The obtained kneaded material was poured into a wooden formwork to form the panel shown in FIG. Five iron rods of φ29 were arranged at a pitch of 75 mm in the formwork.

After leaving the kneaded material for 80 minutes to harden, it was demolded and at the same time the iron rod was removed, followed by drying with microphone mouth wave heating for 25 minutes. After drying, spray a glaze consisting of raw glaze onto the surface of the dried kneaded product to a thickness of 0.5cm.
It was applied so that

After drying by passing through a hot air atmosphere of 80 to 100°C for 5 minutes, heating and baking were performed in a roller kiln (
Firing time: 230 minutes, firing temperature: 900°C). After heating and firing, it was allowed to cool naturally, and after 4 hours, it was taken out of the kiln. The obtained panels were observed for peeling of the glaze, burnt glaze, and unburned coal in the cross section. The results are shown in Table 1.

Comparative Example 1 A panel was manufactured in the same manner as in Example 1 except that no holes were formed, and the same items as in Example 1 were observed. The results are shown in Table 1.

[Margin below]

Shen D:'-'esP As is clear from Table 1, according to the manufacturing method of the present invention, a beautiful glaze surface could be created without causing glaze flaking or glaze boiling. Further, the darkening on the cross section of the panel is slight and not very noticeable.

[Effects of the Invention] As explained above, according to the manufacturing method of the present invention, the following effects can be achieved.

■C02 generated from fly ash board during heating and firing
Since the gas escapes through the holes formed by the rod, it does not affect the glaze surface, preventing flaking of the glaze and darkening of the glaze, and allowing it to flow through the beautiful glaze surface.

■Since the holes function as heat passages, the fly ash board can be fired evenly.

■By forming holes, the weight of the fly ash board can be reduced.

■ By burying reinforcing bars in the holes after firing, the fly ash board can be reinforced without cracking or rusting.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of a fly ash board according to Example 1, and FIGS. 2a and 2b are diagrams showing darkening on the cross section of fly ash boards according to Example t and Comparative Example 1, respectively. Patent applicant: National Housing Industry Co., Ltd.

Claims (1)

[Claims] 1. A kneaded material consisting of fly ash, alkali silicate, and water is poured into a formwork in which rods are arranged, and after the kneaded material is substantially solidified, the rods are kneaded. A method for producing fly ash boards, which involves pulling them out from objects, removing them from the mold, drying them, applying glaze to the resulting perforated molded bodies, and then heating and firing them.