JPH0346419B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a method for manufacturing various ceramic products such as lightweight aggregates, building materials such as tiles, blocks, and bricks, or ceramics, and particularly reduces fuel consumption by low-temperature firing. The present invention relates to a method for manufacturing ceramic products that can reduce

[Known technology and its problems]

Building materials such as lightweight aggregates, tiles, blocks, and bricks, as well as various ceramic products such as ceramics, are usually produced by kneading ceramic raw materials such as volcanic ash, clay, or shale with water, and molding this kneaded material into the desired shape. It is produced by sufficiently drying it in a dryer and then firing it in a firing furnace at a temperature of 1300°C or higher for a desired fixed period of time.

However, in this type of known production method, the firing temperature is as high as 1300° C. or higher, resulting in a huge amount of fuel consumption, which is not preferable from the viewpoint of energy saving or economics.

[Purpose of the invention]

An object of the present invention is to provide a method for producing ceramic products that reduces fuel consumption through low-temperature firing, thereby contributing to energy saving and being economically advantageous.

[Key points of the invention]

In order to achieve the aforementioned object, according to the present invention:
Ceramic raw materials consisting of volcanic ash, clay, or shale are kneaded with an aqueous solvent solution containing borax and slaked lime, and this kneaded product is molded into the desired shape and heated to 1000℃ or more.
It is characterized by being fired at a temperature of 1200℃.

[Specific description of the invention]

Hereinafter, the present invention will be specifically explained in detail.

First, ceramic raw materials such as volcanic ash, clay, and shale are prepared. Volcanic ash is suitable as a raw material for manufacturing lightweight structural aggregates such as cement and mortar, or as a raw material for manufacturing construction materials such as tiles and blocks. It is sieved to a particle size of 4 mm or less. Since this type of volcanic ash itself has low adhesive strength, it is preferable to mix about 10% by weight of Nopporo clay as a binder when using it as a raw material.

Clay is suitable as a base material for ceramics, and various clays such as kaolin are used.

Shale is suitable as a raw material for manufacturing various building materials such as blocks and bricks, such as expanded shale from Horonai, and those with a particle size of 32 mesh (0.5 mm) or less are particularly suitable for use.

In the present invention, the various raw materials described above may be used alone or as a mixture of two or more.

The above-mentioned ceramic raw materials are kneaded with an aqueous medium containing borax and slaked lime and molded into a desired shape. The aqueous medium-aiding agent solution is made by mixing water, borax, and slaked lime in a weight ratio of, for example, 60:2:3, but the above-mentioned ratio is arbitrary and can be freely changed depending on the object of use. It is something that can be used. Further, the above-mentioned molding is performed by molding into a block shape or tile shape using a molding machine, or into granules by using a granulator.

Next, the molded product is dried in a dryer, and if necessary, the above-mentioned aqueous medium and auxiliary solution is sprinkled onto the molded product and absorbed, and then placed in a kiln or rotary kiln at a temperature of 1000°C to 1200°C. Bake for any amount of time. This firing process uses, for example, a mixture of volcanic ash and clay as raw materials (mixing ratio is 75 to 80:20 by weight).
25) is used to manufacture building materials such as tiles and blocks, it is fired in a firing furnace at a firing temperature of 1050°C to 1200°C for approximately 1 hour, and volcanic ash is used as a raw material to manufacture lightweight aggregate. 15 at a firing temperature of 1000°C to 1100°C in a rotary kiln.
Bake for minutes.

According to the method of the present invention described above, since an aqueous solution containing borax and slaked lime is used as the aqueous solvent solution, 1000
It is possible to fire at a low temperature of 1200°C to 1200°C, and by firing at a lower temperature of 100°C or more compared to conventional technology, various ceramic products such as lightweight aggregates, building materials such as tiles, blocks, and bricks, and ceramics can be produced. Therefore, the amount of fuel consumed for firing can be significantly reduced, which is very significant from the viewpoint of energy consumption and from the economic viewpoint.

The present invention will be explained below using examples.

Example 1 100 parts (by weight) of volcanic ash and 10 parts of Nopporo clay as raw materials
(by weight), and this was kneaded and granulated in a granulator using an aqueous medium adjuvant solution mixed in a ratio of 60 parts water: 2 parts borax: 3 parts (by weight) of slaked lime. The obtained granules were dried in a dryer, and further dried in a Trommelk dryer at 5 m/m to 10 m/m and 11 m/m.
The particles were sieved to have a particle size of ~20 m/m, and the aqueous solution of the solvent aid was sprayed onto the particles using a sprayer and absorbed. Next, this granulated material is carried into a rotary kiln, where it is heated at a firing temperature of 1000℃ to 1100℃ for about 15 minutes.
After firing for a few minutes, a lightweight aggregate for use as a ceramic product was obtained.
The volume of the final product had shrunk by about 20% compared to before firing.

The water absorption rate and compressive strength of the above-mentioned product (sample) were measured. Water absorption rate was determined by JISA1135 test method. That is, first, the sample was thoroughly washed with water to remove dust and other particles attached to the surface of the grains, and dried at 100 to 110°C until it reached a constant weight.
Next, this sample was cooled to room temperature and allowed to absorb water in still water at 15 to 25°C for at least 24 hours, then rolled on a highly absorbent cloth to wipe away the visible water film on the surface and dry the surface until it was saturated with water. This weight was expressed as W _S as the weight of the surface dry and water-saturated state. Subsequently, this sample was dried at 100 to 110°C until it reached a constant weight, and then cooled to room temperature in a desiccator. The weight of the sample at this time is taken as the weight of the sample after drying.
Indicated by W _D. Using these W _S and W _D , the water absorption rate Q (weight percentage %) was determined by the following formula.

Q=W _S −W _D /W _D ×100 The above test was conducted twice, and the average value was shown as follows.

The compressive strength is the compressive strength of the concrete obtained after 28 days using this product aggregate as cement aggregate according to the JIS5002 test method.

The results were as follows.

Water absorption rate: 0.9 or less Compressive strength: 450Kg/cm ³ or more The above-mentioned sample has a very low absorption rate compared to conventional technology, and therefore, even if this product is used in cold regions, it will not be easily damaged by freezing. It doesn't happen. (No cracks will occur in the structure.) Also,
It has a high compressive strength and is almost as good as natural gravel, so it has excellent robustness and makes it possible to construct structures with high compressive strength. This is because after firing, the volume of the aggregate shrinks by about 20%, improving its robustness and at the same time reducing its water absorption, making it a highly useful aggregate as a building material.

Further, the above-mentioned firing temperature is 1000° C. to 1100° C., which is considerably lower than the firing temperature of 1300° C. or higher in known technology, and is also useful for energy saving.

Example 2 Volcanic ash was thoroughly dried in a drying kiln at a temperature of 400-600°C. The dried volcanic ash was then mixed with clay in a stirrer. The mixing ratio of the volcanic ash and clay is within the range of 75-80:20-25 by weight. Next, the mixture was molded into a tile shape in a molding machine using the same aqueous solution of the auxiliary agent as in Example 1, and then the aqueous solution of the auxiliary agent similar to that described above was further sprinkled onto the molded product using a sprayer and absorbed.

The molded product in which the aqueous mediating agent solution had been absorbed was then carried into a firing kettle and fired at a firing temperature of 1050°C to 1200°C for about 1 hour to obtain a tile-shaped building material. This building material was extremely lightweight compared to conventional materials.

The water absorption rate and compressive strength of the product (sample) thus obtained were measured in the same manner as in Example 1, respectively.

The results were exactly the same as in the examples.

Furthermore, the above-mentioned firing temperature was low, ranging from 1050°C to 1200°C, and therefore fuel consumption could be reduced.

〔Effect of the invention〕

As described above, the present invention allows firing at a lower temperature than known techniques, and therefore reduces fuel consumption, contributing to energy saving and being economically advantageous.

Claims (1)

[Claims] 1. Knead ceramic raw materials consisting of volcanic ash, clay or shale with an aqueous medium solution containing borax and slaked lime,
A method for producing a ceramic product by low-temperature firing, characterized in that the kneaded product is molded into a desired shape and then fired at a temperature of 1000°C to 1200°C.