JPH0665638B2 - Method for producing ceramic porous body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a ceramic porous body which can be produced at low cost, for example, a ceramic porous body used as a water-permeable pavement plate.

(Prior Art) Conventionally, to manufacture a ceramic porous body that has been used for a water-permeable pavement board, etc., a ceramic aggregate that is a fired product or cerben that has been crushed and sized into ceramics and water glass, glass such as glaze, etc. Quality flux and shape-retaining agent as a temporary binding agent such as methylcellulose and polyvinyl alcohol,
A method has been adopted in which this is press-molded and then fired again to obtain a product.

However, such a conventional manufacturing method has a problem that the firing cost becomes high because firing is performed twice, that is, firing of the aggregate forming the ceramic porous body and firing of the molded product.

Therefore, the inventors of the present invention attempted to obtain a finished product by molding the aggregate into a porous body shape without firing and firing the aggregate once and solidifying with the binder in one firing. Although repeated, the unfired aggregate has a low mechanical strength and is easily crushed, so that if it is directly compression-molded into a porous body shape, the porosity of the porous body is lowered due to the crushing. In particular, the granulated aggregate has a high hygroscopic property, and when the aggregate absorbs moisture, the mechanical strength is further lowered, and therefore it is difficult to compression-mold the aggregate into a porous shape without crushing it.

(Problems to be Solved by the Invention) The present invention solves such a conventional problem and manufactures a ceramic porous body by sintering an aggregate and solidifying a binder (flux) in one firing. The present invention has been completed in order to provide a method for producing a ceramic porous body which is capable of being processed, and which is less likely to cause crushing of aggregate and is easy to handle.

(Means for Solving the Problems) The above-mentioned problems are obtained by kneading and granulating a ceramic raw material to which a pigment is added as needed, drying the mixture until the water content is 3% or less, and then unbaking the granulation. This can be solved by a method for producing a ceramic porous body, which comprises coating the surface of an article with a moisture absorption inhibitor, adding and kneading a flux and a shape-retaining agent to the coated particles, and firing after molding.

Thus, the feature of the present invention is that the diameter is preferably 0.6 to 4 m.
If the water content of the granulated material is approximately 3
%, The surface of the granulated product is coated with a moisture absorption inhibitor such as paraffin, preferably in the unbaked state. Here, if the water content exceeds 3%, the green strength of the granulated product decreases, and the object of the present invention cannot be achieved. The purpose of the coating of paraffin, etc., which is a moisture absorption inhibitor, is to prevent the hygroscopicity of the granulated material and prevent the decrease of the dry strength, and to improve the slipperiness of the surface to improve the molding ability. In the case of paraffin, the amount may be 5 to 10 parts by weight based on 100 parts by weight of the granulated product. The moisture absorption inhibitor such as paraffin coated on the surface of the granulated product is decomposed and scattered during firing, and does not remain on the surface of the product.

Another feature of the present invention is the step of adding a glassy flux and a shape-retaining agent to the granulated product coated with the moisture absorption inhibitor. 5 to 20 parts of the flux is added as powder such as frit to 80 to 95 parts by weight of the granulated product. The shape-retaining property can be enhanced by adding 2-3 parts by weight of a starch-like shape-retaining agent (dextrin).

Next, examples of the present invention will be described.

_{(Example) SiO 2 60~70%, Al 2} O 3 20~24%, K 2 O + Na 2 O3.5~5.5%,
Fe ₂ O ₃ 0.2% or less, TiO ₂ 1.0% or less, CaO 0.5% or less, MgO 0.
5% or less, Igloss 5.5 to 9.5% ceramic raw material with 5% or less metal oxide pigment added, 14 to 16% water added and kneaded, and then a diameter of 0.6 to 4.0 from the perforated plate of the granulator. It was extruded to have a noodle shape of about mm.

Next, use a sieving machine to adjust this to within ± 50% of the average particle size.
The particles were sized so that 95% or more could enter. The spherical granulated product thus granulated was dried until the water content became 3% or less, and then the surface of the granulated product was coated with paraffin as a hygroscopic agent. The coated particles that were coated did not have hygroscopicity, so that the strength did not decrease even during storage, and even though they were not fired, they had high strength and were easy to handle.

Next, 80 to 95 parts by weight of the paraffin-coated coated particles are added to a powdery glassy flux of 5 to 20 parts by weight.
Parts by weight and 2 to 3 parts by weight of the shape-retaining agent were added and kneaded, and molded into a flat plate by a press molding machine at a pressure of 0.2 to 30 kg / cm ² . When this molded product was fired in a furnace at a temperature of 1280 ± 20 ° C by a conventional method, the sintering of the granules and the solidification of the entire compact could be completed at the same time. Obtained by firing twice.

The obtained ceramic porous body has a bending strength of 100 kg / cm ² or more, and the water permeability time specified in JIS A 5403 is 5
It was ~ 60 seconds and showed excellent water permeability.

(Effects of the invention) As described above, the present invention granulates a granulated product by drying the water content of the granulated product to 3% or less and then coating the surface with a moisture absorption inhibitor. This is to prevent crushing of the product and facilitate handling of the granulated product before firing, and to obtain a ceramic porous body by simultaneously sintering the granulated product and solidifying with a binder by one firing. Therefore, the manufacturing cost can be reduced, and the granulated product can be easily handled, so that the workability in the manufacturing process can be improved. Moreover, the ceramic porous body produced by the present invention has the same porosity and water permeability as those produced by the conventional method, and is suitable for use in a water-permeable pavement board or the like. Therefore, the present invention is extremely large in that it contributes to the industrial development as a method for producing a ceramic porous body that eliminates the conventional problems.

[Brief description of drawings]

 FIG. 1 is a block diagram showing an embodiment of the present invention.

Claims (1)

[Claims] 1. A ceramic raw material to which a pigment is added, if necessary, is kneaded, granulated, dried to a water content of 3% or less, and then coated with a moisture absorption inhibitor on the surface of the unbaked granulated product. Then, a flux and a shape-retaining agent are added to the coated particles, and the mixture is kneaded, followed by molding and firing, and a method for producing a ceramic porous body.