TWI570089B - Large ceramic plate and its manufacturing method - Google Patents

Description

Large ceramic plate and manufacturing method thereof

The present invention relates to a large-sized ceramic plate and a method for producing the same, and more particularly to a ceramic plate having low water absorption, a thin shape, and a large size, and a method for producing the same.

Large-scale ceramic plates that can reduce seams and simplify construction and diversification have been put into practical use and are widely used. In addition, the manufacture of large-sized ceramic plates suitable for exterior building materials should be realized, and various proposals for reducing the water absorption of large-sized ceramic plates are proposed.

For example, JP-A 10-236867 discloses that a clay containing 30 to 70% by weight of β-wollastonite (apatite) and 70 to 30% by weight of clay and talc is formed. This large-sized flat sintered body produced by firing at 1000 to 1250 °C. The sintered body disclosed in this document is a so-called "ceramic" (water absorption ratio: more than 5%, less than 22%), which is more than 10% (12.5%) in water absorption (natural water absorption: JIS A5209 (1994)).

Further, Patent Document 2 (JP-A-2003-089570) discloses that talc is formed in an amount of 5 to 30% by weight, and 10 to 40 is formed. 9% by weight of feldspar and terracotta, 10 to 40% by weight of β-wollastonite adjusted to a particle size of 20 to 50% by weight of clay, and calcined Large sheet-like sintered body. The water absorption rate (natural water absorption: JIS A5209 (1994)) of the sintered body disclosed in this document is 3% or less, and is classified into a so-called "smasher" (water absorption rate: more than 1%, less than 5%). Sintered body. Further, in order to achieve low water absorption of the sintered body disclosed in the document, it is fired at a temperature (about 1120 to 1130 ° C) of the needle crystal transition of β-wollastonite.

In the case of the clay which is added in the following ratio, 3 to 20 parts by weight of β-wollastonite, 5 to 20 parts by weight of feldspar, etc. are described in the patent document 3 (JP-A-2012-188331). Glassy minerals, 5 to 20 parts by weight of talc, 10 to 40 parts by weight of vermiculite, refractory clay and other aggregates, 20 to 30% by weight of clay minerals such as clay, 20 to 40% by weight of clay, and fired The resulting ceramic plate has a thickness of 6 mm or more. The water absorption rate (natural water absorption: JIS A5209 (1994)) of the sintered body disclosed in this document is less than 2.5%, and includes a sintered body which is classified into a so-called "chopper". Further, the sintered body disclosed in this document is obtained by firing at a temperature of less than 1160 °C.

Further, according to JIS A5209 (2008), the sintered body classified into "enamel" by JIS A5209 (1994) is a so-called "class II" having a water absorption ratio (forced water absorption) of less than 3% and less than 10%.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 10-236867

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2003-089570

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2012-188331

In order to reduce the water absorption of the ceramic plate, a molten component such as a vitrified component, a co-melted component, an alkali metal, and Ca or Mg is blended in the raw material, and high-temperature firing is attempted. Although these components must be formulated in the case of porcelain, on the other hand, the problem of cracking and deformation due to melting thereof cannot be avoided. In particular, when a thin and large ceramic plate is produced, cracking and deformation are likely to occur after molding and firing, and it is difficult to realize a large ceramic plate having low water absorption.

In order to suppress the occurrence of deformation and cracking during firing, in Patent Document 2, the crystal shape of the ash crystal of the acicular crystal mineral is maintained after the firing, and the preparation and firing temperature of the raw material are worked hard. Further, in Patent Document 3, it is proposed to improve the drying property after molding by using a combination of apatite and aggregate, and to suppress cracking by maintaining the shape of the aggregate during firing.

However, even with these technologies, it is impossible to obtain a so-called "Class I" ceramic plate having a water absorption rate (forced water absorption) of 1% or less according to JIS A5209 (2008), which is obtained with high productivity.

The inventors of the present invention have found that cracking and deformation (especially, drying and cracking of a molded body and deformation at the time of firing) after molding and firing are prevented by the use of the ash-containing mineral ash, and further, Micro-only The amount of talc reduces the Mg component, that is, the chemical change accompanying the firing can be controlled by causing Ca contained in the asbestos to function as a flux. As a result, the following findings have been obtained, and a thin and large-sized fired body having low water absorbability and high productivity (preventing dry cracking and firing cracking and having good shape stability) can be obtained. The present invention is an invention based on the above findings.

Accordingly, it is an object of the present invention to provide a ceramic board which is low in water absorption, high in productivity, thin and large, and a method for producing the same.

Further, the large-sized ceramic plate according to the present invention is characterized in that it contains a Mg element in an amount of 0.5% by mass or more and 2% by mass or less in terms of MgO, and a Ca element in an amount of 2% by mass or more and 15% by mass or less in terms of CaO, and The water absorption rate specified in JIS A5209 (2008) is 1% or less.

Further, the method for producing a large-sized ceramic plate according to the present invention is characterized by comprising at least the following steps; preparing at least (1) clay mineral, (2) clay, (3) vitreous mineral, and (4) Ca-containing. And a step of obtaining a raw material formulation of (5) talc, a step of preparing the raw material formulation to obtain a molded body, and baking the formed body to obtain a ceramic plate, and the foregoing (5) The content of talc is 0% by mass or more and less than 5% by mass based on the total amount of the raw material formulation.

[Formation for carrying out the invention] Large ceramic plate

The large-sized ceramic plate of the present invention contains a Mg element in an amount of 0.5% by mass or more and 2% by mass or less in terms of MgO, and a Ca element in an amount of 2% by mass or more and 15% by mass or less in terms of CaO, and JIS A5209 (2008) The specified water absorption rate is 1% or less. By reducing the amount of Mg in the ceramic plate and having Ca as a fluxing agent, it is possible to obtain a thin and large-sized, low-absorbency and high-productivity (to prevent dry cracking and firing cracking, and to have good shape stability). Sex) ceramic plate.

According to a preferred mode of the present invention, the large ceramic plate of the present invention preferably has a thickness of from 1 mm to 10 mm. More preferably, the thickness is 1 mm or more and 6 mm or less. Further, in the large-sized ceramic plate of the present invention, the length of one side is preferably 400 mm or more and 3000 mm or less. By borrowing the length within this range, the seam can be reduced, so that the construction can be simplified and the design is diversified.

Further, the large-sized ceramic plate in the present invention preferably has a short side/thickness of 80 or more, more preferably 100 or more. Thereby, a thin and large-sized ceramic plate which can be used for exterior use can be obtained.

Further, the large ceramic plate in the present invention preferably has an area of 0.25 m ² or more. Further, the shape thereof is not particularly limited, and is preferably flat.

According to a preferred mode of the present invention, it is preferred that the large ceramic plate of the present invention comprises anorthite. An albite can be formed after firing by using a large amount of a raw material containing Ca (for example, ash feldspar, limestone, ash, etc.). As a result, a ceramic plate excellent in shape stability can be obtained.

According to a preferred mode of the present invention, the large ceramic plate in the present invention preferably has a MgO/CaO ratio of less than 0.4 by mass. By reducing the ratio of Mg of the ceramic plate, it is possible to suppress cracking and deformation caused by firing.

According to a preferred mode of the present invention, it is preferred that the large ceramic plate of the present invention further comprises an aggregate. Details of the aggregates will be described later.

According to a preferred embodiment of the present invention, the large-sized ceramic plate of the present invention further contains 60% by mass or more and 70% by mass or less of Si element in terms of SiO ₂ , and is 15% by mass or more in terms of Al ₂ O ₃ . 25 mass% of Al element in terms of K ₂ O to less than 2 mass%, 4 mass% of K elements, and in terms of Na ₂ O to 0.5 mass%, 1 mass% of the Na element. In addition, the detection and quantification of the elements are performed using a fluorescent X-ray analyzer (for example, Supermini 200 (Science)), and the elements are detected and quantified according to the measurement conditions and concentration methods described in the examples below. With such a composition, although the large-sized ceramic plate is thin, cracking and deformation due to firing can be suppressed, and productivity can be remarkably improved.

use

According to a preferred mode of the present invention, the large ceramic plate of the present invention can be applied to exterior building materials; interior building materials; large ceramic plate products; lining with inorganic plates, glass fiber cloth or plywood such as metal plates and gypsum Composite materials, etc. Especially suitable for exterior building materials.

Large ceramic plate manufacturing method

According to another aspect of the present invention, the present invention provides a method for producing a ceramic plate having low water absorption, high productivity, thinness, and large size as its object.

Further, the method for producing a large-sized ceramic plate according to the present invention is characterized by comprising at least a compound containing at least (1) clay mineral, (2) clay, (3) vitreous mineral, and (4) Ca. And a step of further including a raw material formulation of (5) talc, a step of molding the raw material formulation to obtain a molded body, and a step of firing the molded body to obtain a ceramic plate, and The content of the above (5) talc is 0% by mass or more and less than 5% by mass based on the total amount of the raw material formulation.

According to the method for producing a large-sized ceramic plate according to the present invention, a thin and large-sized ceramic plate which has a water absorption ratio of 1% or less as defined in JIS A 5209 (2008) and which does not cause cracking and deformation can be obtained.

Preparation of raw material preparation

In the method for producing a large-sized ceramic plate according to the present invention, first, at least (1) a clay mineral, and (2) clay and (3) a vitreous mineral, and (4) a compound containing Ca are contained, and, as the case may be, There are (5) talc raw material formulations.

Raw material formulation

Each component contained in the raw material preparation used in the method for producing a large-sized ceramic plate according to the present invention will be described below.

(1) A material which can be suitably used as a clay mineral is a material which forms a skeleton of a ceramic such as ceramics, kaolin or sericite. A better material is pottery. The content of the clay mineral is preferably 20% by mass or more and 60% by mass or less based on the total amount of the raw material formulation. In addition, the total amount of the raw material preparation refers to the total amount of the raw materials constituting the components of the fired body, and does not include water added during wet molding, or a surfactant or a drying step in the drying step such as an organic polymer. ingredient.

(2) As the clay, natural clay or synthetic clay can be used. Specific examples of the natural clay include soils having a strong plasticity as a main body of clay minerals, and examples thereof include a palace clay, a knot clay, a shale clay, a Murakami clay, and a frog clay. As the synthetic clay, those which are artificially produced by using various mineral powders and organic binders as main components can be used. The content of the clay is preferably 20% by mass or more and 50% by mass or less based on the total amount of the raw material formulation.

(3) Materials which can be suitably used as the vitreous mineral are, for example, feldspar and muscovite. A better material is feldspar. The content of the vitreous mineral is preferably 5% by mass or more and 20% by mass or less based on the total amount of the raw material formulation.

(4) A material which can be suitably used as the compound containing Ca is, for example, ash feldspar, limestone, apatite or the like. By using these compounds, anorthite can be formed in ceramics. Among these, the use of limestone is better. Through the use of ash-like minerals of ash, it is possible to prevent formation after forming Or cracking and deformation at the time of firing (especially dry cracking of the molded body or deformation at the time of firing). The content of the compound containing Ca is preferably 3% by mass or more and 20% by mass or less based on the total amount of the raw material formulation.

The raw material formulation used in the method for producing a large-sized ceramic plate according to the present invention further contains (5) talc depending on the case, and the content thereof is preferably 0% by mass or more and less than 5% by mass based on the total amount of the raw material formulation. %. By reducing the Mg component of the talc, which does not contain or contains only a trace amount of talc, the Ca component such as apatite has a function as a flux. Thereby, it is possible to control the chemical change accompanying the firing, and it is possible to obtain a fired body having low water absorption and high productivity. It is preferable that the talc which is required as a raw material of a large ceramic plate contains about 30% of MgO, so it is preferable that the raw material formulation does not contain talc.

The 50% diameter (particle diameter) of the apatite contained in the raw material preparation used in the method for producing a large-sized ceramic plate of the present invention is preferably 20 μm or more. When the particle diameter of the apatite is 20 μm or more, when the extrusion molding method is used as the molding method, the effect of relaxing the shrinkage in the extrusion direction can be increased, and the shrinkage ratio in the longitudinal direction and the transverse direction of the fired body after the firing can be reduced. difference. As a result, shrinkage deformation due to firing can be suppressed, and firing cracking can be prevented.

According to a preferred mode of the present invention, preferably, the 50% diameter of the apatite is 50 μm or less. In the present invention, in order to cohere the limestone with other raw materials, it is preferred to use a limestone which appropriately contains particles having a small particle diameter. The long fiber system has a lower purity than the upper ash stone, and there is a fear that the surface of the large ceramic plate is mass-produced to produce a poor appearance (black spots, etc.). Via the use of grain The asbestos is relatively small in diameter, and it is possible to cause the above-mentioned appearance defects to be produced on the surface of the ceramic plate. If there is one defect in the surface of the large-sized ceramic plate, the loss thereof is also greatly increased. According to the present invention, a large-sized ceramic having no appearance loss and high commercial value can be obtained. Further, in the present invention, since the fly ash having a relatively small particle diameter is used, it is not necessary to use a large ash stone having a long fiber length for the purpose of maintaining the shape of the ash stone after firing.

According to a preferred embodiment of the present invention, it is possible to think of a method of using the above-described composition in which the amount of the elements of Si, Al, Ca, Mg, K, and Na is converted into an oxide by using such a small amount of the ash. In combination with the blended raw material formulation, although the melting of the raw material is promoted during firing, deformation can be suppressed.

According to a preferred mode of the present invention, it is preferred that the raw material formulation used in the method for producing a large-sized ceramic plate according to the present invention further comprises (6) an aggregate. Since the raw material preparation which reduced the alkali component is inferior in drying property compared with the original raw material preparation, it is suppressed by the addition of an aggregate, and it can suppress the rupture of the shaping|molding body.

Further, the particle diameter of the aggregate is preferably 1.7 mm or less, more preferably 0.5 mm or less. By using an aggregate having a particle diameter of 1.7 mm or less, the water absorption rate of the large ceramic plate can be reduced. Further, the preferred aggregate has a particle diameter of 0.1 mm or more. Thereby, when performing wet molding, the drainage at the time of drying of the clay can be better, and the drying time can be shortened. Examples of the material which can be suitably used as the aggregate include ceramsite, vermiculite, etc., and a ceramic granule material using a low water absorbing ceramic such as a type I ceramic tile as a raw material is more preferably used. (Scherben). Further, the content of the aggregate is preferably 5% by mass or more and 30% by mass or less based on the total amount of the raw material formulation.

According to a preferred embodiment of the present invention, the raw material formulation includes the above (1) to (6), and preferably the above (1) clay mineral is contained in an amount of 20% by mass or more and 60% by mass or less based on the total amount of the raw material formulation. 20% by mass or more and 50% by mass or less of the above (2) clay, 5% by mass or more, and 20% by mass or less of the above (3) vitreous mineral, 3% by mass or more, and 20% by mass or less of the above (4) 矽(6) aggregate of the above (5) talc and 5% by mass or more and 30% by mass or less of ashite, 0% by mass or more, and less than 5% by mass. By formulating the raw material so as not to contain a large amount of Mg, a large-sized ceramic plate having a water absorption ratio of 1% or less as defined in JIS A 5209 (2008) and having no cracking or deformation can be obtained.

Forming of raw material formulations

In the method for producing a large-sized ceramic plate according to the present invention, the raw material formulation is molded and molded to obtain a molded body. The method of molding is not particularly limited, and any of a wet molding method and a dry molding method can be used. When the wet molding method is used, it is preferable from the viewpoint that the following advantages can be obtained. That is, since a large mold and a press machine such as a dry molding method are not required, it is possible to adapt to various sizes, and it is possible to obtain not only a flat plate shape but also a shape of a hollow body or a profile (for example, an R curved surface). Further, in the molded body before drying, a ring-shaped roller (Endless Roller) having a concave-convex pattern formed on the surface can be used, and various uneven patterns can be imparted. That is to say, there is no need to impart a large-scale mold such as dry stamping to form a three-dimensional sheet. Type change. On the other hand, when the dry molding method is used, the drying step is not required after the molding, that is, it is preferable from the viewpoint of desiring to shorten the production steps.

The method of wet molding is not particularly limited, and specifically, a method such as an extrusion molding method or a wet press molding method can be preferably used. Among these, the extrusion molding method can be more preferably used. As a result, a large-scale ceramic plate having various sizes and designs that meet the needs of users can be produced without requiring a large-scale press forming apparatus.

In the case of the extrusion molding method, it is preferred to add a plasticizer to the raw material formulation as needed, and to prepare and shape a clay having a suitable moisture content. Thereby, the balance of plasticity and firmness can be appropriately maintained. The preferred moisture content in the clay is 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 25% by mass or less. After the clay is extrusion-molded, it is expanded into a flat shape and rolled by a roll to obtain a plate-like formed body. In addition, in this specification, "the clay" may be included in the meaning of "material preparation".

Firing of a shaped body

In the method for producing a large-sized ceramic plate according to the present invention, the formed body is subsequently fired. According to a preferred embodiment of the present invention, the maximum temperature at which the formed body is fired is preferably from 1100 ° C to 1200 ° C, more preferably from 1100 ° C to 1180 ° C, most preferably from 1120 ° C to 1180 ° C. By firing in this temperature range, a ceramic plate free from chipping and cracking or deformation, thin and large can be obtained.

Drying of the shaped body

According to a preferred mode of the present invention, in the method for producing a large-sized ceramic plate of the present invention, the formed body can be dried (including heating) before firing of the formed body. The maximum temperature at which the formed body is dried is preferably from 50 ° C to 200 ° C, more preferably from 80 ° C to 150 ° C. By drying in this temperature range, a ceramic plate free from dry chips and deformation can be obtained.

Pre-burning of shaped bodies

According to a preferred mode of the present invention, in the method for producing a large-sized ceramic plate of the present invention, the molded body can be pre-fired before firing of the formed body. The temperature of the calcined molded body is preferably 600 ° C or more and 1140 ° C or less, more preferably 800 ° C or more and 1100 ° C or less. By performing calcination in this temperature range, a ceramic plate free from chipping and cracking or deformation can be obtained.

[Examples]

The present invention will be described in more detail based on the following examples, but the invention is not limited to the examples.

Examples 1 to 13 and Comparative Examples 1 to 4 Preparation of raw material preparation

Will be used as clay minerals in pottery, with clay, as feldspar as a vitreous mineral, with aggregates, with ashes, and according to the situation, talc in Table 1 The content described is adjusted and mixed to prepare a raw material preparation. Here, the talc was not added to each of the raw material formulations of Examples 1 to 13 and Comparative Examples 1 to 3, but 5% by mass of talc was added to the raw material formulation of Comparative Example 4. Then, water is added to each raw material preparation to obtain a plastic clay having a water content adjusted to 10% by mass or more and 25% by mass or less. In addition, in Table 1, there is an example in which the total value of the raw material preparations (100% by mass) does not match the total value of the contents of the respective components constituting the raw material preparation, but this is based on the decimal point of the content value of each component. The case where the latter 1 bit is rounded off and adjusted to an integer.

The particle size of the aggregate and the particle size of the asbestos were measured as follows.

Aggregate particle size determination

A plain mesh screen (aperture 250 μm, 1.0 mm, 1.7 mm, frame diameter 200 mm, depth 45 mm) specified in JIS Z 8801-1 (2006) "Test sieve - Part 1: Metal mesh screen", It is determined by "manual screening" in "dry screening" described in "General rules for screening test methods" in JIS Z 8815 (1994).

Determination of particle size of limestone

The particle size was measured by a laser diffraction method using a laser analysis particle size distribution meter "MICROTRA" C158139-SVR (manufactured by LEEDS & NORTHRUP COMPANY). The order of the specific methods is as follows.

(i) Add 1 g of the sample to 100 ml of a 1% by weight aqueous solution of sodium metaphosphate, and stir it in an ultrasonic cleaner to disperse it in the solution for 5 minutes. in.

(ii) 250 ml of a 1 w% aqueous solution of sodium metaphosphate was placed in a measuring device and stirred.

(iii) The suspension of the above (i) is titrated with a burette and adjusted to a concentration suitable for measurement, and the measurement is carried out.

(iv) It was determined that the scanning was performed twice for 30 seconds, and the particle diameter was calculated from the average value.

Forming of raw material formulations (Examples 1 to 4, Comparative Example 1)

The obtained clay was molded into a cylindrical shape by an extrusion molding machine (extrusion molding machine described in JP-A-2010-234802), and was cut in the extrusion direction to be rolled to obtain a width ( A test body having an extrusion direction of 100 mm, a length of 200 mm, and a thickness of 4 mm. In addition, the clays of Examples 1 to 4 and Comparative Example 1 were molded into a cylindrical shape using an extrusion molding machine (extrusion molding machine described in JP-A-2010-234802). This was cut in the extrusion direction and rolled to prepare a green plate having a width of 700 mm, a length (extrusion direction) of 1050 mm, and a thickness of 4 mm.

These test pieces were dried and fired under the conditions described below, and various evaluations of the evaluation 1 described later (destruction generation, shrinkage measurement, measurement of water absorption rate of the fired body, composition analysis, and identification of anorthite) were performed. . In addition, after drying and baking were carried out using the produced green flat plate under the conditions described below, the evaluation of the evaluation 2 described later was performed. Observing the presence or absence of deformation).

(Examples 5 to 13 and Comparative Examples 2 to 4)

The obtained clay was molded into a cylindrical shape by an extrusion molding machine (extrusion molding machine described in JP-A-2010-234802), and was cut in the extrusion direction to be rolled to have a width of 700 mm. A flat plate of 1050 mm in length (extrusion direction) and 4 mm in thickness.

In each of the various green sheets produced, a slice having a width (extrusion direction) of 100 mm, a length of 200 mm, and a thickness of 4 mm was cut so that the short side and the extrusion direction were parallel. Each of the obtained sections was used as a test piece, and these were dried and calcined under the conditions described below, and various evaluations of the evaluation 1 described later were performed. In addition, each of the green sheets of Examples 5 to 13 and Comparative Examples 2 to 4 in which the chips were not cut out was dried and calcined under the conditions described below, and the evaluation of Evaluation 2 described later was performed.

Drying and firing of test body Drying of test body (Examples 1 to 13 and Comparative Examples 1 to 4)

Each of the produced test bodies was dried by heating at 150 ° C for 30 minutes to obtain a dried body.

Drying of the body (Examples 1 to 4, Comparative Example 1)

The dried bodies produced were heated from normal temperature for 10 minutes using a roller kiln. The temperature was maintained at a maximum temperature of 1,140 ° C for 10 minutes, and then cooled for 10 minutes to obtain a fired body.

(Examples 5 to 13 and Comparative Examples 2 to 4)

Each of the produced dried bodies was heated from a normal temperature to a maximum temperature of 1,140 ° C for 20 minutes using a roller kiln, and the maximum temperature was maintained for 7 minutes, and then cooled for 13 minutes to be baked, thereby obtaining a fired body.

Drying and firing of plain plate Drying of plain plate (Examples 1 to 13 and Comparative Examples 1 to 4)

Each of the produced green sheets was dried by heating at 150 ° C for 30 minutes to obtain a dried body.

Drying of the body (Examples 1 to 13 and Comparative Examples 1 to 4)

Each of the produced dried bodies was heated from a normal temperature to a maximum temperature of 1,140 ° C for 20 minutes using a roller kiln, and the maximum temperature was maintained for 7 minutes, and then cooled for 13 minutes to be baked, thereby obtaining a fired body.

Evaluation 1 Rupture

With respect to each of the examples and the comparative examples, the dried body and the fired body described in Table 1 were prepared as test samples, and it was visually confirmed that each of these examples was No cracks are produced. The results are shown in Table 1.

Determination of shrinkage

The length (mm) of the short side and the long side of the fired body was measured using a gauge. The measured values and the short side (100 mm) and the long side (200 mm) of the test piece were compared, and the respective shrinkage ratios (A, B; (%)) of the short side and the long side were calculated. The results are shown in Table 1. Further, in Table 1, the difference (absolute value) between the shrinkage ratio (A) of the short side and the shrinkage ratio (B) of the long side is also shown.

Determination of water absorption

In each of the produced fired bodies, a section having a width (extrusion direction) of 100 mm, a length of 100 mm, and a thickness of 4 mm was cut out as a sample. With respect to each sample, the water absorption rate was measured in accordance with the method for measuring the water absorption rate by the vacuum method defined in JIS A 1509-3 (2008).

Composition analysis

The sample was prepared in the following order, and the oxide-converted concentration of the total element to be detected was quantified by the following measurement conditions and the method of determining the concentration using a fluorescent X-ray analyzer Supermini 200 (Nippon Scientific Co., Ltd.). The results are shown in Table 1.

Production of samples

(a) Each of the fired bodies was crushed with a plastic hammer, and pieces of about 50 mm ² were taken out.

(b) The obtained chips were pulverized in a mortar to prepare a powder of 100 mesh or less.

(c) A medicine wrapper was placed on the press mold, and a polyvinyl chloride ring having an outer diameter of 38 mm, an inner diameter of 31 mm, and a thickness of 5 mm was placed thereon.

(d) The powder prepared in the above (b) is filled into a mountain shape in a ring, and a medicine wrap is placed thereon.

(e) Pressurization (about 5 seconds) until the pressure of 5 MPa is reached.

(f) The powder around the sample (disk shape) was removed by hand pumping, and a measurement sample was prepared.

Measuring condition

. X-ray tube current: 4.00mA

. X-ray tube voltage: 50kV

. Constant temperature: 36.5 ° C

. PR gas amount: 7.0ml/min

. Vacuum degree: 10Pa or less

. Sample form: powder measurement (coated polypropylene film)

. Analysis method: EZ scan

. Measuring diameter: 30mm

. Measurement time: Select "long"

Method for determining concentration

Indicates the oxide-converted concentration of all elements detected.

Identification of anorthite

Using the sample used in the above evaluation (composition analysis), the presence of anorthite in the fired body was confirmed by X-ray diffraction (XRD). The measurement conditions and the identification method of anorthite are as follows. The results are shown in Table 1.

. Measurement conditions: powder method, diffraction angle 2θ=2~70°

. Identification of anorthite: comparison of the 3 strong lines with the equipment library.

Evaluation 2 Whether there is rupture and deformation

The fired body in which the green sheets of Examples 1 to 13 had been dried and fired was visually observed for the presence or absence of cracking and deformation. As a result, it was found that all of the fired bodies can be used as large ceramic plates without cracking, warping, and deformation.

Comparative example 5~7

Large-sized ceramic tiles (large-sized ceramic tiles 1 to 3) were prepared, and the measurement of the water absorption rate, the composition analysis, and the identification of anorthite were evaluated in the same manner as described above for each large-sized ceramic tile. The results are shown in Table 1.

Reference example 1 Preparation of raw material preparation

Mixing the clay as a clay mineral with clay, feldspar as a vitreous mineral, and limestone with the raw material formulation of Example 4. After that, the mixture was mixed, and a powdery raw material preparation was prepared.

Forming of raw material formulations

The obtained raw material formulation was pressed with a surface pressure of 84 MPa using a 100-ton hydraulic press forming machine (manufactured by Goto Iron Works Co., Ltd.) to prepare a molded body having a width of 100 mm, a length of 100 mm, and a thickness of 4 mm as a test body.

Firing of a shaped body

The test body produced was heated from a normal temperature to a maximum temperature of 1,140 ° C for 10 minutes using a roller kiln, and the maximum temperature was maintained for 10 minutes, and then cooled for 10 minutes to obtain a fired body.

The test piece or the fired body produced was subjected to various evaluations similar to the above-described evaluation 1 (breakage generation, shrinkage measurement, water absorption measurement of the fired body, composition analysis, and identification of anorthite). The results are shown in Table 1.

Claims (17)

A large-sized ceramic plate comprising a Mg element in an amount of 0.5% by mass or more and 2% by mass or less in terms of MgO, and a Ca element in an amount of 2% by mass or more and 15% by mass or less in terms of CaO, in JIS A 5209 (2008) The water absorption rate specified in the above is 1% or less, and includes an anorthite having a length of 400 mm or more and 3000 mm or less and a thickness of 1 mm or more and 10 mm or less. The large ceramic plate of claim 1, wherein the MgO/CaO is less than 0.4 by mass. The large ceramic plate of claim 2, further comprising an aggregate. The large-sized ceramic plate according to claim 2, further comprising a Si element in an amount of 60% by mass or more and 70% by mass or less in terms of SiO ₂ and an Al element in an amount of 15% by mass or more and 25% by mass or less in terms of Al ₂ O ₃ . in terms of K ₂ O less than 2 mass%, 4 mass% of K elements, and in terms of Na ₂ O to 0.5 mass%, 1 mass% or less of Na element. The large-sized ceramic plate according to claim 3, further comprising a Si element in an amount of 60% by mass or more and 70% by mass or less in terms of SiO ₂ and an Al element in an amount of 15% by mass or more and 25% by mass or less in terms of Al ₂ O ₃ . in terms of K ₂ O less than 2 mass%, 4 mass% of K elements, and in terms of Na ₂ O to 0.5 mass%, 1 mass% or less of Na element. A manufacturing method for manufacturing a large-sized ceramic plate according to any one of claims 1 to 5, characterized in that it comprises at least the following steps; preparing to contain (1) clay mineral, (2) clay, and (3) glass Minerals, and (4) compounds containing Ca, and depending on the situation a step of (5) a raw material formulation of talc, a step of molding the raw material mixture to obtain a molded body, and a step of firing the shaped body to obtain a ceramic plate, and the content of the (5) talc The total amount of the raw material preparation is 0% by mass or more and less than 5% by mass. The production method of claim 6, wherein 50% of the diameter of the (B) Ca-containing compound is 20 μm or more. The production method of claim 7, wherein 50% of the diameter of the above-mentioned (4) Ca-containing compound is 50 μm or less. The production method according to any one of claims 6 to 8, wherein the Ca-containing compound is a limestone. The production method according to claim 9, wherein the content of the (B) Ca-containing compound is from 3% by mass to 20% by mass based on the total amount of the raw material formulation. The method of claim 10, wherein the raw material formulation further comprises (6) an aggregate having a particle diameter of 1.7 mm or less. The method of claim 10, wherein the raw material formulation comprises the above (1) to (6), and the (1) clay mineral is contained in an amount of 20% by mass or more and 60% by mass or less based on the total amount of the raw material formulation. 20% by mass or more and 50% by mass or less of the above (2) clay, 5% by mass or more and 20% by mass or less of the above (3) vitreous mineral, 3% by mass or more, and 20% by mass or less of the above (4) ash (6) talc of the above (5) talc, and not less than 5% by mass, and 5% by mass or more and 30% by mass or less of the above-mentioned (6) aggregate. The method of claim 11, wherein the raw material formulation comprises the above (1) to (6), and the (1) clay mineral is contained in an amount of 20% by mass or more and 60% by mass or less based on the total amount of the raw material formulation. 20% by mass or more and 50% by mass or less of the above (2) clay, 5% by mass or more and 20% by mass or less of the above (3) vitreous mineral, 3% by mass or more, and 20% by mass or less of the above (4) ash (6) talc of the above (5) talc, and not less than 5% by mass, and 5% by mass or more and 30% by mass or less of the above-mentioned (6) aggregate. The manufacturing method of claim 12, wherein the (1) clay mineral is a ceramic stone, and the (3) glass mineral is a feldspar. The manufacturing method of claim 13, wherein the (1) clay mineral is a ceramic stone, and the (3) glassy mineral is a feldspar. The manufacturing method of claim 14, wherein the maximum temperature at which the shaped body is fired is from 1100 ° C to 1200 ° C. The manufacturing method of claim 15, wherein the maximum temperature at which the shaped body is fired is from 1100 ° C to 1200 ° C.