TW201741265A - Large ceramic plate and manufacturing method therefor being excellent in freeze-thaw resistance, strength and thermal shock resistance - Google Patents

Abstract

The present invention is to provide a large ceramic plate that satisfies freeze-thaw resistance, strength and thermal shock resistance. The large ceramic plate is characterized by having a water absorption rate defined in JIS (Japanese Industrial Standards) A1509-3 (2014) of 1% or less, a crystal phase containing mullite but not quartz, or a crystal phase containing quartz having a concentration of more than 0% by mass and 20% by mass or less. In a preferred embodiment, the large ceramic plate further comprises: Zr in an amount of 3% by mass or more and or 15% by mass or less in terms of ZrO2, Ca in an amount of more than 0% by mass and 1% by mass or less in terms of CaO, and Mg in an amount of more than 0% by mass and 1% by mass or less in terms of MgO, an excellent thermal shock resistance is thus imparted to the large ceramic plate of the present invention.

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 large-sized ceramic plate having high bending strength and excellent thermal shock resistance and a method for producing the same.

Ceramic tiles are recognized as non-combustible materials and are highly reliable materials for designers. In recent years, the popularity of large ceramic plates exceeding the size of ceramic tiles has gradually expanded. Large ceramic plates imported from Europe are Grade 1 blanks. These strengths are excellent in freeze-thaw resistance and other properties. However, since they are brittle materials, they are easily broken when subjected to an impact of durability or higher. On the other hand, a large-sized ceramic plate commercially available in Japan is a grade 3 blank containing anorthite (for example, refer to Patent Document 1).

In addition, in order to realize the production of a large-sized ceramic plate suitable for exterior building materials, various proposals for reducing the water absorption of a large-sized ceramic plate have been proposed. For example, Patent Document 2 describes a large-sized ceramic plate comprising: 0.5 mass in terms of MgO. The water content of the Mg element of 2% or more and 2% by mass or less and the Ca element of 2% by mass or more and 15% by mass or less in terms of CaO is 1% or less as defined in JIS A5209 (2008).

Further, Patent Document 3 describes a ceramic blank in which a plastic clay containing feldspars and quartz containing an alkaline component, three components including lime, a bitter component, and an alumina component are removed, and each component is opposed to each other. The overall weight is at least 10% by weight or more.

Prior art literature

Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. Hei 10-236867

Patent Document 2: Japanese Laid-Open Patent Publication No. 2015-91744

Patent Document 3: Japanese Patent Laid-Open Publication No. 2007-39314

Since the large-sized ceramic plate described in Patent Document 1 uses the asbestos of the fiber mineral in the raw material and is burned so that the ash is left, it is difficult to be broken even if it is subjected to the impact of the durability, but the strength is increased. When the degree of sintering is further increased, the billet is melted and it becomes difficult to maintain the shape.

Since the asbestos contains a large amount of calcium, it is prone to cracking and deformation at the time of firing. It has been proposed that the large-sized ceramic plate disclosed in this document has the above-described composition, so that water absorption is low and high productivity can be obtained (dry cracking, firing cracking, and good shape stability) can be obtained.

For the application of large ceramics in wall materials containing inner and outer The board must meet the required quality for freeze-thaw resistance, strength and thermal shock resistance. Especially in heat resistance, when there is a seam in the tile wall, even if the tile itself breaks, the length of the break does not exceed the length of the tile crack, so that the wall can be suppressed from burning, but the wall of the large ceramic plate is attached. There are few seams, and if the large ceramic plate is broken, there is a possibility that the effect of preventing the burning is lowered. Therefore, there is still a demand for large-scale ceramic plates that can satisfactorily satisfy freeze-thaw resistance, strength, and thermal shock resistance.

Accordingly, the present invention has an object of providing a large-sized ceramic plate satisfying freeze-thaw resistance, strength, and thermal shock resistance.

The large-sized ceramic plate according to the present invention is characterized in that the water absorption rate specified by JIS A1509-3 (2014) is 1% or less, and the crystal phase contains mullite, and further contains no quartz, or contains quartz. The concentration exceeds 0% by mass and 20% by mass or less.

[Best form for carrying out the invention]

Large ceramic plate

The large-sized ceramic plate according to the present invention is characterized in that the water absorption rate specified by JIS A1509-3 (2014) is 1% or less, mullite is contained as a crystal phase, and quartz is not contained, or the concentration of the quartz exceeds 0 when contained. The mass % and the content of 20% by mass or less include a Ca element in an amount of more than 0% by mass and not more than 1% by mass in terms of CaO, and a Mg element in an amount of more than 0% by mass and not more than 1% by mass in terms of MgO. Further, according to a preferred embodiment of the present invention, Zr element in an amount of 3 mass% or more and 15 mass% or less in terms of ZrO ₂ may be further included. Since Ca and Mg which are divalent metal elements are in a predetermined concentration range and mullite is contained in the crystal phase, even if it is grilled in order to make the water absorption rate 1% or less, it does not melt. Further, by setting the quartz concentration to 20% by mass or less, it is difficult to cause cracking with respect to thermal changes. Therefore, according to the present invention, a large-sized ceramic plate which satisfies freeze-thaw resistance, strength, thermal shock resistance, and preferably a light color system can be obtained.

(size)

According to a preferred mode of the present invention, the large ceramic plate according to the present invention preferably has a thickness of 1 mm or more and 10 mm or less. More preferably, the thickness is 1 mm or more and 6 mm or less. Further, the length of one side of the large-sized ceramic plate according to the present invention is preferably 400 mm or more and 3,000 mm or less, more preferably 800 mm or more and 3,000 mm or less. Since the seam can be reduced by making the length within the range, the simplification of the construction and the diversification of the design can be achieved.

Further, the large-sized ceramic plate according to the present invention preferably has a short side/thickness of 80 or more, more preferably 100 or more. According to this, a thin and large ceramic plate which can be applied to exterior use can be obtained.

Further, the large ceramic plate according to 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 a flat plate.

(crystalline phase)

The large-sized ceramic plate according to the present invention contains mullite as a crystal phase, and further contains no quartz, or the concentration of the quartz exceeds 0% by mass and 20% by mass or less when contained.

According to a preferred mode of the invention, the large ceramic plate according to the invention comprises crystalline minerals from feldspar in the crystalline phase. Here, the crystalline mineral derived from feldspar is at least one selected from the group consisting of alkaline feldspar and albite, and is preferably at least one selected from the group consisting of feldspar, perlite, micro plagioclase, celsian, and albite.

According to a preferred mode of the invention, the large ceramic plate according to the invention preferably does not comprise anorthite. The conventional large ceramic plate containing anorthite in the crystal phase contains a large amount of Ca. Therefore, when the degree of firing is increased, deformation due to melting is apt to occur.

According to a preferred mode of the invention, the large ceramic plate according to the invention comprises mullite and anorthite in the crystalline phase, preferably comprising more mullite than anorthite. By making the crystal phase in this manner, deformation due to melting can be suppressed, and the shape stability at the time of production can be improved.

In the present invention, the identification of the crystal phase can be carried out by an X-ray diffraction method (hereinafter sometimes referred to as XRD). In other words, the pulverized sample of the dried ceramic is subjected to X-ray diffraction measurement using, for example, "X'Pert Pro MPD" manufactured by PANalytical Co., Ltd. as a measuring device: a copper target is used, and a Cu-Kα1 wire is used. The voltage was 45 kV, the tube current was 40 mA, the measurement range was 2θ = 5 to 80 deg, the sampling width was 0.033 deg, and the scanning speed was 80 s/step. The presence of the crystalline phase is identified by the magnitude of the peak intensity in the map obtained by XRD. Specifically, reference to crystalline The library, the height of the identifiable peak within the three strongest lines of each crystal identified (for example, mullite: 2θ = 16.46 deg; anorthite: 2θ = 21.98 deg; quartz: 2θ = 20.9 deg; feldspar: 2θ=27.58 deg; albite: 2θ=27.9 deg, etc., the height of the detected peak) was compared. Further, the quantification of quartz, minerals derived from feldspar, and amorphous phase can be calculated by Rietveld analysis.

According to a preferred mode of the present invention, the large ceramic plate according to the present invention preferably has a quartz concentration of 10% by mass or more and 20% by mass or less. In the present invention, the lower the quartz concentration in the large ceramic plate, the more excellent the thermal shock resistance, and it is preferable in this respect. However, among the materials constituting the raw material blend described later, materials having a low quartz concentration are expensive both in natural materials and in synthetic materials. By screening the material by setting the quartz concentration to the above range, various characteristics and economical advantages obtained by the effects of the present invention can be coexisted.

According to a preferred mode of the present invention, the large ceramic plate according to the present invention preferably has a lower limit of the concentration of the crystalline mineral derived from feldspar of 10% by mass, more preferably 15% by mass, further preferably 20% by mass, further preferably 25% by mass. % is further preferably 30% by mass, and still more preferably 35% by mass. The large ceramic plate according to the present invention preferably has an upper limit of the concentration of the crystalline mineral derived from feldspar of 50% by mass, more preferably 45% by mass, further preferably 40% by mass, still more preferably 35% by mass. A suitable concentration range of the crystalline mineral derived from feldspar can be freely combined with the above values, more preferably 20% by mass or more and 40% by mass or less.

When a ceramic having a water absorption ratio of 1% or less, that is, a magnetic material is produced, feldspar blended with a raw material blend can be used as a medium flux. In usual In use, the flux is a substance for assisting the melting of the raw material, and is mainly added for the purpose of chemically reacting with other components after melting to form a heterogeneous crystalline phase or amorphous phase with the raw material blend. On the other hand, it is considered that according to a preferred embodiment of the present invention, the large ceramic plate after firing contains minerals derived from feldspar, and a part of the vitreous mineral contained in the raw material blend does not melt and remains, so that the mineral from the feldspar is burned. The crystalline phase which is homogenous to the raw material blend is also maintained after the formation. The applicant believes that the residual vitreous mineral particles, that is, the crystalline minerals derived from feldspar, are used as nuclei, and other crystal phases and vitreous phases are formed around them, so that the shape can be favorably maintained at the time of firing. . Therefore, it is adjusted to a manufacturing condition in which one of the vitreous minerals is partially melted and chemically changed, and the other portion is kept in the crystal phase, whereby the shape at the time of firing can be favorably maintained. Further, since the temperature change can be performed relatively quickly, the firing time can be shortened, that is, the rapid firing can be performed. In particular, it is considered that in the production of a large-sized ceramic plate having a water absorption ratio of 1% or less, the effect of reducing the skew of the product and suppressing deformation and cracking can be achieved by rapid firing. In addition, when the concentration of the quartz contained in the raw material blend is 20% by mass or less, the vitreous mineral can be effectively used as a core, and cracking is less likely to occur with respect to heat change. Therefore, a large-sized ceramic plate which can satisfy freeze-thaw resistance, strength, and thermal shock resistance can be obtained.

(composition)

According to a preferred embodiment of the present invention, the large-sized ceramic plate according to the present invention preferably contains 60% by mass or more and 70% by mass or less of Si element in terms of SiO ₂ and 15% by mass or more in terms of Al ₂ O ₃ . 25 mass% of Al element, and to K ₂ O in terms of 10 mass% or less of the K in 0.5% by mass, and to Na ₂ O terms and 10 mass% of element Na 0.5% by mass, and to In the CaO conversion, the Ca element is contained in an amount of more than 0% by mass and not more than 1% by mass, and more than 0% by mass and not more than 1% by mass of the Mg element in terms of MgO. In the present invention, the detection and quantification of the elements can be carried out by a conventional method, preferably using a fluorescent X-ray analyzer (for example, Supermini 200 (Rigaku Co., Ltd.)). By having the above composition, the productivity of the large-sized ceramic plate having the above crystal phase can be improved. According to a preferred embodiment of the present invention, the large-sized ceramic plate according to the present invention preferably contains 64% by mass or more and 67% by mass or less of Si element in terms of SiO ₂ and 19% by mass or more in terms of Al ₂ O ₃ . 22 mass% of Al element, and to K ₂ O in terms of more than 1 mass% to 4 mass% of K elements, and to Na ₂ O terms and 7 mass% or less of Na element than 4 mass%, and to In the CaO conversion, the Ca element is 0.1% by mass or more and 0.8% by mass or less, and the Mg element is 0.1% by mass or more and 0.8% by mass or less in terms of MgO.

When the large-sized ceramic plate according to the present invention further contains 3% by mass or more and 15% by mass or less of Zr element in terms of ZrO ₂ , the composition thereof preferably contains 45% by mass or more and 65% by mass or less of Si in terms of SiO ₂ . The element and the Al element in an amount of 15% by mass or more and 30% by mass or less in terms of Al ₂ O ₃ and the Zr element in an amount of 3% by mass or more and 15% by mass or less in terms of ZrO ₂ and 0.5 in terms of K ₂ O a K element having a mass% or more and a mass% of 10% or less, a Na element of 0.5% by mass or more and 10% by mass or less in terms of Na ₂ O, and a Ca element exceeding 0% by mass and 1% by mass or less in terms of CaO, The Mg element is contained in an amount of more than 0% by mass and not more than 1% by mass in terms of MgO. According to a preferred embodiment of the present invention, the large-sized ceramic plate according to the present invention preferably further comprises: 5 mass% or more and 60 mass% or less of Si element in terms of SiO ₂ and 20 mass% or more in terms of Al ₂ O ₃ and 25% by mass or less of the Al element, and a Zr element of 5 mass% or more and 10 mass% or less in terms of ZrO ₂ and a K element of 1 mass% or more and 4 mass% or less in terms of K ₂ O, and Na ₂ O in terms of 4 mass% to 7 mass% of element Na, and in terms of CaO 0.1 mass% to 0.8 mass% of Ca element, and in terms of MgO 0.1 mass% to 0.8 mass% of Mg element.

(water absorption rate)

The large-sized ceramic plate according to the present invention has a water absorption rate of 1% as determined by a vacuum method prescribed in JIS A1509-3 (2014) "Ceramic tile test method - Part 3: Method for measuring water absorption, open porosity, and bulk density" Hereinafter, it is preferably 0.01% or more and 0.5% or less. By making the water absorption rate within this range, the strength of the large ceramic plate can be ensured. Further, since mullite is contained as described above, even if the water absorption is in the range of the range, it is possible to prevent deformation due to melting and to obtain thermal shock resistance. Further, by making the water absorption rate 1% or less, it is possible to suppress the penetration of water into the large ceramic plate. According to this, since damage due to freezing of water can be prevented, it can be suitably used as an exterior material.

When the large ceramic plate of the present invention has an enamel layer, it is preferred to The average expansion ratio of a large ceramic plate is greater than the average expansion ratio of the enamel layer. According to this, even a large ceramic plate can prevent concave warpage.

use

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

Large ceramic plate manufacturing method

According to another aspect of the present invention, an object of the present invention is to provide a method for producing a large-sized ceramic plate that satisfies freeze-thaw resistance, strength, and thermal shock resistance.

Next, the method for producing a large-sized ceramic plate according to the present invention comprises at least the steps of: preparing a composition comprising (1) a clay mineral, (2) a vitreous mineral, and, as the case of the (3) a zirconium-containing mineral; The step of molding the raw material blend to obtain a molded body, and the step of firing the molded body to obtain a large ceramic plate.

According to the method for producing a large-sized ceramic plate of the present invention, a large-sized ceramic plate having a water absorption ratio of 1% or less as defined in JIS A1509-3 (2014) and having freeze-thaw resistance, strength, and thermal shock resistance can be obtained.

According to a preferred mode of the present invention, in the method for producing a large ceramic plate according to the present invention, the raw material blend does not contain quartz or When the concentration of the quartz is more than 0% by mass and 20% by mass or less, it is preferable to contain more than 0% by mass and not more than 1% by mass of Ca element in terms of CaO, and more than 0% by mass and 1% by mass in terms of MgO. The following Mg elements. It is considered that the quartz and the Ca and Mg which are divalent metal elements are prepared as a raw material composition in a predetermined concentration range, and the mullite in the crystal phase is formed at a higher position than the anorthite in the calcination step. When the water absorption rate is 1% or less, the grilling does not melt, and it is difficult to cause cracking with respect to heat change. As described above, since the large-sized ceramic plate of the present invention is excellent in shape stability with respect to heat change, the heating curve at the time of firing can be made steep, that is, so-called rapid firing, and improvement in manufacturing efficiency can be expected.

Preparation of raw material blends

In the method for producing a large-sized ceramic plate according to the present invention, a raw material composition is prepared which first comprises at least (1) a clay mineral, and (2) a vitreous mineral, and then contains (3) a zirconium-containing mineral as the case may be.

Raw material blend

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

(1) As the clay mineral, a material which can be suitably used is, for example, at least one of a material forming a ceramic skeleton such as clay, ceramic, kaolin, or sericite. More preferred materials are either clay or ceramic. As the clay, natural clay or synthetic clay can be used. As natural clay Specific examples include soils having strong plasticity with clay minerals as main bodies, such as the clay, the knot clay, the shale clay, the Murakami clay, and the frog clay. As the synthetic clay, synthetic clay artificially produced using various mineral powders and organic binders as main components can be used.

The content of the preferred clay mineral is 10% by mass or more and 70% by mass or less, and more preferably 15% by mass or more and 60% by mass or less based on the total amount of the raw material blending compound. Further, the total amount of the raw material blend refers to the total amount of the raw materials constituting the components of the fired body, and does not include the water added during the wet molding, the surfactant or the organic polymer, etc. in the drying step or the baking step. Disappearing ingredients.

(2) As the vitreous mineral, materials which can be suitably used are, for example, feldspar and muscovite. A more preferable material is feldspar, and it is further preferably at least one selected from the group consisting of alkaline feldspar and albite. The content of the glassy mineral is preferably 30% by mass or more and 90% by mass or less, more preferably 40% by mass or more and 80% by mass or less based on the total amount of the raw material blending compound.

(3) Examples of the material suitable for use as the zirconium-containing mineral include zircon, zirconia, and zirconium carbonate, and zircon is preferred. The content of the zirconium-containing mineral is preferably 3% by mass or more and 25% by mass or less, more preferably 5% by mass or more and 15% by mass or less based on the total amount of the raw material blending compound.

In order to make the crystal phase of the fired body mainly composed of mullite, the raw material blend used in the method for producing a large ceramic plate according to the present invention preferably does not comprise (4) ash feldspar, limestone, strontium. The compound containing Ca in the limestone is suppressed to a low level. Due to the inclusion of the above compounds, anorthite is formed in the ceramic. Due to the large amount of calcium The burnt body of feldspar melts when it is grilled, and the deformation becomes remarkable, so it is not preferable. When the compound containing the above-mentioned Ca is blended, the content of the compound containing Ca is preferably 0% by mass or more and 5% by mass or less, more preferably 0% by mass or more and 3% by mass or less based on the total amount of the raw material blending compound.

According to a preferred mode of the present invention, the raw material blend used in the method for producing a large-sized ceramic plate according to the present invention may further comprise (5) an aggregate. Since the raw material blend having a reduced melting component is inferior in drying property to the original raw material blend, the occurrence of cracking accompanying drying of the molded body can be suppressed by adding the aggregate.

Further, the preferred aggregate has a particle diameter of 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 lowered. Further, the preferred aggregate has a particle diameter of 0.1 mm or more. According to this, when the wet molding is performed, the green body is easily dehydrated during drying, and the drying time can be shortened. Examples of the material which can be suitably used for the aggregate include refractory clay, vermiculite, etc., and a ceramic granule (Scherben) which uses a low water absorbing ceramic as a raw material, such as a type I ceramic tile, is more preferably used. Further, the content of the preferred aggregate is 0% by mass or more and 30% by mass or less, and more preferably 0% by mass or more and 20% by mass or less based on the total amount of the raw material blending compound.

According to a preferred mode of the present invention, the raw material blend used in the method for producing a large-sized ceramic plate according to the present invention may further comprise (6) a color material. As the color material, a known inorganic pigment can be used, and a pigment for obtaining a colored material can be suitably used. As the pigment, an inorganic pigment containing Fe or Cr can be suitably used. Preferably, the content of the color material is 0% by mass or more and 10% by mass or less based on the total amount of the raw material blending compound, and more preferably It is preferably 0% by mass or more and 5% by mass or less.

According to a preferred embodiment of the present invention, the raw material blending composition comprises the above (1) to (6), preferably with respect to the total amount of the raw material blend, comprising: 10% by mass or more and 70% by mass or less of the aforementioned (1) clay. 30% by mass or more and 90% by mass or less of the above (2) vitreous mineral; 3 mass% or more and 25% by mass or less of the above (3) zirconium compound; 0% by mass or more and 5% by mass or less of the foregoing (4) The compound containing Ca; 0% by mass or more and 30% by mass or less of the above (5) aggregate; 0% by mass or more and 30% by mass or less of the above (6) color material. In this way, it is preferable to contain Ca and quartz in a large amount, and it is preferable to contain 1% by mass or less of Ca in terms of CaO concentration, and further include 20% by mass or less of quartz, more preferably 10% by mass or more and 20% by mass or less of quartz. A large-sized ceramic plate having a water absorption rate of 1% or less as defined in JIS A1509-3 (2014) and satisfying freeze-thaw resistance, strength, and thermal shock resistance can be obtained.

Forming of raw material blends

In the method for producing a large-sized ceramic plate according to the present invention, the raw material blend is then 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.

In the wet molding method, water is added to a raw material blend to prepare a green body and shape. The dry molding method is to form pellets of a raw material blend and to form them. When the wet molding method is used, it is preferable in terms of obtaining the following advantages. That is, since a large mold and a press such as a dry molding method are not required, it can correspond to various sizes, and not only a flat plate shape but also a shape can be accommodated. The shape of the hollow body and the irregular shape (for example, the R curved surface) is easily obtained. Further, in the molded body before drying, a ring-shaped roll having a concavo-convex pattern formed on its surface can be used to impart various uneven patterns. That is, it is not necessary to perform large-scale mold replacement like dry pressing in order to add a three-dimensional surface shape.

On the other hand, when the dry molding method is used, since the drying step is not required after the molding or the drying conditions can be made mild, the amount of energy consumption during production can be reduced, which is preferable in this respect. Further, when the dry molding method is used, since the molded body contains a small amount of water, the internal shrinkage due to shrinkage is small because the drying shrinkage is small. Therefore, it is easy to obtain a thin large-sized ceramic plate having a small warpage or deformation, which is preferable in this respect. Further, in the wet molding method, a method in which a green body is extruded and molded and then rolled to obtain a plate-shaped formed body can be used. However, according to this method, the orientation of the raw material is generated inside the molded body. Since the dry molding method is difficult to produce the orientation of the raw material, the shape stability of the large ceramic plate is excellent, and this is preferable in this respect.

Sintering of shaped body

In the method for producing a large-sized ceramic plate according to the present invention, the formed body is subsequently fired to obtain a fired body. According to a preferred embodiment of the present invention, the maximum temperature at which the shaped body is fired is preferably from 1100 ° C to 1200 ° C, more preferably from 1100 ° C to 1180 ° C, and most preferably from 1120 ° C to 1180 ° C. Due to the firing in this temperature range, a thin large ceramic plate free from chips and cracks or skews can be obtained. The fired body obtained by the baking is subjected to post-processing such as shaping processing or directly to the fired body as a large-sized ceramic plate of the present invention without post-processing.

Drying of the shaped body

According to a preferred mode of the present invention, in the method for producing a large-sized ceramic plate according to the present invention, the formed body can be dried (including heating) before the formation of the formed body. The maximum temperature at which the shaped 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 of dry chips and skew can be obtained.

Pre-burning of shaped body

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

Glazing

The enamel may be glazed before or after firing of the shaped body or before or after calcination. The enamel can be either pulp or powder. When the enamel is glazed after firing of the formed body, it is preferably re-fired. An enamel layer can be formed by firing the enamel.

Example

The invention is illustrated in more detail by the following examples, but the invention is not limited thereto.

Example A1

(Preparation of raw material blend)

The clay as a clay mineral is mixed with feldspar as a vitreous mineral to prepare a raw material blend.

(formation of raw material blend)

The obtained raw material mixture was placed in an ore sieve, mixed and pulverized, and a granulated powder was produced through a spray dryer. The produced granular powder was punched into a size of 1090 mm × 3270 mm × 5.5 mm by a molding pressure of 35 to 40 MPa through a 25000 t dry press molding machine to obtain a molded body.

(drying of the formed body)

Each of the produced test bodies was dried by heating at 150 ° C for 25 minutes to obtain a dried body.

(drying of dry body)

The produced dried body was heated from a normal temperature to a maximum temperature of 1170 ° C for 30 minutes using a roller kiln, and was kept at the highest temperature for 10 minutes, cooled for 20 minutes, and discharged to obtain a fired body, thereby producing a large ceramic of Example A1. board.

Example A2~A4

Clay as a clay mineral and feldspar as a vitreous mineral A large-sized ceramic plate of Examples A2 to A4 was obtained in the same manner as in Example A1 except that the raw material used in Example A1 was changed, and the quartz concentration and composition of the raw material blend were changed.

Example A5

The large-sized ceramic plate of Example 5 was obtained in the same manner as in Example A1, using a raw material blend containing 2% by mass of a pigment containing iron oxide as a main component.

Comparative Example A1, Comparative Example A2, Comparative Example A4~6

Comparative Example was obtained by the same method as Example A1 except that the clay used as the clay mineral and the feldspar which is a vitreous mineral were used in the same manner as in Example A1 except that the raw material used in Example A1 was used, and the quartz concentration and composition of the raw material blend were changed. A1's large ceramic plate.

Comparative Example A3

A mixture of clay and clay as a clay mineral, feldspar as a vitreous mineral, and a limestone are prepared to prepare a raw material blend. Water is added to the raw material blend to obtain a plastic green body having a water content adjusted to 10% by mass or more and 25% by mass or less. The obtained green body was extruded into a cylindrical shape by an extrusion molding machine described in JP-A-2010-234802, and cut along a pressing direction and rolled by a roll to prepare a width of 700 mm and a length (squeezing). A molded body having a pressing direction of 1050 mm and a thickness of 5.5 mm. Each of the prepared test bodies was dried by heating at 150 ° C for 30 minutes, thereby A dried body is obtained. The produced dried body was fired under the same conditions as in Example A1 to obtain a large-sized ceramic plate of Comparative Example A3.

Example B1

A large-sized ceramic plate of Example B1 was obtained in the same manner as in Example A1 except that zircon which is a zirconium-containing mineral was mixed in the raw material mixture.

Comparative example B1~B6

A large-sized ceramic plate of Comparative Examples B1 to B6 was obtained in the same manner as Comparative Examples A1 to A6 except that the raw material blend of Example B1 was used as the raw material mixture.

Evaluation

Determination of water absorption

A section having a width of 100 mm, a length of 100 mm, and a thickness of 5 mm was cut out from each of the produced large ceramic plates as a sample. The water absorption rate of each sample was measured in accordance with the water absorption rate measurement method of the vacuum method prescribed by JIS A1509-3 (2014).

Determination of crystalline phase

A sample was prepared in the following order, and Rietveld analysis was performed on the spectrum detected by the X-ray diffraction apparatus under the following measurement conditions, and the ratio of the crystal phase in the sample was calculated. Further, the amorphous phase in the sample was calculated by an internal standard addition method.

Sample preparation

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

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

(c) A powder paper was placed on the press mold, and a vinyl 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 produced through the above (b) is filled into a mountain shape in a ring, and a powder paper is placed thereon.

(e) Pressing is performed until the pressure of 5 MPa (about 5 seconds).

(f) The powder around the sample (disk shape) was removed by a hand pump to obtain a measurement sample.

Determination conditions: powder method

Measuring device: X'Pert PRO MPD (manufactured by PANalytical Co., Ltd.)

X-ray source: Cu-Kα1

Tube voltage: 45kV

Tube current: 40mA

Measuring range: 2θ=5°~80°

Identification of crystal forms: The 3 strong lines were compared according to the machine library.

Determination of strength

Cut a width of 100mm and length from each large ceramic plate A section of 100 mm and a thickness of 5 mm was used as a sample. For each sample, the bending strength at a span of 290 mm was measured in accordance with the method for measuring the bending strength prescribed in JIS A1509-4 (2014).

Determination of thermal shock resistance

A section having a width of 100 mm, a length of 100 mm, and a thickness of 5 mm was cut out from each of the produced large ceramic plates as a sample. For each sample, a roller hearth type oven equipped with a burner that sprays a flame from the upper side of the sample toward the surface of the sample was used, and the surface of the sample was heated from room temperature to 750 ° C for 1 minute. Immediately after the rapid heating, immediately quench to room temperature. The sample which was subjected to the thermal shock caused under such conditions was visually observed for the damage.

Composition analysis

The sample used for the measurement of the crystal phase was subjected to the following method for determining the measurement conditions and the concentration using the fluorescence X-ray analyzer Supermini 200 (manufactured by Rigaku Co., Ltd.). Quantitative.

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 morphology: powder measurement (polypropylene film coverage)

. Analysis method: EZ scan

. Measuring diameter: 30mm

. Measurement time: Select "long"

Method of obtaining concentration

Indicates the oxide-converted concentration of all elements detected.

The results are shown in Table 1. In the table, "-" means no data. Since the large ceramic plates of Comparative Examples A1 and B1 were broken when they were discharged from the roller kiln, the strength was not measured. Since the large ceramic plates of Comparative Examples A3 and B3 were melted by firing and could not maintain the shape, strength and thermal shock resistance were not measured.

Claims (14)

A large-sized ceramic plate characterized by containing mullite as a crystal phase and not containing quartz, or containing quartz, in a large-sized ceramic plate having a water absorption ratio of 1% or less as defined in JIS A1509-3 (2014). When the concentration is more than 0% by mass and not more than 20% by mass, the Ca element in an amount of more than 0% by mass and not more than 1% by mass in terms of CaO, and the Mg element in an amount of more than 0% by mass and not more than 1% by mass in terms of MgO. The large-sized ceramic plate according to claim 1 further contains Zr element in an amount of 3 mass% or more and 15 mass% or less in terms of ZrO ₂ . The large ceramic plate of claim 1 or 2 further comprising a crystalline mineral derived from feldspar. The large ceramic plate of claim 3, wherein the crystalline mineral derived from feldspar is at least one selected from the group consisting of alkaline feldspar and albite. A large ceramic plate of claim 1 or 2 which does not contain anorthite. The large-sized ceramic plate according to claim 1 which contains 60% by mass or more and 70% by mass or less of Si element in terms of SiO ₂ and 15% by mass or more and 25% by mass or less in terms of Al ₂ O ₃ . element, and to K ₂ O in terms of 0.5 mass% to 10 mass% of K elements, and to Na ₂ O terms and 10 mass% of element Na 0.5% by mass, and in terms of CaO is more than 0 mass % or more of the Ca element of 1% by mass or less and the Mg element in an amount of more than 0% by mass and not more than 1% by mass in terms of MgO. The large-sized ceramic plate according to claim 2, which is composed of Si element in an amount of 45 mass% or more and 65% by mass or less in terms of SiO ₂ and Al in an amount of 15% by mass or more and 30% by mass or less in terms of Al ₂ O ₃ . element, and to ZrO ₂ in terms of 3 mass% to 15 mass% of Zr element, and to K ₂ O in terms of more than 0.5 mass% to 10 mass% of K elements, and to Na ₂ O in terms of 0.5 mass The amount of the Na element is not less than 0% by mass and not more than 1% by mass in terms of CaO, and more than 0% by mass and not more than 1% by mass of the Mg element in terms of MgO. The large ceramic plate of claim 1 or 2, wherein the length of one side is 400 mm or more and 3000 mm or less. A large ceramic plate according to claim 8, wherein the thickness is 1 mm or more and 10 mm or less. A method of manufacturing a large-sized ceramic plate according to any one of claims 1 to 9, characterized in that it comprises at least the steps of: preparing (1) a clay mineral, (2) a vitreous mineral, and (3) a step of blending a raw material containing zirconium mineral; a step of forming the raw material blend to obtain a molded body; and a step of firing the molded body to obtain a large ceramic plate. The manufacturing method of claim 10, wherein the raw material composition comprises: 10% by mass or more and 70% by mass or less of the aforementioned (1) clay mineral; 30% by mass or more and 90% by mass based on the total amount of the raw material blending compound; The following (2) vitreous ore The (3) zirconium-containing mineral of 3 mass% or more and 25% by mass or less. The manufacturing method of claim 10 or 11, wherein the (1) clay mineral is clay, and the (2) vitreous mineral is feldspar. The manufacturing method of claim 10 or 11, wherein the (3) zirconium-containing mineral is zircon. The manufacturing method of claim 10 or 11, wherein the maximum temperature at which the molded body is fired is from 1100 ° C to 1200 ° C.