KR20220168714A - Pattery composition for preventing blotting defects and method for producing ceramic using the same - Google Patents

Abstract

The present invention relates to a ceramic composition for preventing blotting defects, which is produced by using a ceramic composition comprising 0.1 to 10 parts by weight of wollastonite, 0.1 to 7 parts by weight of talc, 0.1 to 10 parts by weight of bone ash, 0.1 to 3 parts by weight of frit, and 0.1 to 10 parts by weight of petalite, with respect to 100 parts by weight of basic ceramic raw materials including 30 to 45 wt% of clay, 25 to 30 wt% of feldspar, and 25 to 40 wt% of silicastone, and a method for producing the same.

Description

Background composition for preventing blotting defects and method for producing ceramics using the same {Pattery composition for preventing blotting defects and method for producing ceramic using the same}

The present invention prevents blotting defects in advance based on basic base materials including clay, feldspar and silica, sufficiently magnetizes, and produces ceramics with excellent firing oil surface. It relates to a body composition for prevention and a method for manufacturing ceramics using the same.

Among the food containers used in daily life, there are containers that need to be rapidly heated or rapidly cooled. An example is a normal cooking pot or an earthenware pot. A property required for these containers is thermal shock resistance capable of withstanding rapid heating and rapid cooling.

Ceramics such as porcelain have low thermal conductivity and low toughness, so when there is a sudden temperature change, capacity change occurs on the surface and inside, and the stress generated from it causes destruction, which is called thermal shock fracture.

Ceramics, originally a compound word of pottery and porcelain, refers to a product formed by molding inorganic materials such as clay, feldspar, silica, pottery stone, etc. alone or in combination, and then hardening them by applying heat. In recent years, research on physically or chemically refining raw materials used to improve physical properties and imparting characteristics of ceramic products or replacing them with other raw materials is actively underway. In order to improve sintering, research on products substituted with other raw materials such as sericite-like ceramics instead of silica and general pyrophyllite-like ceramics is in progress. Petalite) or nepheline syenite is also used.

In ceramics, glaze is applied to prevent permeability of the substrate and to have aesthetic beauty. In heat-resistant ceramics that are repeatedly used for rapid heating and cooling, the thermal expansion rate of both the substrate and the glaze must be small, and it is very important to properly adjust the thermal expansion rate of the substrate and the glaze. It is important.

There are a tunnel kiln, a shuttle kiln, and a roller hearth kiln for firing kilns for producing pottery tableware.

Ceramic tableware manufacturing is an industry that uses excessive energy, and energy costs account for a large portion of production costs.

For a long time, countries around the world have been continuously researching and developing technologies for fast firing in order to reduce energy costs. In the firing process of kitchen ceramics, tunnel kilns and shuttle kilns have been mainly used in Korea. However, due to unnecessarily heating the bogie, the energy intensity is relatively high and the firing time is generally long, so 'Roller hearth kiln', a rapid firing facility, has recently been widely used.

Recently, as some companies have increased the firing temperature of the rapid firing roller hearth kiln (R.H.K) and shortened the firing time, the occurrence of previously unseen Bloating defects has increased rapidly, and the quality of products after firing has decreased. As the production yield declines, problems such as complaints and compensation requests between related companies are increasing. Rather, it is an example of making a problem with a material supplier.

In rapid firing, the substrate must be vitrified in a short time, and within this time, each raw material decomposes and reacts, and the gas decomposition and transition of crystal structure that occur at this time cause great problems to the fired material. Therefore, this is the most important factor in rapid firing, and it can be said that the success or failure of rapid firing depends on how to control it.

Bloating Defects are defects in the body due to gas escaping from the body during firing, and can lead to product swelling, blisters, and pinholes. It is a defect that is commonly related to both the substrate and the glaze, and is composed of gas pockets developed according to firing.

Mainly, the higher the temperature and the shorter the firing time, the higher the possibility of occurrence, trapping of sulfide (SO ₃ ) existing inside the substrate or trapped gas that could not escape, and over-firing , it could be due to bad wedging or a foreign object.

Bloating (or blotting) Defects; Hereinafter referred to as "blotting"] is a defect in clay caused by a lot of gas coming out of clay during firing, and refers to phenomena such as swelling, blisters, and pinholes of the product, and the cause is very Although various, the biggest cause above all is that the magnetization of the material is not sufficiently done when melting the glaze.

These blotting defects show the phenomenon as swelling, bursting, or remaining traces on the surface of the melted and solidified glaze by gas burn-out from the inside of the substrate. Accordingly, considerable research has been conducted to control factors that adversely affect the magnetization of the base material in order to control the quality of a ceramic fast-fired product composed of a three-phase clay-feldspar-silica phase.

Korean Registered Patent Publication No. 10-1283314 (July 2, 2013) discloses basic body materials including 29 to 38% by weight of clay, 28 to 40% by weight of feldspar, and 28 to 40% by weight of silica, and 100 of the basic body raw materials 0.01 to 2 parts by weight of ZrOCl ₂ 8H ₂ O 0.01 to 2 parts by weight, 0.01 to 2 parts by weight of Al(OH) ₃ based on 100 parts by weight of the basic body material, 0.01 to 10 parts by weight of bone ash based on 100 parts by weight of the basic body material A base composition for low-strain high-strength ceramics containing 0.01 to 10 parts by weight of cordierite based on 100 parts by weight of the base base raw material and a method for manufacturing ceramics using the same are described,

Korean Registered Patent Registration No. 10-1508721 (2015.03.30.) discloses 40 to 50% by weight of glass frit for heat-resistant ceramics containing 9 to 16% by weight of lithium oxide (LiO), 10 to 20% by weight of pyrophyllite, and A technique for a body composition for heat-resistant porcelain containing 30 to 40% by weight of clay mineral is described,

Korean Registered Patent Publication No. 10-075377 (August 23, 2007) contains 0.20 to 0.45 mol of Li2O, 0.13 to 0.35 mol of MgO, 0.01 to 0.05 mol of Na2O, 0.01 to 0.12 mol of K2O, 0.01 to 0.06 mol Of CaO, 0.01 to 0.02 mol of ZnO, 1 mol of Al2O3, 3.80 to 5.20 mol of SiO2, 0.01 to 0.10 mol of ZrO2, 0.01 to 0.02 mol of TiO2, a body made of a composition of the Seger formula, A crack-free heat-resistant porcelain glaze with a suitable coefficient of thermal expansion was made on the base of the heat-resistant porcelain, and the Seger formula for the glaze composition of the heat-resistant porcelain without cracks was or 0.01 to 0.10 mol of PbO), 0.01 to 0.05 mol of Na2O, 0.01 to 0.05 mol of K2O, 0.01 to 0.10 mol of CaO, 0.01 to 0.05 mol of ZnO, 0.35 to 1.40 mol of Al2O3, 0.01 to 0.10 mol of B2O3 , 0.00 to 0.02 mol of Fe2O3, 2.95 to 7.50 mol of SiO2, and 0.01 to 0.04 mol of ZrO2, with this Seger-type glaze composition, technology for crack-free heat-resistant porcelain is described,

Korean Registered Patent Registration No. 10-1265943 (May 14, 2013) discloses a mixture of solids containing 20 to 50% by weight of clay, 20 to 45% by weight of feldspar, and 15 to 40% by weight of silica and distilled water to increase the solid content The slurry comprising 35 to 70% by weight contains 0.05 to 0.2 mol/L of Co(NO ₃ ) ₂ solution, 0.1 to 0.3 mol/L of Al(NO ₃ ) ₂ solution and an alkali solution, so that the pH is 7 to 10. A blue base composition for ceramics and a method for manufacturing a blue base using the same are described, and Korean Registered Patent Publication No. 10-1056996 (2011.08.09.) contains 30 to 80% by weight of pottery soil and 10 It can be seen that an unglazed ceramic composition for ceramics consisting of ~50% by weight and 5-30% by weight of chamotte and a method for manufacturing ceramics using the same are described.

1. Domestic Registered Patent Publication No. 10-1283314 2. Korean Registered Patent Publication No. 1015087210000 3. Korean Registered Patent Publication No. 10075377 4. Korean Registered Patent Publication No. 101265943 5. Korean Registered Patent Publication No. 1010569960000

The conventional techniques as described above have a problem of occurrence of major defects on the surface of the glaze due to a mismatch in the composition of the base and the glaze and negligence in quality control of the base composition, and the present invention is intended to solve this problem.

In addition, in order to shorten the ceramic manufacturing process, the present invention excessively shortens the firing time during the operation of the roller hearth kiln (R.H.K.), resulting in defects such as blotting or pinholes that have not been seen before, resulting in ceramic products. Dignity is intended to solve the problem of deterioration.

The present invention is to completely magnetize the body composition by using a composition in which an auxiliary flux is added to the basic body raw material including clay, feldspar and silica in order to solve the above problems.

In addition, the present invention contains 0.1 to 5 parts by weight of talc and 0.1 to 10 parts by weight of wollastonite based on 100 parts by weight of the basic base material composed of 30 to 45% by weight of clay, 10 to 30% by weight of feldspar and 25 to 40% by weight of silica. , 0.1 to 10 parts by weight of bone ash, 0.1 to 3 parts by weight of FRIT, and 0.1 to 10 parts by weight of chlorophyll are formed to improve the physical properties of the base composition, and the base composition before the glaze is completely melted It is to terminate the escape of decomposed substances inside and prevent blotting defects.

The present invention prevents blotting defects with excellent light transmission properties by containing bone ash or talc with excellent meltability and sinterability in a ceramic base composition for high magnetization rapid firing for preventing blotting defects,

In addition, an intermediate layer is formed between the matrix of the glass phase and the crystal phases distributed therein to reduce defects that may occur between the base and the glaze, and to sufficiently magnetize the base and the advantage of enhancing the bonding strength between the base and the glaze. ) to prevent blotting defects, thereby enhancing the quality of ceramics.

Figure 1 Firing curve graph showing the firing temperature range according to the firing time
Figure 2 A graph of the plastic deformation of specimens in which charifeldt, an existing flux, is replaced with various types of flux
Figure 3 is a view showing the measured linear shrinkage of the sample after firing according to the present invention
Figure 4 is a view showing the bending strength of the sample after firing according to the present invention
Figure 5 A graph comparing the light transmittance and absorption according to the firing temperature of the quick-fired ceramics for preventing blotting defects of the present invention and the conventional quick-fired ceramics
Figure 6 Detailed view of the crystallinity measuring device of the present invention

The present invention relates to 0.1 to 10 parts by weight of wollastonite, 0.1 to 7 parts by weight of talc, and bone ash, based on 100 parts by weight of basic raw materials composed of 30 to 45% by weight of clay, 25 to 30% by weight of feldspar, and 25 to 40% by weight of silica. 0.1 to 10 parts by weight, 0.1 to 3 parts by weight of frit, and 0.1 to 10 parts by weight of Petalite were mixed to prepare a base composition, and then the base composition was charged into a ball mill to make balls with a diameter of 0.1 mm to 50 It is set in the range of mm, and the rotation speed of the ball mill is 10 to 500 rpm, and after grinding for 1 to 72 hours, it is transferred to the primary storage tank through a transfer device,

The slurry stored in the primary tank is transported to the de-elimination machine using a pump, and the slurry that has passed through the de-elimination unit continuously passes through a vibrating sieve of about 180 mesh and is then transferred to the secondary storage tank, where the moisture content is 50% ~ 60%, and prepare a slurry with a viscosity of 2.0 to 7.0 poise.

After transferring the slurry to a filter press and using it for dehydration treatment, it is prepared in the form of a plate-shaped cake having a moisture content of 21 to 23% by weight,

After transferring the plate-shaped cake to a plowing machine and transferring it to a de-iron machine,

After the deiron treated slurry (plate-shaped cake) is molded into ceramics using a semi-automatic or fully automatic molding machine (ATM), the dried ceramics are unglazed in a shuttle kiln at a temperature of 750 to 850 ° C. for 5 to 15 hours After cooling to room temperature, a transparent glaze is coated on the surface of the pottery, dried for 1 to 2 hours, transferred to a rapid firing furnace, fired at a temperature of 1200 to 1300 ° C for 1 to 5 hours, and then cooled to room temperature. It is characterized by manufacturing.

In addition, the pottery of the present invention is prepared by adding talc, wollastonite, bone ash, FRIT, and phyllodes to a basic base composition containing clay, feldspar, and silica, and using various types of additives It can be mixed and used to have properties.

Since the physical properties of ceramics can be greatly changed by the substances added, the firing of ceramics has been a research subject in the field of ceramics for a long time. In particular, many studies have been conducted to produce thin and lightweight products while maintaining appropriate strength in modern life patterns where miniaturization and light weight are emphasized. However, most research efforts have been focused on improving product properties through process optimization. That is, by improving the uniformity of the clay slurry or plastic body to prevent defects in the molded body or by adjusting the firing temperature and time to control the shape formation in the body, the strength of the product is improved. improvement is realized.

The present invention proposes a ceramic body composition for rapid firing, which can significantly reduce blotting defects, sufficiently magnetize, and produce ceramics with excellent oil surface, and a method for manufacturing ceramics using the same.

The substrate composition required for producing ceramics can be largely classified into three types. First of all, refractory crystals that act as a skeleton to prevent ceramics from collapsing even at high temperatures

It is a cristalline raw material, a plastic raw material that forms the shape of ceramics, and a flux that stabilizes and connects substances that change at high temperatures.

Silica stone is a typical refractory crystalline raw material, clay is a plastic raw material, and feldspar is a typical fluxing raw material.

The substrate is manufactured using clay-feldspar-silica raw materials, and the components constituting these raw materials are SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , K ₂ O, Na ₂ O, MgO, etc. The role in is as follows:

Components serving as a skeleton of a ceramic substrate include SiO ₂ and Al ₂ O ₃ . Silica is usually used as a natural raw material for SiO ₂ , which improves whiteness and light transmittance in addition to serving as a framework in ceramics. However, SiO ₂ has a very high melting temperature of 1713°C, so if a large amount is added, refractory property is increased, sintering is difficult, and plasticity is also poor.

Al ₂ O ₃ is supplied as raw materials such as feldspar, kaolin and clay. In addition to maintaining the skeleton, the role of Al ₂ O ₃ in the base contributes to widening the firing range and enhancing whiteness by imparting fire resistance to the base.

Components that act as fluxes to lower the firing temperature of ceramic bodies are mainly basic components such as K ₂ O, Na ₂ O, and MgO. Natural raw materials that supply K ₂ O and Na ₂ O include calico feldspar and soda feldspar.

Feldspar is a raw material for ceramics and contains three important components: basic, neutral, and acidic.

Soda feldspar is less viscous than chali feldspar and has a lot of torsion during firing. So, cari feldspar is widely used in substrates, and soda feldspar is widely used as a raw material for glass or glaze.

Because feldspar has a low melting temperature, it is easily melted and physically combines the grains to make them dense, and plays a most important role in the process of firing porcelain, especially by melting kaolin or silica stone during high-temperature firing.

Clay or kaolin existing on earth Nothing is pure. It contains some impurities. There are Fe ₂ O ₃ and TiO ₂ as impurities that show color development or spots in the substrate, and among them, Fe ₂ O ₃ is contained in any natural raw material for ceramics.

Fe ₂ O ₃ has a great effect on the color of the ceramic substrate, so the color of the flame changes depending on whether it is an oxidizing salt or a reducing salt. The higher the Fe ₂ O ₃ content, the darker the color, and appear as black spots on ceramics after firing. The lower the alkali or alkaline earth metal oxide content, the greater the fire resistance.

Fe ₂ O ₃ is known to be a harmful impurity that lowers the sintering temperature to some extent and lowers the whiteness of the material by affecting the sintering temperature. Since it lowers the whiteness quality of the substrate, it is an impurity that can help productivity.

The main fluxing agent for white porcelain is feldspar. In order to make the substrate, the raw material used must have sufficient refractory to maintain the shape of the product, develop crystals, and melt sufficiently to form a glass phase.

The clay used in the body composition of the present invention has excellent plasticity and high alumina content in the clay, so it contains a large amount of bentonite, SiO ₂ and Al ₂ O ₃ , which have high refractory properties, and Taebaekdo stone, which has relatively good plasticity, was used, and the whiteness New Zealand kaolin with low impurities and excellent light transmittance was used to increase the .

In order to fix kaolin clay and change feldspar and silica, a test was conducted to fix feldspar and silica and change New Zealand kaolin, which has low impurities and good light transmission, to increase whiteness in the substrate. Thereafter, the mixture was dissolved and combined in a gel-like manner, and each raw material was wet-mixed using a self-made pot mill.

The pottery of the present invention is prepared by adding calcined talc, wollastonite, bone ash, FRIT, and phyllodesite to a base composition containing clay, feldspar, and silica. Various types of additives may be used and mixed to have required properties. The physical properties of ceramics can be greatly changed by the substances added.

The body composition for quick-fired ceramics according to a preferred embodiment of the present invention,

0.1 to 5 parts by weight of talc, 0.1 to 10 parts by weight of wollastonite, 0.1 to 10 parts by weight of bone ash, based on 100 parts by weight of basic raw materials composed of 30 to 45% by weight of clay, 10 to 30% by weight of feldspar, and 25 to 40% by weight of silica stone. It can be seen that it is composed of 0.1 to 3 parts by weight of FRIT and 0.1 to 10 parts by weight of pyrophyllite.

Clay provides plasticity to the base composition during the molding process and enables it to maintain sufficient molding strength to withstand processes such as movement or decoration of molded ceramics.

In addition, by forming a mullite phase and a glass phase in the base composition after firing, it contributes to making the base have white light transmittance while maintaining sufficient strength in the use environment. Considering this point, it is preferable that clay is contained in an amount of 30 to 45% by weight in basic raw materials including clay, feldspar and silica.

Feldspar starts to melt at a relatively low temperature and acts as a flux that melts raw materials such as silica. Since feldspar contains a lot of K2O and Na2O as alkaline components, increasing the content of feldspar promotes melting and lowers the melting point, enabling firing at a lower temperature. However, when the content of feldspar is increased, since the viscosity of the raw material decreases during firing, the amount of plastic deformation of the base material due to stress such as its own weight increases during firing. That is, when a large amount of feldspar is contained, plastic deformation due to softening increases as the firing of the ceramic body composition progresses. Considering this point, it is preferable that feldspar is contained in an amount of 10 to 30% by weight in basic raw materials including clay, feldspar and silica.

Silica stone increases the whiteness of ceramics and maintains the skeleton of ceramics. Silica is preferably contained in an amount of 25 to 40% by weight in basic raw materials including clay, feldspar and silica.

If the content of silica stone is less than 25% by weight, the whiteness of ceramics may be lowered, and if the content of silica stone exceeds 40% by weight, there is a limit to obtaining ceramics with desired strength.

The talc (Calcined talc) may act as a fluxing agent, and may serve to increase the light transmittance of the ceramic body composition and reduce the firing shrinkage rate. Talc is preferably contained in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the base material.

The wollastonite (Woolastonite) may act as an auxiliary flux and may serve to enhance the light transmittance of the ceramic body composition. Wollastonite is preferably contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the basic base material.

The bone ash may act as a fluxing agent, increase the light transmittance of the self-supporting composition, and reduce the firing shrinkage rate. Bone ash is preferably contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the basic base material.

The frit (FRIT) can act as a strong auxiliary flux, increase the light transmittance of the ceramic body composition, and increase the amount of plastic deformation. Preferably, 0.1 to 3 parts by weight of frit is contained in the ceramic body composition for quick firing based on 100 parts by weight of the basic body raw material.

The petalite is a material with excellent heat resistance. When used at high and normal temperatures, a temperature gradient occurs within the material, and thermal stress generated from such a temperature change can destroy the material. It is preferable to contain 0.1 to 10 parts by weight based on 100 parts by weight of the ceramic base composition.

In general, when these rocky raw materials are used as they are, there is a limit to lowering the firing temperature. Therefore, raw materials such as feldspar and silica are pulverized to 100 micrometers (μm) or less (1 to 100 μm) in order to manufacture ceramics for rapid firing with good magnetization using these base compositions.

When the raw material powder is pulverized in order to reduce the amount of plastic deformation, the deformation during firing is reduced.

When these raw materials are pulverized, not only thermal deformation but also firing temperature can be lowered, which is advantageous for energy saving. When the firing composition of ceramics is pulverized and pulverized and charged separately, the density increases in the molding step, the firing density can be increased, the water absorption is reduced, and the firing temperature is lowered. As a method of pulverizing feldspar, silica, etc. used as a starting material for ceramics, various grinding methods such as dry or wet ball milling and milling media may be used.

Hereinafter, the grinding process by the ball milling method will be described in detail.

The fired composition is loaded into a ball mill and wet-mixed with a solvent. The solvent may be water, alcohol or the like. By rotating at a constant speed using a ball mill, the fired composition is mechanically and chemically ground and mixed uniformly. Balls made of ceramics such as alumina and zirconia may be used for ball milling, and all balls may be of the same size or balls having two or more sizes may be used together. The ball size, milling time, and rotation speed per minute of the ball mill are adjusted to grind to the target particle size. For example, considering the size of the particles, the rotational speed of the ball mill may be set in the range of about 10 to 500 rpm. Ball milling is performed for 1 to 72 hours in consideration of the target particle size.

By ball milling, the starting material is pulverized into fine-sized particles, has a uniform particle size distribution, and is uniformly mixed.

A dehydration process is performed on the starting material in a slurry state. After dehydration using a filter press, the mixture is mixed with a kneading machine. Before the dehydration process, a process of deironizing with a deironizer may be performed in order to remove iron (Fe) contained in the starting material. A generally known method may be used for the iron removal process, and a description thereof is omitted here.

In general, glaze refers to a vitreous lye applied to thinly coat and adhere to a molded and baked substrate when ceramics are manufactured.

The purpose of glazing is not only to make the product beautiful by giving a gloss to the surface, but also to add strength and to make the surface shiny to prevent it from getting dirty. It is also helpful in the practical aspect of increasing resistance to water by removing absorbency.

As for the properties of the glaze, the coefficient of thermal expansion should be almost the same as that of the base material, and the melting point should be lower than that of the base material. It must melt and flow well when the glaze is applied to pottery and baked, forming a thin glass film on the surface by adhering to the substrate. When the glaze does not match the expansion and contraction of the material, peeling or cracking occurs. These cracks are called guanyu (貫乳), and there are ceramics that use them as decorations.

Glazes are generally transparent, but there are milky white, colored, crystallized, unsalted, and cracked glazes.

The composition of the glaze differs in combination and composition according to the firing temperature and soil quality, and is generally classified into porcelain oil and pottery oil. The main component is a silicate compound, and as a raw material used, it is fired at a high temperature (1,200 ~ 1,500 ℃) like porcelain, and there are feldspar, quartz, limestone, kaolin, etc. ) Kaolin, borax, feldspar, limestone, etc. are used for firing. To add color, metal oxide compounds such as iron, copper, and cobalt are mixed.

Glaze is a thin vitreous film fused to the surface of a pottery base, and is generally a mixture of homogeneous silicates. The glaze is hard, does not dissolve in strong acid or strong alkali, or dissolves in very small amounts, and is impermeable to gas and liquid. Depending on the glaze applied, the glaze surface has various effects such as color, texture, light transmission, and degree of gloss.

The glaze used in the present invention used transparent oil.

Transparent glaze is a glaze in the form of transparent crystals, allowing light to pass through the glaze and reach the substrate. Because of its excellent light transmittance, it is used to express the unique color or texture of pottery or substrate colored with color slip or pigment. Since the glaze is also affected by the component oxides in the substrate, transparent glaze is easy to grasp the changed appearance characteristics and color due to the reaction with the glazed substrate.

As for the transparent oil, Indian feldspar, domestic limestone, zinc oxide, Chinese kaolin, domestic silica stone, and wood clay were used in the composition.

A method for manufacturing by firing ceramics molded from the dried body composition is as follows.

For firing, the molded pottery is unglazed in a shuttle kiln for 5 to 15 hours at a temperature of 750 to 850℃ with the primary heating, cooled to room temperature, coated with a transparent glaze on the surface of the pottery, and then dried for 1 to 2 hours. After this, it is transferred to a rapid firing furnace for secondary heating, fired at a temperature of 1200 to 1300 ° C. for 1 to 5 hours, and then cooled to room temperature. The firing is preferably carried out in an oxidizing atmosphere (eg, oxygen (O 2 ) or air (air) atmosphere).

The present invention will be described in more detail through the following examples.

<Example 1>

A base material was prepared by mixing 30 g of clay, 30 g of feldspar, and 40 g of silica, and 0.1 g of talc, 0.1 g of wollastonite, 0.1 g of bone ash, 0.01 g of frit, and 0.1 g of phyllodes were mixed with the base material to prepare a base composition. ,

After loading the body composition into a ball milling machine, the size of the ball is set in the range of 0.1 mm to 50 mm in diameter, and the rotational speed of the ball mill is 10 to 500 rpm for 1 to 72 hours, then the transfer device It is transferred to the primary storage tank through

The slurry stored in the primary tank is transported to the de-elimination machine using a pump, and the slurry that has passed through the de-elimination machine continuously passes through a vibrating sieve of about 180 mesh and is then transferred to the secondary storage tank so that the moisture content is 50% to 60%. %, and prepare a slurry with a viscosity of 2.0 ~ 7.0 poise.

After transferring the slurry to a filter press and using it for dehydration treatment, it is prepared in the form of a plate-shaped cake having a water content of 21 to 23% by weight (viscosity measurement is impossible in a state close to solid after dehydration), The plate-shaped cake is transferred to a plowing machine and transferred to a de-iron machine to de-iron, and then the de-iron treated slurry (plate-shaped cake) is molded into ceramics using a semi-automatic or fully automatic molding machine (ATM), and then dried. The ceramics are unglazed in a shuttle kiln at a temperature of 750-850℃ for 5-15 hours, cooled to room temperature, coated with transparent glaze on the surface of the ceramics, dried for 1-2 hours, and then transferred to a rapid firing furnace. After firing at a temperature of 1200 to 1300 ° C. for 1 to 5 hours, it was cooled to room temperature to manufacture ceramics.

<Example 2>

45 g of clay, 30 g of feldspar, and 25 g of silica were mixed to prepare a base material, and then 10 g of wollastonite, 5 g of talc, 10 g of bone ash, 3 g of frit, and 10 g of phyllodes were mixed with the base material to prepare a base composition,

The ball milling composition is loaded into a ball milling machine, the size of the ball is set in the range of 0.1 mm to 50 mm in diameter, and the rotational speed of the ball mill is 10 to 500 rpm for 1 to 72 hours. It is transferred to the primary storage tank through

The slurry stored in the primary tank is transported to the de-elimination machine using a pump, and the slurry that has passed through the de-elimination machine continuously passes through a vibrating sieve of about 180 mesh and is then transferred to the secondary storage tank so that the moisture content is 50% to 60%. %, and prepare a slurry with a viscosity of 2.0 ~ 7.0 poise.

After transferring the slurry to a filter press and using it for dehydration treatment, it is prepared in the form of a plate-shaped cake having a water content of 21 to 23% by weight (viscosity measurement is impossible in a state close to solid after dehydration),

The plate-shaped cake is transferred to a plowing machine and transferred to a de-iron machine to de-iron, and then the de-iron treated slurry (plate-shaped cake) is molded into ceramics using a semi-automatic or fully automatic molding machine (ATM), and then dried. The ceramics are unglazed in a shuttle kiln at a temperature of 750-850℃ for 5-15 hours, cooled to room temperature, coated with transparent glaze on the surface of the ceramics, dried for 1-2 hours, and then transferred to a rapid firing furnace. After firing at a temperature of 1200 to 1300 ° C. for 1 to 5 hours, it was cooled to room temperature to manufacture ceramics.

<Example 3>

40 g of clay, 25 g of feldspar, and 35 g of silica were mixed to prepare a base material, and then 5 g of wollastonite, 7 g of talc, 1 g of bone ash, 0.5 g of frit, and 5 g of phyllodes were mixed with the base material to prepare a base composition,

The ball milling composition is loaded into a ball milling machine, the size of the ball is set in the range of 0.1 mm to 50 mm in diameter, and the rotational speed of the ball mill is 10 to 500 rpm for 1 to 72 hours. It is transferred to the primary storage tank through

The slurry stored in the primary tank is transferred to the iron desorber using a pump, and the slurry that has passed through the iron desorber is continuously passed through a vibrating sieve of about 180 mesh and then transferred to the secondary storage tank so that the moisture content is 50% ~ 60%, and prepare a slurry with a viscosity of 2.0 to 7.0 poise.

The slurry is transferred to an extrusion filter (filter press) and dehydrated using it to prepare a cake in the form of a plate having a water content of 21 to 23% by weight (viscosity measurement is impossible in a state close to solid after dehydration). The plate-shaped cake is transferred to a plowing machine and transferred to a de-iron machine to de-iron, and then the de-iron treated slurry (plate-shaped cake) is molded into ceramics using a semi-automatic or fully automatic molding machine (ATM), and then dried The ceramics are unglazed in a shuttle kiln at a temperature of 750-850℃ for 5-15 hours, cooled to room temperature, coated with transparent glaze on the surface of the ceramics, dried for 1-2 hours, and then transferred to a rapid firing furnace. After firing at a temperature of 1200 to 1300 ° C. for 1 to 5 hours, it was cooled to room temperature to manufacture ceramics.

<Experimental example>

1. Glaze used in the experiment

Glaze is a thin vitreous film fused to the surface of a pottery base, and is generally a mixture of homogeneous silicates. The glaze is hard, does not dissolve in strong acid or strong alkali, or dissolves in very small amounts, and is impermeable to gas and liquid. Depending on the glaze applied, the glaze surface has various effects such as color, texture, light transmission, and degree of gloss.

Transparent glaze is a glaze in the form of transparent crystals, allowing light to pass through the glaze and reach the substrate. Because of its excellent light transmittance, it is used to express the unique color or texture of ceramics or substrates colored with ColorSlip or pigment. Since the glaze is also affected by the component oxides in the substrate, the transparent glaze is easy to grasp the changed appearance characteristics and color due to the reaction with the glazed substrate.

As for the transparent oil, Indian feldspar, domestic limestone, zinc oxide, Chinese kaolin, domestic silica stone, and wood clay were used in the composition.

2. Sample fabrication and firing

In order to analyze the physical and mechanical properties such as shrinkage, water absorption, and flexural strength of the combined body composition, samples were produced as in the example by molding into a bar type of 5.0 × 0.8 × 0.8cm using a gypsum mold.

In addition, in order to compare the hot load of the body composition, a sample of 13.0 × 3.0 × 1.0 cm was prepared by the same method as in Example. The molded sample was oxidized, and the plastic deformation graph at this time is shown in FIG. Oxidation firing was carried out by setting the maximum firing temperature at room temperature to 1250 ° C in Lindburg Electric Kiln, raising the temperature at 15 ° C / min from room temperature to 600 ° C, and at 20 ° C / min from 600 ° C to 1250 ° C, the firing temperature. It was maintained for 30 minutes at the highest firing temperature and then cooled naturally.

3. Physical property test

The particle size distribution of the body composition used in the present invention was confirmed. The important properties of clay are formability, drying strength, drying shrinkage, firing shrinkage, refractory degree, load softening temperature and firing color. In general, the finer the particles of the body composition, the better the plasticity. However, if there are many fine particles, the shrinkage rate increases, causing cracks and slowing down the drying rate.

In addition, in order to increase the dry strength, the particle size composition should be suitable in addition to the amount of fine particles.

In this way, the particle size and its distribution state are factors that determine the basic characteristics of the substrate. Particle size was analyzed using a MALVERN Mastersizer 2000 particle size analyzer device.

4. Plasticity measurement

The Pfefferkorn method consists of an iron bar and a disc with a diameter of 186 mm. These weights are a total of 1192 g, and they are dropped from a height of 186 mm on a specimen with a diameter of 33 mm and a height of 40 mm, so that the height is the ratio of the initial test specimen (h ₀ ) 40 mm and the length of the specimen after falling (h ₁ ) ( h ₀ /h ₁ ) This is a method that uses water at 3.3 as the plasticity value. It is relatively used in the field of ceramics, but it is a test method that requires the skill of the tester.

5. Pyro plasticity

The crystallinity measurement measures the amount of plastic deformation, and is measured as shown in FIG. 6 for the purpose of accurately understanding the hot deformation characteristics occurring during firing of the substrate.

After aligning the samples side by side and placing them as shown in FIG. 6, visually read the X value to the first decimal place using graph paper.

6. Whiteness measurement (L*, a*, b*)

To measure the degree of color using a colorimeter to quantitatively evaluate the degree of color of a substance, a colorimeter is a device designed for color measurement such as an optical system, sensor, and program to measure color. An optical system is generally a lighting device made of an integrating sphere In other words, the diffused illumination made in the integrating sphere is irradiated onto the surface of the sample, and the light reflected from the surface is read by the sensor of the absorbance photometer.

For chromaticity measurement, there are measurement standards such as diffuse illumination or unidirectional illumination, not illumination methods such as single beam or double beam of a general spectrophotometer.

In addition, in order to display the received information in chromaticity units, there is a built-in formula that integrates the spectral information and expresses it as color coordinates such as L*, a*, b* or L*, C*, h*. Calculate in the program and show the result.

7. Thermal shock resistance measurement

After heating to a certain temperature, and then rapidly cooling, injecting color ink,

Measure how much you can tolerate while changing the temperature difference.

The thermal shock resistance test method measures the firing body in an oven and widens the temperature difference with the water bath.

In the temperature difference 130℃ test, if the temperature of the water in the water tank is 20℃, the fired body is heated up to 150℃ in the oven and rapidly cooled in the water in the water tank. Afterwards, apply colored ink to see if any cracks have occurred and check for cracks.

Table 1 shows the results of the experiment while gradually increasing the temperature difference.

Temperature difference (℃) △T130 △T140 △T150 △T160 crack occurrence
(existence and nonexistence) radish radish radish you

8. Thermal Expansion Coefficient Measurement

The thermal expansion coefficient was measured by adjusting the thermal expansion coefficient difference between the substrate and the glaze to less than 10%.

In ceramics, the thermal expansion behavior of the substrate and the glaze is a very important factor for ceramic cracking, and the measurement of thermal expansion is performed when the material is applied in combination with other materials or when the application temperature is not constant and changes even in the case of a single-phase material. It was usefully used to predict the stress applied to

Accordingly, the sample to be measured was processed into a cylindrical shape having a diameter of φ5 to 6 mm and a length of 50 mm, and then the thermal expansion coefficient was measured by heating at a rate of 10° C./min.

9. Measurement of linear shrinkage

The shrinkage rate of the body composition was measured according to Korean Industrial Standards KS L 4004. After molding the body composition, a shrinkage confirmation line having a size of 10 cm was marked in the direction of the long axis of the specimen.

The marked samples are pre-dried for 24 hours at 20-40 °C on a drying rack. At this time, in order to prevent distortion of the sample, the sample was rotated by 90° at intervals of about 2 hours.

The pre-dried sample is dried in a dryer at 110° C. for 24 hours. The dried samples were calcined at 900 ° C and 1250 ° C, respectively, and the length of the shrinkage line marked on the specimen was measured to 0.05 cm using a vernier caliper, and the average value of the three specimens was obtained.

10. Measure the strength of the tune

The sample was made using a gypsum mold with a diameter of 10 mm, dried at 110 ° C for 24 hours, cooled from room temperature to room temperature in a desiccator, measured with a bending strength meter, and substituted into the formula below save The size of the plastic strength specimen is the same.

Flex strength (Kg/cm ² ) =

p = breaking load (kgs)

L = distance between supports (cm)

d = rod diameter (cm)

11. Light transmittance measurement

The spectrophotometer passes light through a solid sample to be measured using a wavelength range of 240 nm to 2600 nm after selecting the required wavelength range through a high-performance monochromatic light device, and using the principle that reflection occurs while passing the light through the solid sample, the absorption and transmittance of the solid sample , reflectance, diffuse reflectance, etc., so it is essential equipment used for test analysis of physical property research of solid samples in the field of optical materials.

ceremony. Transmittance calculation formula

The raw materials according to each example were combined after performing a residue rate test manually with a MALBERN particle size analyzer, and the chemical composition of the raw materials used is shown in Table 2.

In addition, the base composition is shown in Table 3., and the results of ceramic properties according to each base composition are shown in Table 4.

Chemical composition of raw materials division SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO _K2O TiO ₂ Na ₂ O Li ₂ O P ₂ O ₅ L.O.I clay 50.2 35.8 0.28 0.07 0.06 0.05 0.08 0.06 Tr Tr 12.8 feldspar 65.9 18.8 0.07 0.09 0.09 11.4 0.02 3.03 Tr Tr 0.30 burr 99.5 0.10 0.03 0.01 0.01 0.01 0.02 0.01 Tr Tr 0.35 wollastonite 50.0 0.76 0.15 47.0 0.16 0.08 Tr 0.02 Tr Tr 1.02 talc 64.4 0.40 0.20 0.20 33.4 0.02 Tr 0.03 Tr Tr 1.35 bone hoe 2.1 0.08 0.06 52.9 1.13 0.02 0.01 0.52 Tr 39.8 3.38 Purit 51.6 14.5 0.15 16.6 5.00 1.60 0.15 Tr Tr Tr 0.50 phyllate 77.3 17.1 0.05 Tr Tr 0.18 Tr 0.37 4.01 Tr 1.99

The unit of content in Table 2 is % by weight, and trace amounts are included.

The most important problems in fast firing are body blotting, pinholes and blistering in the oil surface caused by gases generated during the decomposition reaction by impurities and Ig.Loss. The selection of alkali raw materials is important because factors causing defects must be removed and magnetization must be performed in a short time.

What is important in the selection of the body composition for rapid firing is as follows.

1) A raw material with a small number of possible absorption water crystals

2) Raw materials with good plasticity

3) Raw materials with low impurities such as sulfur and iron compounds

4) Raw materials with low organic substances such as carbon, carbonate, and carbonaeus

5) Strong alkali raw material (alkaline earth metal oxide raw material that can act as a strong fluxing agent)

body composition division clay feldspar burr wollastonite talc bone hoe frit phyllate Example 1 30 30 40 0.1 0.1 0.1 0.01 0.1 Example 2 45 30 25 10 5 10 3 10 Example 3 40 25 35 5 7 One 0.5 5 Comparative Example 1 32 30 38 0 0 0 0 0 Comparative Example 2 34 23 35 0 0 0 0 0

<Experiment result>

The degree of blotting defects, brightness, water absorption, linear shrinkage, light transmittance, whiteness, bending strength, plasticity, coefficient of thermal expansion and thermal shock resistance of the ceramics of each Example and Comparative Example described in Table 3 were measured and are shown in Table 4.

Characteristics of ceramics according to base composition division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Bloating defect degree ○ ○ ○ △ X Flower degree (m/m) 5.0 7.8 6.5 4.0 3.3 Absorption rate (%) 0.06 0.06 0.06 0.23 1.02 Line shrinkage (%) 11.3 11.7 11.6 11.4 10.5 Transmittance (%) 85 90 88 80 50 Whiteness (with or without) 92 90 91 92 92 Bending strength (kg/cm2) 1,065 972 950 991 864 Plasticity (%) 27.5 26.8 26.5 27.4 27.2 Coefficient of thermal expansion (× 10 ^-6 /℃) 7.52 7.48 7.50 7.46 7.40 Thermal shock resistance (with/without cracks) radish radish radish radish radish

1) Degree of blotting defects

The degree of blotting defects was judged as good (○), normal (Δ), and poor (X) through visual observation.

In Example 1, Example 2, and Example 3, no blotting defect occurred, and the oil level was good. However, in Comparative Example 1, a small amount of blotting defects occurred, and in Comparative Example 2, a lot of blotting defects occurred, resulting in a very poor oil level.

2) Slump

In Example 1, Example 2, and Example 3, the crystallinity was lowered (value increased) according to the increase in alkali content. In particular, in the case of Examples 2 and 3, it is difficult to use them in production sites because the curing degree is too low and causes distortion defects (especially floor sagging) due to deformation of the utensils during firing. On the other hand, in Comparative Example 1 and Comparative Example 2 having a small alkali content, both showed a high degree of crystallinity (decreased value). This indicates that the change in alkali content has a very large effect on the conversion rate of the body composition.

3) Water Absorption

Water absorption was measured after boiling in a water heating bath for 3 hours. The result is shown in FIG. 5 .

The absorptivity showed a value of 0.06% in Example 1, Example 2, and Example 3, and through this result, it can be seen that the magnetization of the body composition was sufficiently achieved. On the other hand, in both Comparative Example 1 and Comparative Example 2, the absorption rate increased, and in particular, in Comparative Example 2, which had a relatively low alkali content, the absorption rate was 1.02%, indicating that almost no magnetization was achieved.

4) Linear Shrinkage

Linear shrinkage was similar in Example 1, Example 2, Example 3 and Comparative Example 1, and did not show a significant difference. On the other hand, in Comparative Example 2, shrinkage was less due to insufficient magnetization. This indicates that sintering or magnetization is a very important factor in rapid firing.

5) Translucency

Light transmittance was expressed on a scale of 100 points as a sensory test. It can be seen that light transmittance is increased in Examples 2 and 3 with a relatively large amount of alkali added compared to Example 1. On the other hand, in Comparative Example 2, there was no light transmittance at all due to insufficient magnetization. The results of light transmittance properties also show that magnetization is a very important factor in rapid firing.

6) Whiteness

Whiteness was measured using a Minolta colorimeter made in Japan.

Example 1, Example 2, Example 3 and Comparative Example 1 and Comparative Example 2 were all similar and did not show a significant difference between each other.

7) Song Strength

Bending strength was measured by a German NETZSCH M.O.R bending strength tester.

In Example 1, Example 2, and Example 3, the bending strength decreased (or increased in value) according to the increase in alkali content. In particular, in the case of Examples 2 and 3, it was found that the bending strength value of the substrate rather decreased as the closed pores increased in the substrate due to excessive magnetization, that is, due to over-firing. In particular, in Comparative Example 2 having a low alkali content, very low bending strength values were exhibited due to insufficient magnetization.

8) Plasticity

Plasticity measurement was measured according to the German industrial standard PFEFFERKORON method.

Example 1, Example 2, Example 3 and Comparative Example 1 and Comparative Example 2 were all similar and did not show a significant difference between each other. As the amount of clay decreased, the plasticity value also decreased.

9) Coefficient of Thermal Expansion (T.E.C)

The thermal expansion coefficient was measured in the range of 40 to 800 ℃ using a thermal expansion coefficient measuring device (NETZSCH, Germany) of a columnar measuring sample having a diameter of 4 mm and a height of 50 mm.

Example 1, Example 2, Example 3 and Comparative Example 1 and Comparative Example 2 were all similar and did not show a significant difference between each other.

The thermal expansion according to the examples was slightly higher than that of the conventional ceramics of the comparative examples. This is due to the formation of a little glassy formation in the pottery, and the peculiarity is that the expansion rate at 500℃~650℃ was relatively safe. This meant that the amount of free silica was small.

10) Heat shock resistance

The thermal shock resistance test was carried out by applying transparent oil to an 8" inch dish at 1250℃ for 130 min. After firing under the conditions, quenching was carried out in room temperature water at 180 ° C.

Overall, it was stable up to 160 °C. However, in Comparative Example 2, it was unstable at 170 ° C. However, all the body compositions were found to be stable up to 170 ℃.

Referring to the accompanying drawings, FIG. 1 is a firing curve graph showing a firing temperature range according to firing time, and FIG. 2 is a graph of plastic strain of specimens in which calyfeldt, an existing flux, is substituted with various types of fluxes. , Figure 3 is a view showing the measured linear shrinkage of the sample after firing according to the present invention, Figure 4 is a view showing the bending strength of the sample after firing according to the present invention, Figure 5 is a quick-fired ceramics for preventing blotting defects according to the present invention It can be seen that FIG. 6, a graph comparing light transmittance and absorption according to the firing temperature of conventional quick-fired ceramics, shows a detailed view of the crystallinity measuring device of the present invention.

Claims (5)

0.1 to 10 parts by weight of wollastonite, 0.1 to 7 parts by weight of talc, and 0.1 to 10 parts by weight of bone ash with respect to 100 parts by weight of basic raw materials composed of 30 to 45% by weight of clay, 25 to 30% by weight of feldspar, and 25 to 40% by weight of silica. A ceramic body composition for preventing blotting defects, characterized in that it is composed of 0.1 to 3 parts by weight of frit and 0.1 to 10 parts by weight of Petalite. According to claim 1,
By charging the body composition into a ball milling machine, the size of the ball is set in the range of 0.1 mm to 50 mm in diameter, and the rotational speed of the ball mill is 10 to 500 rpm and pulverized for 1 to 72 hours. A body composition for ceramics for preventing blotting defects. 0.1 to 10 parts by weight of wollastonite, 0.1 to 7 parts by weight of talc, and 0.1 to 10 parts by weight of bone ash with respect to 100 parts by weight of basic raw materials composed of 30 to 45% by weight of clay, 25 to 30% by weight of feldspar, and 25 to 40% by weight of silica. Preparing a body composition by mixing 0.1 to 3 parts by weight of frit and 0.1 to 10 parts by weight of phyllate;
The body composition is charged into a ball mill, the ball size is set in the range of 0.1 mm to 50 mm in diameter, and the rotational speed of the ball mill is 10 to 500 rpm for 1 to 72 hours, and the ball mill is ground through a transfer device to the primary storage tank. transferring;
The slurry stored in the primary tank is transferred to the iron desorber using a pump, and the slurry that has passed through the iron desorber is continuously passed through a vibrating sieve of about 180 mesh and then transferred to a secondary storage tank;
Transferring the slurry to an extrusion filter and dehydrating the slurry to prepare it in the form of a plate-shaped cake having a water content of 21 to 23% by weight;
Transferring the plate-shaped cake to a plowing machine, transferring it to an iron de-iron machine, de-ironing, and then molding the de-iron-treated slurry (plate-shaped cake) into ceramics using a semi-automatic or fully automatic molding machine (ATM);
Method of manufacturing ceramics using a base composition for preventing blotting defects, characterized in that comprising: unglazing the molded ceramics, cooling them to room temperature, coating the surface of the ceramics with a transparent glaze, drying them, and cooling them to room temperature. . According to claim 3,
The molded ceramics are unglazed in a shuttle kiln at 750 to 850 ° C for 5 to 15 hours, coated with a transparent glaze on the surface of the ceramics, dried for 1 to 2 hours, and then transferred to a rapid firing furnace to be heated at 1200 to 1300 ° C. A method for producing ceramics using a body composition for preventing blotting defects, characterized in that it is fired at a temperature for 1 to 5 hours. According to claim 3,
The water content of the body composition transferred to the secondary storage tank is 50% to 60%, and the viscosity is 2.0 to 7.0 poise. A method of manufacturing ceramics using a body composition for preventing blotting defects, characterized in that the slurry is prepared.

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