WO2012003792A1

WO2012003792A1 - Medium-low temperature sintered fine bone china and manufacturing method thereof

Info

Publication number: WO2012003792A1
Application number: PCT/CN2011/076837
Authority: WO
Inventors: 江伟辉; 苗立锋; 包镇红; 谭训彦; 虞澎澎; 刘健敏; 朱庆霞
Original assignee: 景德镇陶瓷学院
Priority date: 2010-07-08
Filing date: 2011-07-05
Publication date: 2012-01-12
Also published as: GB2494568B; CN101891455A; GB2494568A; CN101891455B

Abstract

The present invention relates to a medium-low temperature sintered fine bone china and a manufacturing method thereof. The chemical composition of the china is: SiO₂ 52–60%, Al₂O₃ 28–37%, K₂O 1–4%, Na₂O 1–2%, CaO 3–8%, MgO 1–3%, and P₂O₅ 1–3%; the materials used are: bone ash 3–8%, kaolin 32–45%, aluminum oxide 10–20%, and frit 35–50%, while the sintering temperature is between 1170°C–1250°C. A "high temperature bisque firing, low temperature glaze firing" or a "low temperature bisque firing, high temperature glaze firing" dual pass firing technique can be used; a high temperature single pass firing technique can also be used. The fine bone china of the present invention has the visual effect of traditional bone china, improved physical and chemical properties over bone china, and the advantages of a lower bone char usage and a lower firing temperature to enable lower production costs and energy consumption.

Description

Medium and low temperature sintered bone china and production method thereof

Technical field

The invention belongs to the technical field of daily-use ceramics manufacturing, and particularly relates to a medium-low temperature sintered bone china and a production method thereof.

Background technique

Bone china is a kind of soft porcelain invented by British people in the 18th century. It is mainly made of bone carbon. It is added with mineral materials such as clay, feldspar and quartz. It is burnt with high temperature (1250 ° C ~ 1280 ° C) and low temperature glaze. (1100 ° C ~ 1150 ° C) secondary firing process is fired. Bone china has outstanding advantages such as high whiteness, good transparency and fine porcelain. It is recognized as a high-grade daily-use fine porcelain. In the 1970s, China studied and developed some bone china products. After the 1980s, China's Tangshan, Zibo, Jingdezhen and Chaozhou regions successively carried out mass production.

However, bone china also has some inherent disadvantages: 1) poor thermal stability, the national standard for thermal stability of bone china is 140 ° C ~ 20 ° C heat exchange once crack, far lower than daily fine porcelain 180 ° C ~ The standard of heat exchange at 20 °C is not caused by the high thermal expansion coefficient of the main crystal phase calcium phosphate and anorthite of bone china; 2) the range of firing is narrow, because the composition of bone china is located The ternary minimum eutectic point (1290 ° C) of tricalcium phosphate, anorthite and quartz. When the temperature is lower than the lowest eutectic point, the amount of liquid in the porcelain blank is small, the product cannot be sintered, and the temperature reaches or exceeds the lowest eutectic point. At the same time, a large amount of liquid phase is generated at the same time, which causes the product to be easily softened and deformed. Therefore, it is difficult to control the firing. This is also the case that the bone china usually has to be subjected to a secondary firing process (high temperature gas burning and low temperature glaze burning through a profiled concrete). 3) The glaze hardness is low, the root source is the frit glaze suitable for low temperature glaze burning; 4) the billet cost is high, the amount of bone carbon in the traditional bone china billet is generally 40-60%, due to the use The high price of bone carbon leads to the cost of bone china billet Stubbornly high. With the expansion of China's bone china production scale, the demand for bone carbon continues to rise, leading to tight bone carbon supply and rising prices, which directly affects the further development of bone china.

Therefore, reducing the amount of bone carbon in bone china billets and developing new porcelains with the appearance of bone china is a strategic choice for the development of bone china. In the 1980s, Japanese ceramic workers used part or not even using bone carbon to develop ceramic products with an appearance quality close to that of bone china. These products have good transparency and soft color and are called "new bone china". Since the 1990s, China has gradually developed research and development of such products. There are two technical routes that are commonly used to reduce bone carbon consumption. One is to use natural apatite as a raw material instead of bone carbon. CN1072916A discloses a process for producing bone ash porcelain by using apatite, which replaces bone carbon with apatite, adopts traditional high temperature smoldering (1240 ° C ~ 1260 ° C), low temperature glaze firing twice, and its formulation composition It is: 35 to 60% of apatite, 2 to 5% of talc, 10 to 15% of quartz, and 8 to 13% of feldspar. Another technical route to reduce bone carbon usage is to increase quartz, porcelain, and alumina to reduce bone carbon usage. ZL95112612.1 discloses a production process of “reinforcing the ashes porcelain”, which achieves a reduction in the amount of bone carbon by substantially increasing the amount of quartz and quartz glass. The composition of the composition is: 5 to 15% of the amount of ashes or apatite, silicon 5 to 15% of limestone, 30 to 40% of quartz, 10 to 20% of quartz glass, 20 to 25% of clay, 1 to 5% of plasticizer, and 1 to 4% of talc. The main crystal phase is α-cristobalite. The secondary phase is β-Ca ₃ (PO ₄ ) ₂ , anorthite and wollastonite, and the firing temperature is 1220 ° C to 1300 ° C. ZL200610031882.3 discloses a "new type of bone ash porcelain and its production method" which uses a large amount of porcelain stone and a small amount of alumina powder, and its formulation composition is: 5-10% of ashes, 25-35% of kaolin, 45~ of porcelain stone 60%, aluminum powder 5-10%, the main crystal phase is mullite, the secondary crystal phase is β-Ca ₃ (PO ₄ ) ₂ and anorthite, and the firing temperature is 1230 ° C ~ 1300 ° C, in the oxidizing flame Burnt. A large number of applications of alumina powder to reduce the amount of bone carbon is a bone-reinforced porcelain disclosed in ZL200610034842.4 and its production process, and its formulation composition is: synthetic bone powder 8-12%, α-alumina powder 20-25%, Longyan 45 to 50% of washing mud, 13 to 15% of Hunan feldspar, 5 to 8% of Guizhou clay, and firing temperature of 1260 ° C to 1280 ° C. CN1210833A discloses a new bone china and a production method thereof: 2 to 10% of ashes are added on the basis of the feldspar porcelain formula, and the firing temperature is 1325 ° C to 1340 ° C.

technical problem

The object of the present invention is to overcome the inherent disadvantages of the existing bone china, and to provide a medium-low temperature sintered bone china and a production method thereof. The invention further reduces the amount of bone carbon by formula design and process optimization, the bone carbon content is only 3 to 8%, and the firing temperature is lowered to 1170 ° C to 1250 ° C, which overcomes the narrow range of the traditional bone china firing temperature and is easy. Disadvantages such as deformation, porcelain has achieved the appearance of bone china, and physical and chemical properties are better than bone china. It is because the bone china of the present invention has a small amount of bone carbon and has good performance, and achieves the goal of "small and fine". Therefore, the bone china of the present invention is also called "fine bone china".

Technical solution

The invention provides a medium-low temperature sintered bone china, characterized in that the chemical composition is by weight: SiO ₂ 52-60%, Al ₂ O ₃ 28-37%, K ₂ O1 ～ 4%, Na ₂ O1 ~2%, CaO 3 to 8%, MgO1 to 3%, P ₂ O ₅ 1 to 3%, and the blank form obtained from the chemical composition of the porcelain blank is as follows:

The main crystalline phase of Jing Gu Porcelain is mullite, and the secondary crystalline phase is anorthite. It not only maintains the good transparency of traditional bone china, fine porcelain, elegant whiteness, but also physical and chemical properties such as thermal stability. The glaze hardness and coefficient of thermal expansion are superior to those of bone china.

The medium and low temperature sintered bone china provided by the invention can adopt the secondary firing process of the traditional bone china "high temperature burning, low temperature glaze burning" or "low temperature burning, high temperature glaze burning", or can be like ordinary daily fine The high-temperature one-time firing process is applied to porcelain, which is characterized in that the raw material formula used is by weight: 3 to 8% of ashes, 32 to 45% of kaolin, 10 to 20% of alumina, 35 to 50% of frit, and the melting used. The chemical composition of the block is: SiO ₂ 75 to 85%, Al ₂ O ₃ 5 to 9%, CaO 3 to 7%, MgO ₂ to 6%, K ₂ O 2 to 4%, Na ₂ O1 to 3%; sintering temperature range is 1170 ° C ~ 1250 ° C.

The formula of bone china blanks given by Li Jiaxuan's "Ceramics Technology" (published by China Light Industry Press, 2001, 1st edition, P98): 20-60% ashes, 8-22% feldspar, 25-45 kaolin %, quartz 9-20%, compared with this, the refined bone china blank formula of the present invention has three outstanding features: one is the use of less ash, the second is to replace quartz with alumina, and the third is to use frit without feldspar Used as a flux.

The addition amount of the alumina powder in the present invention is very critical. If only 5 to 10% of alumina powder is added as in ZL200610031882.3, the modification effect is not good; otherwise, if it is added as in ZL200610031882.3, 20~ 25% alumina powder will not only significantly increase the firing temperature of the green body, but also significantly reduce the light transmission performance of the porcelain blank. As a result, the light transmission effect of the traditional bone china cannot be achieved at all.

The invention introduces 10-20% alumina powder into the blank formula as a modifier, on the one hand, can improve the strength, whiteness and thermal stability of the porcelain tire, on the other hand, it can enlarge the sintering range of the porcelain blank and reduce the green body. High temperature deformation. The Al ₂ O ₃ particles themselves have high strength, and when they are present alone, they can be uniformly distributed in the ceramic tire to enhance the dispersion of the particles, and improve the high temperature deformation resistance of the green body. Part of the Al ₂ O ₃ particles can also react with SiO ₂ produced by dehydration and decomposition of kaolin, resulting in mullite crystals having high mechanical strength and small expansion coefficient, which is very advantageous for improving the strength and thermal stability of the ceramic tire. . Part of the Al ₂ O ₃ particles are dissolved in the liquid phase of the porcelain billet at a high temperature, which can increase the high temperature viscosity of the liquid phase, and is advantageous for enlarging the firing range of the green body.

An outstanding innovation of the present invention is the introduction of a frit in the blank rather than the use of feldspar as a flux. Compared with feldspar, the frit of the present invention has two distinct characteristics in its chemical composition. The first feature is that the SiO ₂ content of the frit is as high as 75-85%, which is much higher than that of the feldspar 63-71%, which makes the high temperature viscosity of the frit of the present invention higher than that of the feldspar melt. It is much higher, and as the temperature increases, the viscosity of the frit changes less than that of the feldspar melt. Therefore, the use of the frit of the present invention as a flux is more advantageous than the application of feldspar to enlarge the firing range of the green body. The high SiO ₂ content frit also plays two important roles in the bone china blank: First, the high silicon frit has a small thermal expansion coefficient, which is beneficial to lowering the thermal expansion coefficient of the bone china and improving the thermal stability of the bone china; Second, the high silicon frit has the advantages of high transparency and high mechanical strength, which is beneficial to improve the transparency and mechanical properties of the bone china. The second characteristic of the frit of the present invention is that the chemical composition of the frit contains both an alkali metal and an alkaline earth metal oxide, and the synergistic fluxing effect of the two can greatly reduce the firing temperature of the green body. Stone acts as a flux, and since feldspar contains only an alkali metal oxide, its fluxing effect is inferior to that of the present invention.

Although the bone carbon content of the bone china of the invention is reduced to 3 to 8%, it can maintain the good transparency of the bone china, the fine porcelain, and the elegant whiteness. If bone carbon is not used at all like CN1072916A, the texture of the porcelain blank is greatly reduced, and as a result, the appearance of the bone china is lost.

The main crystal phase of traditional bone china is β-Ca ₃ (PO ₄ ) ₂ and anorthite. Since the expansion coefficient of the main crystal phase is large, the expansion coefficient of bone china is as high as 8.0-8.5×10 ^-6 /°C. (RT ~ 500 ° C), resulting in poor thermal stability of bone china; the main crystal phase of the bone china of the present invention is mullite, the secondary crystal phase is anorthite, due to the small expansion coefficient of mullite This makes the bone expansion coefficient of the bone china low, the value is 4.5 ~ 5.2 × 10 ^-6 / ° C (RT ~ 500 ° C), therefore, the fine bone porcelain has the advantage of good thermal stability, the bone china 200 The heat exchange at °C ~ 20 °C does not crack once.

Beneficial effect

The medium-low temperature sintered bone china of the invention has three distinct advantages compared with the existing bone china: first, the sintering temperature is low, the sintering temperature ranges from 1170 ° C to 1250 ° C, and can be fired at a high temperature, and the traditional bone quality Compared with the secondary firing process, the sintering range of porcelain 1220 ° C ~ 1280 ° C significantly reduces energy consumption, and is also conducive to improving the service life of the furnace; second, the amount of bone carbon is small, only 3 to 8%. Fine bone porcelain maintains the characteristics of traditional bone china with good transparency, fine porcelain, elegant whiteness, etc., which greatly reduces the raw material cost of bone china, and is of great significance for expanding the production and application of bone china. Third, physical and chemical properties Well, the optimized amount of alumina powder makes the bone china not only good in light transmission, but also superior in mechanical strength and thermal stability to bone china.

BEST MODE FOR CARRYING OUT THE INVENTION

Example 1: Various raw materials were weighed according to the blank formulation: ash of ash, 40% of kaolin, 13% of alumina powder, and 42% of frit. The chemical composition of the billet is: SiO ₂ 56.48%, Al ₂ O ₃ 31.06%, Fe ₂ O ₃ 0.12%, CaO 5.44%, MgO 1.93%, K ₂ O 1.96%, Na ₂ O 0.87%, P ₂ O ₅ 2.13 %, the chemical composition of the frit is: SiO ₂ 80.65%, Al ₂ O ₃ 5.29%, CaO 5.69%, MgO 4.27%, K ₂ O 2.10%, Na ₂ O 1.92%. The above-mentioned raw materials are put into a ball mill, and the ball mill is mixed to the required fineness (the required fineness of the plastic mud is <10 μm, 75 to 80%, and the fineness of the grouting mud is <10 μm, which is about 75). Then, sieving, iron removal, pressure filtration, mud, stale, molding, and then burning at 1190 ° C ~ 1220 ° C, the sintered body is polished and selected, then the frit glaze is applied, and then at 1190 ° C ~ 1220 °C glaze burn, and finally get the bone china. If a single firing process is used, the glaze is applied after the green body is formed, and then fired at a temperature of 1190 ° C to 1220 ° C.

Embodiments of the invention

Example 2: Various raw materials were weighed according to the blank formula: ash 3%, kaolin 43%, alumina powder 17%, frit 37%, and the chemical composition of the billet: SiO ₂ 53.69%, Al ₂ O ₃ 37.07% , Fe ₂ O ₃ 0.13%, CaO 3.29%, MgO 1.12%, K ₂ O 2.40%, Na ₂ O 1.03%, P ₂ O ₅ 1.27%, chemical composition of the frit: SiO ₂ 79.41%, Al ₂ O ₃ 8.10%, CaO 3.87%, MgO 2.64%, K ₂ O 3.33%, Na ₂ O 2.57%. The above-mentioned raw materials are put into a ball mill, and the ball mill is mixed to the required fineness (the required fineness of the plastic mud is <10 μm, 75 to 80%, and the fineness of the grouting mud is <10 μm, which is about 75). Then, sieving, iron removal, pressure filtration, grinding mud, stale, molding, and then firing at 1200 °C ~ 1250 °C, the sintered body is polished and selected, then the frit glaze is applied, and then at 1100 °C ~ 1130 The glaze is burned at °C, and finally the bone china is obtained. If a single firing process is used, the glaze is applied after the green body is formed, and then fired at a temperature of 1200 ° C to 1250 ° C.

[Correct according to Rule 26 29.07.2011] Embodiments of the present invention

Example 3: Various raw materials were weighed according to the blank formulation: ash of ash, 35% of kaolin, 11% of alumina powder, and 47% of frit. The chemical composition of the billet is: SiO ₂ 56.14%, Al ₂ O ₃ 28.00%, Fe ₂ O ₃ 0.12%, CaO 7.12%, MgO 2.33%, K ₂ O 2.15%, Na ₂ O 1.14%, P ₂ O ₅ 2.99 %, the chemical composition of the frit is: SiO ₂ 77.42%, Al ₂ O ₃ 6.74%, CaO 6.15%, MgO 4.72%, K ₂ O 2.57%, Na ₂ O 2.31%. The firing temperature was 1170 ° C to 1200 ° C, and the other production processes were the same as in Example 2.

Industrial applicability

The performance of the fine bone china prepared by the above various examples is as follows:

Claims

A medium-low temperature sintered bone china characterized by a chemical composition of SiO ₂ 52-60%, Al ₂ O ₃ 28-37%, K ₂ O 1-4%, Na ₂ O 1 ～2%, CaO 3 to 8%, MgO 1 to 3%, P ₂ O ₅ 1 to 3%; the main crystalline phase is mullite, and the secondary crystalline phase is anorthite.

2. A method for producing a low-temperature sintered bone china according to claim 1, comprising a secondary firing process using a high temperature sinter, a low temperature glaze or a low temperature sinter, a high temperature glaze, or a high temperature firing The process is characterized in that the raw material formula used is in the weight ratio: 3 to 8% of ashes, 32 to 45% of kaolin, 10 to 20% of alumina, and 35 to 50% of frits, wherein the chemical composition of the frit is: SiO ₂ 75 to 85%, Al ₂ O ₃ 5 to 9%, CaO 3 to 7%, MgO 2 to 6%, K ₂ O 2 to 4%, Na ₂ O 1 to 3%; sintering temperature is 1170 ° C - 1250 ° C.