Read the application technology of zinc oxide on ceramic products

15-11-2018


    SMM November 10th: Zinc oxide is an important ceramic chemical flux raw material. In the ceramic industry, zinc oxide is widely used in brick glaze and stoneware translucent glaze and process tableware. In the construction of ceramic wall and floor glaze and low temperature porcelain glaze use more. At the 2018 (sixth) China Zinc Oxide Industry Chain Trading Summit hosted by Shanghai Nonferrous Metals Co., Ltd., Mr. Cai Ruinian, Technical Director of Guangdong Sanshui Dahong Glaze Co., Ltd. introduced the application of zinc oxide to glazes. Application technology of zinc oxide on ceramic products.


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    The role and use of zinc oxide in glaze: Zinc oxide has a strong fluxing effect in the glaze, which can reduce the expansion coefficient of the glaze, improve the thermal stability of the product, increase the gloss and whiteness of the glaze, and improve the glaze. Flexibility. The glaze color can be increased while expanding the melting range. However, it should not be used in black glaze or green glaze containing chromium. Zinc oxide is mainly used as a fluxing agent, opacifier, crystallizer in the glaze, and used to make ceramic pigments. 

    Application of Zinc-containing Glazes in Ceramic Products Some ceramic enterprises in Foshan have found through long-term research that zinc oxide can also have special effects in reducing the water absorption rate of ceramic wall tiles. The industry believes that the zinc oxide powder with a fineness of about 1000 mesh is used in the ceramic glaze formulation. Due to the finer grain size, the specific surface area is increased, so that the water absorption rate is lowered. Of course, the higher the mesh, the higher the price of zinc oxide.

    Application of zinc-containing glazes in building ceramics:

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    1. In the third-degree burning range of low temperature 700–1000 °C, zinc oxide and lead oxide are in the frit formulation due to their excellent fluxing effect and wide firing range. Commonly used materials, zinc is a better alternative to lead when required for lead and cadmium.

    2. In the field of wall bricks with medium temperature of 1000–1150°C, the frit is still the main body of the glaze application. The zirconium white frit requires more zinc oxide to help melt and adjust the flatness and oxidation. The amount of zinc added is generally 7–12%. The corresponding transparent frit is not high in zirconium white frit due to high temperature viscosity, so the amount of zinc added is normal, generally 5–10%. There are also a lot of low-zinc frit shares in the market, but while reducing the cost, the range of firing in the application is relatively narrow, while the low-grade 80 zinc, 90 zinc, 95 zinc, etc. are also widely used in low The price of the frit. 

    3. In the field of high temperature 1150–1250°C floor tiles, the main application of glaze is mainly raw glaze, supplemented by frit, so the amount of zinc oxide is much less than the main glaze of the wall tile system. . However, the concept of wall climbing in recent years has caused the wall tile market to shrink a lot, and the market share of the main trend of glazed tiles has increased, so the total amount of zinc oxide in the field of floor tiles is increasing. 


    Application of zinc-containing glaze in daily-use ceramics: 

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    The production of daily-use ceramics can be said to be caused by people's needs for daily life. The most common people in daily life are the most familiar porcelains, such as tableware, tea sets and coffee. With utensils, wine, rice and so on. The indicators for human health in daily-use ceramic products are mainly the amount of heavy metal elements such as lead and cadmium. At present, the high-grade daily-use porcelain is a bone china, which is generally fired by a low temperature glaze of high temperature. The moist and transparent feeling of bone china is mainly derived from the bone china frit. The taste of zinc oxide is very important. Because lead and zinc are associated minerals, the lead element can be cleaned. The amount of lead heavy metal elements dissolved can have a large effect. 


    Application of zinc-containing glazes in sanitary ceramics:

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     Sanitary ceramics are ceramic utensils for sanitary and clean washing. The production process of sanitary ceramics is generally performed once at a temperature of 1250 to 1280 °C. Using kaolin, high plastic clay, quartz and potassium feldspar as the main raw materials, adding water and a small amount of electrolyte, finely pulverizing into a slurry of specified properties; using feldspar, quartz, limestone, dolomite, talc, magnesite Zinc oxide, carbonic acid Ba (chemical formula) as the base glaze raw material; zircon and tin oxide as the white glaze emulsion. Zinc oxide is mainly used as a co-solvent in sanitary ceramics. Due to the requirement of whiteness, more zirconium silicate or aluminum-based brightener is added to the formulation, so the high-temperature viscosity is large, and the addition of zinc oxide can be effective. Lowering the high temperature viscosity will greatly help the firing and glaze texture. In addition, in recent years, sanitary ceramics have the habit of using glazes based on raw glazes, and gradually added high-temperature frit. On the one hand, it reduces the firing temperature to save energy and reduce consumption, on the other hand, it can make the glaze more warm.


[Reserved to keep the source - Shanghai Nonferrous Metals] [Zinc Oxide Summit] Super technology stickers: read the application of zinc oxide in ceramic products https://news.smm.cn/news/100852390









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