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New use of Xinyu Wollastonite in the ceramic industry_ huayu
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  • 发布时间:2020-01-18 15:34
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Since wollastonite has been used in the ceramic industry, its uses can be divided into two major categories: one is to replace the use of vermiculite (SiO2) and limestone (CaCO3); the other is to provide ceramic green bodies and glazes, porcelain enamels and melting Some excellent properties, such as low thermal expansion coefficient, reduced drying and firing shrinkage, enhanced post-fired strength, improved thermal shock resistance, fast firing, easy compression, better adhesion, and better electrical properties. The main products are tiles, sanitary ceramics, tableware, and artistic ceramics. The main determinants of the selection of wollastonite are its chemical composition and firing temperature (991-1196 ° C); and its firing time, furnace atmosphere, powder particle size and shape are also factors that affect selection. In addition, wollastonite is used in other ceramics: various glazed porous ceramics, cookers, building clay products, laterite ceramics, chemical utensils, abrasives bonded with ceramics, refractory materials, high alumina porcelain , Martian plug, electric porcelain, frit and so on.
 
Production of super-large thin ceramic plates
 
Generally speaking, "brittleness" is the biggest disadvantage of ceramic sintered bodies. This article will introduce the application of wollastonite in the manufacture of ceramic green bodies to improve this serious disadvantage, and then develop into manufacturing large-scale ceramic plates with elasticity. Technology. As mentioned earlier, wollastonite is generally mainly used in ceramic glazes. This is because the loss on ignition of wollastonite is less than 2wt%, which is comparable to the gas generated during firing of other traditional ceramic materials. Less glaze quality, so smooth and pinhole-free. When it is applied to the ceramic body, it uses the needle-like structure of the wollastonite powder. During the drying stage and the initial stage of firing, the structure of the ceramic body can be opened, so that water vapor can easily escape from the body Such characteristics are conducive to the rapid firing of the ceramic body. The other reason why wollastonite will be used in the manufacture of large-scale building ceramic plates is to use its needle-like structure as the main structure of the elastomer in the ceramic body. This elastic ceramic body is the same as the ordinary The difference is shown by the results in the following manufacturing examples.
 
Adjustment of the clay
 
According to the mixing ratio of various raw materials, weigh the dry powder prepared in advance and put it into a mixing mill. After mixing for 10 minutes, add 20% by weight of water (dry powder weight), and then mix and stir for 10 minutes to make it a plastic clay.
 
Cylinder blank production
 
An extrusion molding machine was used to produce a cylindrical blank with a diameter of 500mm (outer) and a wall thickness of 35mm, which was then cut and unrolled to produce a blank blank plate with a width of 1520-1550mm, a thickness of 35mm and a length of 500mm. It was rolled several times by the rolling roller, and finally rolled by a flat roller, and the burrs that were cracked on all sides were cut with a cutter to become a flat green embryo with a thickness of 4mm, a width of 1200mm, and a length of about 2400mm (see Figure 4). # p # 分页 Title # e #
 
Drying and vegetarian cooking
 
The drying system is firstly treated with far-infrared radiation for 5 minutes, and then dried with a metal mesh belt dryer for 50 minutes to 350 ° C, and then fired to a temperature of 1150 ° C using a Roller Hearth Kiln.
 
As shown in the above test results (Table 3), replacing the feldspar raw materials of flux (Flux) in the general ceramic body with wollastonite, which is a needle-shaped crystalline mineral, exhibits the effects of flexural strength and elastic properties. great. The water absorption of the general ceramic composition shown in this embodiment is about 1/2 of the elastic body. It is intended to take advantage of this good sinterability to improve its flexural strength.
 
The ceramic tile construction materials have been widely used around the world, and the modernization of large-scale slabs such as curtain walls, rationalization of pollution and mold in residential buildings, and the requirements of changes in living environment In response to these countermeasures, various manufacturers are conducting research aimed at increasing the size of building materials. However, the biggest disadvantage of ceramics occurs when the size is increased due to lightening and thinning: fragility. This article introduces the use of needle-shaped crystal wollastonite, combined with special ceramic forming technology to produce a very large thin ceramic plate, which far exceeds the old ceramic technology and common sense and presents epoch-making physical properties. Moreover, a large ceramic plate with a width of 1.2m, a length of 3.0m, and a thickness of 4mm, which cannot be achieved by ordinary ceramic manufacturers, has been completed. Since the height of each floor of a general high-rise building is about 3.0m, the length of the large-shaped thin-walled ceramic plate can be just posted, so the construction cost of the wall surface can be particularly more economical. It is also different from ordinary concrete slabs, etc. Because its glaze has excellent waterproofness, it is not necessary to put a waterproof layer. As thin as 4mm, its weight cannot be achieved by the old technology. Whether the steel-frame building or the concrete building is connected to the column beam foundation, its weight can be reduced, so the overall economic effect of the structure will become extremely great.