Some fine ceramic products

In Maastricht in The Netherlands two fine ceramic factories can be found SPHINX which has three divisions SANITARY WARE, TILES and TECHNICAL CERAMICS and MOSA which produces PORCELAIN. 

Among other things Sphinx sanitary ware manufactures washbasins and lavatory pans by means of slip casting. The moulds must be able to absorb a lot of water, for example 3 to 4 kg for a single basin. 

That is why they are dried intensively after casting and can then be used several times a day. The average life span of a mould is about 

Pouring clay suspension in a mould for producing a wash basin at Sphinx sanitary (by J.Aarsen). 

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The name fine ceramics is based on the grain size distribution of the hard components in the ceramic mass. This rather differs from the distribution as it is seen in the ceramic branch of industry which produces for instance bricks, the coarse ceramic industry. Another difference is that all fine ceramic products are provided with a protective and in some cases also decorative coating, a so-called glaze. In this section much attention will be paid to glazes because this technique is rather unique for fine ceramics and because it offers the possibility to explore the subject glass and some important physical and chemical properties of materials. 

The process of pulverized cuUet reduction yields a product having near-batch equivalent sizing (—12 mesh (<1.7 mm mm)) and in a furnace-ready condition. Foil-backed paper, lead and other metals, and some tableware ceramics can be removed in an oversized scalping operation after the first pass through the system. Other contaminants are reduced to a fine particle size that can be assimilated into the glass composition during melting. 

Properties of final ceramic products made from fine powders are often dependent on the state of dispersion of the particles in the liquid media. The particles interact with each other and with what is in the medium. Some of the liquid molecules can adsorb onto the solid surface. Some solid surfaces can be ionized to exhibit surface charges. 

Plastic deformation of a moldable powder-additive mixture is employed in several forming methods for ceramics. Extrusion of a moist clay-water mixture is used extensively in the traditional ceramics sector for forming components with a regular cross section (e.g., solid and hollow cylinders, tiles, and bricks). The method is also used to form some oxide ceramics for advanced applications (e.g., catalyst supports, capacitor tubes and electrical insulators). A recent development is the repeated co-extrusion of a particle-filled thermoplastic polymer to produce textured microstructures or fine-scale structures. Injection molding of a ceramic-polymer mixture is a potentially useful method for the mass production of small ceramic articles with complex shapes. However, the method has not yet materialized into a significant forming process for ceramics mainly because of two factors ... 

Traditional ceramics are quite common, from sanitary ware to fine chinas and porcelains to glass products. Currently ceramics are being considered for uses that a few decades ago were inconceivable applications ranging from ceramic engines to optical communications, electrooptic applications to laser materials, and substrates in electronic circuits to electrodes in photoelectrochemical devices. Some of the recent applications for which ceramics are used and/or are prime candidates are listed in Table 1.1. 

Spray drying is used to dry pharmaceutical fine chani-cals, foods, dairy products, blood plasma, numerous organic and inorganic chemicals, rubber latex, ceramic powders, detergents, and other products. Some of the spray-dried products are listed in Table 9.1, which also includes typical inlet and outlet moisture content and tanperatures together with the atomizer type and spray dryer layout used. 

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