2.1 Porcelain. Porcelain was known in China already in very ancient times, and in Europe it began manufacturing factory method for the first time in Meyssen (1710). Porcelain was received with a strong ignition ("burning") plastic materials manufactured by mixing clay, porcelain earth) with powdery feldspar and quartz with a small amount of water. If the firing temperature is not too high, then the form of products stored, only to volume is greatly reduced, because the porcelain "sits" during baking. Simultaneously, the weight (the"crock") is dense (waterproof) and sonorous.

For the manufacture of solid porcelain usually used about 50% of kaolin, 25% of feldspar and 25% quartz. When roasting kaolin first gives constitutional water. He then decomposes on Al2O3 and SiO2, which dissolve in стеклообразно softened feldspar. Further temperature increase feldspar dissolves in increasing quantities of coarse grained quartz. As feldspar enriched silicon dioxide, it is deposited mullite, because with increasing SiO2 content solvent ability feldspar towards муллиту decreases. Therefore ready porcelain consists of a glassy groundmass, which permeated closely interwoven between the needles of mullite and the remaining undissolved grains of quartz (and tiny air bubbles). As a rule, the firing is carried out twice. After the first firing, the so-called "raw firing"going around 900, porcelain put a transparent glaze: received after crude firing more porous shards quickly immersed in глазурную mass - aqueous suspension of kaolin, clay, feldspar and marble. When heated from it formed тугоплавкое glass. The subsequent drying (about 1450) produce a final firing. Often porcelain subjected to yet a third firing in a muffle furnace at red калении after applying paints, i. e. worn out with turpentine finely crushed colored glass. The most stability have paint for acute fire or underglaze paint, applied on neglazurovannyj a crock. However, there is some colour, for which this method is possible. Finally annealed without porcelain glaze called biscuit. Instead of forming of the porcelain paste, based on its plasticity, porcelain mass can be converted into liquid state addition of a minor amount of alkali and cast in the form of plaster. As a result of absorption of water baked plaster form comes a rapid hardening of porcelain products. Porcelain not only for the manufacture of household utensils and art products, but also, and in very large extent, for the manufacture of chemical utensils, and, thanks to its insulating properties - for the manufacture insulators.

From the normal or hard porcelain differs soft-paste porcelain, which produce mainly artistic products. In soft porcelain contains less kaolin and accordingly more "wetlands", for example, feldspar, chalk. This porcelain in accordance with its легкоплавкостью are fired at a lower temperature (usually at 1200-1300). So easy to make it a multicolored подглазурное painting.

Stone materials like porcelain, are dense sonorous and so solid that is not scratched steel; besides, they are very front in relation to chemical attack. Because they are made of clay, they require lower firing temperature than hard-paste porcelain (1200-1300), do not possess such as porcelain, просвечиваемостью and in most cases are not white, grey, yellow or brown color. They often cover only a thin layer of "salt" glaze, which is formed by the evaporation of salt, бросаемой in microwave; due to that on the surface of such products is deposited glassy dual sodium silicate. In the chemical industry is very often used unglazed products of stone material.

Thin stone material is used for the manufacture of vases and other artistic items in architecture for the manufacture of reliefs and decoration of facades. Of stone material manufactured grey painted with blue paint old German vessels (cups etc). Examples of products from the rough brown stone material can serve as water and sewage pipes, and "metlahskie tiles". In the chemical industry used many vessels made of brown stone material: coils, cooling pipes, baths and other.

2.2 Faience, as porcelain, white, or almost white, but it is softer, so that the steel leave scratches on it; he break easier, порист, so in most cases it should be covered with glaze. Faience produced from a mixture of clay, quartz, alkali and minium, sometimes add colouring oxides. Faience fired twice: first without the glaze from 1200-1300 (crude firing, while slightly weaker with icing (final roasting). From fine porcelain make sinks, bathtubs, etc. Some varieties faience often painted titanium acid in a pale cream color (sinks). Examples of unglazed earthenware serve vessels of clay, clay tube etc.

Faience has dirty-grey porous break. Therefore, it glaze, which, thanks to the addition of tin dioxide is white and opaque. Earlier faience often used for making cheap-ware; however, faience made Веджвудом in England, almost entirely replaced the normal faience of the household. A more subtle faience suitable for artistic ceramics. According to its properties фаянсу approaching majolica, covered with glaze.

Ordinary pottery, such as flower pots, pottery, also have a porous break. They are glaze containing mostly lead; it is painted usually added to it oxides of metals. Iron oxide gives yellow, and together with manganese dioxide - brown color; copper glaze colors green.

2.3 Brick. Brick molded from clay and then are fired. Because clay iron oxide bricks mostly painted in red color. Brick has large porosity, because firing is carried out at a relatively low temperature. Badly burnt, thick and very sturdy brick is called clinker.

2.4 Refractory materials. "Refractory" call these materials that is not melting, can withstand the high temperatures (at least 1600). The most commonly used refractory material is fireclay, which consists of a mixture of two types of clays: burnt to the sintering, perhaps more refractory clay (actually fireclay) and red plastic clays (linking clay). There are special deposits of clay, which is being used primarily for the manufacture of fireclay. Fireclay, which usually contains about 42-45% Al2O3 and 50-54% SiO2, primarily used for lining furnaces, high-temperature furnaces and recuperators. For coke-oven, ceramic furnaces and furnaces for the steel industry (for example, oven Siemens - Martin) are used in most cases (for the first time obtained in England) silica. His prepare firing of coarse grained quartz sand, mixed with a small amount of lime mass or clay. Clay contains silica 15-17% Al2O3 and 80-83% SiO2. He soften at 1350, however melts only 1650 above. Refractory properties exceeds lime silica and silica stone (with the content of 1,5-4% CaO, from 0.3 to 2% Al2O3 and 94-96% SiO2), which melts only when 1700-1750. It and is used primarily in the furnaces of the Siemens - Martin. Greater fire resistance have the so-called силлиманиты, which is obtained by firing at high temperature sillimanite, цианита or andalusite (minerals single-ended Al2 SiO5, but different internal structure), which formed as a result mullite, which as already mentioned is an integral part of hard porcelain.

Of refractory substances, not containing or containing SiO2 it in very small quantities, should be called bauxite, and dolomite. High heat-resistant properties, magnesium, zirconium dioxide and mainly graphite (in the absence of air).

Part III. Types of ceramics