Andortid CaO Al2O3 2SiO2 calcium is lower Si content, which causes a lower viscosity of the melt, t

Karamika is a multidisciplinary science that includes all inorganic, nonmetallic materials. One of the oldest human activities. In Babylonia and Assyria appeared first pieces of bricks and tiles that were glazed, mainly turquoise, blue and green - on the basis of copper CuO. Egypt - the first wheel; wako Judah - vases, lamps oilseeds; Greece - slips ...
Alkali or alkaline earth aluminosilicates which form the main flux in the classic ceramic industry. In nature, good luck in huge quantities making massifs, where usually mixed (rarely found pure feldspar). wako Grade isomorphic mixture, comprising a combination wako of two feldspar, for example. Albite (sodium feldspar) and anortid (calcium feldspar).
Andortid CaO Al2O3 2SiO2 calcium is lower Si content, which causes a lower viscosity of the melt, the feldspar easier flowing, easy flowing and in greater quantity in a high temperature can cause sticking to the surface of the object and other types of defects.
Feldspars are highly fissile, all have a hardness of about 5. They are of different colors, from bright, cream, beige to brown. wako Basic odlika- at temperatures above 1150 degrees crossing into the melt. Potassium feldspar, orthoclase has a higher melting tempetatura around 1200- gives higher wako melt viscosity and melt is partially obscured, because the feldspar melting inkogruentno (moved to melt and a new crystalline phase, which is called leucite)
Feldspars are excellent and the main fluxes in the ceramic mass. The important role of feldspar in obtaining wako high-temperature glaze which is indispensable flux. Great application in obtaining enamels, glass, slip, the frit.
In nature, happiness mixed nepheline syenite making group, which is used as a flux. May include wako increased iron content, so they can not be used for white glaze, but can for colored. This group includes
-liskuni (hem.sastavu the alkali and alkaline earth aluminosilicates). Layered silicates that form a large group of minerals with different chemical composition or similar properties. The most famous are muskovit- very stable and difficult to decompose under the influence of the elements (rain, snow). There are frequent companions of clay, feldspar and sand. Black mica or biotite has a large content of iron and easily disintegrate.
-iliti wako here are classified due to the similar structure, and the layered mica, each of which is distinguished by higher calcium content and lower the water content of the mica. Due to the enormous particle dispersibility and plasticity, illite clay minerals still believe.
Carbonates raw materials also represent a salt of carbonic acid and a metal. Widespread in nature, occurring in the form of a huge mountain massif. In traditional ceramics are widely used mainly in the making of refractory materials: magnesite, dolomite bricks and in making traditional pottery and as a raw material for the manufacture of enamel, glass, enamel and different types of ceramic material (which can be used as fluxes-when bring in small quantities, or as opošćivači- when it comes to lower temperatures). Especially used when making mass lower QUALITY- faience, stoneware, often find themselves in the masses of majolica and brick production because the clay as a touch often contain calcium carbonate. The ceramics from carbonate application are the
CaCO 3 occurs in the form of calcite and aragonite. Two modifications, identical chemical wako composition, but different crystallize. Calcite has a lot of nature and aragonite is rare. After the chemical composition wako of CaCO 3 material is resistant to acids and in contact is easily decomposed. Ceramics is an important component of limestone that the mass must be extraordinarily milled, otherwise, larger particles of calcite, after firing passes into calcium oxide, easily absorbs water and becomes calcium hydroxide wako Ca (OH) 2 is satisfied wako and there are cracks with small white cores. How much is an excellent freshly ground limestone to the effect that there is no more powder with Ca (OH) 2 passes together with Si in calcium silicate, which is an integral part of every mass that contains limestone. During the heat treatment limestone decomposes. wako CaCO 3 at a temperature of about 100 decomposes and is converted to carbon dioxide and in the form of gas into the atmosphere, and the CaO. The process of decomposition begins at about 700 and sometimes even in 1000 it is important biscuit. It is important that biscuit which contains calcite should lead to zavržetka reaction, a complete departure gas phase, because otherwise, with low soluble mass can lead to problematic defects if glaze begins to blend a gas phase is not completely out of the system.
A similar raw material, but the vatrostalniji of calcite and its melting point is very high. Magnesium oxide melts at 2700, by color similar to calcite, extremely white, naturally occurring various other tints. Unlike the calcite decomposes at about 600 rpm, well before. Transitions in the oxide as a gas phase goes from ceramic products. The presence of magnesite at in more detail biscuit is not a problem. The density of 2.7-2.8 g / cm 3, Mohs hardness of 3.5, it is easy to pound. Very compact wako wall, no cepljivos