Clay – fine-grained sedimentary rock pulverized when dry, plastic when wet. Clay consists of one or more minerals of the kaolinite group (derived from the area in China Kaolin), montmorillonite or other layered aluminosilicates (clay minerals), but may contain both carbonate and sand particles. Usually, a rock-forming mineral is kaolinite clay, composition: 47% (by weight) of silicon oxide (IV) (SiO2), 39% of aluminum oxide (Al2O3) and 14% water (H2O).
Al2O3 and SiO2 – make up a large part of the chemical composition of yellow clay, brown, blue, green, purple and even black colors. Coating of ions caused by impurities – chromophores primarily iron in the valency three (red) or 2 (green, bluish).
The properties of clay: plasticity, fire and air shrinkage, fire resistance, taking, color ceramic crock, viscosity, shrinkage, porosity, swelling, dispersion. Clay is the most stable waterproofing is one of its qualities. Due to this, the clay soil – the most stable type of soil developed on vacant lots and wasteland. Development of a plant root system clay deposits possible. Vodonepropuskaemost clay useful to preserve the quality of groundwater – a significant part of the quality of artesian springs lies between the clay layers.
1Mineraly contained in clays
2Mineraly polluting clay and kaolin
4.5Primenenie in medicine and cosmetology
The minerals contained in the clay
Kaolinite (Al2O3 · 2SiO2 · 2H2O)
Andalusite, kyanite, and sillimanite (Al2O3 · SiO2)
Halloysite (Al2O3 · SiO2 · H2O)
Gibbsite (Al2O3 · 3H2O)
Diaspora (Al2O3 · H2O)
Aluminum oxide (Al2O3)
Monotremes (0,2 [K2MgCa] 0 · Al2O3 · 2SiO2 · 1,5H2O)
Montmorillonite (MgO · Al2O3 · 3SiO2 · 1,5H2O)
Muscovite (K2O · Al2O3 · 6SiO2 · 2H2O)
Cover with (Al2O3 · SiO2 · 2H2O)
Pyrophyllite (Al2O3 · 4SiO2 · H2O)
Minerals, contaminants and kaolin clay [edit | edit wiki text] Quartz (SiO2)
Gypsum (CaSO4 · 2H2O)
Dolomite (MgO · CaO · 2CO2)
Calcite (CaO · CO2)
Glauconite (K2O · Fe2O3 · 4SiO2 · 10H2O)
Limonite (Fe2O3 · 3H2O)
Magnetite (FeO · Fe2O3)
Serpentine (3MgO · 2SiO2 · 2H2O)
Siderite (FeO · CO2)
The main source of argillaceous rocks is feldspar, which when exposed to the decay phenomena kaolinite formed hydrates and other aluminum silicates. Some sedimentary clay formed in the process of local accumulation mentioned minerals, but most of them are deposits of water flows, dropped to the bottom of lakes and seas.
Clay – is a secondary product of the earth’s crust, sedimentary rock, formed as a result of the destruction of rocks during weathering.
The use of
Clay is the basis of pottery, brick production. Mixed with water, clay forms a dough-like plastic mass which is suitable for further processing. Depending on the place of origin of the natural raw materials has significant differences. One can be used in pure form or another it is necessary to sift and mix to obtain a material suitable for the manufacture of various products.
Technical ceramics – a large group of ceramic products and materials obtained by heat treatment of mass given chemical composition of minerals and other raw materials of high quality that have the necessary strength, electrical properties (high specific volume and surface resistivity greater dielectric strength, low tangent of dielectric losses).
For the production of cement is first extracted from limestone and clay quarries. Limestone (approximately 75% of the amount) was crushed and thoroughly mixed with the clay (about 25% of the mixture). The dosage of the raw materials is an extremely difficult process, as the lime content must meet the specified number of up to 0.1%.
These relationships are defined in the literature concepts of “lime”, “flinty” and “luminous” modules. Since the chemical composition of the starting raw materials is constantly fluctuating due depending on the geological origin, it is easy to understand how difficult it is to maintain the constancy of the modules. In modern cement plants is well-established control with a computer in combination with the automatic analysis methods.
A legitimate slurry prepared according to the chosen technology (dry or wet method) is introduced into the rotary kiln (up to 200 m long and up to 2.7 m in diameter) and calcined at a temperature of about 1450 ° C – the so-called sintering temperature. At this temperature, the starting material is melted (sintered), it leaves the furnace at a more or less large lump of clinker (sometimes called Portland cement clinker). Firing occurs.
The clinker material formed by these reactions. Upon exiting the rotary kiln falls into the clinker cooler, where it is quenching from 1300 to 130 ° C. After cooling, the clinker is ground with a small amount of gypsum (6% maximum). cement grain size ranges from 1 to 100 microns. It is better to illustrate the concept of “specific surface area”. If we sum the surface area of the grains in one gram of cement, the cement grinding depending on the thickness are obtained value from 2000 to 5000 cm² (0.2-0.5 m²). The majority of the cement in special containers transported by road or rail. All overload produced pneumatically. A smaller part of the cement production is delivered in moisture- and paper bags. Stored cement at construction sites mainly in silos.
Applications in medicine and cosmetology
Most often in medicine and cosmetics using kaolin.
The clay used in medicine, for example, clay is a part some medicinal ointments, antidiarrheal agents.
In a cosmetics foundation clay masks, certain ointments.
Treatment of clay and mud are widely used in kurort leche Nii skin, gynecological diseases, diseases of the musculoskeletal system
White clay can be used as an antidote thanks to the sorbent properties (macaws are known for what they eat clay, so the birds neutralize toxins in unripe fruits [citation needed 1048 days]).
The edible clay
Main article: geophagy
food additives in livestock feed (montmorillonite clay)
for coloring foods in cooking – lev kashaya clay.
Types of clay
There are several varieties of clay. Each of them is used in its own way. Clay with the number of the plasticity of 0.17 to 0.27 is called light, more than 0.27 – heavy. Most of the produced and marketed clay are kaolin, which is used in the pulp and paper industry and in the manufacture of porcelain and refractory products. Second in importance are the usual materials for construction clay and shale. Fire clay is used to make refractory bricks and other high-temperature products.
An important place among the species occupies a bentonite clay. It is believed that the clay was formed as a result of the chemical disintegration of volcanic ash. When immersed in water, it swells, increasing its volume several times. It is primarily used in drilling fluids during drilling.
Smectite is valued for its bleaching properties with petroleum purification. Filters of the smectite used in the purification of vegetable oils minerally.
Pottery clay, also known as the lump, finds application in the manufacture of pottery. Clay or shale, is an important raw material which together with the limestone used in the manufacture of Portland cement.
The most common in nature are red clay, white clay (kaolin), clay sandstone. Grades clay – for the production of porcelain, earthenware, and refractory products – kaolin.
The biblical story of the creation of Adam and Eve’s fall from grace and exiled them from heaven (Genesis, I-V) has generated extensive literature apocryphal nature. The largest monument of this kind is the so-called “Book of Adam”, which describes the life of Adam and Eve after the expulsion from paradise.
The famous book, often ironic or contemptuous, the idiom “a colossus with feet of clay”, meaning something majestic, powerful-looking, but essentially weak and easily destroyed, also goes back to the biblical story of Babylonian King Nebuchadnezzar, who had a sinister dream. He saw a huge statue, whose head was of gold, breast and arms of silver, belly and thighs – copper, knees – of iron, and feet – from clay. The stone that fell from the hill hit a colossus on clay feet, and he turned to dust. The king gathered the priests and the prophets, but no one was able to interpret his dream, except for the Jewish prophet Daniel, who interpreted the dream as a fatal omen of the coming destruction and the death of the Babylonian kingdom.
We know another being – Golem of Prague, the character of the Jewish mythology, a man from nonliving matter – clay, lively Kabbalists with the help of secret knowledge.