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Perlite is a kind of silicon glass rocks naturally consisting of crystallized water 2-6% and heated perlite sudden temperature up to more than 870 ° V evaporate water and evaporate very quickly, resulting in the expansion of the granules composed of a number of cells and double the size of (4 - 20 times) As a result Expansion and aerobic bubbles within the granules, which makes it lightweight pearly color and due to the unique characteristics and characteristics of expanded perlite granules are used in many fields of agriculture, industrial and construction.
• Expanded perlite is produced as an insulating material in the form of expanded white granules from the wild rocky material called perlite by processing the raw material industrially by heat which leads to its expansion and then exposed to high temperatures. 35 and 240 kg / m3 The granules are used as a heat insulating material to fill cavities and voids in construction areas. The material contains open pores filled with air is subject to high water absorption and therefore is sometimes treated with silicon to reduce the absorption of water and moisture can be mixed expanded perlite with cement to give light concrete insulation in various forms.
• Expanded uses of perlite industrially due to its multiple properties and advantages and the ability to heat insulation for low and high temperatures, it is economical and widespread around the world and easy to use to reduce its thermal conductivity and non-combustibility reduces evaporation and is used in isolation of liquid gas tanks, fuel, chemicals, transport containers and cooling boxes and used in the mixing of hydrogen and helium When stored in bifurcated spherical containers, the expanded perlite is placed between the two casings with air drawn from them.
• For its high insulation capacity in high grades exceeding 1100 m is used in the industries of metals, iron, steel and thermal castings and enter into the manufacture of thermal insulation.
7- Aerated Concrete:
It is a low-density light concrete because of the size of the cells and pores distributed in it, which is produced by the addition of powder or solution in the form of a mixture that reacts in the presence of water within the fresh concrete mass during the process of mixing. Aluminum powder is added to cement, sand and water in a central mixer. Immediately after mixing, the mixture, which is in the form of a liquid paste, is poured into molds to the desired size in the design.
Aluminum reacts with lime and calcium aluminate and hydrogen gas react to form porous cells in concrete, and sodium hydroxide can be added to accelerate the hydrogen generation needed to form porous cells. This invention was registered in Sweden in 1929 and is found in the markets of the Kingdom under the name Seborex. The density of aerated concrete ranges from (200 to 1400) kg / m3. The resistance of this type of concrete to breakage is reduced. Its heat conductivity increases with increasing density. It should be treated to avoid moisture absorption .
8 - Foam glass:
It is an inert material and consists of clear glass that does not contain any bonding materials between its molecules and is classified by the type of insulation materials with a cellular structure and density of (140 kg / m 3), and thermal conductivity to (0.55 W / m) only when The temperature of (20) C, although it contains a high porosity of the air spaces, but it has a high mechanical resistance to break, tensile, bending and shear, which is not permeable to water and is not combustible and the thermal stability is between (- 260 ° C) and (+ 430 ° C). It can be used in places where the temperature does not exceed (250 ° C)