The density range of calcium silicate material is roughly 100-2000kg/m3. Lightweight products are suitable for use as insulation or filling materials; products with medium density (400-1000kg/m3) are mainly used as wall materials and refractory covering materials; products with a density of 1000kg/m3 and above are mainly used as wall materials, Use of ground materials or insulating materials. The thermal conductivity mainly depends on the density of the product, and it increases with the rise of the ambient temperature. Calcium silicate material has good heat resistance and thermal stability, and good fire resistance. It is a non-combustible material (GB 8624-1997) and will not produce toxic gas or smoke even at high temperatures. In construction projects, calcium silicate is widely used as a refractory covering material for steel structure beams, columns and walls. Calcium silicate refractory board can be used as wall surface, suspended ceiling and interior and exterior decoration materials in ordinary houses, factories and other buildings and underground buildings with fire-proof requirements.
Microporous calcium silicate is a kind of thermal insulation made of siliceous materials, calcium materials, inorganic fiber reinforced materials and a large amount of water after mixing, heating, gelation, molding, autoclave curing, drying and other processes. Insulation material, its main component is hydrated silicic acid and calcium. According to the different hydration products of the product, it can usually be divided into tobe mullite type and xonotlite type. Because of the different types of raw materials, mixing ratios and processing conditions used in them, the physical and chemical properties of the calcium silicate hydrate produced are also different.
There are mainly two different types of silicon derivation crystal products used as insulation materials. One is torbe mullite type, its main component is 5Ca0.6Si02. 5H2 0, heat-resistant temperature is 650℃; the other is xonotlite type, its main component is 6Ca0.6Si02. H20, heat-resistant The temperature can be as high as 1000°C.
Microporous calcium silicate insulation material has the advantages of light bulk density, high strength, low thermal conductivity, high use temperature, and good fire resistance. It is a kind of block heat insulation material with better performance. It is one of the most widely used thermal insulation materials in industries abroad, and a large number of products are produced and used in China.
Silica materials are materials with silicon dioxide as the main component, which can react with calcium hydroxide under certain conditions to form a cementitious mainly composed of calcium silicate hydrate; calcium materials are materials with calcium oxide as the main component. After hydration, it can react with silica to form a cementitious mainly hydrated calcium silicate. In the manufacture of microporous calcium silicate insulation materials, the siliceous raw materials generally use diatomaceous earth, very fine quartz powder can also be used, and bentonite can also be used; the calcium raw materials generally use lime slurry and slaked lime that are digested by lump lime Powder or lime paste, industrial wastes such as calcium carbide slag, etc. can also be used; asbestos fibers are generally used as reinforcing fibers. In recent years, other fibers such as alkali-resistant glass fibers and organic sulfuric acid fibers (such as paper fibers) have been used for reinforcement; The main additives used in the process are water: glass, soda ash, aluminum sulfate and so on.
The raw material ratio for the production of calcium silicate is generally: CaO/Si02=O. 8-1. O, reinforcing fibers account for 3%-15% of the total amount of silicon and calcium materials, additives account for 5%-lo y6, and water 550%-850%. When producing tobe mullite-type microporous calcium silicate insulation material with a heat-resistant temperature of 650 ℃, the vapor pressure generally used is o. 8～1.1MPa, the holding room is 10h. When producing xonotlite-type microporous calcium silicate products with a heat-resistant temperature of 1000°C, raw materials with higher purity should be selected to make CaO/Si02 =1. O, the vapor pressure reaches 1.5MPa, and the holding time reaches more than 20h, then xonotlite-type calcium silicate hydrate crystals can be formed.
Calcium silicate board characteristics and application range
Microporous calcium silicate thermal insulation material mainly has the following characteristics: the use temperature is high, and the use temperature can reach 650°C (I type) or 1000°C (type II) respectively; ②The raw materials used are basically all It is an inorganic material that does not burn, and belongs to Class A non-combustible material (GB 8624-1997). It will not produce toxic gas even when a fire occurs, which is very beneficial to fire safety; ③Low thermal conductivity and good insulation effect ④Low bulk density, high strength, easy to process, can be sawed and cut, convenient for on-site construction; ⑤Good water resistance, no decomposition and damage in hot water; ⑥Not easy to age, long service life; ⑦Soak it in When in water, the resulting aqueous solution is neutral or weakly alkaline, so it will not corrode equipment or pipelines; ⑧The raw materials are easy to obtain and the price is cheap.
Because the microporous calcium silicate material has the above-mentioned characteristics, especially its outstanding heat insulation, temperature resistance, non-combustibility, and no toxic gas release, it has been widely used in building fire protection projects. At present, it has been widely used in various industries such as metallurgy, chemical industry, electric power, shipbuilding, construction, etc. It is used as a thermal insulation material on various equipment, pipelines and accessories, and it also has a fire protection function.