The vermiculite is hydromica type minerals, it is under natural conditions of various kinds of mica hydration and two secondary change into. Along with the modern architecture development, vermiculite and has great application prospect in building.
Application of vermiculite in the important properties are heated to 300℃above it can foam ( expansion ), the volume can be increased by 6～ 8 times.
Foaming vermiculite has many valuable properties, one of the most important properties are as follows:
In 1, low density (80~ 200 kg / m3), its density is only ordinary concrete 1/ 30 to1/ 10.
In 2, the high sound absorption coefficient, at frequencies up to 100Hz to 0.7～ 0.8.
In 3, high fire resistance.
In 4, the melting temperature of1350 ℃.
In5,260℃to 1100 ℃using.
In 6, small thermal expansion coefficient:1.4× 10-5/ C
7, non-toxic.
Beautiful silver and gold, low moisture absorption, long life, is it there is nothing comparable to this advantage, and vermiculite perlite nature as nature, some even more than it. As the foaming vermiculite has these properties, thus making it in modern architecture has been widely used.
1domestic and foreign resources distribution of vermiculite
1.1world vermiculite resource distribution overview
World vermiculite reserves of about 600000000T, including China and Russia reserves accounted for about 2/3, other are mainly distributed in the United States and South africa.
The United States of America vermiculite mainly distributed in Montana's LIBBY, reserves of about80000000 T, the United States of America vermiculite accounted for2/3 of total reserves, is the world's largest vermiculite mineral; South Africa's total reserves of73000000 T, is the main origin of Palmer Bora region, the reserves of South Africa vermiculite reserves more than 90%; the Soviet Union a total of more than 20vermiculite deposit, wherein the oversize as the cove Dole and wave the vermiculite deposit, estimate the total reserves of nearly200000000 t.
1.2 our country resource distribution of vermiculite
China's vermiculite wider distribution, but are distributed in the north of China, mainly in Xinjiang, Hebei, Inner Mongolia, Liaoning, Shanxi, Shaanxi and other provinces; in Sichuan, Hubei, Gansu provinces have distribution, mainly in metamorphic rock area. A large scale, is the most representative of Xinjiang Yuli County and dry Braque vermiculite mine, reserves are estimated to reside the world the second, occupy countrywide reserves more than 90%, our country of vermiculite flakes by burning test, expansion ratio is highest.
2vermiculite can produce the following building materials and products
2.1 foaming vermiculite
Practice indicates that it is effective to heat insulation ( insulation ) material, it can be used as the exterior of the building, roof, floor, fire insulation ( insulation ) material. It has the fluidity, can be filled with any shape concave. The density of the material is only 100~ 200 kg / m3.
There is also a hydrophobic expanded vermiculite, the absorbent and the suction temperature is only common foaming vermiculite1/3.
Expanded vermiculite has good adsorption performance, can well absorb the gas and organic matter, can be used for purifying gas and waste water.
Foaming vermiculite production process is as follows: Vermiculite to remove impurities, grinding into 1~ 2mm particles, screening to remove fine powder. Then the difference in elevation type double tube parallel rotary furnace foamed in place, hardening, annealing, cooling. Foaming temperature must be controlled under350℃ ~ 400 ℃, foaming time 8 ~10 minutes, from a foamed rotary furnace out of the foaming vermiculite to sieving, removing the unexpanded particles.
2.2vermiculite insulation, sound insulation board
This kind of plate on human health is absolutely harmless, it can be carried on the housing and insulation, sound insulation, heat insulation, do not release any gas when heated, never aging. Vermiculite insulation board with foaming vermiculite as main raw material, with a wide range of uses:
① the need of high temperature-resistant public and production room decoration.
The public and production facilities of fire protection board. For example station, hotel, theater, cinemas, hotels and various types of industrial workshop.
In house, warehouse, bank, Arsenal, hotel, cinema, gym, club, hotel as noise, heat insulation wall.
The mixed with other materials made of composite materials, such as fire-resistant partition, door, fire ceiling partition.
The steel tower, steel structure protection sleeve.
Vermiculite plate sound insulation index than in most soundproof material is good, but its cost is very low. The performance is as follows,
Dimensions ( mm ):150x 150,200x 200,300x 300,600x 600
Thickness ( mm ):8,10,12,16,20
Density:600/ 700kg / m3
Flexural strength:1.5 ～2 MPa
Thermal conductivity: from 0.15 to0,16 w / m·card
Flame spread index: L=0
Heat resistance: not less than 3hours
Sound absorption coefficient ( f=500):0.45
Toxicity ( including in the flame effect ): no
2.3fire prevention vermiculite slate
Fire vermiculite plate prepared by the following method: vermiculite grinding and fine grinding to head 200, and a liquid binder is mixed, then molded into various specifications sheet, and at 100℃drying. The liquid binder for water glass and sodium silicate phosphor. Can also be vermiculite powder and water glass or phosphate sodium silicate mixture is coated onto the need to fire equipment and the object surface, the coating thickness affects the fire, generally the thicker the fire.
Vermiculite fire board does not contain asbestos. Its uses are as follows:
①for metal, wood, concrete brick roof structure and fire protection, the fire resistance of up to 0.5~ 2.5 hours.
The engineering system and ventilation fire protection and when the chimney through the roof and ceiling interlining chimney outside surface fire protection facilities.
The required burning resistance greater than 0.5 hours draught device lining.
Fire vermiculite board service life not less than 15 years.
2.4vermiculite concrete
In order to improve the various thermal insulation ( insulation ) performance, also can use vermiculite concrete, the concrete by adopting foaming vermiculite as a fine filler.
With vermiculite concrete can be produced for building wall materials. This kind of wall material not only light weight, and the insulation ( insulation ), noise performance, in the modern high-rise building is widely used.
Vermiculite concrete can be made of different density, such as ceramic mold stone concrete density of 900kg / m3, by adjusting the ceramsite, vermiculite, cement ratio, can be prepared with lower density, thermal insulation ( insulation ) noise performance better haydite and vermiculite concrete. The haydite and vermiculite vermiculite concrete or concrete can also join the gravel.
Density of 400~ 500 kg / m3vermiculite concrete in the multistory buildings can be used for the exterior caulking and whitewash. Vermiculite concrete and preparation and use and ordinary concrete. Using vermiculite concrete as an exterior caulking and whitewash can reduce the material consumption ( its density is only ordinary concrete 1/ 3), saving labor and can also improve the performance of external wall insulation ( insulation ).
To further improve the civil and industrial buildings and industrial piping and pipeline heat insulation ( insulation ) performance, can also use the mechanical injector device for spraying foaming vermiculite powder and water glass ( sodium silicate or phosphorus ) mixture. Also in the energy, including nuclear power station thermal insulation.
3conclusions
To sum up, vermiculite, building materials and other building materials has many incomparable advantages, so its use is very extensive, and the production of this kind of building material process is relatively simple, investment province, the cost is relatively low, it is a great development prospects of modern building materials.
