1. Vermiculite is a silicate mineral, which is a mica sub-organism. Its main chemical composition: 22MgO · 5Al2O3 · Fe2O3 · 22SiO2 · 40H2O
The theoretical molecular formula after roasting and expansion: ( OH) 2 (MgFe) 2 · (SiAlFe) 4O104H2O
2. The original ore vermiculite is a layered structure with a small amount of water between layers. After heating at 900-950 ℃, it can be dehydrated, bursted and expanded to 4-15 times the original volume , forming a porous light body material. It has thermal insulation, high temperature resistance, insulation, antifreeze, earthquake resistance, acid and alkali corrosion resistance, sound insulation and other properties.
Physical and chemical properties of vermiculite
1. The chemical composition of vermiculite
Content ( %
2. Physical and chemical properties
g / cm3
Expanded vermiculite bulk weight kg / m3
Refractory melting point
Uses of vermiculite
1. Used for thermal insulation
Expanded vermiculite has the characteristics of being porous, light weight and high melting point, and is most suitable for high temperature insulation materials ( below 1000 ℃) and fireproof insulation materials. The fifteen-centimeter-thick cement vermiculite board was burned at 1000 ℃ for 4-5 hours, and the temperature on the back was only about 40 ℃. The seven-centimeter thick vermiculite slab was burned at a high temperature of 3000 ℃ for five minutes by a flame-welded flame net. The front side melted, and the back was still not warm by hand. So it surpasses all insulation materials. Such as asbestos and diatomite products.
Vermiculite can be used as thermal insulation materials in high-temperature facilities, such as thermal insulation bricks, thermal insulation boards and thermal insulation caps in the smelting industry. Any equipment that requires thermal insulation can be insulated with vermiculite powder, cement vermiculite products (vermiculite bricks, vermiculite plates, vermiculite pipes, etc.) or asphalt vermiculite products. Such as walls, roofs, cold storages, boilers, steam pipes, liquid pipes, water towers, converter furnaces, heat exchangers, dangerous goods storage, etc.
2. Used for sound insulation layer
Vermiculite expanded due to the formation of fine air gap layer, forming a porous insulation material, when the frequency of 2000C / S, vermiculite thickness 5mm when the sound absorption rate of 63%, a thickness of vermiculite 6mm when the sound absorbing rate of 84%, vermiculite The sound absorption rate is 90% when the stone thickness is 8mm.
3. For radiation protection facilities
Vermiculite can absorb radiation. The vermiculite plate installed in the laboratory can replace the high-priced lead plate to absorb scattered radiation by 90%. The thickness of vermiculite is 65mm, which is equivalent to a 1mm lead plate.
4. For plant cultivation
Because vermiculite powder has good water absorption, air permeability, adsorption, looseness, non hardening and other properties, and it is sterile and non-toxic after high temperature roasting, which is conducive to the rooting and growth of plants. It can be used for planting, seedling raising and cutting of precious flowers and trees, vegetables, fruit trees and grapes, as well as for making flower fertilizer and nutrient soil.
5. Manufacturing for chemical coatings
Vermiculite having corrosion resistance to acid, of 5% or less of sulfuric acid, hydrochloric acid, acetic acid, 5% aqueous ammonia, sodium carbonate, anti-corrosive effect. Because of its light weight, looseness, smoothness, large diameter-to-thickness ratio, strong adhesion, and high temperature resistance, it can also be used as a filler in the manufacture of paints (fireproof paints, anti-irritant paints, waterproof paints) to prevent paint Settling and sending product performance.
6. For friction materials
Expanded vermiculite has sheet-like and thermal insulation properties, can be used for friction materials and braking materials, and has excellent performance, non-toxic and harmless, and is a new environmentally friendly material for environmental pollution.
Expanded vermiculite specifications and technical indicators (factory standard)
Particle ( mm ) or (mesh)
Volumetric weight ( kg / m3 )
Pass rate ( % )
Thermal conductivity (kcal / m · h · degree)
2 0 mesh
4 0 mesh
6 0 mesh