The name of vermiculite is based on two Latin words: vermiculus – a worm, and lithos – a stone. Why a stone is understandable, because vermiculite is a natural mineral that is formed in the earth’s crust. In fact, it is hydromica. But the addition of the “worm” material received because of the appearance, which really resembles small worms or caterpillars.
Let’s clarify right away that a person in economic activities uses expanded vermiculite. For this, natural material is crushed and fired at a temperature of 500-1000 degrees. In the process of firing, the vermiculite structure becomes porous, an increase in volume takes place up to 25 times. That is why the material was named expanded. It is very light, free-flowing, porous, with a scaly structure and odorless.
There is GOST 12865-67, which distinguishes three fractions of expanded vermiculite:
- Large – with grains from 5 to 10 millimeters.
- Medium – with grains from 0.6 to 5 millimeters.
- Fine – with grains up to 0.6 mm.
The rest of the characteristics of vermiculite are as follows:
- On a mineralogical scale, it has a hardness of 1-1.5.
- The density of the expanded material is 0.065-0.13 g / cm3.
- It begins to melt at a temperature of 1350 degrees. This property provides vermiculite refractoriness, which is four times higher than that of conventional cement-sand mortars..
- Does not wear off, but its lubricating properties are similar to graphite.
- Does not rot, does not decompose, is biologically stable, rodents and insects do not start in it, is neutral to the action of acids and alkalis.
- It has good sound and heat insulation performance. Sound absorption coefficient of vermiculite – 0.7-0.8, thermal conductivity – 0.04-0.062 W / m · K.
The area of use of vermiculite is very wide. Like perlite, which we wrote about in detail, agrovermiculite is actively used in agriculture. If you want to improve the soil in your garden and vegetable garden, use this beneficial natural supplement. Vermiculite is also able to accumulate minerals and water in its porous structure, and then gradually release them for plants. This helps to improve the supply of nutrients to the soil and reduce losses from irrigation. Agrovermiculite is also used for growing seeds.
As for construction, expanded vermiculite is used for the following purposes:
- As an insulating backfill in wall structures, for floor insulation, including the creation of a warm floor system, attics and roof structures.
- In the process of creating paints and varnishes.
- To create lightweight concrete (vermiculite concrete), flooring, screeds.
- For the production of heat-insulating plasters, other building mixtures.
- As insulation for chimneys.
- For the production of thermal insulation boards (vermiculite boards).
The undoubted advantages of expanded vermiculite include:
- Environmental cleanliness. It is a natural material that can only be fired..
- No harmful substances are released during operation.
- Backfilling with fine fraction vermiculite allows you to fill all voids and effectively insulate walls, floors, ceilings, roofs.
- Vermiculite is not afraid of bacteria, rodents, and other pests.
- Plaster with the addition of vermiculite makes the facade attractive, crack-resistant. In terms of thermal insulation properties, a layer of vermiculite-cement plaster with a thickness of 25 millimeters is equivalent to a layer of ordinary cement-sand plaster with a thickness of 100 millimeters..
- This natural material is relatively inexpensive. The most expensive products include vermiculite slabs, but they also cost about 1,400-2,300 rubles for a product measuring 1200×600 millimeters (the price depends on the thickness). A cubic meter of expanded dry vermiculite for backfill can cost 6,000-8,000 rubles.
Russia has its own vermiculite deposits and the production of expanded vermiculite is well established, so this material can be confidently called local. When choosing options for home insulation, be sure to pay attention to vermiculite, which has decent characteristics and many advantages..