On the shelves of garden shops for a long time appeared packaging with the inscription "Vermiculite." Most gardeners and gardeners, as well as ordinary citizens, do not know what kind of material it is and why it is needed. So, vermiculite - what is it and where is it used? We will try to answer this question in the article, as well as to tell in detail about how and from which it is obtained, and about the possibilities of using this mineral.
What kind of material is this?
Natural vermiculite is a natural mineral from the hydromica group, formed as a result of leaching and weathering of biotite mica. Outwardly, it looks like a plate-like crystal of a yellowish-brown color. But after heating it to a temperature of 900 ° C it turns into expanded vermiculite. Its plates become like columns, somewhat reminiscent of worms, which was reflected in the name, because vermiculus is translated from Latin into Russian as “worm, worm-like”.
Physicochemical Characteristics
Vermiculite, found in nature, is colored silver, golden, brown, green and black. It contains oxides of silicon, iron, calcium, potassium, magnesium and other trace elements.
In addition, it does not contain heavy metals and any toxic components, and also does not react with alkalis and acids. Due to this, vermiculite is widely used for plants both in decorative floriculture and in gardening.
It is also important that this mineral is not subject to decay and decomposition under the influence of natural and biological factors. Because of this, various microorganisms, insects and animals do not settle in it.
It is worth emphasizing, speaking about vermiculite, that it is a highly porous material with excellent moisture-absorbing properties. The water absorption coefficient of this mineral is 400%. This means that 100 g of vermiculite can absorb 400 ml of water.
Thus, this natural mineral has the following properties:
- environmental friendliness;
- durability;
- chemical and biological inertness when interacting with aggressive environments;
- low thermal conductivity;
- high fire resistance;
- low density.
Where is it mined?
This natural material was accidentally discovered in the 19th century, and has since been explored and mined. As already mentioned, vermiculite is a mineral whose deposits exist both in Russia - in the Krasnoyarsk Territory, the Kola Peninsula, the Irkutsk and Chelyabinsk Regions, and in the near abroad: in Kazakhstan, Uzbekistan, and Ukraine. In addition, its production is conducted in Australia, India, South Africa, Uganda and the United States. In the state of Montana, near the town of Libby, the largest and most profitable American mineral deposit is located.
How is recycling
The extracted vermiculite is subjected to special processing at processing plants. There, mica is selected and sorted, some of which is subsequently sent to electrical production, and the rest is hydrothermally processed in conveyor ovens at a temperature of about 760 ° C.
As a result of this effect, individual particles of the mineral are stratified and swollen, and expanded vermiculite is obtained at the output. During further processing, the resulting mass is crushed to a predetermined value.
Features of Expanded Vermiculite
As already mentioned, this natural mineral undergoes industrial processing by roasting, during which it significantly increases in volume and exfoliates into worm-like particles. A similar change is due to water, which is in the structure of vermiculite in a bound state. Under the influence of high temperatures, it heats up and is converted into steam, which spreads, delaminates the mica plates, thereby increasing the volume. Thus, we can talk about expanded vermiculite that this is a “burned” mineral with a changed structure.
What are the fractions?
This mineral is ground to different fractions, which are classified according to size. There are 5 groups in total, where 1 is the largest, the size of a small coin, and 5 is a suspension resembling dust or fine sand. Unfinished vermiculite - insulation, widely used in construction for backfilling into hollow panels.
In floriculture and plant growing, vermiculite from 2 to 4 fractions is usually used. This material in its dry form is quite light, but after wetting, its weight increases almost 5 times, due to the absorbed and retained water.
Fields of application
Recently discovered, a mineral such as vermiculite and its derivatives have found many different applications today:
- Ecology, oil and chemical industries. Few people will be able to answer when asked about vermiculite, that it is an excellent sorbent that can bind alkalis and acids. This property allows you to use it to neutralize a variety of chemicals in production, as well as to limit oil spills.
- Nuclear industry and energy. It is used as an absorber of such radioactive elements as cobalt-58, strontium-90 and cesium-137, as well as a reflector of gamma radiation.
- Automotive and aviation industry. A variety of sound-absorbing and heat-insulating materials and products are made from vermiculite.
- In industrial and civil engineering, vermiculite is used as follows:
- insulation, as well as sound and heat insulators for roofs and floors;
- for filling as a warming material in hollow panels;
- as an integral component of various plasters, lightweight concrete and dry building mixtures;
- in the manufacture of concrete and cement blocks, as well as heat-insulating mastics as a filler;
- in the manufacture of fireproof and heat-resistant boards, panels and other wall materials;
- when arranging bulk floors.
5. In industrial and private crop production and gardening. Let us consider in more detail how vermiculite is used for plants.
Features of use in crop production
This mineral, which has undergone industrial processing, is widely used at all stages of plant growth and development:
- when germinating seeds and for rooting cuttings that are not affected by various microorganisms - pathogens and fungi, and also receive all the necessary nutrients and trace elements;
- to create various soil mixtures and give them the necessary friability and porosity;
- when growing hydroponic crops;
- as a drainage layer for a variety of plantings of both potted and garden plants;
- for mulching landings;
- for winter storage of various onion and corm onion crops: vermiculite not only maintains normal temperature and gas conditions, but also prevents damage to planting material by various diseases and pathogens;
- in the process of creating compost.
Speaking about vermiculite - what it is, what it is needed for, it is worth recalling a few simple rules that you must follow when working with it:
- The used material can be reused, but only after obligatory calcination.
- Since it absorbs a lot of water and gives it to plants for a long time, one should remember this and not allow excessive watering, which can lead to waterlogging of the soil and death of plants.
- Two mineral substances - perlite, vermiculite - have similar properties, which allows you to use them together when growing plants.
- It is important to remember that vermiculite interacts with hard water and can “shift” the acidity of the soil to the alkaline side. That is why most experts recommend using pure vermiculite only for germinating seedlings or when working with hydroponic crops, when the qualitative composition of water is known and constant.