#Vermiculite in India

Vermiculite is a hydrated laminar minerals resembling micaceous in appearance . It undergoes significant expansion when heated. Exfoliation occurs when the mineral is heated sufficiently, and the effect is routinely produced in commercial furnaces

. Vermiculite is a safe inert material and is light in colour.

vermiculite mines 

Moulded shapes: this process involves mixing exfoliated vermiculite with inorganic bonding agents such as silicates and  to produce an 'earth damp' mixture.

The moulded shapes and boards are used in:

Open fireplaces

High-temperature or refractory insulation

Acoustic panels

Fireproofing of structural steel  and pipes

   

vermiculite factory 

 

Calcium silicate boards: exfoliated vermiculite is added to a calcium silicate slurry. This is then dewatered by pressing and processes to form a flat board which is then heat cured under pressure (typically 10-15 bar) for periods of up to 24 hours.

Brake linings: finer grades of exfoliated vermiculite are being used in brake linings primarily for the automotive market. The properties  includes  its thermal resistance, ease of addition to other raw materials to achieve a homogeneous mix, and its shape and surface characteristics.

exfoliated vermiculite expanded 

vermiculite roof  insulation

vermiculite floor insulation 

Roof and floor screeds and insulating concretes: exfoliated vermiculite (typically the finer grades) can be added at site to Portland cement and other aggregates, additives , and water to produce roof and floor concrete screeds which are lightweight and insulating. In many cases, vermiculite-based roof screeds are used in enhancements  with other insulation materials, such as polystyrene board, to form a total roofing system. A bituminous binder can also be used with exfoliated vermiculite to produce a dry, lightweight roof screed which has the advantages of low thermal conductivity, low moisture content, and ease of placement by pouring from the bag and then tampering.

Soilless growing media: exfoliated vermiculite is combined with other materials such as perlite  or compost to produce soiless growing  media for the professional horticulturalist and for the home gardener. These mixes boosts faster root growth  and give quick anchorage to young roots. This mixture helps retain air, plant food, and moisture, releasing them as the plant requires them.Exfoliated vermiculite is also used as a hydroponics grow media

seed germination with  expanded vermiculite 

Seeds germination : vermiculite, alone or mixed with soil or peat, is used to germinate seeds; very little watering is required.

Storing bulbs and root crops: pour vermiculite around bulbs placed in container. If clumps are dug, allow to dry for a few hours in the sun and then place in cartons or bushel baskets and cover with vermiculite. The absorptive power of vermiculite acts as a regulator that prevents mildew and moisture fluctuation during the storage period. It will not absorb moisture from the inside of stored tubers, but it does take up free water from the outside, preventing storage rot.

As a soil conditioners : Where the native soil is heavy or sticky, gentle mixing of vermiculite - up to one-half the volume of the soil - is recommended. This creates air channels and allows the soil mix to breathe. Mixing vermiculite in flower and vegetable gardens or in  potted  plants will provide the necessary air to maintain vigorous plant growth. Where soils are sandy, mixing of vermiculite into the soil will allow the soil to hold the water and air needed for growth.

As loose-fill  insulation : Exfoliated vermiculite treated with a water repellent is used to fill the pores and cavities of masonry construction and hollow air cavities work to enhance fire ratings   thermal insulation, and acoustic performance. Expanded vermiculite has also been used as thermal insulation in the attics and walls of houses and in water heaters, fire safes, stoves, furnaces, and refrigerators

Refractory/Insulation gunning and casting mixes: exfoliated vermiculite can be combined with high alumina  cements and other aggregates such as expanded shale, clay, and slate to produce refractory/insulation concretes and mortars. In the early days of their use, these products were batched at or very close to the place of installation; this continues to be the case in some limited circumstances, however more and more use is being made of pre-batched, proprietary mixes. Mixes containing vermiculite are used in areas where strength and corrosion/abrasion resistance are of secondary importance, the most important factor being the insulation performance of the in-place refractory lining. These mixes are used in industries including iron/steel, cement, and hydrocarbon processing

As a lightweight aggregate for plasters , lightweight concrete compounds, fireproofing mortar, and cementitious spray fireproof  : Exfoliated vermiculite is used in both hand and spray-applied general building plasters to improve coverage, ease of handling, adhesion to a wide variety of substrates, fire resistance, and resistance to chipping/cracking/shrinkage.

As a hot topping(ladel) : both exfoliated and crude vermiculite have been used for hot topping in the steel industry. When poured onto molten metal, crude vermiculite exfoliates immediately and forms an insulating layer, allowing the material to be transported to the next production process without losing too much heat.

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Used in in-ground swimming pools to provide a smooth pool base: Finer grades of exfoliated vermiculite plus Portland cement may be combined either on-site or in a factory premix to provide a base for swimming pool vinyl liners. These mixes are pumped into place using a rotor stator pump, or hand poured.

  Perlite and vermiculite have been used for years to amend professional potting soils made from peat moss (called "soilless" mixes or artificial soils because they literally contain no soil). They also have been used in outdoor mixes, in turfgrass and outdoor plantings, for gardens, for special 100% perlite or vermiculite growing applications, and increasingly for commercial and amateur hydroponic growing and water conservation (especially in landscaping and gardening). 

Essentially perlite and vermiculite are used in the horticultural industry because they both provide aeration and drainage, they can retain and hold substantial amounts of water and later release it as needed, they are sterile and free from diseases, they have a fairly neutral pH (especially perlite which is neutral), and they are readily available, non-toxic, safe to use, and relatively inexpensive. As a rule of thumb, perlite tends to last longer, has a more neutral pH, and functions much better in hydroponics, outdoor applications, lawns and gardens (in part because it is stronger). Nevertheless, for decades they both have been used by professionals, dedicated amateurs and gardeners. Perlite and vermiculite have been used for years as an aggregate in lightweight, insulating concrete and plaster, and as a loose fill insulation material for concrete masonry blocks, cavity walls, and in residential homes. They also are used in a variety of specialty applications ranging from fireproofing sprays, chimney fills, interstitial floors, acoustical sprays, etc.