Vermiculite has been used in various industries for over 80 years. It is used in the construction, agricultural, horticultural, and industrial markets.
VERMICULITE:(Mg,Fe++,Al)3(Al,Si)4O10(OH)2·4(H2O)
In commerce, vermiculite which expands more than 10 times the original volume is regarded of good quality. With an expansion below 10 times the original volume, vermiculite is considered of low grade.
VERMICULITE is the name used in commerce for a group of micaceous minerals that expand or exfoliate many times (commercial varieties esfoliate 8 to 20 times or more) the original thickness when heated. They show the characteristic micaceous structure of basal cleavage and occur as soft, pliable inelastic laminae. Their basal cleavages are not so perfect as those of mica. Vermiculite exists in a wide range of colours from black through various shades of brown to yellow. Its chemical composition varies widely consisting of a complex hydrated aluminium, magnesium silicate and hence the analysis of the mineral is of little use in determining the vermiculite for commercial utility; a technical trial of the material provides the only satisfactory test. Vermiculite owes its commercial utility to its property of exfoliation when heated. It exfoliates into a yellow to bronze coloured mass giving an appearance of a cluster of worms - vermiculus, an Italian word for worm from which it has derived its name as vermiculite. Some authorities quote the Latin word vermiculari from which the name vermicultie might have been derived.
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Properties Vermiculite crystallizes in the monoclinic system, and the crystal faces are often marked wth triangular lines at 60 degrees and 120 degrees. X-ray studies have indicated that vermiculite constitutes a specific type with a definite structure differing from that of mica or chlorite. From the tabulation of a number of analyses, Gruner has stated that its average composition can be represented by the formula 22MgO. 5Al2O3, 22SiO2. 40H2O whereas J. B. Myers gives the structural formula as (OH)2. (Mg,Fe)3 (Si, Al, Fe)4.O10.4H2O. The indefinite and variable chemical composition of vermiculite is indicated by the following ranges of major constituents in percentages: Silica, 31-41 Alumina, 10-17 Iron oxides, 5-22 Magnesium oxide, 11-13 Total water content (free water and water of crystallization) Nineteen varieties of vermiculite have been identified and listed. Colloquilly (mostly in England) vermiculite is known as Sunshine, Feather Gold and Golden mica. In Japan, it is known as Leach stone. Its hardness reanges from 1.5 to 3. The specific gravity of the crude material as mined is about 2.5, fusion point is approximately 1335ºC and specific heat is 0.2. The property of exfoliation together with the development of golden, bronzy or silvery lustre on heating is the outstanding characteristic ofvermiculite. This is one of the most important characteristics by which vermiculite differs from mica. Exfoliation commences from varying temperatures with different samples, in some cases as low as 150ºC. In industrial practice a temperature range between 800ºC-1100ºC (for a period of 4 seconds to 2 minutes) is employed. The exfoliation takes place solely in a direction perpendicular to the cleavage. Exfoliation is said to result from the expulsion of combined water by the purely mechanical effect of the sudden formations of steam. Certain qualities of vermiculite exfoliate and develop lustre when immersed in cold hydrogen peroxide (H2O2) or other oxidising agents such as a mixture of potassium permanganate (K2MnO4) and hydrochloric acid (HCl). In these cases the exfoliation is probably caused by the mechanical force involved in the liberation of oxygen from the reagent by the catalyst present in the vermiculite. It has been suggested that exchangeable magnesium ions present in the water layers are responsible for the liberation of oxygen. The moisture content of the mineral has a bearing on its price, and the combined water content gives an indication of exfoliation properties.
Vermiculite is the mineralogical name given to hydrated laminar magnesium-aluminum-ironsilicate which resembles mica in appearance.
Vermiculite mines are surface operations where ore is separated from other minerals, and then screened or classified into several basic particle sizes.
When subjected to heat vermiculite has the unusual property of exfoliating or expanding into worm-like pieces (the name vermiculite is derived from the Latin 'vermiculare' - to breed worms).
This characteristic of exfoliation, the basis for commercial use of the mineral, is the result of the mechanical separation of the layers by the rapid conversion of contained water to steam.
The increase in bulk volume of commercial grades is 8 to 12 times, but individual flakes may exfoliate as many as 30 times. There is a color change during expansion that is dependent upon the composition of the vermiculite and furnace temperature.
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.
Vermiculite is one of the safest, most unique minerals in the entire world. A hydrated Magnesium Aluminum Silicate, it is lightweight, inorganic (incombustible), compressible, highly absorbent, non-reactive (yet compatible in many chemical compositions as a functional filler), may have a high cation exchange capacity (surface chemistry may be modified), and is available locally and globally. Vermiculite is used in thousands of applications from potting soils, light weight concrete, fire protection construction materials, intumescent applications, as a UN approved packaging material for the safe shipment of hazardous liquids, texturizers in paints and coatings, and most recently as nanocomposites for films, coatings and barrier applications.
1.Silver white ones:
(1) Specs:
Particlediamet（mm） |
Lapis |
Water |
Specificvolume (times) |
0.3-1 |
<5% |
<5% |
>3.9 |
1-2 |
<5% |
<5% |
>6 |
2-4 |
<8% |
<5% |
>7 |
(2) Chemical components:
Elements |
SiO2 |
AL2O3 |
MgO |
CaO |
FeO |
Fe2O3 |
TiO2 |
content（%） |
41.2 |
12.68 |
24.22 |
0.96 |
1.54 |
4.06 |
1.33 |
Elements |
K2O |
P2O5 |
H2O |
Na2O |
MnO |
TfeO |
Burning Loss |
content（%） |
5.97 |
0.06 |
3 |
1.6 |
0.043 |
5097 |
6.71 |
Besides the product specs mentioned above, we can produce according to your requirements.
2.Golden ones:
(1) Chemical components:
Components |
SiO2 |
Al2O3 |
MgO |
CaO |
PH |
Fe2O3 |
impurity |
Content (%) |
41 |
18 |
21 |
0.8 |
8-11 |
3.5 |
<3 |
(2)Expanded vermiculite:
Levels |
Standard (mm) |
SpecificWeight(Kg/m3) |
Water Absorption(%) |
Impurity（%） |
1 |
>4 |
145 |
475 |
<3 |
2 |
2.5-4 |
190 |
450 |
<3 |
3 |
<2.5 |
200 |
420 |
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