Vermiculite

The name of vermiculite minerals comes from Latin, with "worm like" and "worm shaped" meaning. When vermiculite is suddenly heated to 200 to 300 degrees, it will be generated along the c axis of its crystal.
Vermiculite is a clay mineral similar to montmorillonite. It is a silicate with layered structure. Generally, biotite is altered by hydrothermal or weathering. It sometimes appears in the form of coarse biotite (which is a false appearance of vermiculite) and sometimes becomes finely ground. When vermiculite is heated to 300 degrees Celsius, it expands 20 times and bends. At this time, the vermiculite is somewhat like leech (leech commonly known as leech), so it has such a name. Vermiculite is generally brown, yellow and dark green, and has the same luster as oil. After heating, they become gray. Vermiculite can be used as building material adsorbent, fireproof insulating material, mechanical lubricant, soil conditioner, etc.
The introduction of vermiculite:
The properties and structure of vermiculite
Vermiculite, a magnesium aluminum silicate secondary metamorphic mineral, resembles a mica, usually formed by the hydrothermal alteration or weathering of the black (gold) mica, which is flexed when it is heated and dilated in the form of a leech, so it is called vermiculite.
The chemical formula of vermiculite is (Mg, Ca) 0.7 (Mg, Fe, Al) 6.0[(Al, Si) 8.0] (OH4.8H2O).
Vermiculite is divided into vermiculite ore and expansive vermiculite by stages. According to color classification, vermiculite can be classified into vermiculite, silver vermiculite and milky vermiculite.
The volume of vermiculite raw ore can be rapidly expanded by 8-20 times after high temperature roasting, and the specific gravity after expansion is 130-180kg/m3.
Under normal temperature and humidity, the C0 of Mg saturated vermiculite is 1.436nm, and there is a double water molecule layer between the layers, but the water molecular layer is incomplete. After water saturation, the C0 increases to 1.481nm. At this time, the whole layer of water molecules is filled. After partial dehydration of vermiculite by slow heating, the C0 of the vermiculite changed from 1.436 to 1.382nm. With continued dehydration, double layer water molecules will be reduced to single layer water molecules and C0 to 1.159nm. Further dehydration will change to a completely dehydrated structure (c0=0.902nm) and a structure with interphase of monolayer water molecular structure (c0=1.159nm), and its C0 is 2.06nm. After dehydration, the structure is similar to talc, and C0 is 0.902nm.