Natural mica has exceptional physical characteristics. It can be found throughout the world, most notably in the presence of Paleozoic rocks. Accessible deposits are located primarily in India, on the American continent, in southern Africa and in Russia.
As a mineral, mica has a special characteristic - it can be cleft to obtain very thin flakes of constant thickness.
Mica's chemical composition places this mineral in the aluminum silicate group. Two types are extracted - Muscovite, in which there is a predominance of potassium and Phlogopite, in which the presence of magnesium can be detected.
K Al2 (Al Si3 O10) (OH)2
This is the most widespread mineral, and the name comes from the city of Moscow - in the Middle Ages, large deposits were used nearby to make windows.
It contains potassium and is light in appearance.
The mechanical properties are better than those of Phlogopite.
K Mg3 (Al Si3 O10) (OH)2
Phlogopite contains magnesium and is dark in appearance.
It can withstand higher temperatures than Muscovite.
Mica's chemical composition places it in the aluminium silicates group. Two types are extracted - Muscovite, in which there is a predominance of potassium and Phlogopite, in which the presence of magnesium can be detected.
Mica can withstand temperature in excess of 1000°C / 1830°F (Phlogopite), it is flame-retardant, non-flammable, does not give off fumes, and conducts very little heat, especially perpendicular to its strata.
Natural mica has a dielectric strength greater than 25 kV/mm (625 V/mil), has good resistance to arcing and electrical erosion, and is permeable to microwaves.
Mica is tolerant of water and most chemical agents, such as solvents, acids, bases and mineral oils.
Mica has good compressive strength. It behaves well in the presence of tensile and bending stresses. It has a high modulus of elasticity.
Retaining the properties of natural mica
COGEBI has perfected technology that allows the agglomeration of mica fragments to create a homogenous material in continuous production. The COGEBI process subjects the mineral to the action of a highly pressurized water jet, producing flat particles several microns thick, whose physical and chemical properties have been carefully preserved.
The resulting water slurry is fed to a special type of paper machine, which forms a continuous sheet of mica paper. At this stage, there is no need for a binding agent to hold the particles together, because their existing natural intermolecular attraction is usually sufficient.
This 100% mica paper is called Cogemica produced in Lot (Belgium) or Remika produced in Tabor (Czech Republic), and is based on either Muscovite or Phlogopite.
All the products marketed by COGEBI are asbestos-free. Mica, supplied in the form of flakes, is innoxious and has extremely good thermal and mechanical properties, making it a suitable alternative to asbestos in a wide range of applications.