What is mica?
Mica is a group of shiny minerals that belong to the classification of sheet silicates and non-metallic minerals, which means that it has a unique layered or two-dimensional sheet structure and is mainly found in metamorphic, sedimentary, and igneous rocks.
Chemical composition of mica
Mica is a natural mineral material with high chemical stability and is inert to solvents.
The main members of the mica family, muscovite, phlogopite and biotite, have the following chemical composition:
Muscovite (KAl2[AlSi3O10][OH]2, is composed of elements Potassium, Aluminum, Oxygen, Hydrogen, and Silicon.
Phlogopite (KMg3[AlSi3O10][OH]2), is composed of elements Potassium, Magnesium, Oxygen, Hydrogen, Aluminum, and Silicon.
Biotite (K[Mg, Fe]3[AlSi3O10][OH]2), is composed of elements Potassium, Oxygen, Hydrogen, Aluminum, Silicon, Magnesium, and Iron.
How many types of mica are there?
There are 37 kinds of mica, mainly muscovite, phlogopite, biotite, sericite, lepidolite, green mica, etc. The mica family is divided into three subfamilies of muscovite, biotite, and lepidolite. The mother subfamily mainly includes the more common muscovite, sericite, and the relatively rare sodium mica, the biotite subgroup includes phlogopite and biotite, and the lepidolite subgroup includes lepidolite and iron lithium.
Different mica species contain different elements and form in slightly different ways, so there are some differences in their colors.
Muscovite is also called ordinary mica or potassium mica. The flakes are colorless and transparent, and those containing impurities are slightly light yellow, light green, red and other colors.
Phlogopite is an aluminum silicate containing iron, magnesium, and potassium, and is usually yellowish-brown or reddish-brown, sometimes gray-green.
Biotite i
a silicate mineral because it contains iron, so the color is darker, brown, or black, and the color becomes darker as the iron content increases.
Sericite is a kind of natural fine-grained muscovite, which belongs to the subspecies of muscovite. The crystal aggregates are massive, showing gray, purple rose, white, and so on.
Lepidolite is the most common lithium mineral and one of the important minerals for extracting lithium. It usually also contains metal elements such as rubidium and cesium. It usually appears purple or pink, or it may be colorless.
Green mica is also a kind of iron-containing mica, and its color becomes darker with the increase of iron content, but its other elements are different from phlogopite, so the color is also different from phlogopite.
Iron lepidolite contains lithium and rubidium elements and is generally light brown or dark gray-green.
What are the characteristics of mica?
Mica has good elasticity, toughness, insulation, high-temperature resistance, acid and alkali resistance, corrosion resistance, strong adhesion, and other characteristics.
The physical properties of mica mainly depend on the size of mica crystals, the peeling property determined by cleavage and hardness, and the color transparency and elasticity of mica. Mica has perfect cleavage and can be peeled off. In theory, muscovite can be peeled into about 10 slices, and phlogopite can be peeled into about 5 or 10 flakes.
The thermal conductivity of mica is very poor, the melting point is 1200-1300 ℃; the specific gravity is 2.76-3.10. The hardness is 2~3 on the (001) plane, and 4 on the vertical (001) plane; it has excellent insulation and is hardly soluble in acid.
Is mica harmful to the human body?
Mica generally does not cause damage to the skin. Mica is a relatively common natural mineral that is often added to cosmetics and has a good moisturizing effect.
Occupational exposure case studies have shown that repeated exposure to large amounts of dust can irritate and possibly lead to lung scarring (fibrosis), which can lead to abnormal chest x-rays, weakness, shortness of breath, coughing, and weight loss.
Countries that mine mica
The main countries where mica is mined include India, Madagascar, China, Russian Federation, Finland, Malaysia, Spain, America, Sudan, South Korea, Canada, Argentina, Peru, Iran, South Africa, and Sri Lanka.
What is mica used for?
Mica is widely used, and high-quality mica can be made into various industrial insulating materials such as mica sheets, mica rolls, and mica tape. Ultrafine mica powder has the characteristics of anti-aging and corrosion resistance, and also plays many roles in life.
Application of mica sheets, rolls, and tapes in industrial electrical insulation
Mica sheets, mica rolls, and mica tapes are often used as insulating materials for electrical equipment and electrical equipment, used in capacitors, microwave ovens, steam boilers, smelting furnace windows, mechanical parts, etc., and can also be compounded with other reinforcing materials to improve their performance.
Application of mica powder in plastics
For example, if plastic is used outdoors for a long time and exposed to sunlight for a long time, the mechanical properties of the plastic product will be reduced, which will affect its use. This is because the ultraviolet light in sunlight breaks most chemical bonds and destroys polymer materials. To prolong life, some anti-ultraviolet aging agents, such as mica powder, are often added to polymer plastics. The layered structure of mica powder can improve the toughness and crack resistance of polymer plastic materials, and can also make the material have an ultraviolet light shielding effect through the polarizing effect of the mica layer.
The application of mica powder in beauty
Cosmetic-grade mica has a unique flaky structure, silky luster, and smooth texture, making the cosmetic powder as light and delicate as silk. Give cosmetics soft touch, soft luster, and strong skin adhesion. The crystalline transparency of mica powder allows the makeup color to maintain a consistent intensity and is also suitable for various shades of color.
Other applications
Mica is also widely used in chemical industries such as the building materials industry, fire protection industry, fire extinguishing agent, welding electrodes, papermaking, asphalt paper, rubber, and pearlescent pigments.
Highmica uses mica material to make mica paper, mica sheet, mica roll, mica tapes, mica tubes, and mica gasket for industrial use.
Visit highmica to know more information about mica products.
