Mica Chemische Eigenschaften,Einsatz,Produktion Methoden
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Beschreibung
Cosmetic mica, potassium aluminum silicate dehydrate, is refined and ground to particles of ≤150 μm. This material imparts a natural translucence when used up to 20% in formulations of face powder blushes. Mica is available as wet ground (creamy) or as dry ground (matte).
Chemische Eigenschaften
Mica (muscovite), takes the form of a colorless,
odorless solid that separates into flakes or thin sheets
of hydrous silicates.
Occurrence
Mica exists in nature in a wide variety of compositions. Muscovite and phlogopite are the only natural micas of commercial importance. Vermiculite, although not considered a true mica by most mineralogists, is a micaceous mineral formed from the weathering of phlogopite or biotite and is also of commercial importance.
Verwenden
mica is used as a texturizer and coloring agent in cosmetics, it provides a “glimmer” or “shimmering” quality in makeup powders. Mica is the group name for a series of ground silicate minerals with similar physical properties but varied chemical composition. Micas range in color from colorless to pale green, brown, or black.
Definition
Any of several silicates of vary-ing chemical composition but with similar physicalproperties and crystalline structure. All character-istically cleave into thin sheets that are flexible andelastic. Synthetic mica is available. It has electri-cal and mechanical properties superior to those ofnatural mica; it is also water free.
Vorbereitung Methode
Mica is a nonfibrous, natural silicate, found in plate form in
nine different species. These materials are hydrous silicates,
and the predominant minerals of commerce are
muscovite, a hydrous aluminosilicate, and phlogophite, a
magnesium silicate. Sheet forms of mica in the form
of muscovite have historically been mined by hand from
pegmatites.
Allgemeine Beschreibung
MICA, a generic term, refers to any of a group of approximately 30 silicate minerals occurring as non-fibrous plates. Muscovite (hydrated aluminium potassium silicate[KAl2(AlSi3O10)(F, OH)2 ])and phlogopite (potassium magnesium aluminum silicate hydroxide) are the two major micas of commerce. Micas are commonly found in ordinary rocks. Inhalation of mica dust presents an occupational hazard.
Reaktivität anzeigen
MICAS have generally low chemical reactivity.
Hazard
(Dust) Irritant by inhalation, may be dam-aging to lungs. Pneumoconiosis.
Health Hazard
Mica dust causes
pneumoconiosis.
Landwirtschaftliche Anwendung
Biotite is a widely distributed and important rockforming
mineral of the mica group. The general term
designates all ferro-magnesium micas, also called black
mica or magnesium-iron mica. This black and plate-like
mineral is found in some igneous rocks, such as granite.
It is tetrahedral mica with aluminum substituted for
silicon in the tetrahedral sheet, and ferrous (Fe
2+) or
magnesium (Mg
2+)io ns in the octahedral sheet.
Potassium release occurs more easily
with biotite than with muscovite. Biotite is used as the
source of soil potassium. It is more easily weathered to
chlorite than muscovite and, therefore, is less common in
sediments. Although commercially unimportant under
hydrothermal conditions, biotite transforms to
vermiculite which expands on heating and has
widespread application as light-weight concrete, plaster
aggregate, insulation, plant growing medium and
lubricant.
Industrielle Verwendung
Commercial mica is of two main types: sheet,and scrap or flake. Sheet muscovite is used asa dielectric in capacitors and vacuum tubes inelectronic equipment. Lower-quality muscoviteis used as an insulator in home electrical productssuch as hot plates, toasters, and irons.
Scrap and flake mica is ground for use in coatingson roofing materials and waterproof fabrics,and in paint, wallpaper, joint cement, plastics,cosmetics, well-drilling products, and avariety of agricultural products.For many years, glass-bonded mica hasbeen used in every type of electrical and electronicsystem where the insulation requirementsare preferably low-dissipation factor at high frequencies,a high-insulation resistance anddielectric-breakdown strength, along withextreme dimensional stability. Glass-bondedmicas are made in both machinable grades andprecision-moldable grades. Basically, the materialconsists of natural mica flake bonded witha low-loss electrical glass.
The availability of synthetic mica resultedin the development of so-called ceramoplastics,consisting of high-temperature electricalglass filled with synthetic mica. Ceramoplasticsprovide an increase in the electrical characteristicsover those of natural mica, and, inaddition, are more easily molded and havegreater thermal stability.
Sicherheitsprofil
The dust is injurious to
lungs.
mögliche Exposition
Mica is used as reinforcing filler for
plastics, substitute for asbestos; for insulation in electrical
equipment; used in the manufacture of roofing shingles,
wallpaper and paint.
Inkompatibilitäten
Silicates react with lithium.
Waste disposal
Consider recycling, otherwise,
this chemical must be disposed of in compliance with existing
federal and local regulations. Landfill.
Mica Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
