Siliciumdioxid Chemische Eigenschaften,Einsatz,Produktion Methoden
R-Sätze Betriebsanweisung:
R36/37/38:Reizt die Augen, die Atmungsorgane und die Haut.
R36/37:Reizt die Augen und die Atmungsorgane.
R22:Gesundheitsschädlich beim Verschlucken.
S-Sätze Betriebsanweisung:
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S37/39:Bei der Arbeit geeignete Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
S36:DE: Bei der Arbeit geeignete Schutzkleidung tragen.
S36/37/39:Bei der Arbeit geeignete Schutzkleidung,Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
Chemische Eigenschaften
white crystals or powder
Physikalische Eigenschaften
Colorless amorphous (i.e., fused
silica) or crystalline (i.e., quartz)
material having a low thermal
expansion coefficient and
excellent optical transmittance
in far UV. Silica is insoluble in
strong mineral acids and alkalis
except HF, concentrated H
3PO
4, NH
4 HF
2 , concentrated alkali metal hydroxides. Owing to its
good corrosion resistance to
liquid metals such as Si, Ge, Sn,
Pb, Ga, In, Tl, Rb, Bi, and Cd, it
is used as crucible container for
melting these metals, while silica
is readily attacked in an inert
atmosphere by molten metals
such as Li, Na, K Mg, and Al.
Quartz crystals are piezoelectric
and pyroelectric. Maximum
service temperature 1090°C.
Verwenden
Silicon(IV) oxide, amorphous is used as carriers, processing aids, anti-caking and free-flow agents in animal feed. Defoamer applications such as paint, food, paper, textile and other industrial applications. Synthetic silicon dioxides are used as a rheology control agent in plastics. It is also used to manufacture adhesives, sealants and silicones.
Definition
ChEBI: A silicon oxide made up of linear triatomic molecules in which a silicon atom is covalently bonded to two oxygens.
Allgemeine Beschreibung
contains sodium stabilizing counterion
Hazard
Not toxic if ingested, inhaled silica dust can
cause silicosis; carcinogen.
Landwirtschaftliche Anwendung
Silica is silicon dioxide, one of the most abundant
materials on the earth's crust. Quartz is an example of
silica. It is used as a filler in fertilizers, and also, in the
manufacture of glass, ceramics, abrasives, rubber and
cosmetics.
Sicherheitsprofil
The pure unaltered form is considered a nuisance dust. Some deposits contain small amounts of crystahne quartz and are therefore fibrogenic. When diatomaceous earth is calcined (with or without fluxing agents) some sdica is converted to cristobalite and is therefore fibrogenic. Tridymite has never been detected in calcined batomaceous earth. See also other silica entries
mögliche Exposition
Diatomaceous earth is used as
a filtering agent and as a filler in construction materials,
pesticides, paints, and varnishes. The calcined version
(which has been heat treated) is the most dangerous and
contains crystallized silica, and should be handled as silica.
See also other entries on silica
Versand/Shipping
This material is not singled out by DOT
in its
Performance-Oriented Packaging Standards.
läuterung methode
Purification of silica for high technology applications uses isopiestic vapour distillation from concentrated volatile acids and is absorbed in high purity water. The impurities remain behind. Preliminary cleaning to remove surface contaminants uses dip etching in HF or a mixture of HCl, H2O2 and deionised water [Phelan & Powell Analyst 109 1299 1984].
Inkompatibilitäten
Silica, amorphous is a noncombustible solid. Generally unreactive chemically. Incompatible with fluorine, oxygen difluoride, chlorine trifluoride. Soluble in molten alkalis and reacts with most metallic oxides at high temperature.
Waste disposal
Sanitary landfill.
Siliciumdioxid Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
