Difference between revisions of "Fumed silica"
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| + | [[File:Fumed silica process.png|thumb|Schematic of the production of fumed silica Image Credit: [https://commons.wikimedia.org/wiki/File:Fumed_silica_process.svg Wikipedia] ]] | ||
== Description == | == Description == | ||
| − | [Degussa] A colloidal form of [[silica]] | + | [Degussa] A lightweight, fluffy white powder that is a colloidal form of [[silica]]. Fumed silica, also called aerosol silica, is made by the combustion of silicon tetrachloride in a hydrogen-oxygen furnace. This produces tiny, non-crystalline, spherical particles of varying sizes. Untreated fumed silica is hydrophilic, but many commercial products have been treated to make them hydrophobic. Generally, silanes or siloxanes are used to replace hydroxyl groups on the surface and thus prevent the absorption of moisture. Fumed silica is approved by the U.S. FDA for use in food products. |
== Synonyms and Related Terms == | == Synonyms and Related Terms == | ||
Revision as of 11:28, 8 August 2023
Description
[Degussa] A lightweight, fluffy white powder that is a colloidal form of Silica. Fumed silica, also called aerosol silica, is made by the combustion of silicon tetrachloride in a hydrogen-oxygen furnace. This produces tiny, non-crystalline, spherical particles of varying sizes. Untreated fumed silica is hydrophilic, but many commercial products have been treated to make them hydrophobic. Generally, silanes or siloxanes are used to replace hydroxyl groups on the surface and thus prevent the absorption of moisture. Fumed silica is approved by the U.S. FDA for use in food products.
Synonyms and Related Terms
aerosol silica; colloidal silica; pyrogenic silica; thermal silica;
Commercial products: Aerosil® [Evonik]; Cab-O-Sil [Cabot]; HDK [Wacker Chemie]; Zandosil [Dow Corning]; Reolosil [Tokuyama Corp.]; Konasil [OCI]; Orisil [Orisil]; XYSIL [Xunyuchem]
Applications
- Matting agent
- Thickener
- Filler
- Desiccant to kill insects
Risks
- Inhalation may cause silicosis; used dust mask.
- Integra Chem: SDS
Physical and Chemical Properties
- CAS = 112945-52-5
- Composition = SiO2
- Density = 2.0 - 2.2 g/cm3
- Melting point = 1700 C
- Decomposition = >2000C
- Moisture content = 0.5-2.5 % (Hydrophilic); 0.5% (hydrophobic)
- Adsorbed moisture = 6%
- Refractive index = 1.46
- Particle size = 5-40 nm
Resources and Citations
- Wikipedia: Fumed silica Access July 2023
- George Wypych, 'FILLERS – ORIGIN, CHEMICAL COMPOSITION, PROPERTIES, AND MORPHOLOGY, in Handbook of Fillers (Fourth Edition), 2016Chapter 2.1.79.1 Fumed Silica