| Revision as of 13:14, 8 January 2003 editHeron (talk | contribs)Administrators29,256 edits mineralogical details; deleted "formerly", as it's still used in some countries← Previous edit | Revision as of 13:22, 8 January 2003 edit undoHeron (talk | contribs)Administrators29,256 edits other mechanical propertiesNext edit → | ||
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| '''Asbestos''' is a |
'''Asbestos''' is a group of fibrous ]s. The fibres are typically mixed with cement or woven into mats. It is used in buildings for its flame-retardant and insulating properties, its tensile strength, flexibility, and its resistance to chemicals, but is now known to be ] and is banned in many countries. | ||
| == Types of asbestos == | == Types of asbestos == | ||
| *], or white asbestos, is obtained from Canadian serpentine rocks. It is less friable, and therefore less likely to be inhaled, than the other types and is |
*], or white asbestos, is obtained from Canadian serpentine rocks. It is less friable, and therefore less likely to be inhaled, than the other types and is the type most often used industrially. | ||
| *], or brown asbestos, is an amphibolic variety from Africa. | *], or brown asbestos, is an amphibolic variety from Africa. | ||
| *], or blue asbestos, is an amphibolic variety from Africa and Australia. | *], or blue asbestos, is an amphibolic variety from Africa and Australia. It is the fibrous form of ]. | ||
| Notes: Serpentine rocks are those with with curled fibres. Amphibolic rocks have straight, needle-like fibres. | Notes: Serpentine rocks are those with with curled fibres. Amphibolic rocks have straight, needle-like fibres. | ||
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| The amphibolic types, in their fibrous form, are friable and therefore the most carcinogenic, although they also exist in safer non-fibrous forms. | The amphibolic types, in their fibrous form, are friable and therefore the most carcinogenic, although they also exist in safer non-fibrous forms. | ||
| Other asbestos minerals, such as ], ] and ] are not used industrially but occur in traces. |
Other asbestos minerals, such as ], ] and ] are not used industrially but occur in traces. | ||
| In the United States, asbestos was one of the first hazardous air pollutants regulated under Section 112 of the ] of 1970. | In the United States, asbestos was one of the first hazardous air pollutants regulated under Section 112 of the ] of 1970. | ||
Revision as of 13:22, 8 January 2003
Asbestos is a group of fibrous metamorphic minerals. The fibres are typically mixed with cement or woven into mats. It is used in buildings for its flame-retardant and insulating properties, its tensile strength, flexibility, and its resistance to chemicals, but is now known to be carcinogenic and is banned in many countries.
Types of asbestos
- Chrysotile, or white asbestos, is obtained from Canadian serpentine rocks. It is less friable, and therefore less likely to be inhaled, than the other types and is the type most often used industrially.
- Amosite, or brown asbestos, is an amphibolic variety from Africa.
- Crocidolite, or blue asbestos, is an amphibolic variety from Africa and Australia. It is the fibrous form of riebeckite.
Notes: Serpentine rocks are those with with curled fibres. Amphibolic rocks have straight, needle-like fibres.
The amphibolic types, in their fibrous form, are friable and therefore the most carcinogenic, although they also exist in safer non-fibrous forms.
Other asbestos minerals, such as tremolite, actinolite and anthophyllite are not used industrially but occur in traces.
In the United States, asbestos was one of the first hazardous air pollutants regulated under Section 112 of the Clean Air Act of 1970.
Asbestos sometimes gets into phone lines and causes problems with DSL and modem connections.
See also: List of minerals, Eternit