Asbestos
This article is about the minerals. For the city of the same name in Russia, see Asbestos (city).
Asbestos (Ancient Greek ἄσβεστος asbestos, German 'unvergänglich'; historically also called mountain flax or amiant) is a collective name for various naturally occurring, fibrous crystallized silicate minerals which, after processing, yield technically usable fibers of varying lengths. The fibre of magnesioriebeckite or crocidolite from the hornblende group (also called blue asbestos) is bluish, the fibre of chrysotile (serpentine group) is white or green. Other minerals belonging to asbestos are grunerite (amosite, brown asbestos), anthophyllite and actinolite. Chrysotile, also known as white asbestos, has had by far the widest technical application, largely as a reinforcing fiber in asbestos cement.
Asbestos was also called "miracle fibre" because it has great strength, is heat and acid resistant, provides excellent insulation and the asbestos fibres can be spun into yarns and these woven. With these prerequisites, asbestos has been able to establish itself in the shipyard industry for shipping, in thermal insulation, the construction industry, the car tyre industry and for textiles in the field of industrial safety and filtration. Due to the now clearly established health hazards posed by asbestos, its use is now banned in many countries, including the USA (permitted for certain applications), the EU and Switzerland (since 1990). Today, the focus is mostly on disposal.
Asbestos Minerals
Asbestos-type minerals occur in two fine-fibered siliceous mineral groups, categorized as follows:
| Asbestos Group | Mineral names | Sum formula | Trivial name | Comments |
| Serpentine Group | (Clino-)Chrysotile | (Mg,Fe,Ni)3Si2O5(OH)4 | White asbestos | the most widely used type of asbestos in industry |
| Amphibole Group | Grunerite / Ferro-Anthophyllite / Mysorite | Fe7Si8O22(OH)2 | Brown Asbestos | "Amosite" |
| Riebeckite / Crocidolite / Magnesioriebeckite | Na2Fe2+3Fe3+2Si8O22(OH)2 | Blue Asbestos | ||
| Tremolit | Ca2Mg5Si8O22(OH)2 | |||
| Actinolite | Ca2(Mg, Fe)5Si8O22(OH)2 | |||
| Anthophyllite | (Mg, Fe)7Si8O22(OH)2 |
Properties
Asbestos is very resistant to heat up to about 1000 °C and weak acids as well as very many chemicals and has a higher weight-specific tensile strength than steel wire. It is rot-proof and mixes very well with cement. At temperatures above 1200 °C, asbestos converts to olivine and its modifications. At even higher temperatures, asbestos sublimates. Due to the fineness of the fibres, the material is very durable.
Questions and Answers
Q: What is asbestos?
A: Asbestos is a set of six silicate minerals occurring naturally.
Q: What is the most common form of asbestos found in buildings?
A: White asbestos makes up 95% of the asbestos found in buildings.
Q: What properties of asbestos made it an attractive component in building materials and other products?
A: Asbestos's fibrous, heat-resistant and non-flammable properties made it an attractive component in building materials and other products.
Q: Is asbestos dangerous for human health?
A: Yes, asbestos is extremely dangerous for human health as it can cause lung diseases such as asbestosis, emphysema and mesothelioma if its fibres get loose in the air.
Q: Has asbestos been used by people throughout history?
A: Yes, people have used asbestos throughout history. Ancient Egyptian people used asbestos.
Q: Can asbestos also harm animals?
A: Yes, it can also harm animals such as livestock or pets.
Q: Was asbestos replaced by other materials in most applications by 1980?
A: Yes, asbestos was linked to lung cancer in the early 1970s, and was replaced by other materials in most applications by 1980.
