Asbestos is a type of silicate material that is fibrous, highly resistant to heat, and a fire retardant. As a matter of fact, asbestos is more of a general term, and it actually refers to a group of six silicate minerals that can be found in nature. They are microscopic so their durable fibers cannot be seen with the naked eye. The six silicate minerals are:
- Amosite
- Chrysotile
- Tremolite
- Anthophyllite
- Actinolite
- Crocidolite
Asbestos has many industrial and commercial applications because of its amazing, near-magical properties. Amosite and Chrysotile are the most commonly used forms of asbestos. On the flipside, asbestos has many health hazards which is why, in 1989, the EPA issued a ban on the use of asbestos. The ruling was known as the Asbestos Ban and Phase-Out Rule (ABPR). However, asbestos manufacturers filed a lawsuit against the EPA and the Fifth U.S. Circuit Court of Appeals overturned the ban.
The EPA did not appeal the Circuit Court ruling. Part of the court’s ruling stated that the ban could apply to products that were not being manufactured or imported at the time the ban was issued. That allowed the EPA to ban the use of asbestos in several types of paper, flooring felt, and rollboard. Asbestos is still widely utilized in the United States, and we’ll look at common applications later in this article. But for now, let’s take a look at the properties of asbestos.
Chemical Properties of Asbestos
- Asbestos fibers are insoluble in water and in organic solutions, and they do not evaporate in air.
- They are completely odorless.
- They do not travel through soil.
- They are chemically inert.
- Asbestos is nonflammable.
- They show resistance to acids, except for chrysotile, which dissolves in acid.
Physical Properties of Asbestos
- The one outstanding physical property that makes asbestos a celebrity in the field of industrial chemistry is that its tensile strength supersedes that of steel.
- It has a great thermal stability.
- Its electrical resistance is considered to be excellent, thus making it a good electrical insulator.
- The thermal resistance of asbestos makes it an insulator to heat.
- Its fibers are flexible and strong enough to be spun into a flame retardant material that is also chemically inert and a good insulator of heat and electricity.
- Itsability to bind with insulating materials makes it the ideal choice to be used as a material in construction.
It’s interesting to note that many asbestos minerals have a non-asbestos counterparts which have almost identical chemical compositions. For example, anthophyllite, tremolite, and actinolite have a non-asbestos form, and the word ‘asbestos’ is added after these silicate minerals to differentiate them from the non-asbestos form. On the other hand, amosite, chrysotile, and crocidolite have multiple non-asbestos forms that have distinct names.A mineral has fibrous as well as non-fibrous forms, and they might occur in the same deposit. That’s why it is important to determine the formation of asbestos; the pressure and temperature is able to metamorphose only some of the igneous rock into asbestos.
Applications
Asbestos is commonly used in the construction, automobile, and other industries. The most common uses of asbestos are:
- The automotive industry uses asbestos to make brake linings, brake pads, insulation for brake shoes, gaskets, clutch facings, and for materials used in valve packing.
- The construction industry uses asbestos in buildings. They are utilized in electrical and heating ducts, insulation for pipes, cement products and so forth.
- Asbestos is used in the home to make roofs, siding shingles, insulation material, ceiling joints, paints etc.
- It is also used to make fire-proof clothing.
Health Hazards
Asbestos is found in nearly two-thirds of the rocks present in the Earth’s crust. It is found all over the planet and reaches the surface of the earth through erosion. Surprisingly, about 10,000 to 15,000 fibers are inhaled every day by humans, but a low-level exposure does not pose any health risks.
However, continuous exposure to asbestos is one of the major causes of lung diseases, such as asbestosis and mesothelioma. Long-term exposure to asbestos can lead to lung cancer as well, which is why caution needs to be exercised while working with asbestos.
