Wherever any substance is put in fire it burns and changes into ash. But asbestos is one such material that does not burn in fire. That is why the fireman wear clothes made from asbestos when they enter the burning house. In fact their clothes, shoes, gloves, helmets etc. are all made from the fibres of this material.
‘Asbestos’ is a Greek word that means ‘inextinguishable’ or ‘unquenchable’. The invention of this material is not new. The Romans used asbestos sheet 2,000 years ago for wrapping dead bodies in order to preserve them.
Asbestos is obtained from mines. It is formed by the dissociation of olivine. Olivines are the silicates of calcium and magnesium. Due to some chemical reactions in the mines, olivine changes into fibres of asbestos. Asbestos obtained from mines is dried and then its fibres are separated with the help of machines. Threads and ropes are made from these fibres. They are then used for making clothes, sheets, mats etc.
Asbestos is very useful material. It is used for making fire-proof clothes, paper and is used as heat insulator in furnaces. It is also used for making fire proof tiles for buildings. In cold countries, water pipes are coated with this material so that water may not freeze in the pipes. It is also used for making fire proof paints, rubber, plaster and porcelain.
Asbestos is a bad conductor of both head and electricity. It is least affected by acids and alkalises. It does not burn even at the temperature of 2000º C to 3000º C. Some special varieties of asbestos are now available which do not burn even at 5000º C. This is used in research laboratories.
Canada produces 75% of the total world production of asbestos. America manufactures maximum number of item from asbestos, though the raw material obtained in this country is only 5%.
