Study on the thermal decomposition of chrysotile asbestos

This article reports the possibility of detoxification of chrysotile asbestos through a low temperature heating and grinding treatment. The effect of thermal treatment at different temperatures in the range from 500 to 725 A degrees C for 3 h on raw natural asbestos was characterized by thermal analysis, X-ray diffraction, and scanning electron microscopy. It was found that an isothermal treatment at 650 A degrees C caused the complete dehydroxylation of chrysotile Mg3Si2O5(OH)(4). Transformation of the dehydroxylated phase to forsterite Mg2SiO4 was obtained by heat treatment in the range 650-725 A degrees C. The study of microstructure changes of heated asbestos show the destruction of characteristic fibers of chrysotile and formation of strips of forsterite. It is easily milled to pulverulent-shape material by mechanical milling in vibratory mill.