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Badania azbestu i materiałów zawierających azbest w obecności fosforytów ze złóż Syrii i Tunezji

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Domka L. , Jałoszyńska M. , Kozak A.

Rocznik Ochrona Środowiska

2007

tom Tom 9

345-358

Asbestos (from the Greek word asbestos) means indestructable, inextinguishable. This is trade name regarding group of six minerals with fibrous structure, resistant to acids and bases, fire-proof, not conducting heat and electricity. These are hydrated silicates belonging to two groups of minerals: serpentinites and amphiboles. Minerals from group of serpentinites are characterized by chain structure where n of anions [SiO3] are repeated through the whole crystal along the single chain in the direction of the axis. Minerals from the group of amphibole have the ribbon type of structure, forming in the result of silica - oxygenic tetrahedrons chains overlapping. These chains are bound between themselves with bonds of interpolated cations. Sodium, magnesium, iron and calcium belong to main cations contained in amphiboles. Initially asbestos was treated as the harmless substance. Only in eighties and nineties of XX century suitable services took concrete position in the matter of harmfulness of asbestos on human health and natural environment. Investigations proving above every doubt harmfulness of asbestos filaments on human health were carried out in early seventies of the last century. Since then process of withdrawing asbestos from production has started and arduous and expensive process of removing materials containing asbestos. Samples of asbestos together with phosphorite were irradiated by microwave field of 80 W of power and then melted in muffle stove for 2 hour in the temperature 1000oC in the presence of KHSO4 as the flux, in the carried out investigations. Second series of samples (mixture of asbestos and phosphorite) was subjected to only microwave field of 80 W of power. Results of both series were followed in scanning electron microscope SEM and on the basis of derivatographic and X-ray analysis results. In both cases, when samples underwent one cycle of microwaves and ten cycles of microwaves one can see the clear change of the sample structure in the SEM photographs. In both cases fibers of asbestos melted into one piece (photo 2 and 3). Photo 3 of sample subjected to ten cycles of microwaves shows change of the sample structure from fibrous to amorphous additionally, which is devoid of carcinogenic properties