Morphological behavior of Tremolite subjected to grinding

Oliviero Baietto,Giovanna Zanetti,Paola Marini

doi:10.5194/egusphere-egu22-7250

Abstract

&lt;p&gt;The main morphological characteristic, related to the dangerousness of the six minerals defined as asbestos, is the crystallization of the mineral itself with a fibrous habit.&lt;/p&gt;&lt;p&gt;In different geological conditions these minerals can crystallize even with different morphological aspect. The fibrousness of the mineral is fundamental to define its carcinogenicity because, when these fibres are inhaled, they can cause serious diseases.&lt;/p&gt;&lt;p&gt;Different studies has already showed that the grinding of fibrous minerals can showed a decrease in dehydroxylation and breakdown temperatures due to the increase in lattice strain and the decrease in crystallinity.&lt;/p&gt;&lt;p&gt;In this study the answer to the grinding of different Tremolite with different crystal habit are studied. Tremolite, which is classified as carcinogenic substances group 1 by the IARC, is a hydrated calciummagnesium silicate (Ca2Mg5Si8O22(OH)2), belonging to the tremolite-ferro-actinolite series, that can crystallize with two different habits: fibrous, known as asbestiform, or prismatic, known as non-asbestiform.&lt;/p&gt;&lt;p&gt;This decision arises from the need to verify if the tremolite with prismatic habit, if subjected to a grinding process, can produce potentially harmful fibers. These events can happen during natural degradation processes of rocks (weathering of outcrops) or during anthropic intervention, such as the mechanized excavation or earthmoving process (transport).&lt;/p&gt;&lt;p&gt;Following the definition of fiber from the Health and Safety Executive, a dimensional analysis, based on a direct measurement of the particle size (length and diameter), has been carried out. The results of this research indicate that the prevalent morphology of an amphibolic mineral can change habit. Moreover, the production of prismatic components in an amphibolic mineral by means of grinding action (digging or earthmoving), can generally be a safer situation for the exposed subjects, such as workers and inhabitants.&lt;/p&gt;

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