The Effect of Grinding on Tremolite Asbestos and Anthophyllite Asbestos

Bloise, Andrea; Kusiorowski, Robert; Gualtieri, Alessandro F.

doi:10.3390/min8070274

Cited by 19 publications

(12 citation statements)

References 43 publications

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“…any treatment that induces a complete chemical structural transformation of asbestos, as a preferable way to landfilling (The European Parliament resolution of 14 March, 2013) on asbestos-related occupational health threats and prospects for abolishing all existing asbestos [2012[ / 2065). Several studies have recently investigated asbestos inertization, via thermal, thermochemical, biological, mechanical treatments (Turci et al, 2007(Turci et al, , 2011a; Gualtieri et al, 2011;Kusiorowski et al, 2015a;Yamamoto et al, 2016;Spasiano, 2018;Bloise et al, 2018aBloise et al, , 2018bBloise, 2019).…”

Section: Introductionmentioning

confidence: 99%

Thermal inertization of amphibole asbestos modulates Fe topochemistry and surface reactivity

Pacella

Tomatis

Viti

et al. 2020

Journal of Hazardous Materials

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This study discloses the morphological and chemical-structural modifications that occur during thermal degradation of amphibole asbestos. Low-iron tremolite and iron-rich crocidolite were heated at temperatures ranging from r.t. to 1200°C. Heating promoted a complex sequence of iron oxidation, migration and/or clustering and, finally, the formation of brittle fibrous pseudomorphs consisting of newly formed minerals and amorphous nanophases. The effects of the thermal modifications on toxicologically relevant asbestos reactivity were evaluated by quantifying carbon-and oxygen-centred, namely hydroxyl ( % OH), radicals. Heating did not alter carbon radicals, but largely affected oxygencentred radical yields. At low temperature, reactivity of both amphiboles decreased. At 1200°C, tremolite structural breakdown was achieved and the reactivity was further reduced by migration of reactive iron ions into the more stable TO 4 tetrahedra of the newly formed pyroxene(s). Differently, crocidolite breakdown at 1000°C induced the formation of hematite, Fe-rich pyroxene, cristobalite, and abundant amorphous material and restored radical reactivity. Our finding suggests that thermally treated asbestos and its breakdown products still share some toxicologically relevant properties with pristine fibre. Asbestos inertization studies should consider morphology and surface reactivity, beyond crystallinity, when proving that a thermally inactivated asbestos-containing material is safe.

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Section: Introductionmentioning

confidence: 99%

Thermal inertization of amphibole asbestos modulates Fe topochemistry and surface reactivity

Pacella

Tomatis

Viti

et al. 2020

Journal of Hazardous Materials

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“…A reaction that occurs on grinding, such as this redox reaction, is generally known as a mechanochemical reaction [22,23]. High-intensity grinding, like planetary ball milling, has the ability to modify crystal structures of solid substances and/or induce a chemical reaction, which is referred to as mechanochemical reaction [24,25]. Mechanochemical reactions have a positive influence on hydrometallurgical processes and have been applied for metals dissolution from ores [2,5,22,23,[26][27][28]; however, these studies only focused on investigation of the reaction mechanism.…”

Section: Introductionmentioning

confidence: 99%

Structural Change Analysis of Cerianite in Weathered Residual Rare Earth Ore by Mechanochemical Reduction Using X-Ray Absorption Fine Structure

et al. 2019

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Prolonged high-intensity grinding can modify the crystal structure of solid substances and/or induce chemical reaction, which is referred to as mechanochemical reaction. Such reactions can exert positive influences on hydrometallurgical processes, therefore, many researchers have applied mechanochemical reactions for metals dissolution from minerals. The mechanism of mechanochemical reaction has been investigated using solid analyses and simulations. Structural changes caused by mechanochemical reactions are not yet sufficiently clarified because the ground samples are amorphous. The objective of this study was to analyze structural changes of cerianite in weathered residual rare earth ore by mechanochemical reduction. The ore was ground by planetary ball milling for 10, 60 and 720 min. Structural change was analyzed by the X-ray absorption near-edge structure and extended x-ray absorption fine structure analysis at the cerium LIII- and K-edges. These analyses revealed that the structural change of cerianite in this ore induced by mechanochemical reduction involved oxygen vacancy production. The process of the oxygen vacancy formation was closely coupled with the quantum effect of localization–delocalization of the 4f electron of cerium.

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“…At higher temperature value, the crystallization of forsterite [41] generates a sharp exothermic peak recorded at about 830 • C (Figure 6a; Table 2). After thermal analysis, the chrysotile structure has completely changed at a molecular scale because of a phenomenon called pseudomorphosis, which leads to the complete transformation of asbestos minerals into non-hazardous silicates such as forsterite [42,43]. DTG curves appear to be similar for most of the samples and show the main endothermic peaks related to the mineralogical phases decomposition between 500 and 830 °C (Figure 7).…”

Section: Thermal Analysis Characterizationmentioning

confidence: 99%

Assessment of Serpentine Group Minerals in Soils: A Case Study from the Village of San Severino Lucano (Basilicata, Southern Italy)

Punturo

Ricchiuti

Bloise

2019

Fibers

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Naturally occurring asbestos (NOA) is a generic term used to refer to both regulated and un-regulated fibrous minerals when encountered in natural geological deposits. These minerals represent a cause of health hazard, since they have been assessed as potential environmental pollutants that may occur both in rocks and derived soils. In the present work, we focused on the village of San Severino Lucano, located in the Basilicata region (southern Apennines); due to its geographic isolation from other main sources of asbestos, it represents an excellent example of hazardous and not occupational exposure of population. From the village and its surroundings, we collected eight serpentinite-derived soil samples and carried out Differential Scanning Calorimetry (DSC), Derivative Thermogravimetric (DTG) and Transmission Electron Microscopy with Energy Dispersive Spectrometry (TEM-EDS), in order to perform a detailed characterization of serpentine varieties and other fibrous minerals. Investigation pointed out that chrysotile and asbestos tremolite occur in all of the samples. As for the fibrous but non-asbestos classified minerals, polygonal serpentine and fibrous antigorite were detected in a few samples. Results showed that the cultivation of soils developed upon serpentinite bedrocks were rich in harmful minerals, which if dispersed in the air can be a source of environmental pollution.

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The Effect of Grinding on Tremolite Asbestos and Anthophyllite Asbestos

Cited by 19 publications

References 43 publications

Thermal inertization of amphibole asbestos modulates Fe topochemistry and surface reactivity

Thermal inertization of amphibole asbestos modulates Fe topochemistry and surface reactivity

Structural Change Analysis of Cerianite in Weathered Residual Rare Earth Ore by Mechanochemical Reduction Using X-Ray Absorption Fine Structure

Assessment of Serpentine Group Minerals in Soils: A Case Study from the Village of San Severino Lucano (Basilicata, Southern Italy)

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