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Transformation of Asbestos-Containing Slate Using Exothermic Reaction Catalysts and Heat Treatment
발열반응 촉매제와 열처리를 이용한 석면함유 슬레이트의 무해화 연구
Econ. Environ. Geol. 2019 Dec;52(6):627-35
Published online December 31, 2019;  https://doi.org/10.9719/EEG.2019.52.6.627
Copyright © 2019 the Korean society of economic and environmental gelology.

Sungjun Yoon1, Hyeonyi Jeong1, Byungno Park1, Yongun Kim1, Hyesu Kim1, Jaebong Park2 and Yul Roh2*
윤성준1 · 정현이1 · 박병노1 · 김용운1 · 김혜수1 · 박재봉2 · 노열2*

1Chonnam National University Center for Asbestos and Environment, Gwangju 61186, Republic of Korea
2Department of Geological and Environmental Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
1전남대학교 석면환경센터, 2전남대학교 지질환경과학과
Received November 6, 2019; Accepted December 16, 2019.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
 Abstract
Cement–asbestos slate is the main asbestos containing material. It is a product made by combining 10~20% of asbestos and cement components. Man- and weathering-induced degradation of the cement–asbestos slates makes them a source of dispersion of asbestos fibres and represents a priority cause of concern. When the asbestos enters the human body, it causes cellular damage or deformation, and is not discharged well in vitro, and has been proven to cause diseases such as lung cancer, asbestos, malignant mesothelioma and pleural thickening. The International Agency for Research on Cancer (IARC) has designated asbestos as a group 1 carcinogen. Currently, most of these slats are disposed in a designated landfill, but the landfill capacity is approaching its limit, and there is a potential risk of exposure to the external environment even if it is land-filled. Therefore, this study aimed to exam the possibility of detoxification of asbestos-containing slate by using exothermic reaction and heat treatment. Cement–asbestos slate from the asbestos removal site was used for this experiment. Exothermic catalysts such as calcium chloride(CaCl2), magnesium chloride(MgCl2), sodium hydroxide(NaOH), sodium silicate(Na2SiO3), kaolin[Al2Si2O5(OH)4)], and talc[Mg3Si4O10(OH)2] were used. Six catalysts were applied to the cement–asbestos slate, respectively and then analyzed using TG-DTA. Based on the TG-DTA results, the heat treatment temperature for cement–asbestos slate transformation was determined at 750°C. XRD, SEM-EDS and TEM-EDS analyses were performed on the samples after the six catalysts applied to the slate and heat-treated at 750°C for 2 hours. It was confirmed that chrysotile[Mg3Si2O5(OH5)] in the cement– asbestos slate was transformed into forsterite (Mg2SiO4) by catalysts and heat treatment. In addition, the change in the shape of minerals was observed by applying a physical force to the slate and the heat treated slate after coating catalysts. As a result, the chrysotile in the cement–asbestos slate maintained fibrous form, but the cement–asbestos slate after heat treatment of applying catalyst was broken into non-fibrous form. Therefore, this study shows the possibility to safely verify the complete transformation of asbestos minerals in this catalyst- and temperature-induced process.
Keywords : asbestos-containing slate, chrysotile, catalyst, transformation, heat treatment

 

December 2019, 52 (6)