• Korean Journal of Mineralogy and Petrology
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• v.33 no.4
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• pp.407-417
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• 2020

The capacity of the designated landfill site for asbestos-containing waste is approaching its limit because the amount of asbestos-containing slate is increasing every year. There is a need for a method that can safely and inexpensively treat asbestos-containing slate in large capacity and at the same time recycle it. A cement kiln can be an alternative for heat treatment of asbestos-containing slate. We intend to develop a pilot scale device that can simulate the high temperature environment of a cement kiln using a high temperature plasma reactor in this study. In addition, this reactor can be used to inactivate asbestos in the slate and to synthesize one of the minerals of cement, to confirm the possibility of recycling as a cement raw material. The high-temperature plasma reactor as a pilot scale experimental apparatus was manufactured by downsizing to 1/50 the size of an actual cement kiln. The experimental conditions for the deactivation test of the asbestos-containing slate are the same as the firing time of the cement kiln, increasing the temperature to 200-2,000℃ at 100℃ intervals for 20 minutes. XRD, PLM, and TEM-EDS analyses were used to characterize mineralogical characteristics of the slate before and after treatment. It was confirmed that chrysotile [Mg3Si2O5(OH)4] and calcite (CaCO3) in the slate was transformed into forsterite (Mg2SiO4) and calcium silicate (Ca2SiO4), a cement constituent mineral, at 1,500℃ or higher. Therefore, this study may be suggested the economically and safely inactivating large capacity asbestos-containing slate using a cement kiln and the inactivated slate via heat treatment can be recycled as a cement raw material.

• Economic and Environmental Geology
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• v.52 no.6
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• pp.627-635
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• 2019

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℃. 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℃ 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.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.4
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• pp.201-208
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• 2011

Objectives: According to the compliance of the asbestos-related regulation, every building has to be inspected for asbestos presence before its abatement work. This study was performed for identifying the types and contents of asbestos in building bulk samples. Materials and Methods: Bulk samples were collected during the asbestos inspection in 2010. We grouped the bulk samples into the regulated asbestos containing materials(RACM), presumed asbestos containing materials(PACM), and construction products. Additionally, the types of asbestos in all bulk samples were identified by polarization microscopy(PLM). Results: The RACMs were from building, house, pipe and facility. The RACMs were found mainly building (72.1%) and house (93.7%). The contents of chrysotile in building, house and facility were 66.9% (1-90%), 89.7% (2-90%) and 11.0% (2-90%), respectively. PACMs were surfacing material, thermal system insulation (TSI), and miscellaneous material. The miscellaneous materials that showed a high detection rate (79.2%) were ceiling, roofing and wall materials. Among them, the roofing materials had high chrysotile content(9.7%, 2-21%), followed by wall (8.7%, 2-21%) and ceiling (3.4%, 1-17%). In the construction products, asbestos was found mainly in slate (92.6%, 2-21%), including chrysotile. The slate had high asbestos content (9.7%, 2-21%), followed by cement flat board (8.7%, 2-19%) and textile (3.4%, 1-17%) Conclusions: Utilizing these results, it would be contributed to construct a useful ACM database and prevent from asbestos exposure to workers in the asbestos abatement and maintenance works.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.2
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• pp.184-193
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• 2015

Objectives: This study focused on three aspects: characterizing concentrations of airborne particles by size distributions and asbestos fibers generated by various building materials; analyzing the characteristics of fibers produced by each simulation and asbestos fibers released from ACBMs; and investigating correlations of airborne asbestos fibers and particles generated and association of particle and asbestos concentrations. Methods: We selected three ACBMs including an insulation board, cement asbestos slate and wallboard. We constructed 4 scenarios; a) crushing with a hammer; b) cutting with a industrial knife; c) brushing with a metal brush; and d) tightening & loosening with a hand drill. We implemented one simulation for 30 seconds followed by 30 seconds resting period. We repeated a total of 5 cycles for 5 minutes. Results: The highest concentration of particulate & fibrous matters was from crushing with a hammer in each scenario followed by brushing with a metal brush, cutting with a industrial knife, and tightening & loosening with a hand drill. For ACBMs studied, asbestos concentrations were highest from an insulation board followed by cement asbestos slate, and wallboard. No difference in terms of concentration was found between an insulation board and asbestos slate. Fibers with $5{\sim}20{\mu}m$ in length were included in 76~90% of total fibrous matters. The distribution of the straight form fibers was greater than that of the curl form. About 90% of $PM_{Total}$ released from ACBMs was consisted of $PM_{10}$ while only 10% of $PM_{Total}$ was $PM_{2.5}$. Particulate matters like $PM_{2.5}$ was significantly correlated with fibrous matters($R^2=0.81$). Conclusions: We found ACBMs can significantly release asbestos fibers as well as $PM_{2.5}$. Concentrations of asbestos generated by ACBMs were well correlated with $PM_{2.5}$.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.423-432
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• 2017

Objectives: This study was conducted to evaluate asbestos handling history of workers at automobile manufacturing plants in Korea. Methods: National regulations on asbestos and Korea Occupational Safety and Health Agency(KOSHA) database on the information of asbestos containing products were reviewed. We investigated asbestos related materials from one automobile manufacturing plant. Material safety data sheets(MSDS) collected in 2010, work environment monitoring results reported from 2000 to 2013, trade union reports and asbestos survey reports were reviewed. We also interviewed workers with long career and did walk-through survey. Results: The Ministry of Labor in Korea has permitted asbestos manufacturing since 1990. In 1997, the use of crocidolite and amosite asbestos were banned. In 2007, the Korean government announced a total ban on the manufacturing, importation and use of all kinds of asbestos, which took full effect in 2009. A total of 174 asbestos products information from KOSHA database was analyzed. Extruded cement panel for building, special brake for crane farm machinery, gasket, joint sheet and thermal insulator were produced until 2007. From automobile manufacturing plant survey, we confirmed that asbestos containing materials(ACM) such as gasket, heating induction materials have been used until 2011. Asbestos containing building materials(ACBM) such as bamlites, slate and ceiling tex were reported at 122 asbestos dismantling projects in 2014. Conclusion: Although the use of all kinds of asbestos were banned from 2009, ACMs and ACBMs installed before 2009 were still found at automobile manufacturing plant until 2011 and 2014 respectively. In particular, asbestos slates should be managed because most of slates had not been removed until 2014.

• Economic and Environmental Geology
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• v.56 no.4
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• pp.457-473
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• 2023

Asbestos has been produced, imported and used in various industries in Korea over the past decades. Since asbestos causes fatal diseases such as malignant mesothelioma and lung cancer, the use of asbestos has been generally banned in Korea since 2009. However, there are still many asbestos-containing materials around us, and safe management is urgently needed. This study aims to examine asbestos-related trend changes using major asbestos-related keywords based on the asbestos trend analysis using big data for the past 32 years (1991 to 2022) in Korea. In addition, we reviewed both domestic trends related to the production, import, and use of asbestos before 1990 and asbestos-related policies from 2023 to 2027. From 1991 to 2000, main keywords related to asbestos were research, workers, carcinogens, and the environment because the carcinogenicity of asbestos was highlighted due to domestic production, import, and use of asbestos. From 2001 to 2010, the main keywords related to asbestos were lung cancer, litigation, carcinogens, exposure, and companies because lawsuits were initiated in the US and Japan in relation to carcinogenicity due to asbestos. From 2011 to 2020, the high ranking keywords related to asbestos were carcinogen, baseball field, school, slate, building, and abandoned asbestos mine due to the seriousness of the asbestos problem in Korea. From 2021 to present (2023), the main search keywords related to asbestos such as school, slate (asbestos cement), buildings, landscape stone, environmental impact assessment, apartment, and cement appeared.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.223-228
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• 2021

The final disposal method for asbestos building materials is to be landfilled at a designated waste landfill in accordance with the Waste Management Act. However, it is difficult to secure a domestic designated waste landfill site to landfill the entire amount of asbestos waste, which is expected to emit more than 400,000 ton/year by 2044. In this study, a detoxification treatment was performed on a ceiling tex with a density of 1.0 to 1.2g/cm³ containing 3 to 7% of chrysotile, and it was used as a reinforcing fiber for extruded panels. It was confirmed that asbestos components were detoxified through the reaction process using 30% oxalic acid and carbon dioxide, and it was recognized that these detoxifying properties were maintained even after extrusion molding. However, it was found that milling to a fiber size of less than 1mm for complete detoxification of asbestos resulted in a decrease in reinforcing performance. Therefore, in the case of using detoxified asbestos fibers in the extrusion molding process, it is considered desirable to add fibers with a length of 5mm or more to improve the reinforcing performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.5029-5037
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• 2015

The objective of this study is to investigate the distribution of asbestos containing materials and to evaluate risk assessment method in some schools, Korea. For the survey on ACM risk assessment, we used both EPA AHERA rule and ASTM rule. We investigated 100 schools between January and December in 2010. Detection rate of the ACM according to construction year showed that before 1980's, 1990's, 2000's, after 2000's buildings were 100%, 94.1%, 100% and 62.5%, respectively. Compared with school types, detection rate of the ACM in Kindergarten, Elementary, Middle, High, Special Education schools were 100%, 97.1%, 92.9%, 100%, 80%, respectively. Ceiling textiles contained chrysolite/mixed amosite(2~8 %) and wall cement flat boards contained chrysolite(6~11 %). Also, gasket contained chrysolite(16~17 %), slate roof contained chrysolite(10~13 %). In this study, risk assessment EPA AHERA rule of ACM showed that all materials were "Pool" grade. And, ASTM rule risk assessment showed that all materials were "Q&M program" grade.