• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.159.2-159.2
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• 2010

Asbestos is the collective name for a group of naturally occurring minerals in their fibrous form and hydrous silicates of magnesium and a mineral fiber that has been used commonly in a variety of building construction materials for insulation and as a fire-retardant. Asbestos has been used for a wide range of manufactured goods, because of its fiber strength and heat resistant properties. Nevertheless harmful of asbestos is quite serious. Exposure to airborne friable asbestos may result in a potential health risk because persons breathing the air may breathe in asbestos fibers. Continued exposure can increase the amount of fibers that remain in the lung. Fibers embedded in lung tissue over time may cause serious lung diseases including asbestosis, lung cancer. In this paper, we carried out as fundamental study for dispose of asbestos cement slate safely and perfectly. Melting Temperature of asbestos need to more than $1,520^{\circ}C$ and specially asbestos cement slate need more energy than that of pure asbestos. We need to decrease melting temperature of asbestos cement slate for economical efficiency. To the purpose, glass and bottom ash were chosen as additives for basicity control. we analyzed about properties of asbestos cements slate, melting characteristics on the additives ratio and temperature. We confirmed about harmlessness of melting slag through analysis of scanning electron microscope(SEM) and x-ray diffractometer(XRD).

• KIEAE Journal
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• v.11 no.3
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• pp.57-62
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• 2011

Asbestos have been used around the world because of reliable and cost-effective physicochemical characteristics. After incubation period about 15-40 years asbestos can cause various cancers, including malignant mesothelioma when inhaled into the air. These properties turned out, asbestos have been banned from using in developed countries. Also in Korea also, the use of asbestos was banned across the board by revision of Industry Safety and Health Act in February 2009. Therefore, the problem of asbestos is not when using. It is about dismantling, maintenance, and the final processing of asbestos waste. Asbestos Cement slates which is Widely distributed throughout the country as roofing materials has much scattering potential compare with inside materials. Also Ministry of Environment is planning to introduce legislation 'Asbestos Safety Management Act' through Environment Announcement and The same Act. 24 show as follows. Minister of Environment or governor should do survey on the actual condition targeting rural buildings with slates and partly or fully fund to dissolve, remove asbestos slate which was used in each buildings. Therefore, to solve these problems, database-building and necessity of management strategies have been continually arisen. So this study was performed. Its application value is very high in terms of its political, economic. Asbestos Cement Slates database could build to collect national registered building data and then using GIS, asbestos cement Slates distribution map were constructed in each province's cities and counties of the country. And this map by Application, construction was to visualize by application, construction of year. Through these results, information of Asbestos Cement Slates could visually inform to policy makers, asbestos dismantling and management contractor, and civilian and it would alleviate the gap of knowledge information. This is expected to be utilized by medium and long-term and effective plan for demolition and dismantling of asbestos cement Slates.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.137-143
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• 2014

Asbestos is given to a variety of six naturally occurring silicate minerals. These minerals possess high tensile strength, flexibility, resistance to chemical and thermal degradation, and electrical resistance. These minerals have been used for decades in thousands of commercial products, such as insulation and fireproofing materials, automotive brakes, textile products, cement and wallboard materials. When handled, asbestos can separate into microscopic-size particles that remain in the air and are easily inhaled. It is now known that prolonged inhalation of asbestos fibers can cause serious and fatal illnesses including malignant lung cancer, mesothelioma, and asbestosis. Therefore the use of asbestos and asbestos products has dramatically decreased in recent years. Also all constructions including asbestos should be removed under strictly controlled conditions and very tightly implemented health & safety management systems. In this study, the process of the removal work of the asbestos cement slate was analyzed by IDEF-0 modeling and evaluated by 4M risk assessment method. The results show that removal work of the asbestos cement slate was classified five process and eighteen detail process. The risk of safety side the higher than the risk of health side in 4M risk assessment.

• Proceedings of the Korea Concrete Institute Conference
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• 1992.10a
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• pp.214-217
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• 1992

The asbestos has many advantages in engineering aspect. The objective of this report is to investigate and analyze the influence of the asbestos in secondary cement-product. For this purpose, several asbestos -ratio are examined and the relationship between asbestos-ratios and strength is studied. From the present tests, it ti found that the strength of the press-out cement-product was the maximum value at the asbestos-tratio of 11%

• Journal of Environmental Science International
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• v.24 no.7
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• pp.927-937
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• 2015

This study was performed to identify and quantify the asbestos fibers released from two types of asbestos-cement slate roofs. One is a plant roof installed in 1987 which contained 15% chrysotile, and the other is a residential roof installed before 1983 which contained 12% chrysotile. The concentrations of asbestos fibers in air surrounding asbestos-cement slate roofs and in the falling water harvested from the same roofs on rainy days ranged from 0.0012 to 0.0018 f/mL and from 1,764 f/L to 10,584 f/L, respectively. The concentration of inorganic fibers in the soil around asbestos-cement slate roofs was from 217 to 348 f/g. With the above results, the excess lifetime cancer risk (ELCR) for the risk assessment of the asbestos fibers released from asbestos-cement slate based on US EPA IRIS (Integrated risk information system) model is within 5.5E-06 ~ 6.5E-06 levels which indicates that the levels do not exceed "the acceptable risk(1.0E-05)" recommended by WHO. The asbestos concentration in air, drained rainfall and soil around the plant slate roof was higher than that around residential slate roof, but the excess lifetime cancer risk (ELCR) from residential slate was higher than that from plant slate. This suggested that the enclose and encapsulation of residential roofs have priority in removal policy to minimize the exposure risk.

• 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.23 no.3
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• pp.196-204
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• 2013

Objectives: The purpose of this study is to analyze the number and influence factors of asbestos fibers in the air of farmhouses with asbestos cement slate roofing, as well as in rainwater per unit area of the asbestos cement slate roofing. Methods: At a distance of 1 m from the end of asbestos cement slate roofing in 20 farmhouses, the asbestos fiber in the air was collected three times on a clear day downwind from the prevailing wind. Rainwater falling from the slate roofing was collected four times with a 1.05-m rainwater pipe on a rainy day at the 20 farmhouses, filtered with a MCE filter, and analyzed with a phase contrast microscope. Results: The geometric mean of the number of asbestos fibers in the air of farmhouses with slate roofing was 0.11 fiber/L, and no samples exceeded the recommended standard of 10 fiber/L. As a result of multiple regression analysis, a factor which gave a significant influence to the asbestos fiber content in the air was the gross area of slate roofing at the target farmhouses. The number of asbestos fibers included in rainwater collected per 1 m2 of slate roofing was 1,753 fiber/$L{\cdot}m2$. As a result of multiple regression analysis, the number of asbestos fibers contained in rainwater per 1 m2 of slate showed a significantly higher tendency as the year of slate roofing installation at the target farmhouses receded. Conclusions: It was confirmed for the first time in Korea that asbestos from asbestos cement slate roofing scatters into the air.

• 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.

• Journal of Environmental Health Sciences
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• v.34 no.1
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• pp.108-115
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• 2008

This study was performed to investigate the current status, in Korea, of the production of asbestos containing products (ACPs) such as asbestos cement products, asbestos friction materials, asbestos joint sheets, asbestos textile products, and other asbestos-containing products from May 2 to July 30, 2007. The information on ACPs was obtained through written questionnaires from 16 of the 27 companies that produce ACPs in Korea. The production amounts of asbestos containing gaskets were 70 tons in 2004, 90 tons in 2005, and 55 tons in 2006 in 4 companies and that of asbestos friction materials were 435.5 tons in 2004, 540.4 tons in 2005, and 454.3s ton in 2006 in 10 companies. The type and number of ACPs were:- 19 asbestos cement products, produced by 2 companies; 47 asbestos friction materials produced by 18 companies; 12 asbestos joint sheets productes by 4 companies; 18 asbestos textile products from 3 companies, and 6 other asbestos products from 5 companies. The database of ACPs was constructed to include the products name, identification number, name of company, production year, composition, asbestos content (%), usage, specification, and a picture. The database will be used to efficiently identify ACPs and to avoid asbestos exposure in workers and the general population.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.3
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• pp.307-320
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• 2009

This study was conducted not only to review airborne asbestos levels reported in workplaces in Korea, but also to analyze their levels according to various characteristics All asbestos concentration reported as either geometric mean (GM) and geometric standard deviation (GSD) or ranges were transformed to arithmetic mean to estimate exposure level. In addition, weighted arithmetic means (WAMs) were calculated to weigh asbestos levels based on the different number of samples. Differences of asbestos levels among several characteristics such as industry type, decade, operation and sampling and analytical methods were analyzed using analysis of variance (ANOVA). The number of articles studying asbestos levels from workplaces was found to be 9 including two report types. Five of those were reported prior to 1990s and rest of them after 1990s. Only several industries such as asbestos textile, asbestos cement, brake-lining repair shops were studied, while various industries using asbestos or asbestos containing materials (ACMs) were not studied. ANOVA found that asbestos exposure levels (WAM = 5.26f/cc) reported from textile industry were significantly higher than those from other industries (cement = 0.63f/cc, brake-lining = 0.2f/cc - 0.47f/cc) (p < 0.0001). Average exposure levels studied prior to the 1990s (3.13f/cc) were found to be significantly higher than that (0.86f/cc) after the 1990s (p<0.0001). All WAMs reported until the 1994 were found to be higher than the current occupational exposure limits (0.1f/cc). This study recommends that retrospective exposure to asbestos based on various industry types and operations should be assessed.