• Economic and Environmental Geology
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• v.44 no.5
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• pp.451-462
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• 2011

Asbestos or its applications have been used for long times and for various purposes in our life because of their merits, namely fire resistance, electric insulation and chemical resistance capacity etc. Despite of theses many merits, one of the problems of asbestos is shown toxicity according to its fiber type. So we need data to solve about this problem. In this paper, we study on the technical method of asbestos waste treatment and on the trends of asbestos researches and developments by the analysis of its patents and DWPI database materials. As a result, the asbestos-waste treatment data in the its related patents is used 267 cases to analyze. These data are divided into 86(32.5%) cases of solid waste disposal(B09B). 41(16.6%) cases of separation(B01D) and 27(10.2%) of lime, magnesia, slag, cement and their composites(C04B).

• Resources Recycling
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• v.29 no.1
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• pp.35-42
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• 2020

Even asbestos-containing waste (ACW) are highly harmful to humans, it continues being produced due to the massive disposal of asbestos-containing products. A development of asbestos detoxification and recycling technologies is required. Heat treatment using microwave is the most efficient method for ACW detoxification. However, microwave heat treatment method has the limitation that asbestos does not absorb microwave at room temperature. That is why, in this study, ACW was detoxified by microwave heat treatment adding the ACW between SiC plates, which are inorganic heating elements that absorb microwaves at room temperature. In order to improove the heat transfer, ACW was crushed and pulverized and then heated using microwave. Microwave heat treatment temperature and time variables were adjusted to investigate the detoxification properties according to heat treatment conditions. After heat treatment, treated ACW was analyzed for detoxification properties through crystal structure and microstructure analysis using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Microwave heat treatment method using SiC plate can be heated up to the target temperature within a short time. Finally, complete asbestos detoxification was confirmed from the crystal structure and the microstructure when the microwave heat treatment was performed at 1,200℃ for at over 60 minutes and at 1,300℃ for at over 10 minutes.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.2
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• pp.161-166
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• 2020

In accordance with the amendment of the Industrial Safety and Health Act of 2007, Korea completely prohibited the import, distribution and manufacture of asbestos like Europe and Japan. Accordingly, the current problem of asbestos is the safe maintenance and disposal of asbestos construction material, the disposal of asbestos, and the final disposal of asbestos building materials. If the asbestos building material is made harmless, it may be classified as general waste or as recyclable waste. Therefore, this study evaluated the physical and chemical characterization of detoxified asbestos powder and the applicability of secondary products. In this study, it was found that applying the appropriate temperature and pressure for catalysis during asbestos desalination through low temperature chemical treatment was the most important factor.

• 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 Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.324-330
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• 2018

In accordance with the amendment of the Industrial Safety and Health Act of 2007, Korea completely prohibited the import, distribution and manufacture of asbestos like Europe and Japan. Accordingly, the current problem of asbestos is the safe maintenance and disposal of asbestos construction material, the disposal of asbestos, and the final disposal of asbestos building materials. In the past, Korea used 100,000 tons of asbestos every year, and the building materials using it exceeded 1 million tons per year. These asbestos building materials continued to be used until 2006, and the Ministry predicted that these materials would continue to be maintained until 2044. When the permeable hardening agent is applied to the asbestos building material installed in the pre-pretreatment step for the harmless treatment of the asbestos waste and the dismantling is carried out, the scattering of the asbestos is suppressed in the disassembling step, detoxification treatment conditions can be improved. Therefore, permeable hardeners should be stably penetrated into asbestos building materials. In this study, it is suggested that pre - pretreatment methods for the harmlessization of waste asbestos building materials with medium density level can be presented. In order to efficiently perform pre - treatment for chemical harmlessness in the future, the mixing ratio of permeable hardener and middle water Optimization is the most important factor.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.6
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• pp.434-441
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• 2014

This study is purposed to measure airborne asbestos concentrations at demolition sites and surrounding areas of asbestos containing buildings in Seoul and examine whether the measurement results correspond with allowable exhaust standard for asbestos of the Asbestos Safety Control Act. The airborne asbestos concentrations for 37 sites were below the detection limit ($7fiber/mm^2$) in 101 (35%) out of 288 samples. The whole average airborne asbestos concentration in 37 sites was $0.003{\pm}0.002f/cc$(max 0.0013 f/cc) and almost the whole airborne asbestos concentrations were satisfied with allowable exhaust standard for asbestos, 0.01 f/cc, of the Asbestos Safety Control Act. So possibility of asbestos exposure is not yet a major concern at current levels for sites demolished of asbestos containing buildings in Seoul. Looking at each sampling point, the average airborne asbestos concentrations in boundary line of site, entrance of sanitation, around the workplace (in), around the workplace (out), negative pressure units, storage area for waste, outlet for waste and residential area of residents were respectively $0.002{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.005{\pm}0.004f/cc$, $0.005{\pm}0.003f/cc$ and $0.003{\pm}0.002f/cc$. As a result, all sampling points of study were satisfied with allowable exhaust standard for asbestos, 0.01 f/cc, of the Asbestos Safety Control Act.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.251-255
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• 2005

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.28 no.2
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• pp.135-143
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• 2018

Objectives: There have been many studies on exposure assessment of workers at companies using asbestos as a raw material and at sites of the removal of materials containing asbestos. However, no research has been carried out on the asbestos exposure of workers in industries involving asbestos-containing waste, such as workers at collection and transportation service companies, mid-treatment companies(solidification of asbestos-containing waste), and landfill sites. The objective of this study was to assess the asbestos exposure concentrations of workers in industries handling waste containing asbestos. Methods: For this study, we carried out field investigations at 15 companies: seven collection and transportation service companies, three mid-treatment companies, and five final treatment companies(landfill sites). We took both personal and area samples. Results: The range of asbestos exposure levels of workers handing asbestos-containing wastes at collection, mid-treatment, and landfill companies were 0.000 fibers/cc-0.009 fibers/cc, 0.000 fibers/cc-0.038 fibers/cc, and 0.000 fibers/cc-0.024 fibers/cc, respectively. Conclusions: The asbestos exposure levels of workers at mid-treatment companies were higher than those at collection and transportation companies and at final treatment companies. In the case of collection and transportation workers, the possibility of exposure to levels exceeding those found in the present study is not particularly high considering the characteristics of the work. However, in the case of intermediate or final disposal workers, it is considered that there is a possibility of exposure to levels above those found in this study.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.438-442
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• 2020

Studies on the recovery conditions and optimization process for valuable metal recovery through chemical treatment from detoxified asbestos-containing waste composed of calcium silicate, larnite, merwinite, and akermanite were conducted. The main components, Si, Ca, and Mg, of detoxified asbestos-containing waste (DACW) were separated and recovered in the form of SiO₂, CaSO₄, and Mg(OH)₂ compounds, respectively. Each separated component was confirmed through X-ray diffraction (XRD) and inductively coupled plasma spectrometer (ICP) analysis. The recovery conditions for each component were first treating them with an acid to separate SiO₂ and subsequently with H₂SO₄ to recover Ca in the form of sulfate, CaSO₄. The remaining Mg was recovered by precipitation with Mg(OH)₂ under strong basic conditions. This study suggested that it is possible to convert existing treatment process of asbestos waste by landfill through recovering the components into a resource-recycling green technology.

• Journal of the Korean Geophysical Society
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• v.6 no.1
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• pp.13-23
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• 2003

Dipole-dipole resistivity and ground penetrating radar(GPR) surveys were performed on an abandoned landfill site filled with asbestos containing material. The main purpose of the study was to estimate spatial extension and volume of the landfill for evaluting the cost for developing appropriate remedial alternatives. Assuming that the bedrock is within 10 m depth, dipole spacings of 2, 2.5 and 5m were set for six survey lines for resistivity measurements. For More detailed information, GPR suvey using 225 Mhz antenna was carried out for twelve survey lines for the shallower information. DC resistivity structures showed few tens ~ hundreds ohm-m for the landfill or alluvial laver, and 1,000~ 5,000 ohm-m for the bedrock. The depth to bedrock is found out to be approximately 5m. GPR survey results represented very clear reflection and/or diffraction events from the boundaries as well as from the blocky construction wastes. With high-resolution GPR survey, depth of the bedrock was resolved up to 2m, which in turn, could be a good indicator for estimating the volume of the landfill. Those depths of bedrock were confirmed by backhoe excavation data for 13 sites. The total area and volume of the landfill were to be approximately 3,953 .$m^2$ and 4,033 $m^3$, respectively.