• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
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• pp.105-110
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• 2006

In order to utilize coal fly ash (hereafter : coal ash ) discharged from coal boiler as a material for civil engineering usage such as snow melter or soil improver, we have to prevent leaching hazardous elements such as fluorine boron and heavy metals from the coal ash because the leaching concentrations of some elements in the ash exceed the Japanese standards for environmental soil quality. Through the laboratory experiments and mill trials we confirmed that the leaching concentrations of fluorine, boron and heavy metals were maintained below their environmental standards by mixing with fixation chemicals and curing for a short time.

• Journal of Magnetics
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• 제18권3호
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• pp.365-369
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• 2013

Coal ash is known to contain a noticeable amount of valuable elements, including transition metals and lanthanides. Therefore it is quite actual problem to extract them for metallurgy and other applications. This paper presents the results of high gradient magnetic and mechanical separation, microscopy, element analyses and optical spectroscopy of brown coal ash taken from the combustion camera and chimney-stalk of Angren thermal power station. The separated magnetic fraction was 3.4 wt.%, where the content of Fe in ferrospheres increased to 58 wt.%. The highest contents of Fe and rare earth elements were found in the fine fractions of $50-100{\mu}m$. Optical absorption spectroscopy of water solutions of the magnetic fractions revealed $Fe^{2+}$ and $Fe^{3+}$ ions in the ratio of ~1:1. The separated coal ash could be used for cleaning of technological liquid waste by means of the high gradient magnetic field.

• 한국농공학회논문집
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• 제48권5호
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• pp.73-80
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• 2006

The mono-layer cover system is composed of soils only as a filling material and various plants are planted on the surface to control the water balance in the cover system. In this paper, the mono-layer cover system was considered as an alternative landfill final cover system and developed a model that could utilize industrial by-product (especially, coal ash & phosphogypsum) as additive filling materials. The mixture of granite soil, coal ash, and phosphogypsum was placed as a cover material in a box constructed with cement. Laboratory tests were carried out to investigate the environmental effect on the utilization of coal ash & phosphogypsum and to determine the mxing ratio of each materials. In the leaching test, all materials showed lower heavy metal concentration than the threshold values of regulation. The optimum mixing ratio of materials which was applied to field model test was determined to soil (4) : coal ash (1) : phosphogypsum (1) on the volume base. Field model tests were continued from February to July, 2004 in the soil box that was constructed with cement block. It was verified that coal ash and phospogypsum mixed with soil was to be safe environmentally and the water balance of mono-layer cover system was reasonable.

• 한국결정성장학회지
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• 제3권2호
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• pp.185-201
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• 1993

본 연구의 목적은 석탄회의 물리.화학적 및 미세구조적 특성들을 규명하여 석탄회의 산업화를 증가시키는 것이다. 실험에 의하면 석탄회의 3주성분들은 $SiO_2$, $Al_2O_3$ 및 C이며 quartz와 mullite의 결정상을 함유하고 있다. 석탄회는 미세구조적 형태에 따라서 7가지로 선별되며, cenosphere는 floater와 건식분리된 cenosphere들로 구분되며 $SiO_2$와 $Al_2O_3$ 로 구성되어 있다. Cenosphere 응집은 고온과 고압의 조건하에서 작은 입경의 cenosphere들이 흡착과 neck growth에 의해 형성된다.

• 환경영향평가
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• 제26권6호
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• pp.563-573
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• 2017

매년 화력발전소에서 약 800톤이상 되는 석탄재가 발생되고 있다. 발생되는 석탄재 중 재활용되고 남은 석탄재는 회처리장에 매립되고 있다. 현재 회처리장 용량에는 한계가 있고, 석탄재 매립으로 인한 환경영향의 우려로 회처리장 신규 확보도 어려운 상황이다. 환경영향 최소화라는 측면에서 석탄재 재활용 및 유효이용이 향후 장기적 국가적으로 시급하게 해결해야 할 문제로 인식되고 있다. 따라서, 본 연구는 국내 석탄재 재활용 확대를 가로막고 있는 문제점을 분석하여 해외 사례를 바탕으로 친환경적 국토관리와 자원순환사회를 위한 석탄재 재활용 확대 방안을 제안 하고자 하였다. 국내 석탄재 재활용 확대 방안은 다음과 같다. 첫째, 석탄재를 재활용 할 수 있는 법적 근거를 마련하는 것이다. 이를 위해서는 환경성 예측 평가에 대한 기법과 기준 및 체계 개발이 필요하다. 둘째, 이해관계자들의 인식 전환을 유도하는 것이다. 석탄재의 환경 안전성에 대한 연구 및 홍보가 필요하며 이해관계자들의 적극적인 의사소통 및 정보 제공이 필요하다. 셋째, 석탄재 재활용을 활성화 할 수 있는 실제적인 지원방안이 필요하다. 정책방안으로는 석탄재 처리비 지원, 석탄재 공급센터 설치 등이 있다.

• Asian Journal of Atmospheric Environment
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• 제6권1호
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• pp.67-72
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• 2012

The chemical characterization of water-soluble organic carbon in ash emitted from a coal combustion boiler has not been reported yet. A total of 5 ash samples were collected from the outlet of an electrostatic precipitator in a commercial 500 MW coal-fired power plant, with their chemical characteristics investigated. XAD7HP resin was used to quantify the hydrophilic and hydrophobic water-soluble organic carbons (WSOC), which are the fractions of WSOC that penetrate and remain on the resin column, respectively. Calibration results indicate that the hydrophilic fraction includes aliphatic dicarboxylic acids and carbonyls (<4 carbons), amines and saccharides, while the hydrophobic fraction includes aliphatic dicarboxylic acids (>4-5 carbons), phenols, aromatic acids, cyclic acid and humic acid. The average mass of the WSOC in the ash samples was found to depend on the bituminous coal type being burned, and ranged from 163 to 259 ${\mu}g$ C/g of ash, which corresponds to 59-96 mg C of WSOC/kg of coal combusted. The WSOC mass accounted for 0.02-0.03 wt% of the used ash sample mass. Based on the flow rate of flue gas produced from the combustion of the blended coals in the 500 MW coal combustion boiler, it was estimated that the WSOC particles were emitted to the atmosphere at flow rates of 4.6-7.2 g C/hr. The results also indicated that the hydrophilic WSOC fraction in the coal burned accounted for 64-82% of the total WSOC, which was 2-4 times greater than the mass of the hydrophobic WSOC fraction.

• 터널과지하공간
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• 제22권6호
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• pp.449-461
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• 2012

화력발전소에서 발생하는 석탄회를 지반침하의 방지를 위하여 갱내충전용으로 사용하고자 한다. 따라서 영동화력발전소에서 발생하는 석탄회를 이용하여 기본적인 물리적 특성 및 유동 특성을 파악하였으며, 한보탄광의 제1사갱을 대상으로 모형갱도를 제작하여 총 8회의 수압식 충전실험을 수행하였다. 석탄회의 비중은 2.34이고 입도분석결과 실트질 모래인 SM에 해당한다. Slump 시험 및 Flow 유동시험 결과 석탄회 70 wt,% 이하에서 액상형태로 나타나므로 모형충전실험에서는 석탄회 60 wt,%를 적용하였다. 모형충전시험결과 갱내수 유, 무에 상관없이 토출구를 사갱이나 수갱 바닥에 위치시키는 것이 충전효율을 향상시키는데 유리한 방법임을 확인하였다.

• 환경영향평가
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• 제22권2호
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• pp.135-145
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• 2013

The recycling of coal bottom ash generated from coal power plants in Korea has been limited due to heterogenous characteristics of the materials. The most common management option for the ash is disposal in landfills (i.e. ash pond) near ocean. The presence of large coarse and fine materials in the ash has prompted the desire to beneficially use it in an application such as fill materials. Prior to reuse application as fill materials, the potential risks to the environment must be assessed with regard to the impacts. In this study, a total of nine test cells with bottom ash samples collected from pretreated bottom ash piles and coal ash pond in a coal-fired power plant were constructed and operated under the field conditions to evaluate the leachability over a period of 210 days. Leachate samples from the test cells were analyzed for a number of chemical parameters (e.g., pH, salinity, electrical conductance, anions, and metals). The concentrations of chemicals detected in the leachate were compared to appropriate standards (drinking water standard) with dilution attenuation factor, if possible, to assess potential leaching risks to the surrounding area. Based on the leachate analysis, most of the samples showed slightly high pH values for the coal ash contained test cells, and contained several ions such as sodium, potassium, calcium, magnesium, chloride, sulfate, and nitrate in relatively large quantities. Three elements (aluminum, boron, and barium) were commonly detected above their respective detection limits in a number of leachate samples, especially in the early leaching period of time. The results of the test cell study indicate that the pollutants in the leachate from the coal ash test cells were not of a major concern in terms of leaching risk to surface water and groundwater under field conditions as fill materials. However, care must be taken in extending these results to actual applications because the results presented in this study are based on the limited field test settings and time frame. Structural characteristics and analysis for coal bottom ash may be warranted to apply the materials to actual field conditions.

• 한국지반환경공학회 논문집
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• 제14권4호
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• pp.53-58
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• 2013

연약지반에 시공되는 수평배수층의 설계는 사용할 수평배수재의 투수성에 대한 재료 조건인 No.200체 통과백분율을 확인하여 재료의 사용 여부를 정하고, 시공장비의 주행성 확보를 위한 수평배수층의 두께를 산정한다. 그리고 이 수평배수층이 양호하게 장기적으로 배수성을 유지할지를 검토하고, 필요 시 방안을 강구하는 등 순차적인 단계로 실시한다. 본 연구에서는 회사장 혼합석탄재를 사용하여 실제 수평배수층을 시공하면서 그 과정과 결과를 고찰함으로써 연약지반에서 수평배수재로 이들 혼합석탄재를 원활하게 활용하기 위한 시스템을 제시하고 있다. 즉, 회사장 혼합석탄재는 회사장마다 그리고 같은 회사장에서도 위치에 따라 $75{\mu}m$보다 작은 세립분의 함유량이 불규칙하고 그 양이 상당히 많기 때문에 어느 정도까지는 세립분이 제거되도록 체로 선별하여 사용하여야 한다는 사실을 확인하며, 현장에서의 대량 선별을 위한 체의 눈금 크기, 선별 방법 등의 구체적 사항들을 제안하고 실제 시공을 위해서는 적절한 선별기 제작의 필요성을 기술하고 있다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.19-24
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• 2003

Recently, the by-product of coal ash has been increased by increase of consumption of electric power. So in view of environmental aspect, it is important to secure a reclaimed land and treatment utility for coal ash. This is an experimental study to compare and analyze the properties of high volume coal-ash concrete using the bottom ash. For this purpose, the mix proportions of concrete according to the replacement ratio of bottom ash(l0, 20, 35, 50%). And then air content, slump, compressive strength, durability test were performed. According to test results, it was found that the compressive strength of bottom ash concrete was similar to that of plain concrete(BA0). And the carbonation depth of bottom ash concrete increased as the replacement ratio of bottom ash.