• 한국지반환경공학회 논문집
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• 제10권3호
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• pp.5-12
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• 2009

본 연구는 발전소의 적치장에서 채취한 석탄회의 정적 및 동적 강도를 제시하였다. 석탄회는 주로 저회로 이루어져 있으며 정적 및 동적 강도를 평가하기 위하여 NGI형 단순전단시험, 반복단순전단시험 및 직접전단시험을 수행하였으며, 이러한 시험으로부터의 강도를 모래의 강도와 비교하였다. 본 연구에 사용된 석탄회 속에 있는 저회는 입도분포에 의하면 모래로 분류되었으며 모래보다 높은 강도 특성을 보였다. 석탄회를 토목공사에 활용되기 위해서 사질토와 석탄회를 50:50의 비율로 배치플랜트에서 섞어 사용하는 것은 사질토층과 석탄회층을 교대로 층별 시공하는 것보다 비효율적이다. 혼합시공과 층별시공을 모사하기 위하여 모래와 석탄회가 50:50으로 조성된 시료를 준비하였다. 시험결과 혼합에 의한 시료가 층별시료보다 약간 큰 정적 및 동적 강도를 나타내었다. 높은 강도는 주로 저회의 모난 입자로부터 기인된 것으로 보인다. 혼합시료에서 액상화시의 반복응력비는 반복횟수가 증가함에 따라 층별시료보다 급격히 감소하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1075-1082
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• 2008

Recently, coal ashes which are increasing annually are buried in ash ponds as industrial wastes. However, buried coal ashes can pollute ground water and ground due to leachate from coal ashes, which are serious environmental problem. Even though a lot of researches on recycling of coal ashes have been conducted, only 15% of coal ashes are recycled up to now. And those recycled coal ashes are not bottom ashes but fly ashes. So in this study, it was proved that Bottom Ash can be used as an alternative material to O.P.C(Ordinary Portland Cement) according to laboratory test results and test field construction. Also bottom ash is more economical and environmentally friendly than O.P.C.

• 한국결정성장학회지
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• 제6권4호
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• pp.627-639
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• 1996

분기별 안산 및 보령 석탄회에 대한 특성변화를 조사하였고 안산 석탄회에 대한 수비 선별시 산처리의 영향을 고찰하고자 하였다. 분기별 안산 및 보령 석탄회의 주결정상은 mullite와 quartz였고, 주성분은 $Al_{2}O_{3}$와 $SiO_{2}$로서 발전소 및 채취시기에 따른 큰 변화가 없었다. 반면, 입도분포는 수 $\mu\textrm{m}$에서 백 $\mu\textrm{m}$ 이상의 넓은 입도분포를 갖으며 morphology는 안산 석탄회의 경우에 큰 변화가 있었다. 따라서 석탄회는 점토의 대체원료로 사용가능하나 원ㄹ의 안정적 수급을 위해서는 반드시 선별화가 선탱되어야 한다. 안산 석탄회의 수비처리시 pH를 조절함으로서 분산성이 향상되었기 때문에 4단계에서 대부분 cenosphere를 얻을 수 있었고 입도분포도 감소하였다. 또한 4단계에서 포집된 시료의 비표면적은 비처리 석탁회보다 크게 감소한 $1.24\;m^{2}/g$이었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권6호
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• pp.475-482
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• 1999

The electrostatic precipitation characteristics of two kinds of fly ashes, one derived from a fluidized bed combustor(FBC), the other from a pulverized coal(PC) fired furnace, have been studied on a pilot plant. Experiments have been carried out to enhance the collection efficiency while changing the operating conditions for two kinds of coal ashes, respectively. It has been shown that collection efficiency is affected by many factors such as shape of the ashes, dust contents, humidity, and temperature, etc. Experimantal results showed that collection efficiency of the FBC ashes was higher than that of the PC fly ash in spite of the small size of the FBC ashes. The experimetal results have been applied to the collection efficiency equations to show that the modified Deutsch equation was well agreed with experiment results if modification parameter k was set to 0.6 for the fluidized bed fly ashes and to 0.43 for the pulverized coal fly ashes.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권7호
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• pp.32-40
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• 2013

This study was objected to evaluate the potential impact on the groundwater environment of the coal bottom ash used as fill materials on the land surface. From four coal-fired power plants, bottom-ashes were collected and analyzed through sequential extraction and column leaching tests following the meteoric water mobility procedure. The column tests shown leaching heavy metals including Pb, As, B, Cu, Zn, Mn, Ni, Ba, Sr, Sb, V, Cr, Mo, and Hg. The relatively high concentrations of B, Sr, Ba, and V in leachate were attributed to both the higher concentrations in the bottom ash and the relatively higher portion of leachable state, sorbed state, of metals. Bottom-ash samples from the D-plant only show high leaching potential of sulfate ($SO_4$), probably originated from the coal-combustion process, called the Fluidized Bed Combustion. Consequently, to manage recycling bottom ashes as fill materials, an evaluation system should be implemented to test the leaching potentials of metals from the ashes considering the absolute amount of metals and their state of existence in ashes, and the coal-combustion process.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.616-620
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• 2001

The objectives of this study are to investigate the suitability of various coal fly ashes and incineration ashes for zeolite synthesis. Zeolite P and hydroxysodalite are produced from coal fly ash and paper sludge incineration ash. When soluble and acid-soluble materials in incineration fly ash are removed by the water washing or acid washing before hydrothermal synthesis, hydroxysodalite can be produced. The factors to make solid-liquid separation difficult are the calcium component and the unburned carbon in ash.

• 에너지공학
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• 제27권2호
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• pp.61-69
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• 2018

Rare earth elements together with Y and Sc (REEs) are essential in the development of technology for clean and efficient use of energy. In recent years coal deposits have much attention and attracted as a promising alternative raw sources for rare earth elements, not only because the REEs concentrations in many coals or coal ashes are equal to or higher than those found in conventional types of REEs ores but also because of the world wide demand for REEs in recent years has been greater than supply. In the coal ashes, REEs are mainly associated with carbonates, silicates and aluminosilicates in ashes at 800 and $1100^{\circ}C$. These elements are known to be powerful environmental tracers in natural biogeochemical compartments. In this study, to reviewed the REEs originating and distribution patterns in coal ash samples from the bedrock and/or soil weathering that were entrapped by lichens and mosses was investigated. The REEs patterns of different organisms species allowed minor influence of the species to be highlighted compared to the regional lithology.

• 한국환경농학회지
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• 제38권1호
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• pp.10-16
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• 2019

BACKGROUND: Coal ashes generated from thermal power plants have been known as beneficial materials for agricultural use because of their nutrient elements. However, there is limitation to recycle them due to their alkalinity. The objective of this study was to evaluate the effectiveness or safety of the coal ashes for their heavy metals on agricultural recycling when adjusted to pH of 5 with sulfuric acid. METHODS AND RESULTS: Concentration of hydrogen which is needed to adjust pH of coal ash was estimated by using a buffering curve and then the amount of sulfuric acid was changed by the estimation before incubation. Each of fly ash (FA) and bottom ash (BA) was collected from both thermal plants of Yeongdong (YD) and Yeongheung (YH). The pH values of coal ashes increased to 4.76 (from 4.34) after incubation with sulfuric acid for 56 days, closer to the targeted pH. Coal ashes also increased the contents of available phosphorus by 2-fold (165 mg/kg) and 11-fold (1,137 mg/kg) for YDBA and YDFA, respectively, compared to the control. CONCLUSION: The utilization of coal ash with its acidity regulation would be very beneficial to agriculture sector and further suggest promising environmental safety against heavy metals.

• Asian Journal of Atmospheric Environment
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• 제4권2호
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• pp.80-88
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• 2010

In order to offer a better understanding of air pollution of China as well as East Asia we attempted to characterize the chemical properties of the raw coal materials mined in China and their combusted bottom ashes generated from coal fired power plant. To this end, we measured the chemical characteristics of individual bottom ashes and feed coal fragments collected at a coal fired power generator which was operated with the raw coal dug at a coal mine in China. The chemical properties of these two sample types were determined by a synchrotron radiation X-ray fluorescence (SR-XRF) microprobe method. Through an application of such technique, it was possible to draw the 2D elemental maps in and/or on raw coal fragments and fired bottom ashes. The pulverized fine pieces of feed coal mainly consisted of mineral components such as Fe, Ca, Ti, Ca, and Si, while Fe was detected as overwhelming majority. The elemental mass of combusted bottom ash shows strong enrichment of many elements that exist naturally in coal. There were significant variations in chemical properties of ash-to-ash and fragment-to-fragment. Although we were not able to clearly distinguish As and Pb peaks because of the folding in their X-ray energies, these two elements can be used as tracers of coal fire origin.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.613-618
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• 1999

This paper discuss the chemical, physical and mineral properties of classified fly ashes by electrostatic precipitator and calcinated fly ashes at 50$0^{\circ}C$. The electrostatic precipitator in coal fired power plant has a number of hopper in the direction of flue gases. The properties of fly ashes collected at each hopper in the electrostatic precipitator are different. Superfine, fine and ordinary fly ashes can be collected respectively at each hopper. The carbon content in fly ash is influenced on the viscosity of paste. By calcination, the carbon content in fly ash is decreased and the fluidity of paste is improved.