• 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.

• KEPCO Journal on Electric Power and Energy
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• 제7권1호
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• pp.153-159
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• 2021

A two-step process for increasing the leaching efficiency of yttrium and neodymium from coal fly ash were investigated at solid loadings of 5.0 g ash ~1,000 g ash/l of 1.0 N~10.0 N H₂SO₄, temperature ranging from 30℃ to 90℃, ultrasonic leaching time of 1~10 hours, and ultrasonic power of 25~200 W. The yttrium and neodymium from coal fly ash were effectively leached into ion phases by step change of the first conventional dissolution at room temperature and then the second heating process with the aid of ultrasonic wave, and maximum leaching efficiency of yttrium and neodymium obtained were 66 % and 63 %, respectively. The activation energies for the leaching reaction of yttrium and neodymium at second heating process dependent on leaching time and temperature were derived to be 41.540 kJmol^-1 and 507.92 kJmol^-1, respectively. The optimum conditions for the maximum leaching of yttrium and neodymium were found to be the solid loading of 250 g ash/l of H₂SO₄, solvent concentration of 2.0 N H₂SO₄, and second step process of temperatures of 30℃ for 3 hours and then 90℃ for 4 hours with ultrasonic intensity of 100 W.

• 한국지반환경공학회 논문집
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• 제11권5호
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• pp.25-34
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• 2010

본 연구에서는 전국 화력발전소에서 부산되는 7,200만톤에 이르는 누적 매립회량을 대량 활용하기 위해 매립회의 특성 연구를 진행하였다. 일부 화력발전소에서는 비회와 저회가 분리되어 매립되고 있으나, 대부분의 화력발전소에서는 혼합 매립되고 있어 매립회의 공학적 특성이 규명되지 않아 이러한 공학적 특성을 규명하고자 영흥화력본부, 삼천포화력본부에서 부산되는 매립회와 비회를 사용하여 실험을 실시한 후 두 발전소의 매립회와 비회의 공학적 특성을 비교 분석하였다. 석탄회를 건설재료로 활용하기 위해 시료의 물리적 특성을 규명하고자 비중, 단위중량, 입도분석시험을 실시하였고, 역학적 특성을 규명하고자 삼축투수시험, 직접전단시험, 일축압축강도시험, 다짐시험을 실시하였다. 그리고 각 발전소에서 부산되는 석탄회의 특성을 알아보고자 무연탄 및 유연탄을 사용하는 발전소에서 부산된 석탄회의 공학적 특성들을 비교 고찰하였다. 시험결과 경량성의 건설재료로써 유연탄 발전소에서 부산된 석탄회를 사용하는 것이 유리하며 뒷채움재로의 활용은 투수계수가 상대적으로 큰 무연탄을 사용하는 발전소에서 부산되는 석탄회를 사용하는 것이 효과적이라 판단된다. 본 논문에서는 영흥화력본부의 비회가 가장 작은 투수계수를 나타냈으므로 불투수층을 요구하는 현장에 적용하기에 가장 적합할 것이라 판단된다.

• 대한환경공학회지
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• 제35권8호
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• pp.547-553
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• 2013

본 논문에서는 석탄화력발전소에서 배출되는 비산재의 $CO_2$ 건식흡수제의 첨가제 및 담체로써의 효과를 검토하였다. 이를 위해 필요에 따라 비산재와 $CO_2$ 포집 유효 성분인 NaOH, CaO 및 물을 조합하여 여러 종류의 흡수제를 제조한 후, $CO_2$ 흡수 실험을 포함한 흡수제의 특성 분석을 수행하였다. 그 결과, 조건에 따라 흡수율과 흡수 온도, 속도 및 탈기 현상 등, 비산재 투입에 의한 다양한 효과를 확인할 수 있었고 NaOH, CaO 및 비산재와 물이 첨가되어 제조된 흡수제에서 비산재 효과가 가장 크게 나타났다. $550^{\circ}C$에서 본 흡수제의 $CO_2$ 흡수율은 비산재가 첨가되지 않은 흡수제에 비해 35.6% 높았고 흡수 종료 후, $CO_2$ 탈기 현상도 관측되었다. 이는 비산재 첨가 때문으로 흡수제 내, 유효 성분들이 비산재 주변으로 분산도가 높고 상대적으로 미세한 입자로 존재하였다. 또한 비산재의 담체 역할이 확인되며 NaOH로 인해 흡수제 내 포졸란 반응이 억제되기 때문이다. 탈기 현상도 비산재 첨가로 인한 현상으로 NaOH, CaO가 비산재와 물리, 화학적 결합을 형성하여 Na와 Ca에 포집되어 있는 $CO_2$의 결합력이 약화되기 때문으로 판단된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.101-102
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• 2015

Significant amount of bottom ash has been stored in the pond site of Hadong coal power plant located at southeast region of Korea. In order to address strong environmental regulation that is going to be enforced in the near future, it is necessary to consume waste bottom ash stored in the pond site in a sustainable manner. In this research, the chemical and mineral characteristics of various sized bottom ash samples from Hadong coal power plant were analyzed using XRF, XRD, and particle size analyzer. According to the experimental results, the chemical compositions of bottom ash was slightly changed in terms of Al and Fe content. As the size of the bottom ash increased, cristobalite was observed as a result of crystallization. The mineralogical composition and its size distribution of powder type bottom ash indicated that significant amount of fly ash is included together with small sized bottom ash.

• 한국응용과학기술학회지
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• 제16권3호
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• pp.217-221
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• 1999

This study was carried out to synthesis the zeolite using the bituminous coal fly ash emitted from power plant that occurs several environmental problems. In spite of fly ash has contained high content of $SiO_2$ and $Al_2O_3$, it disposed mainly landfill. If the effective methods to recover the $SiO_2$ and $Al_2O_3$ were developed, the fly ash could be utilized valuable raw materials. In this study, fly ash was used as raw material to synthesize the zeolite by pressurized hydrothermal reaction. Also, experimental parameters included temperature($70{\sim}110^{\circ}C$, and pressure($140{\sim}200$ psi) of crystallization were investigated. The more crystallization pressure was increased, the more Zeolite 4A was synthesized at 70 and $90^{\circ}C$. Zeolite 4A of metastable phase tend to be transformed into sodalite of stable phase at $110^{\circ}C$.

• 자원리싸이클링
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• 제24권4호
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• pp.67-75
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• 2015

국내 석탄화력발전소 11곳의 석탄회(비산재, 바닥재 및 매립회) 및 매립장 상등수를 채취하여 희유금속의 함량분포를 살펴보았다. 주요 전략광물인 이트륨(Yttrium) 및 네오디뮴(Neodymium)의 경우 약 23 ~ 75 mg/kg 범위로 나타났으며 별도의 회수기술 개발에 대한 가치가 충분한 것으로 판단되었다. 연간 발생하는 비산재 및 바닥재와 더불어 매립회의 양을 감안하면 국내 석탄화력발전소가 보유하고 있는 희유금속은 약 1.67조 원의 가치가 있는 것으로 조사되어 도시광산으로서 충분한 경제적 가치가 있는 것으로 판단된다.

• 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.

• 펄프종이기술
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• 제42권4호
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• pp.78-83
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• 2010

In this study, the possibility of the use of a new raw material in paperboard industry was investigated. Fly ash is one of the residues generated in the combustion of coal and generally captured from the chimney of coal-fired power plant. This material is utilized in many industries including cement, soil stabilization, composite etc., but it is not used in paper industry. Three types of fly ashes were collected from Hadong, boryeong and Seocheon steam power plants and we investigated their properties by scanning electron micrographs and particle size distribution. Papers were manufactured with KOCC and fly ashes, and the physical properties such as bulk, tensile strength, internal bond strength and ISO brightness were measured to identify the effects of fly ash on the paper properties.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1996년도 춘계학술발표회 초록집
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• pp.88-96
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• 1996

The characteristic analysis of fly ash generated from a fired power plant using bunker-C oil has been investigated. Ash size distribution by an optical microscopy with image processing technique, morphological shape by a scanning electron microscope(SEM) and microscope, chemical composition by the inductively coupled plasma emission spectrometry(ICP), and resistivity measurement as a function of temperature and moisture content by the resistivity meter are performed. A study of physical, chemical and electrical characteristics of bunker-C fly ash plays an important role of improving the performance of an electrostatic precipitator and protecting air pollution. The samples of bunker-C fly ash for analysis were collected from the electrostatic precipitator hopper of Ulsan Power Plant Unit 1 and Pusan Power Plant Unit 1. Mass median diameter(MMD) of bunker-C fly ash was measured 12.7${\mu}{\textrm}{m}$, while MMD of fly ash generated from the mixture of bunker-C oil(40%) and domestic anthracitic coal(60%) was 25.7${\mu}{\textrm}{m}$. The morphological structure of bunker-C fly ash consisted of fine particles of non-spherical shape. The primary chemical components of bunker-C fly ash were composed of SiO2(2.36%), Al2O3(4.91%), Fe2O3(14.33%) and C(11.84%). Resistivity of bunker-C fly ash was found to be increased with increasing temperature at the range of 100~15$0^{\circ}C$ and was measured 103~104 ohm-cm.