• 한국환경농학회지
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• 제14권3호
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• pp.338-344
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• 1995

현미중 카드뮴의 분석을 위한 보다 효율적인 방법을 찾기 위해 현미중 카드뮴의 공정시험방법을 표준으로 수종의 습식 및 건식방법에 대해 카드뮴의 회수율, 표준편차 및 표준방법과의 상관성등을 비교, 검토한 결과 현미 시료량 50g, 회화온도 $600^{\circ}C$의 건식방법은 회수율이 79.6%로 표준분석방법(87.2%)을 제외한 타 분석방법보다 높고, 표준편차도 평균${\pm}2.6$으로 표준분석방법의 평균+6.4 보다 약간 작았으며, 표준분석방법으로 분석된 카드뮴함량과의 상관성($r=0.977^{\ast\ast}$)도 크게 높아 본 방법은 습식으로 분해하는 현행 수질오염 공정시험 방법과 함께 현미중 카드뮴 분석방법으로 사용하여도 좋을 것으로 판단된다.

• 한국건축시공학회지
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• 제11권4호
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• pp.363-370
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• 2011

본 연구에서는 화력발전소에서 발생하는 폐기물인 리젝트 애시를 자원화하기 위하여 시멘트 혼합재로 사용하는 방안을 검토하고자 하였다. 이를 위하여 포졸란 활성도 비교를 통하여 효율적인 리젝트애시의 분말도를 선정하였으며, 현재 널리 사용되고 있는 콘크리트용 혼합재인 플라이애시와 비교하였다. 고분말 리젝트애시와 플라이애시를 슬래그시멘트와 혼합하여 시멘트복합체를 제조하였으며, 제조한 시멘트복합체 및 고분말 리젝트애시의 성능 평가를 위하여 페이스트(응결, 유동성, 기기분석), 모르타르(압축강도) 실험을 실시하였다. 기기분석 결과 고분말 리젝트애시의 수화반응기구는 플라이애시와 유사하지만 미세조직이 치밀해지는 특성을 나타내었다. 물성 측정결과에서는 고분말 리젝트애시가 플라이애시와 비교하여 응결지연이 감소하고, 초기강도 및 장기강도에서 우수한 성능을 나타내었다. 따라서 리젝트애시의 분말도를 $6,000cm^2$/g 수준으로 상향시킨다면 시멘트 복합체에 활용하는 것이 가능하며, 시멘트 물성 향상에도 기여할 수 있을 것으로 예상된다.

• Computers and Concrete
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• 제5권5호
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• pp.449-459
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• 2008

This paper focuses on the application of two dimensional orthogonal polynomials in the regression analysis for the relationship of product parameters viz. compressive strength, bulk density and water absorption of fly ash cement bricks with other process parameters such as percentages of fly ash, sand and cement. The method has been validated by linear and non-linear two parameter regression models. The use of two dimensional orthogonal system makes the analysis computationally efficient, simple and straight forward. Corresponding co-efficient of determination and F-test are also reported to show the efficacy and reliability of the relationships. By applying the evolved relationships, the product parameters of fly ash cement bricks may be approximated for the use in construction sectors.

• 대한기계학회논문집B
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• 제22권12호
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• pp.1691-1701
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• 1998

Fly ash produced in coal combustion is a fine-grained material consisting mostly of spherical, glassy, and porous particles. A study on the formation mechanism of the fly ash from coal particles in the pulverized coal power plant is investigated with a physical, morphological, and chemical characteristic analysis of fly ash collected from the Samchonpo power plant. This study may contribute to the data base of domestic fly ash, the improvement of combustion efficiency, fouling phenomena and ash collection in the electrostatic precipitator. The physical property of fly ash is determined using a particle counter for the measurement of ash size distribution. Morphological characteristic of fly ash is performed using a scanning electron micrograph. The chemical components of fly ash are determined using an inductively coupled plasma emission spectrometry(ICP). The distribution of fly ash size was bi-modal and ranged from 12 to $19{\mu}m$ in mass median diameter. Exposure conditions of flue gas temperature and duration within the combustion zone of the boiler played an important role on the morphological properties of the fly ash such as shape, particle size and chemical components. The evolution of ash formation during pulverized coal combustion has revealed three major mechanisms by large particle formation due to break-up process, gas to particle conversion and growth by coagulation and agglomeration.

• 에너지공학
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• 제26권4호
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• pp.74-83
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• 2017

Coal-fired power plants supply roughly 50 percent of the nation's electricity but produce a disproportionate share of electric utility-related air pollution. Coal combustion technology can facilitate volume reduction of up to 90%, with the inorganic contaminants being captured in furnace bottom ash and fly ash residues. These disposal coal ash residues are however governed by the potential release of constituent contaminants into the environment. Accelerated carbonation process has been shown to have a potential for improving the chemical stability and leaching behavior of bottom ash residues. The aim of this work was to quantify the volume of $CO_2$ that could be sequestrated with a view to reducing greenhouse gas emissions and stabilize the contaminated heavy metals from bottom ash samples. In this study, we used PC boiler bottom ash, Kanvera reactor (KR) slag and calcined waste lime for measuring chemical analysis and heavy metals leaching tests were performed and also the formation of calcite resulting from accelerated carbonation process was investigated by thermo gravimetric and differential thermal analysis (TG/DTA).

• 보존과학회지
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• 제37권1호
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• pp.13-24
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• 2021

Safflower, a natural dye representing red, is the dye that materials and dyeing method are recorded in the literature, including materials and dyeing. Although the safflower is the same, the ash used as a mordant is recorded differently in each literature, which greatly affects the aesthetic perspective in realizing the traditional safflower red. Therefore, the optimal conditions for realizing the traditional safflower red were sought. The experiment was conducted by pH investigation, dyeing and color analysis by dyeing solution water, concentration, and temperature by ash, and the unique color of red was confirmed. As a result of the test, the pH point of time when the uniq ue color was expressed was 11.53 as goosefoot ash (natural bedrock water), which was 1:100 for concentration and 70℃ for temperature, which was easier to extract red pigment than other ash, indicating that it is suitable for safflower dyeing. The analysis of the ash showed that K and Si play an important role in dyeing, especially Si, which is an element that inhibits carthamon. The color of red was similar to that of KS Standard vivid purplish red in the ash of the goosefoot, and the other ash was deep purplish pink. In the light of findings, it was possible to quantify the dyeing method through traditional materials and find the standard color of red color, and it is judged to be a basic data for studying the unique color of natural materials.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.477-483
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• 2000

Fly ash is the unburned residue resulting from the combustion of coal in utility and industrial boilers such as thermal power plants. Annually about 5 million tons of fly ash is being produced in korea. Less than 25 percent of total volume of fly ash is currently being used effectively for some ways. In the future, the volume of fly ash discharge from thermal power stations will be increasing more and more, and the development of the utilization of high volume fly ash is required. Fly ash has a lower compacted density and specific gravity than coarse grained natural aggregates but equivalent strength properties indicating that the fly ash could be used as a structural fill materials. So, clay-fly ash mixtures can be used as a fill material in the construction of embankments. Laboratory tests have been carried out to determine the physical, chemical, and geotechnical characteristics of the clay and fly ash. The fly ash is mixed with the clay in different proportions and the geotechnical characteristics of the mixtures have been studied also. In this study describes the results of the experimental study. The implications of the use of clay and clay-fly ash mixtures on the stability of embankments are discussed.

• Korean Chemical Engineering Research
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• 제52권2호
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• pp.233-239
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• 2014

석탄 연소 시 발생하는 회가 보일러 벽면에 부착되어 일어나는 슬래깅 현상은 보일러의 열효율을 감소시키고 보일러 안정성에도 악영향을 준다. 이러한 슬래그의 유동 특성은 회의 용융 특성과 관련이 있는데 이는 회의 화학적 조성에 영향을 받는다. 본 연구에서는 회의 용융특성을 TMA(Thermo-Mechanical Analysis) 장비를 이용하여 분석하였다. 이 테스트는 회의 수축률에 따른 용융온도(T25%, T50%, T75%, T90%)를 정량적으로 측정 하는 방법이다. TMA에서 측정된 각각의 온도는 용융단계별 특성을 나타낸다. TMA로 분석된 결과 값에 XRF 장비를 이용하여 분석한 회의 성분 조성이 미치는 영향을 분석하였다. 회에 포함된 성분 중 refractory, fluxing contents가 회분의 용융온도에 미치는 영향을 확인할 수 있었다. Refractory contents 성분인 $SiO_2$, $Al_2O_3$의 함량이 많을수록 전체적인 용융온도가 올라가며 $SiO_2/Al_2O_3$가 커질수록 고온에서의 용융온도인 T75%, T90%가 낮아지는 것을 알 수 있었다. 이와 달리 fluxing contents 성분인 $Fe_2O_3$, $K_2O$, CaO의 함량이 많아질수록 전체적인 용융온도가 낮아지며 이중 $K_2O$, CaO는 초기 용융 온도인 T25%를 낮추는데 큰 역할을 하는 것으로 판단되었다. TMA 분석과 회의 조성 비교를 통하여 회의 용융 특성을 예측하고 설명할 수 있었다.

• 한국농공학회논문집
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• 제55권3호
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• pp.129-140
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• 2013

Bottom Ash is industrial by-product from a thermoelectric power plant. An immense quantities of bottom ash have increased each year, but most of them is reclaimed in ash landfill. In this study, in order to raise recycling rate of Bottom Ash, it is suggested to cure Bottom Ash (BA) mixtures mixed with cement, lime, Fly Ash (FA), and oyster shell (OS). Mixtures of 5~20 % mixing ratio had been cured for 1, 3, 7, 14, and 28 days using sealed curing and air-dry curing method. Unconfined compressive strength test was conducted to determine strength and deformation modulus ($E_{50}$) change for mixtures as mixing ratio and curing day, water contents of mixtures were measured after test. As a result, strength and $E_{50}$ were increased as mixing ratio and curing days, but values and tendencies of them appeared in different as kind of mixture, mixing ratio, curing method, and curing days. The results showed the addition of cement, lime, Fly Ash, and oyster soil in Bottom Ash could improved strength and $E_{50}$ and enlarge its field of being used.

• 자원리싸이클링
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• 제5권3호
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• pp.44-49
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• 1996

국내 석탄발전소에서 배출되고 있는 비산회의 재활용에 가장 큰 문제점은 비산화에 혼입되어 있는 미연탄소분이다. 본 연구는 기존 포말부유선광법으로 유연탄비산회의 미연탄소분을 제거할 때 기포제종류 및 첨가량의 영향, 포집제 첨가량의 영향을 실험하고, 여기에서 수율, 회수율, 미연분제거율, 공정효율을 구하였다. 또한 비산회정제 전후의 화학적 성분을 분석하여 성분변화를 확인하였다. 실험결과는 유연탄 비산회 중의 미연탄소분을 92.4%까지 제거할 수 있었으며, 그 결과 비산회의 순도를 99.4%까지 높일 수 있었다.