• 한국자원식물학회지
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• 제20권1호
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• pp.93-98
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• 2007

석탄회의 시용은 토양의 pH를 증가시키는 경향을 보였으며, 무연탄회 보다는 유연탄회에서 그 효과가 더 현저하였다. 석탄회 시용에 의한 토양 pH 교정효과는 토양중 유효인산의 함량을 증대시켰으나 공시토양의 높은 pH와 고온, 건조한 환경으로 인하여 석탄회의 시용량이 증가하여 토양 중의 인산함량이 높을수록 식물체에 함유된 인산의 함량이 오히려 낮아지는 경향을 보였다. 토마토의 수량은 식물체내의 인산함량이 높은 처리구에서 많아 식물체 중의 인산 함량의 증가가 식물의 수량을 증가시키는 요인이 된 것으로 생각된다. 수확기별로 보면 모든 처리구에서 제 2과방의 주된 수확시기인 7월 21일에서 7월 30일 사이에 주당 수확된 과실의 수가 많았고, 과실의 개별 무게가 무거워 수량이 가장 많았다. 결론적으로 석탄회의 시용은 토양의 물리화학성을 개량시키는데 기여하는 것으로 생각된다.

• 한국세라믹학회지
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• 제40권7호
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• pp.702-708
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• 2003

포틀랜드 시멘트 양(중량)을 플라이 애쉬로 50 wt%까지 치환한 페이스트, 모르터 내지 콘크리트 시편을 만들어 플라이 애쉬가 모르터/콘크리트의 온도, 자유석회량 및 강도 등에 미치는 영향을 조사하였다. 페이스트의 수화열을 측정하여 환산식에 따라 일반 포틀랜드 시멘트 콘크리트의 경우와 비교할 때, 플라이 애쉬를 50 wt% 함유한 콘크리트의 양생 7일 온도(상승)는 약 45% 저하되었다. 전자의 경우 온도 상승은 33.4$^{\circ}C$이며 후자의 경우는 18.7$^{\circ}C$였다. 한편 철근 콘크리트의 제조에 사용되는 시멘트의 플라이 애쉬 함유량은 철근부식의 방지를 위하여 30 wt%를 초과하지 않는 게 바람직하다. 플라이 애쉬를 혼합한 콘크리트의 강도가 순수 포틀랜드 시멘트 콘크리트의 강도보다 양호하기 위해서는 양생기간이 28일 이상 되어야 한다. 그리고 플라이 애쉬 50 wt%를 함유한 시멘트를 가지고도 360 kg/$\textrm{cm}^2$ 이상의 28일 강도를 얻을 수 있었다.

• 한국세라믹학회지
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• 제34권5호
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• pp.528-534
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• 1997

There have been many studies on the preparation of slip, forming and drying in the slip casting process. However, is has not been yet on the rheological properties of consolidated body which largely affect on the workability. It was investugated that the rheological properties of the consolidated bodies formed by slip casting in the form of cakes from well dispersed(slip C) and weakly agglomerated slip(slip B) in the clay and clay-fly ash systems. The state of dispersion of slip was found to affected the critical moisture content which was largely affected by the pore and moisture distribution of the consolidated body. The cake C show lower critical moisture content than cake B in the clay system. However, the cake B gives lower critical moisture content than cake C in the clay-fly ash system.

• 자원환경지질
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• 제21권1호
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• pp.97-106
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• 1988

The purpose of this study is to collect basic data which are prerequisite for quantitative analysis of coal logging data. The study involves laboratory measurements of physical properties such as seismic velocities (P,S-waves), resitivity and density of domestic and imported foreign coals. The relationships between these properties were analyzed by using cross-plots. Correlation between the physical properties of coal and the results of chemical analysis (calorie, fixed carbon, ash, moisture, volatile matter and sulfur contents) was also studied to obtain ideas about coal quality analysis using logging data. Summarized results are as follows: 1. $V_P$ is exponentialy related to $V_S$. And the average value of $V_P$ is about l.8 times as large as $V_S$. 2. Since coal has very low density compared with surrounding sedimentary rocks, density logging is appeared to be the best method for identifying coal seams and evaluating their qualities. 3. For the case of domestic coals, the ash contents and calorie show a perfect inverse relationship. Since the density increases as increase of ash content with a well-defined functional form, the ash content of domestic coals can be estimated by density measurements. 4. Because of low ash content, low density and high resistivity, foreign coals and domestic lignites are easily distinguished from domestic coals.

• 한국환경과학회지
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• 제29권11호
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• pp.1015-1024
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• 2020

Using the waste(sand wastr and boiler ash) in fluidized bed inciverator, lightweight aggregate concrete was produced and a recycling plan was prepated. The first, the result of the leaching test shows that the waste fluid sand and boiler ash did not exceed the effluent standard. This indicates that there is no harmful effect for recycling. The second, in the lightweight aggregate test using waste fluid sand and boiler ash, the sample that combined cement, waste fluid sand, and sand showed the highest compressive strength, and the mix proportion was 10: 7: 3. Lightweight aggregate concrete that combined cement, waste fluid sand, boiler ash, and sand had a low compressive strength by and large. The third, the same results were identified in the relation between the content of SiO₂ and that of Na₂O. As the SiO₂ content is lowered, the overall viscosity and plasticity of the concrete also decrease, which is not a good condition to form concrete. As for Na₂O, as the content increases, the viscosity of the sample and the viscosity of the cement are remarkably lowered, and the strength of the finished concrete is lowered. Therefore, it was concluded that the higher the content of SiO₂ and the lower the content of Na₂O, the more suitable it is to mix with cement to produce concrete. Fourth, from the fluidized bed incinerator currently operated by company A in city B, a total of 14,188 tons/year were discharged as of 2016, including 8,355 tons/year of bottom ash (including waste fluid sand) and 5,853 tons/year of boiler ash. The cost for landfill bottom ash and boiler ash discharged is 51,000 won/ton, and the total annual landfill cost is 723,588,000 won/ year. Assuming that the landfill tax to be applied from the year 2018 is about 10,000 won/ton, and if there is no reduction in waste disposal charge, an additional landfill tax of 141,880,000 won/year will be imposed. Consequently, the sum total of the annual landfill cost will be 865,468,000 won/year. Therefore, if the entire amount is used for recycling, the annual savings of about 8.7 billion won can be expected.

• 한국연초학회지
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• 제20권1호
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• pp.5-12
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• 1998

Pot experiment was conducted to investigate the effects of fly ash on growth responses and on accumulation of the heavy metals in soil. Two kinds of fly ash, anthracite and bituminous coal, were treated with different levels of 0, 0.4, 0.8, and 1.2 kg/pot(20L). Tobacco growth was better by application of fly ash than that by the control. However, the early stage of growth by application of bituminous coal, 1.2 kg/pot, was decreased due to the boron toxicity occurred by fly ash. Generally, tobacco yield was significantly increased with applying fly ash, showing the highest yield at 1.2 kg/pot for anthracite and at 0.8 kg/pot for bituminous coal. The content of total nitrogen in leaves was higher with fly ash than that of the control, while the content of calcium in leaves was low, Contents of heavy metal and the other minerals were not significantly different between the control and the treatment of fly ash. Soil pH after experiment was linearly increased with application level of fly ash, indicating that the application of bituminous coal was more effective than that of anthracite. Contents of available phosphate, exchangeable $Ca^{2+}$+ and $Mg^{2+}$ in soil were increased by application of fly ash, especially with bituminous coal. Contents of Cu, Cr, and Ni were increased with application level of bituminous coati even if the contents were still lower than critical levels for farming land. The other heavy metals were similar between the control and the application of fly ash.

• 한국재료학회지
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• 제27권2호
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• pp.76-81
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• 2017

Recently, there have been many efforts to establish suitable processes for recycling fly ash, which is produced in thermal power plants and which poses serious environmental problems. Use of fly ash as a major ingredient of ceramic tiles can increase fly ash utilization, as well as reduce the cost of raw materials in ceramic tile production. In this study, the effects of fly ash addition on ceramic tile properties such as bending strength, water absorption and porosity were investigated. A manufacturing process of ceramic tile was developed for utilization of fly ash with high carbon content. In this approach, it is important to hold the ceramic tiles at a temperature that is sufficient for carbon oxidation, before the pores supplying oxygen to the inside of the ceramic tile are sealed. Ceramic wall tiles were manufactured with 0-40wt% of fly ash addition. The water absorption and porosity of the fired body were slightly changed with increasing fly ash content up to 30wt% and decreased with greater amounts of fly ash addition. The bending strength of ceramic tile including 10wt% fly ash increased, reaching a level comparable to that of ceramic tile without fly ash.

• 한국산림과학회지
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• 제99권5호
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• pp.706-710
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• 2010

Understanding of chemical composition and energy contents in tree is important to develope strategies of renewable energy policy to cope with climate change. Residual biomass as renewable energy source was evaluated and focused on the bark-containing branches. Chemical analysis studies were conducted for different part of yellow poplar (Liriodendron tulipifera), which were partitioned to inner bark, outer bark, small branches, medium branches, big branches and trunk. The variations in hydrophobic extractives, hydrophilic extractives, lignin, carbohydrate compositions, energy contents (higher heating value) and the ash content were determined. The inner and outer bark had higher ash content, hydrophobic and hydrophilic extractives content, and higher energy content than those of tree trunk. Polysaccharides content in inner and outer bark was quite lower than those of stem or branches. Based on the energy content of residual biomass, replacement of fossil fuel and greenhouse gas emission abatement were calculated.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.203-206
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• 1999

An experimental study is carried out to investigate the characteristics of concrete containing high volume fly ash. The compressive and tensile strength of fly ash concrete is slightly lower than those of ordinary concrete between 7and 28 days, however, the long-term compressive strength is significantly higher at 180 days. In durability, the high volume fly ash concretes are generally higher resistance of freeze and thaw and lowe chloride penetration, however, the depth of carbonation is increased with increasing fly ash content.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.1221-1226
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• 2000

Influence of characters of fly ash on the fluidity of cement paste with polycarboxylic acid type superplasticizer has been investigated in connection with the particle size of distribution, unburned carbon content, specific surface area and shape of fly ash. The fluidity of paste is increased with increasing roundness of fly ash and it is decreased with increasing n-value of Rosin-Rammler distribution function. There is a linear correlation between roundness/n-value and fluidity of fly ash cement paste.