Assessment of oyster shells and bottom ash for improvement of coastal saline soil through empirical tests
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Porous ceramics have a great potential to be utilised for adsorption purposes. In this study, the effects of fly ash addition in porous clay-fly ash composites via polymeric replica technique were investigated. The results shows that the fly ash addition from 1:1 to 1:1.5 (clay:fly ash ratio) have promoted favourable results for compressive strength (0.228-0.284 MPa), porosity (97.0-97.4 percent) and densities (2.358-2.439 g/cm 3 ) respectively. When the fly ash ratio addition was increased up to 1:2 (clay:fly ash ratio), the compressive strength (0.18 MPa) reduced significantly. However, the density was bounced back to 2.404 g/cm 3 at the same ratio. This condition was occurred due to high concentration of mineral contents when fly ash addition has increased. Based on XRD pattern, the intensities between mullite and quartz was reduced when clay:fly ash ratio increased from 1:1 to 1:1.5. As the clay:fly ash ratio was increased up to 1:2, the intensities of mullite and quartz showed an increment in XRD pattern. However, there were only 4 percent of changes in porosity when the fly ash addition was 1:2 (clay: fly ash ratio). The reticulated structures of porous clay-fly ash composites were similar although fly ash addition has increased from 1:1 to 1:2.
Mullite
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화력발전소에서 배출되는 석탄회는 주변 환경을 오염시키고 매립지 확보의 문제 등을 유발하여 이를 해결하고자 선진국에서는 일찍부터 석탄회의 재활용을 적극 추진하고 있다. 그러나 석탄회의 재활용은 주로 비산재를 중심으로 이루어지고 연소보일러 하부에서 발생되는 Bottom ash는 재활용 비중이 상대적으로 낮은 실정이다. bottom ash의 재활용 비중을 증가시키기 위해서는 Bottom ash에 포함되어 있는 여러 유해물질을 파악하는 연구가 선행되어야 할 것이다. 이에 본 연구는 화력발전소에서 발생하는 Bottom ash에 함유된 유해물질을 파악하고, 이들의 용출 특성을 확인하는 연구를 수행하였다. XRD, XRF를 통해 Bottom ash의 구성성분을 파악하고, 함량분석, 용출실험 등을 통하여 중금속 및 각종 무기이온을 분석하였다. 그 결과 Bottom ash의 성분은 SiO₂＞ Al₂O₃＞ Fe₂O₃＞ CaO＞ MgO 순으로 SiO₂와 Al₂O₃, Fe₂O₃의 성분이 각각 63.2 %, 18.9 %, 7.8 %로 전체의 90 %이상을 차지했다. 용출 실험 결과 Cr??의 함량이 0.13 ㎎ L?¹로 다소 높은 결과를 보였으나, 다른 항목은 검출되지 않았다. Bottom ash의 용출 결과를 폐기물관리법 기준과 비교 분석한 결과 그 기준을 넘는 항목은 없음을 알 수 있었다. 이는 Bottom ash의 재활용 시 발생 가능한 환경문제는 최소화되어 재활용 범위가 보다 광범위하게 확장될 수 있음을 의미한다.
Incinerator bottom ash
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As electricity increases every year in our country,the emissions from coal-fired power plants fly ash also increase and the environmental problem of fly ash is increasingly serious. Due to the use of fly ash much less than the total emissions,new areas of development and utilization of fly ash become a research hotspot. This paper analyzed the composition and morphology of fly ash. And the main application of fly ash were also discussed. The fly ash as adsorbent were used to remove SO2,CO2 and Hg in flue gas. This paper emphasized the present situation of the SCR denitration catalyst,the removal effect of NOxwith fly ash loading with transition metals as low-temperature SCR denitration catalyst and the preparation method of catalyst. Fly ash has been proved to have good removal effect of SO2,CO2,Hg and NOxin many studies. Because of good application of fly ash in flue gas treatment,the future development direction of fly ash to control pollution was propoesd.
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1. Uses of Fly Ash in Cement and Concrete 2. Effect of Fly Ash on the Properties of Fresh Concrete 3. Effect of Fly Ash on the Structural Properties of Hardened Concrete 4. Admixtures in Fly Ash Concrete 5. Miscellaneous Opportunities for Fly Ash Use 6. Fly Ash Usage in Waste Management 7. Special Problems Including Use Constraints 8. Types and Properties of Fly Ash 9. Effect of Fly Ash on the Durability of Concrete 10. Applications of Fly Ash in Special Concretes
Properties of concrete
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The Suminoe oyster, Crassostrea ariakensis, is currently under consideration for introduction to the Chesapeake Bay for aquaculture and to restore lost fishery resources once provided by the native Eastern oyster. To assess the suitability of the Suminoe oyster for substitution into native oyster markets, we provided whole triploid oysters for home cooking to consumers in coastal North Carolina and asked them to complete a survey on qualities of the Suminoe oyster. Participants reported the frequency with which they would consume the oyster inside and outside of the existing oyster season, how they would consume the oyster and the price they might be prepared to pay for the Suminoe oyster relative to the native oyster. Because participants prepared the Suminoe oysters themselves, consumer evaluations incorporated not only attributes of the oyster meat but also the ease with which the oysters could be shucked and prepared. Consumers rated the Suminoe oyster's aroma, appearance, texture and flavor as likeable. As a result of the oyster's tissue quality and the ease with which it could be shucked, 81% indicated that they would purchase the Suminoe oyster if it is introduced. Only 19% of survey participants said they would pay more for Suminoe than Eastern oysters when both are available. This contrasts sharply with the 45% that would be prepared to pay a higher price for the Suminoe oyster than they would normally pay for Eastern oysters at times when the Eastern oyster is not available. Consumers generally indicated that they would prepare the non-native oyster in similar ways to the native oyster. Thus, our study indicates that the Suminoe oyster is considered by consumers in eastern North Carolina to be a close substitute for the native oyster. Consequently, the Suminoe oyster might serve as a successful substitute for the lost fishery resource of the native oyster.
Ostreidae
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Fly ash can include toxins from high levels of bottom ash in some circumstances, such as burning of solid waste to generate power (resource recovery facilities or waste-to-energy conversion), and combining fly ash and bottom ash together delivers corresponding quantities of contaminants. Under some conditions, fly ash can be classified as non-hazardous waste, but if it is not blended, it can be classified as hazardous waste. The goal of this research was to find out about the differences between fly and bottom ash, as well as the influence of fly ash on bottom ash in terms of avoiding abrasion. In addition, the study's goal was to see how fly ash affected coconut fiber's resistance to abrasion. This study employed a quantitative technique in which the researcher used primary data sources such as questionnaires and observations, as well as secondary data sources such as prior studies. The findings revealed that fly ash had no effect on bottom ash in terms of avoiding abrasion. Furthermore, it is well known that neither fly ash nor bottom ash are effective against coconut fiber. Fly ash has a coarser texture than bottom ash, according to the findings. The regression test revealed that there was no difference between fly ash and bottom ash, as well as coconut coir, in terms of reducing abrasion
Incinerator bottom ash
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Fly ash is one of the most voluminous industrial byproducts that result from coal combustion. This study examines the physical and chemical characteristics of fly ash with the aim of: differentiating between high-Ca fly ash with low Ca ash, and exploring the statistical variability of fly ash properties. The paper describes the results of the laboratory tests used to evaluate the cementing characteristics of Class C fly ash obtained from power plant burning subbituminous Wyoming coal. Laboratory tests demonstrate that fly ash can be effectively used as cement surrogates in portland cement concrete, for intermediate strength fly ash concrete or flowable fills, and for low strength clay soil stabilizer.
Statistical Analysis
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Current US national standards for using fly ash in concrete (ASTM C618) state that fly ash must come from coal combustion, thus precluding biomass-coal co-firing fly ash. The co-fired ash comes from a large and increasing fraction of US power plants due to rapid increases in co-firing opportunity fuels with coal. The fly ashes include coal fly ash, wood fly ash from pure wood combustion, biomass and coal co-fired fly ash SW1 and SW2. Also wood fly ash is blended with Class C or Class F to produce Wood C and Wood E. Concrete samples were prepared with fly ash replacing cement by 25%. All fly ash mixes except wood have a lower water demand than the pure cement mix. Fly ashes, either from coal or non coal combustion, increase the required air entraining agent (AEA) to meet the design specification of the mixes. If AEA is added arbitrarily without considering the amount or existence of fly ash results could lead to air content in concrete that is either too low or too high. Biomass fly ash does not impact concrete setting behaviour disproportionately. Switch grass-coal co-fired fly ash and blended wood fly ash generally lie within the range ofmore » pure coal fly ash strength. The 56 day flexure strength of all the fly ash mixes is comparable to that of the pure cement mix. The flexure strength from the coal-biomass co-fired fly ash does not differ much from pure coal fly ash. All fly ash concrete mixes exhibit lower chloride permeability than the pure cement mixes. In conclusion biomass coal co-fired fly ash perform similarly to coal fly ash in fresh and hardened concrete. As a result, there is no reason to exclude biomass-coal co-fired fly ash in concrete.« less
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A quantitative understanding of the efficiency of fly ash as a mineral admixture in cement-based materials is essential for its effective utilisation. The present paper is directed towards a specific understanding of the efficiency of fly ash in cementitious materials systems by considering the independency of fly ash and its dependency on the characteristics of the cementitious materials system. A new method of quantitatively evaluating the strength effect of fly ash is proposed, in which two parameters, the strength-effect index and the strengthening factor, are employed to study strength development in fly ash mortars and concretes and to further analyse the influences of water to binder ratio (w/b) and the replacement amount of fly ash on strength. Results indicate that the strength effect of fly ash in mortar systems is different from that in concrete; the strength effect of fly ash varies with both amount of fly ash and w/b. Furthermore, in a concrete system, two different optimal w/b ratios are used to maximise the strength-effect index and the strengthening factor of fly ash, respectively. An optimum amount of fly ash exists for an optimal unit strength-effect index in concrete. It is shown that the method presented in this paper is reasonable and effective in assessing the efficiency of fly ash. This information will strengthen the effective utilisation of fly ash in cementitious materials and design of fly ash concrete.
Cementitious
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