共查询到20条相似文献，搜索用时 15 毫秒
1.
利用湖泊底泥和粉煤灰制备瓷质砖的实验研究 总被引：6，自引：0，他引：6
将湖泊底泥引入瓷质砖的生产, 既可消除污染, 又能减少传统的瓷质砖生产中所需的粘土.以武汉市东湖底泥和湖北黄石电厂粉煤灰为主要原料, 辅以伟晶花岗岩、石英为添加剂, 设计4个底泥含量分别为4 0 %、5 0 %、6 0 %和70 %的配方, 每一配方压制6片生坯, 分别在1 190, 1 175, 1 160, 1 130, 1 115和1 100℃下烧成.XRD分析显示瓷坯中的莫来石晶相随烧成温度的升高而增加.在1 160~1 175℃烧成的瓷坯的吸水率和断裂模数测试结果分别为0.0 8%~ 0.2 0 %和39.36~ 51.0 8MPa, 表明利用湖泊底泥和粉煤灰作为主要原料可以烧制瓷质砖, 二者的总用量可达75 %~ 80 %. 相似文献
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为了粉煤灰的高附加值综合利用,采用酸浸法对准格尔地区循环流化床粉煤灰进行了镓的浸出实验研究,考察了多种因素对镓的浸出率的影响,包括粉煤灰粒度,酸的种类与浓度、酸浸温度与时间、固液比等。结果表明,提高镓的浸出率的适宜条件为:粉煤灰粒度200目,盐酸的浓度6 mol/L,酸浸温度应大于160℃,酸浸时间6 h,液固比在5∶1~6∶1之间为宜。在优选的工艺条件下,镓的浸出率可达80%以上。从粉煤灰中提取镓,使其作为一种资源加以利用,是提高粉煤灰综合利用价值的有效途径。 相似文献
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W. F. Tan L. A. Wang C. Huang J. E. Green 《International Journal of Environmental Science and Technology》2013,10(3):465-472
Municipal solid waste incineration fly ash blended with pine sawdust and shale, using a neotype trefoil rotary kiln to form lightweight aggregates, is an effective and a potential means method of fly ash disposal. The optimum sintering conditions of Trefoil rotary kiln were determined in terms of an orthogonal test by measuring the pellets’ bulk density, granule strength, 1 h water absorption. As far as the kinetics is concerned, an integral method of Coats–Redfern was introduced to analyze the kinetics characteristics of the mixture samples. Also, the kinetic triplets (apparent activation energy, pre-exponential factor and reaction order) were estimated by the reaction of kinetics model functions. It is shown that the optimum sintering conditions are as follows: (a) preheating temperature of 500 °C, (b) sintering temperature of 1130 °C, (c) holding time of 4 min. The optimum reaction models of the four stages are Avrami–Erofeev, Mample, Avrami–Erofeev and There-dimensional diffusion (Jander), respectively. 相似文献
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《矿物学报》2013,(Z1)
The glass-ceramics was prepared from coal fly ash, limestone and Na2CO3 by sintering processes. Effects of the crystallization temperature (850–1100 ℃) on crystallization behavior, microstructure, sintering character and chemical stability of the glass-ceramics samples were analyzed by means of DTA, XRD, SEM and other analytical methods. The results show that the main crystalline phase of as-prepared glass-ceramics after crystallization treatment is gehlenite (Ca2Al2SiO7). The species of crystalline phases keep the same, however, the main crystalline intensity, line shrinkage rate and bulk density increase first then decrease with the increasing of heat treatment temperature. Water absorption of the samples was reduced as the heat treatment temperature rising. The glass-ceramics display high performance crystallization properties and chemical stability. The optimized glass-ceramics with desired sintering character and chemical stability was obtained by crystallized at 1050 ℃. 相似文献
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《Applied Geochemistry》2005,20(7):1309-1319
Petroleum coke has been used as a supplement or replacement for coal in pulverized-fuel combustion. At a 444-MW western Kentucky power station, the combustion of nearly 60% petroleum coke with moderate- to high-sulfur Illinois Basin coal produces fly ash with nearly 50% uncombusted petroleum coke and large amounts of V and Ni when compared to fly ash from strictly pulverized coal burns. Partitioning of the V and Ni, known from other studies to be concentrated in petroleum coke, was noted. However, the distribution of V and Ni does not directly correspond to the amount of uncombusted petroleum coke in the fly ash. Vanadium and Ni are preferentially associated with the finer, higher surface area fly ash fractions captured at lower flue gas temperatures. The presence of uncombusted petroleum coke in the fly ash doubles the amount of ash to be disposed, makes the fly ash unmarketable because of the high C content, and would lead to higher than typical (compared to other fly ashes in the region) concentrations of V and Ni in the fly ash even if the petroleum coke C could be beneficiated from the fly ash. Further studies of co-combustion ashes are necessary in order to understand their behavior in disposal. 相似文献
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Ganesh Chandra Kisku Sandeep Yadav Rajnish Kumar Sharma Mahendra Pal Singh Negi 《Environmental Earth Sciences》2012,67(7):2109-2120
Coal, a fossil fuel, is the largest source of energy for the generation of electricity in India. In order to study the potential environmental hazards by coal based power plants, particulate matters were collected using Stack Monitoring Kit and gaseous pollutants by Automatic Flue Gas Analyzer. The morphological and chemical properties, mineralogical composition and particle size distributions have been determined by SEM–EDX, XRD and CILAS. The data revealed the presence of particulate matters, SO2, NOx in the range of 236–315, 162–238, 173–222 mg/Nm3 respectively. The emission of CO2 was in the range of 43,004–60,115 Nm3/h with an average of 52,830 Nm3/h. Among the elements, Fe > Mn > Al > Zn > B > Ni > Cr > Cu were present in substantially higher proportion than Pb > Mo > Cd > Se > As > Hg. It was found that most of the elements were concentrated on fly ash surface rather than coal, bottom ash and pond ash. This variation may be attributed to the fineness of fly ash particles with large surface ratio to mass. Mineralogical studies of coal and fly ash by X-ray diffraction revealed the presence of mullite, quartz, cristobalite and maghemite. Presence of mullite and quartz found in fly ash indicate the conversion of complex minerals to mullite and quartz at high temperature. Transfer Coefficient was calculated to determine the ratio of the enrichment of trace elements in fly or bottom ash with respect to coal and pond ash. 相似文献
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燃煤固体产物的矿物组成研究 总被引：12，自引：1，他引：12
利用X射线衍射、穆斯堡尔谱与扫描电子显微镜等方法研究中国典型燃煤煤种的燃烧产物的矿物学特征，揭示出不同化学成分以及不同类型产物中矿物组成的差异性。根据化学成分，可将燃煤固体产物分为硅铝质、铁质和钙质三组，硅铝质产物结晶相主要为莫来石和石英，而结渣中基本为莫来石；铁质产物中主要矿物包括α-Fe2O3、γ-Fe2O3与Fe3O4，其含量随锅炉燃烧湿度的变化而变化；钙质产物中矿物种类复杂，飞灰石检出石灰、石膏和石英，沾污中检出石膏、赤铁矿和石类，而结渣中还发现钙的硅酸盐矿物。上述矿物分布特征是由不同成分的硅酸盐熔体在不同热力学条件下的结晶行为所决定的。 相似文献
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Huang Wenhui Yang Qi Department of Energy Resources Geology China University of Geosciences Beijing Peng Suping Department of Geology Engineering China University of Mining Technology Beijing Zhao Zhigen Department of R 《中国地质大学学报(英文版)》2001,12(4)
INTRODUCTIONMany environmental problems may arise during coal min-ing and utilization. Among these prob1ems, much attention hasbeen paid to S(), and NO. emission during coal combustion.But the environmental effects produced by hazardous elementsduring coal mining and utilization are also important and de-serve to be studied (Goodazi, 1995; Finkelman, 1993; Valk-ovic, l983). For example, when coal wastes are used for landreclamation, the harmful elements in them may pollute water,soil an… 相似文献
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The aim of the present study is the petrographic and chemical characterization of the coal at the Figueira Power Plant, Paraná, Brazil, prior and after the beneficiation process and the chemical characterization of fly and bottom ashes generated in the combustion process.Petrographic characterization was carried out through maceral analysis and vitrinite reflectance measurements. Chemical characterization included proximate analysis, determination of calorific value and sulphur content, ultimate analysis, X-ray diffraction, X-ray fluorescence, Inductively Coupled Plasma — Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma — Atomic Emission Spectrometry (ICP-AES) analysis, and determination of Total Organic Carbon (TOC) content.Vitrinite reflectance analyses indicate a high volatile B/C bituminous coal (0.61 to 0.73% Rrandom). Maceral analyses show predominance of the vitrinite maceral group (51.6 to 70.9 vol.%, m.m.f). Except of the Run of mine (ROM) coal sample, the average calorific value of the coals is 5205 kcal/kg and ash yields range from 21.4 to 38.1 wt.%. The mineralogical composition (X-ray diffraction) of coals includes kaolinite, quartz, plagioclase and pyrite, whereas fly and bottom ashes are composed by mullite, ettringite, quartz, magnetite, and hematite. Analyses of major elements from coal, fly and bottom ashes indicate a high SiO2, Al2O3, and Fe2O3 content. Trace elements analysis of in-situ and ROM coals by ICP-MS and ICP-AES show highest concentration in Zn and As. Most of the toxic elements such as As, Cd, Cr, Mo, Ni, Pb, and Zn are significantly reduced by coal beneficiation. Considering the spatial distribution of trace elements in the beneficiated coal samples, which were collected over a period of three months, there appears to be little variation in Cd and Zn concentrations, whereas trace elements such as As, Mo, and Pb show a larger variation.In the fly and bottom ashes, the highest concentrations of trace elements were determined for Zn and As. When compared with trace element concentrations in the feed coal, fly ashes show a significant enrichment in most trace elements (As, B, Be, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Sb, Tl, and Zn), suggesting a predominantly volatile nature for these elements. In contrast, Sn is distributed evenly within the different ash types, whereas U shows depleted concentration in both bottom and fly ash samples.According to the International Classification of in-seam coals the Cambuí coals are of para/ortho bituminous rank of low grade (except for the ROM sample), and are characterized by the predominance of vitrinite macerals. 相似文献
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《Applied Geochemistry》2001,16(7-8):911-919
A total of 48 samples, feed (run-of-mine) coals and their combustion residues (fly ash and bottom ash) were systematically collected twice a week over a 4 week period (June 1998) from two boiler units (I and II) of the Cayirhan power plant (630 MW) that burns zeolite-bearing coals of late Miocene age. The feed coals are high in moisture (22.8% as-received) content and ash (44.9%) yield and total S content (5.1%), and low in calorific value (2995 kcal/kg). The mineralogy of the feed coals contains unusually high contents of the zeolites (clinoptilolite/heulandite and analcime), which are distributed within the organic matter of coal. Other minerals determined are gypsum, quartz, feldspar, pyrite, dolomite, calcite, cristobalite and clays. Common minerals in the crystalline phase of the combustion residues are anhydrite, feldspar, quartz, hematite, lime and Ca–Mg silicate. Minor and trace amounts of magnetite, cristobalite, maghemite, gehlenite, calcite and clinoptilolite/heulandite are also present in the combustion residues. Trace element contents of the feed coals, except for W, fall within the estimated range of values for most world coals; however, the mean values of Mn, Ta, Th, U and Zr are near maximum values of most world coals. Elements such as As, Bi, Ge, Mo, Pb, Tl, W and Zn are enriched more in the fly ash compared to the bottom ash. 相似文献
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Xue Song Wang 《Environmental Earth Sciences》2014,71(4):1673-1681
Magnetic fractions of coal fly ashes from three power plants were obtained by wet magnetic separation method. Quartz and mullite were the crystalline minerals dominating the nonmagnetic fractions. Magnetic fractions contained magnetite, hematite, and, to a lesser extent, quartz and mullite. Iron speciation by Mössbauer spectroscopy indicated the presence of Fe2+ and Fe3+ in aluminosilicate glass in magnetic fractions apart from magnetite and hematite. Chemical analyses revealed that magnetic fractions had about 2.5 times higher concentrations of Co and one to two times higher concentrations of Ni, Cu, Zn, Mo, and Cd. The dominant magnetic minerals were ferrimagnetic, and multi domain and stable single domain grains contributed mainly to the magnetic enhancement of fly ash samples. 相似文献
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矿物微粉制备的硅酸铝质高强陶瓷 总被引：1，自引：0，他引：1
介绍了一种以蓝晶石微粉和αAl2 O3 微粉为主要原料 ,一步煅烧法制备硅酸铝质高强陶瓷的工艺方法 ,并对制品的烧结性能、显微结构进行了分析。 (1)由该方法制得的硅酸铝质陶瓷 ,体积密度为 2 0 9～ 2 12 g/cm3 ,气孔率为 2 5 58%～ 2 8 54% ,常温耐压强度高达 180 87～ 315 30MPa ,在烧结过程中体积收缩率为 0 4 9%～ 2 73%。与传统烧结方法生产的同类产品相比 ,工艺流程简化 ,烧结温度降低 2 0 0～ 2 50℃以上 ,材料的耐压强度仍得到较大幅度的提高 ,是一种值得向生产领域推广应用的方法。 (2 )制品强度的提高 ,主要得益于纤维状莫来石的交错排列。 (3)陶瓷的烧结温度以 1350℃为宜。 相似文献
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Lallan Prasad Gupta Hodaka Kawahata Mio Ltakeuchi Hidekazu Ohta Yoshiro Ono 《Resource Geology》2006,56(2):191-196
Abstract. Oxidation and reduction processes can influence extent of leaching of elements from solid waste. Three samples of municipal solid waste combustion fly ash were subjected to oxidizing and reducing conditions in order to evaluate leaching of elements in the Milli-Q water and fly ash (liquid to solid ratio, 100) mixtures. Although the oxidizing and reducing conditions were applied for 6 hours only, elements like Cs, Li, Mg, Sb, Tl and V leached more under oxidizing condition than under reducing condition in the case of all three ash samples. Cadmium, Pb and Zn leached more from all samples under reducing condition than under oxidizing condition. Leaching of other elements like Al, Ba, Cr, Cu, Ni and Rb was inconsistent with oxidizing or reducing conditions and varied from sample to sample, suggesting that factors other than redox may be more important in controlling leaching of these elements. Strong acid neutralization capacity of the fly ash samples let the pH vary within a narrow range, and thus severely limited the extent of leaching during the course of the experiment. Lead and Zn were the most sensitive while K and Na were the least sensitive to changes in redox conditions. 相似文献
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利用干馏后的油页岩灰渣,湿法提取氧化铝作为发光材料基质,经采用高温固相法合成 CaAl2O4 : Eu3 + ,R + ( R = Li,Na,K,Rb) 荧光粉。最佳合成条件为: 烧结温度1 200 ℃,烧结时间3 h,助熔剂加入量3 wt%,激活离子配比3 mol%; 实验发现辅助激活离子为Li + 时,CaAl2O4 : Eu3 + , Li + 的发光强度最强。样品荧光光谱分析结果表明,发射光谱在615 nm 处出现强谱峰,归属为Eu3 + 的5D0→7F2 跃迁辐射。 相似文献
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为研究季节冻土地区冷阻层的路基温度场效应,基于ANSYS软件热分析原理,以粉煤灰土、橡胶颗粒改良粉煤灰土和聚丙烯纤维改良粉煤灰土3种冷阻层材料为研究对象,模拟季节冻土地区道路路基温度场,研究其阻止热量交换的效果。结果表明：采用粉煤灰土为冷阻层的道路的最大冻深为1.32 m,温度梯度最低值为-17.606℃/m;采用橡胶颗粒改良粉煤灰土为冷阻层的道路的最大冻深为0.94 m,温度梯度最低值为-23.563℃/m;聚丙烯纤维改良粉煤灰土为冷阻层的道路的最大冻深为1.20 m,温度梯度最低值为-19.557℃/m。橡胶颗粒改良粉煤灰土冷阻效果最佳,其确保路基土处于零上温度不冻结状态的最小摊铺厚度为0.33 m,适宜作为季节冻土地区的冷阻材料。 相似文献
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江西玉山石煤烧结包裹与钒转化的研究 总被引：7，自引：0，他引：7
江西玉山含钒石煤既是低热值能源,又是一种新类型钒矿资源。为充分利用这种资源,在600～1150℃下进行了氧化培烧和钠化焙烧,测定了煤灰的松装密度d和钒转化率η,研究厂烧结包裹作用。结果表明:温度升高,煤灰烧结严重,对钒包裹几率加大,钒转化率降低。石煤作为能源利用时,燃烧温度不宜超过950℃,石煤钠化焙烧提钒最佳温度775℃。在两种焙烧条件下的石煤烧结机理作了探讨,并进一步得出玉山石煤烧结与包裹的关系式。 相似文献
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沁水盆地煤岩高温高压实验变形特征 总被引：1，自引：0，他引：1
对沁水盆地不同地区选取的5组煤岩样品进行高温高压变形实验,结果证实,在相同的实验条件下,(1)采自不同地区的煤岩强度在较低温压条件下表现出一致性,在较高温压条件下显现出差异性;(2)高煤级煤No.3煤样在某一温压条件下（100℃、100MPa）,应力应变强度都是最低的,为煤岩组分影响的结果。在不同的实验条件下, 煤岩在高温高压条件下（温压大于200℃、200MPa）,随着温度与围压增高,应力应变强度在降低,但这主要是温度影响的结果。在温压为100℃、100MPa和500℃、500MPa时,煤岩应力应变强度均很低,但却存在着本质的差别:前者产生的应力应变强度只有部分真实地代表了煤岩的强度（应变量ε<3％）,而持续的应力应变强度（应变量ε>3％）则是围压作用的结果;后者煤岩低应力应变强度显示出明显的韧性状态, 主要表现在温度对煤岩产生的影响。 相似文献
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淮南二叠纪煤及其燃烧产物地球化学特征 总被引：11，自引：1，他引：11
采用仪器中子活化分析法INAA（instrumental neutron activation analysis)测试了淮南煤田二叠纪主采煤层原煤煤样的地球化学组成，用X－射线荧光光谱XRFS（X－ray fluorescence spectrometry)测试了田家庵和洛河电厂的粉煤灰地球化学组成并与煤样作了对比分析，用电子探针测试了飞灰中主要类型颗粒的化学组成，淮南煤中多数微量元素属正常水平，与克拉克值相比，元素Se,S,As,Sb,Br,U和Cl等在煤中趋于富集，其他元素均趋于分散，有机亲和性弱的亲石元素趋于在粉煤灰中聚集，与铁关系密切的金属元素在粉煤灰中有明显的富集，有机亲合性强的元素在燃烧过程中趋于以气态形式向空气中逸散，粉煤灰中因矿物与粒度的分异明显，致使其化学组成在不同的粒度级和比重级中的分布也有较大的不同，飞灰中一些不定形颗粒主要由铁的氧化物和少量其他金属氧化物组成，硅酸盐类颗粒主要由硅，铝和铁的氧化物所组成，而玻璃珠主要由硅和铝的氧化物组成，残碳中测得的砷，硫和氯的含量最高，说明其对这些元素具有较强的吸附能力，研究粉煤灰的成分特点有助于粉煤灰的综合利用和评价其对环境的 影响。 相似文献