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Sample records for volume fly ash

  1. Durability properties of high volume fly ash self compacting concretes

    Energy Technology Data Exchange (ETDEWEB)

    P. Dinakar; K.G. Babu; Manu Santhanam [Indian Institute of Technology, Chennai (India). Building Technology Division

    2008-11-15

    This paper presents an experimental study on the durability properties of self compacting concretes (SCCs) with high volume replacements of fly ash. Eight fly ash self compacting concretes of various strength grades were designed at desired fly ash percentages of 0, 10, 30, 50, 70 and 85%, in comparison with five different mixtures of normal vibrated concretes (NCs) at equivalent strength grades. The durability properties were studied through the measurement of permeable voids, water absorption, acid attack and chloride permeation. The results indicated that the SCCs showed higher permeable voids and water absorption than the vibrated normal concretes of the same strength grades. However, in acid attack and chloride diffusion studies the high volume fly ash SCCs had significantly lower weight losses and chloride ion diffusion.

  2. Experimental Study on Volume for Fly Ash of Building Block

    OpenAIRE

    Ling Wang; He Sun; Zhihui Sun; Enqing Ma

    2013-01-01

    Fly ash is a waste substance from thermal power plants, steel mills, etc. That is found in abundance in the world. It has polluted the environment, wasting the cultivated land. This study introduces an experimental research on fly ash being reused effectively, the study introduces raw materials of fly ash brick, production process and product inspection, fly ash content could be amounted to 40%~75%. High doping fly ash bricks are manufactured, which selects wet fly ash from the power plants, ...

  3. Self compacting concrete incorporating high-volumes of fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Bouzoubaa, N. [Natural Resources Canada, Ottawa, ON (Canada). International Centre for Sustainable Development of Cement and Concrete; Lachemi, M. [Ryerson Polytechnic Univ., Toronto, ON (Canada). Dept. of Civil Engineering

    2004-07-01

    Self-compacting concrete (SCC) is now widely used in reinforced concrete structures. Fine materials such as fly ash ensure that the concrete has the necessary properties of high fluidity and cohesiveness. An experimental study was conducted in which 9 SCC mixtures and one control concrete were produced in order to evaluate SCC made with high-volumes of fly ash. The content of the cementitious materials remained constant at 400 kg/cubic metre, but the ratio of water to cementitious material ranged from 0.35 to 0.45. The viscosity and stability of the fresh concrete was determined for self-compacting mixtures of 40, 50 and 60 per cent Class F fly ash. The compressive strength and drying shrinkage were also determined for the hardened concretes. Results showed that the SCCs developed a 28-day compressive strength ranging from 26 to 48 MPa. It was concluded that high-volumes of Class F fly ash could offer the following advantages to an SCC: reduced construction time and labour cost; eliminate the need for vibration; reduce noise pollution; improve the filling capacity of highly congested structural members; and, ensure good structural performance. 19 refs., 8 tabs., 2 figs.

  4. SCC with high volume of fly ash content

    Directory of Open Access Journals (Sweden)

    Bakhrakh Anton

    2017-01-01

    Full Text Available Self-compacting concrete is a very perspective building material. It provides great benefits during the construction of heavily reinforced buildings. SCC has outstanding properties such as high flowability, dense structure and high strength due to specific quality of aggregates, fillers, their proportion in mix, use of polycarboxylate-based superplasticizers. Main disadvantages of SCC are high price and the difficulty of obtaining a proper mix. Use of fillers, such as fly ash type F, is a way to make SCC cheaper by replacing part of cement. Fly ash also provides some technological and operating advantages. In this paper the influence of high volume (60% from cement fly ash type F on the properties of concrete mixture and hardened concrete is investigated. The result of the work shows the possibility of reduction the cost of SCC using ordinary fillers and high amount of fly ash. The investigated SCC has low speed of hardening (7-day compressive strength at the range of 41.8 MPa and high volume of entrained air content (3.5%.

  5. The Effects of Design Strength, Fly Ash Content and Curing Method on Compressive Strength of High Volume Fly Ash Concrete: A Design of Experimental

    National Research Council Canada - National Science Library

    Mochamad Solikin; Budi Setiawan

    2017-01-01

    ...) and the its durability increases significantly. This paper reports investigation on the effect of design strength, fly ash content and curing method on compressive strength of High Volume Fly Ash Concrete...

  6. Radiological and material characterization of high volume fly ash concrete.

    Science.gov (United States)

    Ignjatović, I; Sas, Z; Dragaš, J; Somlai, J; Kovács, T

    2017-03-01

    The main goal of research presented in this paper was the material and radiological characterization of high volume fly ash concrete (HVFAC) in terms of determination of natural radionuclide content and radon emanation and exhalation coefficients. All concrete samples were made with a fly ash content between 50% and 70% of the total amount of cementitious materials from one coal burning power plant in Serbia. Physical (fresh and hardened concrete density) and mechanical properties (compressive strength, splitting tensile strength and modulus of elasticity) of concrete were tested. The radionuclide content (226Ra, 232Th and 40K) and radon massic exhalation of HVFAC samples were determined using gamma spectrometry. Determination of massic exhalation rates of HVFAC and its components using radon accumulation chamber techniques combined with a radon monitor was performed. The results show a beneficial effect of pozzolanic activity since the increase in fly ash content resulted in an increase in compressive strength of HVFAC by approximately 20% for the same mass of cement used in the mixtures. On the basis of the obtained radionuclide content of concrete components the I -indices of different HVFAC samples were calculated and compared with measured values (0.27-0.32), which were significantly below the recommended 1.0 index value. The prediction was relatively close to the measured values as the ratio between the calculated and measured I-index ranged between 0.89 and 1.14. Collected results of mechanical and radiological properties and performed calculations clearly prove that all 10 designed concretes with a certain type of fly ash are suitable for structural and non-structural applications both from a material and radiological point of view. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Mechanical behaviour and durability of high volume fly ash cementitious composites

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    Usman Haider

    2016-10-01

    Full Text Available The purpose of this research is to separate different morphological particles of ASTM class F fly ash, and study their effect on mechanical behaviour and durability of high volume cementitious mixtures. In this research wet separation of raw fly ash is carried out, which resulted in three layers of different morphological particles. The first layer of particles float, comprise of about 1-5% of fly ash, is identified as cenospheres or hollow spheres. The second layer of particles is measured to be 55-60% of raw fly ash and consisting of porous spherical and rounded particles rich in Si and Al. The third layer particles is measured to be about 35-40% of raw fly ash. High volume fly ash cementitious composites containing second or third layer particles are tested under compression and bending, highlighting a higher strength and ductility in comparison to cementitious ones containing raw fly ash particles

  8. Recyclability of Concrete Pavement Incorporating High Volume of Fly Ash

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    Isamu Yoshitake

    2015-08-01

    Full Text Available Recyclable concrete pavement was made from fly ash and crushed limestone sand and gravel as aggregates so that the concrete pavement could be recycled to raw materials for cement production. With the aim to use as much fly ash as possible for the sustainable development of society, while achieving adequate strength development, pavement concrete having a cement-replacement ratio of 40% by mass was experimentally investigated, focusing on the strength development at an early age. Limestone powder was added to improve the early strength; flexural strength at two days reached 3.5 MPa, the minimum strength for traffic service in Japan. The matured fly ash concrete made with a cement content of 200 kg/m3 achieved a flexural strength almost equal to that of the control concrete without fly ash. Additionally, Portland cement made from the tested fly ash concrete was tested to confirm recyclability, with the cement quality meeting the Japanese classification of ordinary Portland cement. Limestone-based recyclable fly ash concrete pavement is, thus, a preferred material in terms of sustainability.

  9. Recyclability of Concrete Pavement Incorporating High Volume of Fly Ash.

    Science.gov (United States)

    Yoshitake, Isamu; Ishida, Takeo; Fukumoto, Sunao

    2015-08-21

    Recyclable concrete pavement was made from fly ash and crushed limestone sand and gravel as aggregates so that the concrete pavement could be recycled to raw materials for cement production. With the aim to use as much fly ash as possible for the sustainable development of society, while achieving adequate strength development, pavement concrete having a cement-replacement ratio of 40% by mass was experimentally investigated, focusing on the strength development at an early age. Limestone powder was added to improve the early strength; flexural strength at two days reached 3.5 MPa, the minimum strength for traffic service in Japan. The matured fly ash concrete made with a cement content of 200 kg/m3 achieved a flexural strength almost equal to that of the control concrete without fly ash. Additionally, Portland cement made from the tested fly ash concrete was tested to confirm recyclability, with the cement quality meeting the Japanese classification of ordinary Portland cement. Limestone-based recyclable fly ash concrete pavement is, thus, a preferred material in terms of sustainability.

  10. The Effects of Design Strength, Fly Ash Content and Curing Method on Compressive Strength of High Volume Fly Ash Concrete: A Design of Experimental

    OpenAIRE

    Solikin Mochamad; Setiawan Budi

    2017-01-01

    High volume fly ash concrete becomes one of alternatives to produce green concrete as it uses waste material and significantly reduces the utilization of Portland cement in concrete production. Although using less cement, its compressive strength is comparable to ordinary Portland cement (hereafter OPC) and the its durability increases significantly. This paper reports investigation on the effect of design strength, fly ash content and curing method on compressive strength of High Volume Fly ...

  11. Properties of High-Volume Fly Ash Concrete Reinforced with Natural Fibres

    Directory of Open Access Journals (Sweden)

    Rafat SIDDIQUE

    2012-12-01

    Full Text Available Properties of high-volume fly ash concrete incorporating san fibres are presented in this paper. For this investigation, initially, three concrete mixtures were made with 35%, 45%, and 55% of Class F fly as partial replacement of cement. After this, three percentages (0.25, 0.50, and 0.75% of san fibres (25 mm length were added in each of the fly ash concrete mixtures. San is a natural bast fibre, and is also known as Sunn Hemp (Botanical name: Crotalaria Juncea. It is grown in Indian Sub-Continent, Brazil, Eastern and Southern Africa, and also in some parts of U.S.A. Tests were performed for compressive strength, splitting tensile strength, flexural strength, and impact strength at the ages of 28, 91 and 365 days. Tests were also performed for fresh concrete properties. 28 days test results indicated that san fibres reduced the compressive strength of high-volume fly ash concrete by 2 to 13%, increased splitting tensile strength by 6 to 26%, flexural strength by 5 to 14%, and enhanced impact strength tremendously (by 100 to 300% depending upon the fly ash content and fibre percentage. Later age (91 and 365 days results showed continuous increase in strength properties of high-volume fly ash concrete. This was probably be possible due to the pozzolanic action of fly ash, leading to more densification of the concrete matrix, and development of more effective bond between fibres and fly ash concrete matrix.

  12. An Experimental Study of High Strength-High Volume Fly Ash Concrete for Sustainable Construction Industry

    Science.gov (United States)

    Kate, Gunavant K.; Thakare, Sunil B., Dr.

    2017-08-01

    Concrete is the most widely used building material in the construction of infrastructures such as buildings, bridges, highways, dams, and many other facilities. This paper reports the development, the basic idea, the main properties of high strength-high volume fly ash with application in concrete associated with the development and implementation of Sustainable Properties of High Volume Fly Ash Concrete (HVFAC) Mixtures and Early Age Shrinkage and mechanical properties of concrete for 7,28,56 and 90days. Another alternative to make environment-friendly concrete is the development of high strength-high-volume fly ash concrete which is an synthesized from materials of geological origin or by-product materials such as fly ash which is rich in silicon and aluminum. In this paper 6 concrete mixtures were produced to evaluate the effect of key parameters on the mechanical properties of concrete and its behavior. The study key parameters are; binder material content, cement replacement ratios, and the steel fibers used to High Volume Fly Ash mixtures for increasing performance of concrete.

  13. Influence of Utilization of High-Volumes of Class F Fly Ash on the Abrasion Resistance of Concrete

    Directory of Open Access Journals (Sweden)

    William PRINCE

    2007-01-01

    Full Text Available Utilization of large volumes of fly ash in various concrete applications is a becoming a more general practice in an efforts towards using large quantities of fly ash. Around the world, Class C or Class F or both as available have been used in high volumes in cement-based materials. In India, majority of fly generated is of Class F type as per ASTM C 618. Yearly fly ash generation in India is approximately 95 million tonnes. Out of which around 15-20% is utilized in cement production and cement/concrete related activities. In order to increase its percentage utilization, an investigation was carried out to use it in concrete.In this paper, abrasion resistance of high volume fly ash (HVFA concretes made with 35, 45, 55, and 65% of cement replacement was evaluated in terms of its relation with compressive strength. Comparison was made between ordinary Portland cement and fly ash concrete. Test results indicated that abrasion resistance of concrete having cement replacement up to 35 percent was comparable to the normal concrete mix with out fly ash. Beyond 35% cement replacement, fly ash concretes exhibited slightly lower resistance to abrasion relative to non-fly ash concretes. Test results further indicated that abrasion resistance of concrete is closely related with compressive strength, and had a very good correlation between abrasion resistance and compressive strength (R2 value between 0.9018 and 0.9859 depending upon age.

  14. Optimisation of nano-silica modified self-compacting high-Volume fly ash mortar

    Science.gov (United States)

    Achara, Bitrus Emmanuel; Mohammed, Bashar S.; Fadhil Nuruddin, Muhd

    2017-05-01

    Evaluation of the effects of nano-silica amount and superplasticizer (SP) dosage on the compressive strength, porosity and slump flow on high-volume fly ash self-consolidating mortar was investigated. Multiobjective optimisation technique using Design-Expert software was applied to obtain solution based on desirability function that simultaneously optimises the variables and the responses. A desirability function of 0.811 gives the optimised solution. The experimental and predicted results showed minimal errors in all the measured responses.

  15. Statistical evaluation of the mechanical properties of high-volume class F fly ash concretes

    KAUST Repository

    Yoon, Seyoon

    2014-03-01

    High-Volume Fly Ash (HVFA) concretes are seen by many as a feasible solution for sustainable, low embodied carbon construction. At the moment, fly ash is classified as a waste by-product, primarily of thermal power stations. In this paper the authors experimentally and statistically investigated the effects of mix-design factors on the mechanical properties of high-volume class F fly ash concretes. A total of 240 and 32 samples were produced and tested in the laboratory to measure compressive strength and Young\\'s modulus respectively. Applicability of the CEB-FIP (Comite Euro-international du Béton - Fédération Internationale de la Précontrainte) and ACI (American Concrete Institute) Building Model Code (Thomas, 2010; ACI Committee 209, 1982) [1,2] to the experimentally-derived mechanical property data for HVFA concretes was established. Furthermore, using multiple linear regression analysis, Mean Squared Residuals (MSRs) were obtained to determine whether a weight- or volume-based mix proportion is better to predict the mechanical properties of HVFA concrete. The significance levels of the design factors, which indicate how significantly the factors affect the HVFA concrete\\'s mechanical properties, were determined using analysis of variance (ANOVA) tests. The results show that a weight-based mix proportion is a slightly better predictor of mechanical properties than volume-based one. The significance level of fly ash substitution rate was higher than that of w/b ratio initially but reduced over time. © 2014 Elsevier Ltd. All rights reserved.

  16. A Study on the Evaluation of Field Application of High-Fluidity Concrete Containing High Volume Fly Ash

    Directory of Open Access Journals (Sweden)

    Yun-Wang Choi

    2015-01-01

    Full Text Available In the recent concrete industry, high-fluidity concrete is being widely used for the pouring of dense reinforced concrete. Normally, in the case of high-fluidity concrete, it includes high binder contents, so it is necessary to replace part of the cement through admixtures such as fly ash to procure economic feasibility and durability. This study shows the mechanical properties and field applicability of high-fluidity concrete using mass of fly ash as alternative materials of cement. The high-fluidity concrete mixed with 50% fly ash was measured to manufacture concrete that applies low water/binder ratio to measure the mechanical characteristics as compressive strength and elastic modulus. Also, in order to evaluate the field applicability, high-fluidity concrete containing high volume fly ash was evaluated for fluidity, compressive strength, heat of hydration, and drying shrinkage of concrete.

  17. Compression Behavior of Confined Columns with High-Volume Fly Ash Concrete

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    Sung-Won Yoo

    2017-01-01

    Full Text Available The use of fly ash in ordinary concrete provides practical benefits to concrete structures, such as a gain in long-term strength, reduced hydration heat, improved resistance to chloride, and enhanced workability. However, few studies with high-volume fly ash (HVFA concrete have been conducted that focus on the structural applications such as a column. Thus, there is a need to promote field applications of HVFA concrete as a sustainable construction material. To this end, this study investigated the compressive behavior of reinforced concrete columns that contain HVFA with a 50 percent replacement rate. Six columns were fabricated for this study. The study variables were the HVFA replacement rate, tied steel ratio, and tie steel spacing. The computed ultimate strength by the American Concrete Institute (ACI code conservatively predicted the measured values, and, thus, the existing equation in the ACI code is feasible for confined RC columns that contain HVFA. In addition, an analysis model was calibrated based on the experimental results and is recommended for predicting the stress-strain relationship of confined reinforced concrete columns that contain HVFA.

  18. Impact of Micro Silica on the properties of High Volume Fly Ash Concrete (HVFA)

    Science.gov (United States)

    Sripragadeesh, R.; Ramakrishnan, K.; Pugazhmani, G.; Ramasundram, S.; Muthu, D.; Venkatasubramanian, C.

    2017-07-01

    In the current situation, to overcome the difficulties of feasible construction, concrete made with various mixtures of Ordinary Portland Cement (OPC) and diverse mineral admixtures, is the wise choice for engineering construction. Mineral admixtures viz. Ground Granulated Blast Furnace Slag (GGBS), Meta kaolin (MK), Fly Ash (FA) and Silica Fume (SF) etc. are used as Supplementary Cementitious Materials (SCM) in binary and ternary blend cement system to enhance the mechanical and durability properties. Investigation on the effect of different replacement levels of OPC in M25 grade with FA + SF in ternary cement blend on the strength characteristics and beam behavior was studied. The OPC was partially replaced (by weight) with different combinations of SF (5%, 10%, 15%, 20% and 25%) and FA as 50% (High Volume Fly Ash - HVFA). The amount of FA addition is kept constant at 50% for all combinations. The compressive strength and tensile strength tests on cube and cylinder specimens, at 7 and 28 days were carried out. Based on the compressive strength results, optimum mix proportion was found out and flexural behaviour was studied for the optimum mix. It was found that all the mixes (FA + SF) showed improvement in compressive strength over that of the control mix and the mix with 50% FA + 10% SF has 20% increase over the control mix. The tensile strength was also increased over the control mix. Flexural behaviour also showed a significant improvement in the mix with FA and SF over the control mix.

  19. Fracture Toughness and Impact Strength of High-Volume Class-F Fly Ash Concrete Reinforced with Natural San Fibres

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    Rafat SIDDIQUE

    2008-06-01

    Full Text Available Results of experimental investigation carried out to study the effects of addition of natural san fibres on the fracture toughness and impact strength of high-volume fly ash concrete are presented in this paper. San fibres belong to the category of ‘Natural Bast Fibres’, also known as ‘Sunn Hemp’. Its scientific (botanical name is Crotalaria Juncea. It is mostly grown in the Indian Sub-Continent, Brazil, Eastern and Southern Africa, and in some parts of the U.S.A. Initially, a control mixture without fly ash was designed. Then, cement was replaced with three percentages (30, 40 and 50% of low-calcium (Class F fly ash. Three percentages of san fibres (0.30, 0.60 and 0.90%, having 25 mm length, were used. Tests were performed for compressive strength, fracture toughness, and impact strength at the ages of 28 and 91 days.The test results indicated that the replacement of cement with fly ash decreased the compressive strength and fracture toughness, and had no significant effect on the impact strength of plain (control concrete. Addition of san fibres did not affect significantly the compressive strength, increased the fracture toughness and impact strength of high-volume fly ash concrete as the percentage of fibres increased.

  20. Properties of concrete incorporating high volumes of class F fly ash and san fibers

    Energy Technology Data Exchange (ETDEWEB)

    Rafat Siddique [University of Wisconsin-Milwaukee, Milwaukee, WI (United States). Department of Civil Engineering and Mechanics, UWM Center for By-Products Utilization, College of Engineering and Applied Science

    2004-01-01

    The results of an experimental investigation to study the effects of replacement of cement (by mass) with three percentages of fly ash and the effects of addition of natural san fibers on the slump, Vebe time, compressive strength, splitting tensile strength, flexural strength and impact strength of fly ash concrete are presented. San fibers belong to the category of 'natural bast fibers.' It is also known as 'sunn hemp.' Its scientific (botanical) name is Crotalaria juncea. A control mixture of proportions 1:1.4:2.19 with W/Cm of 0.47 and superplasticizer/cementitious ratio of 0.015 was designed. Cement was replaced with three percentages (35%, 45% and 55%) of class F fly ash. Three percentages of san fibers (0.25%, 0.50% and 0.75%) having 25-mm length were used. The test results indicated that the replacement of cement with fly ash increased the workability (slump and Vebe time), decreased compressive strength, splitting tensile strength and flexural strength and had no significant effect on the impact strength of plain (control) concrete. Addition of san fibers reduced the workability, did not significantly affect the compressive strength, increased the splitting tensile strength and flexural strength and tremendously enhanced the impact strength of fly ash concrete as the percentage of fibers increased.

  1. Fly ash for defluoridation

    Energy Technology Data Exchange (ETDEWEB)

    Tzimou-Tsitouridou, R.

    1985-05-01

    The authors report a study of the use of a lignite fly ash to retain fluoride ions and remove them from their solutions, with a view to the use of this process for the defluoridation of water. Results are presented and the chemistry of the process is examined.

  2. A brief on high-volume Class F fly ash as cement replacement – A guide for Civil Engineer

    Directory of Open Access Journals (Sweden)

    Alaa M. Rashad

    2015-12-01

    Full Text Available Disposal of fly ash (FA resulting from the combustion of coal-fired electric power stations is one of the major environmental challenges. This challenge continues to increase with increasing the amount of FA and decreasing the capacity of landfill space. Therefore, studies have been carried out to re-use high-volumes of fly ash (HVFA as cement replacement in building materials. This paper presents an overview of the previous studies carried out on the use of high volume Class F FA as a partial replacement of cement in traditional paste/mortar/concrete mixtures based on Portland cement (PC. Fresh properties, mechanical properties, abrasion resistance, thermal properties, drying shrinkage, porosity, water absorption, sorptivity, chemical resistance, carbonation resistance and electrical resistivity of paste/mortar/concrete mixtures containing HVFA (⩾45% as cement replacement have been reviewed. Furthermore, additives used to improve some properties of HVFA system have been reviewed.

  3. Fly ash mixtures as flexible structural materials for low-volume roads

    OpenAIRE

    Lahtinen, Pentti

    2001-01-01

    Extensive research and several studies have been carried out on the recycling of industrial by-products in soil construction in Finland in the 1990's. The research and studies have been made mainly in the laboratory of SCC Viatek Ltd SGT in cooperation with the public research institutes. The main beneficiaries have been the industry, the national road administration and the municipalities. The Doctoral Thesis focuses on the versatile usage opportunities of the fly ashes (FA) from the com...

  4. Fly ash quality and utilization

    Energy Technology Data Exchange (ETDEWEB)

    Barta, L.E.; Lachner, L.; Wenzel, G.B. [Inst. for Energy, Budapest (Hungary); Beer, M.J. [Massachusetts Inst. of Technology, Cambridge, MA (United States)

    1995-12-01

    The quality of fly ash is of considerable importance to fly ash utilizers. The fly ash puzzolanic activity is one of the most important properties that determines the role of fly ash as a binding agent in the cementing process. The puzzolanic activity, however is a function of fly ash particle size and chemical composition. These parameters are closely related to the process of fly ash formation in pulverized coal fired furnaces. In turn, it is essential to understand the transformation of mineral matter during coal combustion. Due to the particle-to-particle variation of coal properties and the random coalescence of mineral particles, the properties of fly ash particles e.g. size, SiO{sub 2} content, viscosity can change considerably from particle to particle. These variations can be described by the use of the probability theory. Since the mean values of these randomly changing parameters are not sufficient to describe the behavior of individual fly ash particles during the formation of concrete, therefore it is necessary to investigate the distribution of these variables. Examples of these variations were examined by the Computer Controlled Scanning Electron Microscopy (CCSEM) for particle size and chemical composition for Texas lignite and Eagel Butte mineral matter and fly ash. The effect of combustion on the variations of these properties for both the fly ash and mineral matter were studied by using a laminar flow reactor. It is shown in our paper, that there are significant variations (about 40-50% around the mean values) of the above-listed properties for both coal samples. By comparing the particle size and chemical composition distributions of the mineral matter and fly ash, it was possible to conclude that for the Texas lignite mineral matter, the combustion did not effect significantly the distribution of these properties, however, for the Eagel Butte coal the combustion had a major impact on these mineral matter parameters.

  5. Dielectric properties of fly ash

    Indian Academy of Sciences (India)

    Unknown

    Abstract. This paper reports the dielectric properties of fly ash. The dielectric measurements were performed as a function of frequency and temperature. The sample of fly ash shows almost similar behaviour in the frequency and temperature range studied. The large value of dielectric constant in the typical frequency range.

  6. Immobilization and volume reduction of heavy metals in municipal solid waste fly ash using nano-size calcium and iron-dispersed reagent.

    Science.gov (United States)

    Mallampati, Srinivasa Reddy; Mitoma, Yoshiharu; Simion, Cristian; Lee, Byoung Ho

    2015-10-01

    This study was conducted to examine the synthesis and application of novel nano-size calcium/iron-based composite material as an immobilizing and separation treatment of the heavy metals in fly ash from municipal solid waste incineration. After grinding with nano-Fe/Ca/CaO and with nano-Fe/Ca/CaO/[PO₄], approximately 30 wt% and 25 wt% of magnetic fraction fly ash were separated. The highest amount of entrapped heavy metals was found in the lowest weight of the magnetically separated fly ash fraction (i.e., 91% in 25% of treated fly ash). Heavy metals in the magnetic or nonmagnetic fly ash fractions were about 98% and 100% immobilized, respectively. Additionally, scanning electron microscopy combined with energy-dispersive X-ray spectrometry (SEM-EDS) observations indicate that the main fraction of enclosed/bound materials on treated fly ash includes Ca/PO₄-associated crystalline complexes. After nano-Fe/Ca/CaO/[PO₄] treatment, the heavy metal concentrations in the fly ash leachate were much lower than the Japan standard regulatory limit for hazardous waste landfills. These results appear to be extremely promising. The addition of a nano-Fe/Ca/CaO/PO₄mixture with simple grinding technique is potentially applicable for the remediation and volume reduction of fly ash contaminated by heavy metals. After grinding with nano-Fe/Ca/CaO and nano-Fe/Ca/CaO/[PO₄], approximately 30 wt% and 25 wt% of magnetic fraction fly ash were separated. The highest amount of entrapped heavy metals was found in the lowest weight of the magnetically separated fly ash fraction (i.e., 91% in 25% of treated fly ash), whereas heavy metals either in the magnetic or nonmagnetic fly ash fractions were about 98% and 100% immobilized. These results appear to be very promising, and the addition of nano-Fe/Ca/CaO/PO₄mixture with simple grinding technique may be considered potentially applicable for the remediation and volume reduction of contaminated fly ash by heavy metals.

  7. Electrodialytic treatment of fly ash

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Pedersen, Anne Juul; Kirkelund, Gunvor Marie

    Heavy metals are removed from the fly ashes by an electrodialytic treatment with the aim of up-grading the ashes for reuse in stead of disposal in landfill.A great potential for upgrading of bio- and waste incineration ashes by electrodialytic treatment exists. In the future, the applicability...

  8. A comparative study of self-consolidating concretes incorporating high-volume natural pozzolan or high-volume fly ash

    KAUST Repository

    Celik, Kemal

    2014-09-01

    The purpose of this study is to compare the effects of Portland cement replacement on the strength and durability of self-consolidating concretes (SSC). The two replacement materials used are high-volume natural pozzolan (HVNP), a Saudi Arabian aluminum-silica rich basaltic glass and high-volume Class-F fly ash (HVFAF), from Jim Bridger Power Plant, Wyoming, US. As an extension of the study, limestone filler (LF) is also used to replace Portland cement, alongside HVNP or HVFAF, forming ternary blends. Along with compressive strength tests, non-steady state chloride migration and gas permeability tests were performed, as durability indicators, on SCC specimens. The results were compared to two reference concretes; 100% ordinary Portland cement (OPC) and 85% OPC - 15% LF by mass. The HVNP and HVFAF concrete mixes showed strength and durability results comparable to those of the reference concretes; identifying that both can effectively be used to produce low-cost and environmental friendly SCC. © 2013 Elsevier Ltd. All rights reserved.

  9. CZECH FLUID SULFOCALCIC ASH AND FLY ASH

    Directory of Open Access Journals (Sweden)

    Frantisek Skvara

    2016-10-01

    Full Text Available Sulfocalcic ash is formed during the fluidized bed combustion of coal in the presence of limestone. It differs from classical fly ash by its composition and properties. Sulfocalcic ash contains free CaO, CaSO₄ and partially sintered aluminosilicates. In contact with water, it produces Ca(OH₂, expansive ettringite and a small amount of the CSH phase. There is little information about these ashes in the literature. At present, the possibility of using fluid sulfocalcic ashes is quite limited because of the formation of expansive ettringite. More research in the field of sulfocalcic ashes is a necessity because increasing quantities of this product are rejected by the energy-generation industry.

  10. Fly ash. Quality recycling material

    Energy Technology Data Exchange (ETDEWEB)

    Blomster, D.; Leisio, C.

    1996-11-01

    Imatran Voima`s coal-fired power plants not only generate power and heat but also produce fly ash which is suitable raw material for recycling. This material for recycling is produced in the flue gas cleaning process. It is economical and, thanks to close quality control, is suitable for use as a raw material in the building materials industry, in asphalt production, and in earthworks. Structures made from fly ash are also safe from an environmental point of view. (orig.)

  11. Characterisation of Turkish fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    Bayat, O. [Cukurova University, Adana (Turkey). Mining Engineering Dept.

    1998-07-01

    The mineralogical, morphological, physical and chemical properties of 7 fly ashes from coal fields in Turkey are compared. The mineral matter in the fly ashes, determined by X-ray diffraction, is dominated by anhydride, lime, quartz and hematite + ferrite spinel. The three low-calcium ashes have the typical, relatively simple, crystalline phase Q, M, H and FS. The high-calcium fly ashes have the most complex assemblage of crystalline phases. The much higher calcium concentrations in these samples result in the formation of lime (CaO), melilite ((Ca, Na){sub 2}(Mg,Al,Fe)(Si,Al){sub 2}O{sub 7}) and merwinite. The presence of anhydride in all samples indicates that the high activity of calcium not only promotes the formation of sulfates from calcite but also the dehydration of gypsum during and after combustion, which occurs at temperatures above 400-500{degree}C. It is important to understand the interaction of high-calcium fly ashes with water occurring in Portland cement (C{sub 3}A,C{sub 2}S), Ah, which hydrates to give gypsum and lime, with the latter hydrating to give the Ca(OH){sub 2} solutions that promote pozzolonic reactions. Some of the particles comprised irregularly formed, vesicular particles with some well-formed individual spheres in Catalagzi and Tuncbilek fly ashes. About 55-80 wt% was less than 45 {mu}m in size for Yatagan, Soma, Yenikoy and Afsin-Elbistan fly ashes. The fly ashes were mainly composed of CaO, SiO{sub 2} and Al{sub 2}O{sub 3}. They have a potential use in wastewater treatment since they can be easily obtained in large quantities at low price or even free. The chemical and mineralogical compositions of the high-calcium Turkish fly ashes investigated make them a good binding agent and a possible substitute for slags, pozzolana and gypsum in the amelioration of clinker. 53 refs., 10 figs., 5 tabs.

  12. Evaluation of fly ash quality control tools.

    Science.gov (United States)

    2010-06-30

    Many entities currently use fly ash in portland cement concrete (PCC) pavements and structures. Although the body of knowledge is : great concerning the use of fly ash, several projects per year are subject to poor performance where fly ash is named ...

  13. Utilization of Coal Fly Ash

    Science.gov (United States)

    1992-01-01

    sample. Harrison et al. (1985) found that most of the aliphatic hydrocarbons were paraffins and terpenoids . Roy et al. (1984) found the majority of their...P. Rombout, "Effects of Acute Inhalation of Respirable Coal Fly Ash on Metabolic Defense Capability of the Rat Lung," Inhalation Toxicology, v.2: 361

  14. Degradation of self-compacting concrete (SCC) due to sulfuric acid attack: Experiment investigation on the effect of high volume fly ash content

    Science.gov (United States)

    Kristiawan, S. A.; Sunarmasto; Tyas, G. P.

    2016-02-01

    Concrete is susceptible to a variety of chemical attacks. In the sulfuric acid environment, concrete is subjected to a combination of sulfuric and acid attack. This research is aimed to investigate the degradation of self-compacting concrete (SCC) due to sulfuric acid attack based on measurement of compressive strength loss and diameter change. Since the proportion of SCC contains higher cement than that of normal concrete, the vulnerability of this concrete to sulfuric acid attack could be reduced by partial replacement of cement with fly ash at high volume level. The effect of high volume fly ash at 50-70% cement replacement levels on the extent of degradation owing to sulfuric acid will be assessed in this study. It can be shown that an increase in the utilization of fly ash to partially replace cement tends to reduce the degradation as confirmed by less compressive strength loss and diameter change. The effect of fly ash to reduce the degradation of SCC is more pronounced at a later age.

  15. Strength Properties of Processed Fly Ash Concrete

    Directory of Open Access Journals (Sweden)

    Sivakumar Anandan

    2015-07-01

    Full Text Available The present paper reports on the mechanical treatment of fly ash for improving the delayed reactivity of fly ash with the hydration product of cement. Grinding of fly ash was carried out in a ball mill for different time durations and processing time was optimized for maximum fineness. Concrete mixes were prepared using various proportions of processed and unprocessed fly ash replacement in cement (25% and 50%. The influence of steel fiber addition on the mechanical properties of the concrete was studied for different curing periods. The test results on pozzolanic activity and lime reactivity indicate that the processed fly ash exhibited a higher strength gain than the unprocessed fly ash, with a maximum increase in compressive strength of up to 12%. Improved pozzolanic properties were noticed due to the increase in fineness of the fly ash particles.

  16. Identifying glass compositions in fly ash

    Directory of Open Access Journals (Sweden)

    Katherine eAughenbaugh

    2016-01-01

    Full Text Available In this study, four Class F fly ashes were studied with a scanning electron microscope; the glassy phases were identified and their compositions quantified using point compositional analysis with k-means clustering and multispectral image analysis. The results showed that while the bulk oxide contents of the fly ashes were different, the four fly ashes had somewhat similar glassy phase compositions. Aluminosilicate glasses (AS, calcium aluminosilicate glasses (CAS, a mixed glass, and, in one case, a high iron glass were identified in the fly ashes. Quartz and iron crystalline phases were identified in each fly ash as well. The compositions of the three main glasses identified, AS, CAS, and mixed glass, were relatively similar in each ash. The amounts of each glass were varied by fly ash, with the highest calcium fly ash containing the most of calcium-containing glass. Some of the glasses were identified as intermixed in individual particles, particularly the calcium-containing glasses. Finally, the smallest particles in the fly ashes, with the most surface area available to react in alkaline solution, such as when mixed with portland cement or in alkali-activated fly ash, were not different in composition than the large particles, with each of the glasses represented. The method used in the study may be applied to a fly ash of interest for use as a cementing material in order to understand its potential for reactivity.

  17. Thaumasite formation in concrete and mortars containing fly ash

    Energy Technology Data Exchange (ETDEWEB)

    D.M. Mulenga; J. Stark; P. Nobst [Bauhaus-University, Weimar (Germany). F.A. Finger-Institute of Material Sciences

    2003-12-01

    Due to recent reports on deterioration of concrete structures, the thaumasite form of sulfate attack has become a subject of study and close investigation. This paper investigates the formation of thaumasite in concrete and mortars containing fly ash. The results show that thaumasite formation can occur within 84 days of exposure to sulfate solutions. High volumes of fly ash can limit or promote thaumasite formation depending on the type of cement used. Thaumasite and ettringite were found among the deterioration products. However, the thaumasite formation in the specimen prepared from sulfate resisting Portland cement was not accompanied by deterioration, except by 50% fly ash addition. The mixtures of Portland limestone cement with 40% fly ash exhibited a very limited thaumasite formation while the mixtures with 50% had no thaumasite at all. It is concluded that thaumasite can also be formed in mixtures incorporating fly ash.

  18. Geopolymer Mortar with Fly Ash

    Directory of Open Access Journals (Sweden)

    Saloma

    2016-01-01

    Full Text Available The cement industry accounts for about 7% of all CO2 emissions caused by humans. Therefore, it is necessary to find another material in order to support sustainable material. An alternative way is replacing cement material with alternative material as fly ash. Fly ash as binder need to be added alkaline activator in the form of sodium silicate (Na2SiO3 or potassium silicate (K2SiO3 and sodium hydroxide (NaOH or potassium hydroxide (KOH. The purpose of this research is to analyze the effect of activator liquid concentration on geopolymer mortar properties and to know the value of compressive strength. Molarity variation of NaOH are 8, 12, 14, and 16 M with ratio of Na2SiO3/NaOH = 1.0. Ratio of sand/fly ash = 2.75 and ratio of activator/fly ash = 0.8. The cube-shaped specimen 50 × 50 × 50 mm is cured by steam curing with a temperature of 60°C for 48 hours. The experimental result of fresh mortar reported that the molarity of NaOH affect the slump flow and setting time, higher of NaOH produces the smaller value of slump and the faster time of setting. The experimental of density results reported that the increase of specific gravity when the molarity of NaOH increased. The experimental results of the compressive strength are showed that the maximum compressive strength of geopolymer mortar 14 M is 10.06 MPa and the lowest compressive strength produced by geopolymer mortar 8 M is 3.95 MPa. Testing the compressive strength of geopolymer mortar 16 M produces compressive strength lower than 14 M geopolymer mortar is 9.16 MPa.

  19. Effect of Copolymer Latexes on Physicomechanical Properties of Mortar Containing High Volume Fly Ash as a Replacement Material of Cement

    Directory of Open Access Journals (Sweden)

    El-Sayed Negim

    2014-01-01

    Full Text Available This paper investigates the physicomechanical properties of mortar containing high volume of fly ash (FA as partial replacement of cement in presence of copolymer latexes. Portland cement (PC was partially replaced with 0, 10, 20, 30 50, and 60% FA. Copolymer latexes were used based on 2-hydroxyethyl acrylate (2-HEA and 2-hydroxymethylacrylate (2-HEMA. Testing included workability, setting time, absorption, chemically combined water content, compressive strength, and scanning electron microscopy (SEM. The addition of FA to mortar as replacement of PC affected the physicomechanical properties of mortar. As the content of FA in the concrete increased, the setting times (initial and final were elongated. The results obtained at 28 days of curing indicate that the maximum properties of mortar occur at around 30% FA. Beyond 30% FA the properties of mortar reduce and at 60% FA the properties of mortar are lower than those of the reference mortar without FA. However, the addition of polymer latexes into mortar containing FA improved most of the physicomechanical properties of mortar at all curing times. Compressive strength, combined water, and workability of mortar containing FA premixed with latexes are higher than those of mortar containing FA without latexes.

  20. Effect of copolymer latexes on physicomechanical properties of mortar containing high volume fly ash as a replacement material of cement.

    Science.gov (United States)

    Negim, El-Sayed; Kozhamzharova, Latipa; Gulzhakhan, Yeligbayeva; Khatib, Jamal; Bekbayeva, Lyazzat; Williams, Craig

    2014-01-01

    This paper investigates the physicomechanical properties of mortar containing high volume of fly ash (FA) as partial replacement of cement in presence of copolymer latexes. Portland cement (PC) was partially replaced with 0, 10, 20, 30 50, and 60% FA. Copolymer latexes were used based on 2-hydroxyethyl acrylate (2-HEA) and 2-hydroxymethylacrylate (2-HEMA). Testing included workability, setting time, absorption, chemically combined water content, compressive strength, and scanning electron microscopy (SEM). The addition of FA to mortar as replacement of PC affected the physicomechanical properties of mortar. As the content of FA in the concrete increased, the setting times (initial and final) were elongated. The results obtained at 28 days of curing indicate that the maximum properties of mortar occur at around 30% FA. Beyond 30% FA the properties of mortar reduce and at 60% FA the properties of mortar are lower than those of the reference mortar without FA. However, the addition of polymer latexes into mortar containing FA improved most of the physicomechanical properties of mortar at all curing times. Compressive strength, combined water, and workability of mortar containing FA premixed with latexes are higher than those of mortar containing FA without latexes.

  1. Possibilities of utilizing power plant fly ashes

    Directory of Open Access Journals (Sweden)

    Mezencevová Andrea

    2003-09-01

    Full Text Available The burning of fossil fuels in industrial power stations plays a significant role in the production of thermal and electrical energy. Modern thermal power plants are producing large amounts of solid waste, mainly fly ashes. The disposal of power plant waste is a large environmental problem at the present time. In this paper, possibilities of utilization of power plant fly ashes in industry, especially in civil engineering, are presented. The fly ash is a heterogeneous material with various physical, chemical and mineralogical properties, depending on the mineralogical composition of burned coal and on the used combustion technology. The utilization of fly ashes is determined of their properties. The fineness, specific surface area, particle shape, density, hardness, freeze-thaw resistance, etc. are decisive. The building trade is a branch of industry, which employs fly ash in large quantities for several decades.The best utilization of fluid fly ashes is mainly in the production of cement and concrete, due to the excellent pozzolanic and cementitious properties of this waste. In the concrete processing, the fly ash is utilized as a replacement of the fine aggregate (fine filler or a partial replacement for cement (active admixture. In addition to economic and ecological benefits, the use of fly ash in concrete improves its workability and durability, increases compressive and flexural strength, reduces segregation, bleeding, shrinkage, heat evolution and permeability and enhances sulfate resistance of concrete.The aim of current research is to search for new technologies for the fly ash utilization. The very interesting are biotechnological methods to recovery useful components of fly ashes and unconventional methods of modification of fly ash properties such as hydrothermal zeolitization and mechanochemical modification of its properties. Mechanochemistry deals with physico - chemical transformations and chemical reactions of solids induced by

  2. Effects of fly ash fineness on the mechanical properties of concrete

    Indian Academy of Sciences (India)

    1. Introduction. Fly ash is an industrial waste and a material of puzzolanic characteristic occurring due to burn- ... important factor affecting index of puzzolanic activity was fineness of the fly ash, not its chemical composition. ..... Siddique R 2003 Performance characteristics of high-volume class f fly ash concrete. Cement and ...

  3. Characteristics of spanish fly ashes

    Directory of Open Access Journals (Sweden)

    de Luxán, M. P.

    1988-03-01

    Full Text Available The purpose of this study is the characterization of fly ashes produced by Spanish thermoelectric power plants, according to sampling taken in 1981 and 1982. The study takes in the following characteristics: physical characteristics (size distribution of particles, ...; chemical ones (chemical analysis...; and mineralogical ones (application of instrumental techniques of X-ray diffraction and infrared absorption spectroscopy. From a general point of view, it can be said that the samples of Spanish fly ashes are similar to those produced in other countries. The results obtained are a contribution to the knowledge of Spanish fly ashes and form part of the antecedents of investigations carried out in subsequent years.

    Este trabajo tiene por objeto la caracterización de las cenizas volantes producidas en las Centrales Termoeléctricas españolas, según un muestreo realizado entre 1981 y 1982. El estudio comprende las siguientes características: físicas (distribución del tamaño de partículas,...; químicas (análisis químico, …; y mineralógicas (aplicación de las técnicas instrumentales de difracción de rayos X y espectroscopía de absorción infrarroja. Desde un punto de vista general, se puede afirmar que las muestras de ceniza volante estudiadas son semejantes a las producidas en otros países. Los resultados obtenidos son una aportación al conocimiento de las cenizas volantes españolas y forman parte de los antecedentes de las investigaciones llevadas a cabo en años posteriores.

  4. Physicochemical characterization of Spanish fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    Querol, X.; Umana, J.C.; Alastuey, A.; Bertrana, C.; Lopez-Soler, A.; Plana, F.

    1999-12-01

    This article summarizes the results obtained from the physical, chemical, and mineralogical characterization of 14 fly ash samples. Major features that influence the utilization of each fly ash for zeolite synthesis are evidenced, and several fly ash types were selected as potential high-quality starting material for zeolite synthesis and ceramic applications. The main parameters influencing this selection were relatively small grain size; high Al and Si contents; high glass content; low CaO, S, and Fe contents; and relatively low heavy metal concentration. The Compostilla and Cou He fly ashes have high potential applications because of the low content of major impurities (such as Ca, Fe, and S) and the low content of soluble hazardous elements. The Espiel, Escucha, Los Barrios, As Pontes, Soto de Ribera, Meirama, Narcea, and Teruel fly ashes have important application potential, but this potential is slightly limited by the intermediate content of nonreactive impurities, such as Fe and Ca. The La Robla fly ash is of moderate interest, since the relatively high Ca and Fe oxide contents may reduce its potential applications. Finally, the Puertollano fly ash also has limited application because of the very high concentration of some heavy metals such as As, Cd, Ge, Hg, Pb, and Zn. From a mineralogical point of view, the Compostilla, Espiel, and Soto de Ribera fly ashes show the highest aluminum-silicate glass content and, consequently, the highest industrial application potential.

  5. Physiochemical characterization of Spanish fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    Querol, X.; Umana, J.C.; Alastuey, A.; Bertrana, C.; Lopez Soler, A.; Plana, F.

    1999-12-01

    This article summarizes the results obtained from the physical, chemical, and mineralogical characterization of 14 fly ash samples. Major features that influence the utilization of each fly ash for zeolite synthesis are evidenced, and several fly ash types were selected as potential high-quality starting material for zeolite synthesis and ceramic applications. The main parameters influencing this selection were relatively small grain size; high Al and Si contents; high glass content; low CaO, S, and Fe contents; and relatively low heavy metal concentration. The Compostilla and Dou He fly ashes have high potential applications because of the low content of major impurities (such as Ca, Fe, and S) and the low content of soluble hazardous elements. The Espiel, Escucha, Los Barrios, As Pontes, Soto de Ribera, Meirama, Narcea, and Teruel fly ashes have important application potential, but this potential is slightly limited by the intermediate content of nonreactive impurities, such as Fe and Ca. The La Robla fly ash is of moderate interest, since the relatively high Ca and Fe oxide contents may reduce its potential applications. Finally, the Puertollano fly ash also has limited application because of the very high concentration of some heavy metals such as As, Cd, Ge, Hg, Pb, and Zn. From a mineralogical point of view, the Compostilla, Espiel, and Soto de Ribera fly ashes show the highest aluminum-silicate glass content and, consequently, the highest industrial application potential. (author)

  6. Treatment of fly ash for use in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Boxley, Chett [Park City, UT

    2012-05-15

    A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with a quantity of spray dryer ash (SDA) and water to initiate a geopolymerization reaction and form a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 40%, and in some cases less than 20%, of the foam index of the untreated fly ash. An optional alkaline activator may be mixed with the fly ash and SDA to facilitate the geopolymerization reaction. The alkaline activator may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

  7. Adsorption of phenolic compounds on fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Akgerman, A.; Zardkoohi, M. [Texas A and M Univ., College Station, TX (United States). Chemical Engineering Dept.

    1996-03-01

    Adsorption isotherms for adsorption of phenol, 3-chlorophenol, and 2,4-dichlorophenol from water onto fly ash were determined. These isotherms were modeled by the Freundlich isotherm. The fly ash adsorbed 67, 20, and 22 mg/g for phenol, chlorophenol, and 2,4-dichlorophenol, respectively, for the highest water phase concentrations used. The affinity of phenolic compounds for fly ash is above the expected amount corresponding to a monolayer coverage considering that the surface area of fly ash is only 1.87 m{sup 2}/g. The isotherms for contaminants studied were unfavorable, indicating that adsorption becomes progressively easier as more solutes are taken up. Phenol displayed a much higher affinity for fly ash than 3-chlorophenol and 2,4-dichlorophenol.

  8. NPK Fertilizer with Slow Release Fly Ash

    Directory of Open Access Journals (Sweden)

    Nadhira Izzatur Silmi

    2018-01-01

    Full Text Available Fly ash is the solid of the remaining coal combustion carried along with the exhaust gas and captured by the air controller. Fluids in fly ash are Al2O3, SiO2, Fe2O3, CaO, MgO, Na2, and SO3 which are similar to zeolites. So that fly ash can be used as a substitute for zeolite for various carrier of fertilizer. The result of slow release test is known that N element has higher release level. The NPK fertilizer activity test of Fly Ash Slow Release was done on chilli plant with parameter of variation of fertilizer composition and plant height. Based on research result, fly ash-TSP 2: 1 fertilizer has the best result.

  9. Geotechnical characterization of some Indian fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.K.; Yudhbir [Indian Institute for Technology, Kanpur (India). Dept. of Civil Engineering

    2005-10-01

    This paper reports the findings of experimental studies with regard to some common engineering properties (e.g., grain size, specific gravity, compaction characteristics, and unconfined compression strength) of both low and high calcium fly ashes, to evaluate their suitability as embankment materials and reclamation fills. In addition, morphology, chemistry, and mineralogy of fly ashes are studied using scanning electron microscope, electron dispersive x-ray analyzer, x-ray diffractometer, and infrared absorption spectroscopy. In high calcium fly ash, mineralogical and chemical differences are observed for particles, {gt}75 {mu} m and the particles of {lt} 45 {mu} m size. The mode and duration of curing significantly affect the strength and stress-strain behavior of fly ashes. The geotechnical properties of fly ash are governed by factors like lime content (CaO), iron content (Fe{sub 2}O{sub 3}) and loss on ignition. The distinct difference between self-hardening and pozzolanic reactivity has been emphasized.

  10. Treatment of fly ash for use in concrete

    Science.gov (United States)

    Boxley, Chett; Akash, Akash; Zhao, Qiang

    2013-01-08

    A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with an activator solution sufficient to initiate a geopolymerization reaction and for a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 35% of the foam index of the untreated fly ash, and in some cases less than 10% of the foam index of the untreated fly ash. The activator solution may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

  11. Treatment of fly ash for use in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Boxley, Chett [Park City, UT; Akash, Akash [Salt lake City, UT; Zhao, Qiang [Natick, MA

    2012-05-08

    A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with an activator solution sufficient to initiate a geopolymerization reaction and for a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 35% of the foam index of the untreated fly ash, and in some cases less than 10% of the foam index of the untreated fly ash. The activator solution may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

  12. Design and evaluation of high-volume fly ash (HVFA) concrete mixes, report E : hardened mechanical properties and durability performance of HVFA concrete.

    Science.gov (United States)

    2012-10-01

    A rising concern in todays construction industry is environmental responsibility. : The addition of fly ash is a leading innovation in sustainable design of concrete. Fly ash, : a waste by-product of coal burning power plants, can be used to repla...

  13. Heavy metals in MSW incineration fly ashes

    DEFF Research Database (Denmark)

    Ferreira, Celia; Ribeiro, Alexandra B.; Ottosen, Lisbeth M.

    2003-01-01

    is characterized regarding its physical-chemical properties: pH, solubility, chemical composition, and leaching, amongst others. Results indicate a high alkalinity and the presence of large amounts of calcium, chlorides, sulfates, carbonates, sodium and potassium. Metal concentrations in fly ash are: 6,2 g....../kg for zinc, 2,4 g/kg for lead, 1,7 g/kg for iron, and 7,9 g/kg for magnesium. Copper, manganese, chromium and cadmium are also present with 546, 338, 104 and 91 mg/kg of fly ash, respectively. These results are extremely important in subsequent studies on the treatment of fly ash....

  14. Study on solidification for municipal solid waste incineration fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Lu, C.; Liu, Q.; Yang, J.; Xi, W. [Chongqing Univ., Chongqing (China); Huang, B. [Southwest Petroleum Univ., Chengdu (China)

    2008-07-01

    The appropriate management of municipal solid waste (MSW) is a major environmental issues, despite the significant efforts to prevent, reduce, reuse and recycle waste. Two primary options can be used for managing MSW incineration fly ash. These are landfill disposal or incineration. Incineration is effective in toxic substance destruction, waste volume reduction and energy recovery, as compared with landfill. MSW fly ash generally contains higher content of easily leachable heavy metals such as lead, cadmium, and zinc. In China, source separation of municipal solid wastes is not well practiced and has resulted in high concentrations of heavy metals being detected in the MSW fly ash. This paper presented a preliminary study to examine the properties of MSW fly ash and the fixing abilities of ordinary Portland cement and hydrated time on heavy metals. The paper discussed the effects of experimental parameters on the properties of solidified fly ash and the optimal technology conditions. The fly ash used in the study was collected from solid waste incineration plants in Shenzhen, Shanghai, and Chongqing, China. It was concluded that the effect on solidification got better and the leaching quantities of heavy metals such as zinc, lead, cadmium, or chromium decreased with the addition of cement used as adhesive. The optimal proportion of cement was 8 per cent. 14 refs., 5 tabs., 2 figs.

  15. Electrodialytic removal of heavy metals from fly ashes

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul

    2002-01-01

    The aim of the Ph.D. work was to develop the electrodialytic remediation method for removal of heavy metals from fly ashes. The work was focused on two types of fly ashes: fly ashes from wood combustion and fly ashes from municipal solid waste incineration....

  16. Swirl chamber for vitrification of fly ashes

    Directory of Open Access Journals (Sweden)

    Zarzycki Robert

    2017-01-01

    Full Text Available The study presents the concept of a swirl chamber used for vitrification of fly ashes. It assumes the use of coal dust in the process of fly ash melting. The coal dust supplied to the swirl chamber and gasified in the atmosphere of O2, CO2 and H2O allows for obtaining combustible gases composed of CO and H2, which are burnt with the pneumatically supplied fly ash. The above process allows for obtaining a product in the form of a molten slag which does not contain coal grains. The study presents numerical calculations for the process of combustion and gasification of coal dust and opportunities for ensuring adequate parameters in the fly ash melting zone. The combustible gases obtained during the process of gasification can be supplied to the chamber of a pulverized-bed boiler.

  17. The impacts of coal refuse/fly ash bulk bends on water quality and plant growth

    Energy Technology Data Exchange (ETDEWEB)

    Stewar, B.R.; Daniels, W.L. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States)

    1995-09-01

    There is considerable interest in the beneficial reuse of coal fly ash as a soil amendment on coal refuse piles. One method of application would be to blend the coal refuse and the fly ash before deposition in a refuse pile. A field experiment was initiated to measure the effects of bulk blending fly ash with coal refuse on water quality and plant growth parameters. Fly ash (class F) from three sources were used in the experiment. Two of the fly ashes were acidic and the third was alkaline. Trenches were excavated in a coal refuse pile to a depth of 2 m and the refuse was blended with fly ash and then returned to the trench. In other plots the ash was applied as a surface amendment. A treatment of a bulk blend of 5% (w/w) rock phosphate was also included in the experiment. Large volume lysimeters were installed in some trenches to collect the leachates. The fly ash treatments appear to improve the quality of the leachates when compared to the leachates from the untreated plots. The fly ash amended treatments have lower leachate concentrations of Fe and Al. Initially the fly ash treatments showed high levels of leachate B, however those levels have decreased with time. Millet (Setaria italica) yields from the first year of the experiment were highest n the alkaline fly ash and rock phosphate blended plots. In the second growing season, the two bulk blends with alkaline fly ash had the highest yields. In the third growing season all treatments had higher yield levels than the untreated control plots. The positive effects of the fly ash on leachate quality were attributed to the alkalinity of the ash, and the increase in yield was attributed to the increases in water holding capacity due to fly ash treatments.

  18. Fly Ash Amendments Catalyze Soil Carbon Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Amonette, James E.; Kim, Jungbae; Russell, Colleen K.; Palumbo, A. V.; Daniels, William L.

    2003-09-15

    We tested the effects of four alkaline fly ashes {Class C (sub-bituminous), Class F (bituminous), Class F [bituminous with flue-gas desulfurization (FGD) products], and Class F (lignitic)} on a reaction that simulates the enzyme-mediated formation of humic materials in soils. The presence of FGD products completely halted the reaction, and the bituminous ash showed no benefit over an ash-free control. The sub-bituminous and lignitic fly ashes, however, increased the amount of polymer formed by several-fold. The strong synergetic effect of these ashes when enzyme is present apparently arises from the combined effects of metal oxide co-oxidation (Fe and Mn oxides), alkaline pH, and physical stabilization of the enzyme (porous silica cenospheres).

  19. Application of TEM to characterize fly ash- and slag cements

    NARCIS (Netherlands)

    Pietersen, H.S.

    1999-01-01

    A Portland fly ash cement containing 20% of a fine fly ash and a blast furnace slag cement of approximately 290 days old were examined with analytical transmission electron microscopy, in order to examine the (local) microstructure in these cements in detail. In the Portland fly ash cement the fly

  20. Treatment of MSW fly ashes using the electrodialytic remediation technique

    DEFF Research Database (Denmark)

    Ferreira, Celia; Ribeiro, Alexandra B.; Ottosen, Lisbeth M.

    2004-01-01

    In the present work the electrodialytic remediation technique is applied for the treatment of fly ash, a hazardous by-product resulting from the incineration of municipal solid waste. Results are presented for an experiment conducted for 40 days at 38 mA, with a continuously stirred cell....... Experimental parameters monitored include voltage drop, pH and electrolyte's volumes. Evolution of heavy metal concentration with time in the different compartments is analysed. The performance of sodium gluconate for heavy metals extraction from fly ash in different pH conditions is evaluated in batch...... separating chambers III and IV and the dissolution of a large percentage of sample during the treatment. 39% of zinc, 14% of lead, 18% of copper and 60% of cadmium were removed from fly ash using the electrodialytic technique and these results are compared with previously reported experiments on similar...

  1. Development of fly ash quality control system

    Energy Technology Data Exchange (ETDEWEB)

    Ban, K. [Chubu Electric Power Company Inc., Nagoya (Japan). Thermal Power Dept.

    1997-12-31

    Since fly ash is designated as one of the by-products in the Japanese law related to the promotion of effective use of reclaimed materials (the recycling law) that prescribes the promotion of effective use of reclaimed materials, it is necessary to promote its effective use positively. However, there can be problems in using fly ash as it is difficult to assure a product with uniform properties, because the properties of fly ash can vary depending on the type of coal and the burning conditions of the boilers. For this reason, studies were made from 1994 to 1995 through experiments on the ash handling system of the No. 3 coal-fired boiler at the Hekinan Thermal Power Plant. The study was made in response to the needs of the users who wanted to effectively use the ash, and included the development of a quality control system for the selection and storage of ash which measured and analyzed the properties of the ash in real time. This paper outlines this quality control system and describes the results of the studies to date. 10 figs., 4 tabs.

  2. Potential use of fly ash to soil treatment in the Morava region

    Science.gov (United States)

    Bulíková, Lucia; Kresta, František; Rochovanský, Martin

    2017-09-01

    Soil treatment by binders is a standard technology and leads to optimal utilization of excavated soils in road constructions. Soil treatment is controlled in the Czech Republic by EN 14227-15 and Technical Requirement TP 94. Soil treatment using fly ash has not been performed in the Czech Republic, although there is a sufficient normative base. Fly ash produced by burning of hard coal in the Moravian region was tested as a potential binder. Fly ash samples were mixed with loess loams (CI). Tested siliceous fly ash of class F (ASTM C618) did not showed hydraulic properties but it showed positive effect on reducing maximum dry density of mixtures, increasing the IBI value (Immediate bearing index) and decreasing tendency to volume changes when the amount of fly ash was increased. The results of laboratory tests demonstrate the possibility of using fly ashes as a binder for soil treatment.

  3. Fly ash utilization to ecology purpose products

    Energy Technology Data Exchange (ETDEWEB)

    Sasae, T.; Kinugawa, M. (En-Tech Research Institute Inc. (Japan))

    1993-01-01

    Fly ash contains many elements necessary for plant growth. En-Tech Research Institute has a 100 ton/month fly ash granulation plant which produces 0.5-10mm diameter granules which are used in the cultivation of approximately 15,000 Onsidumu and Denpharae orchids in a 3,000 m[sup 2] greenhouse and as a soil improver for a 1,600m[sup 2] test lawn. The granules are also used as agricultural chemical adsorbents for drainage of the test lawn. Orchids cultivated using the fly ash granules are shipped to market as cut flowers regularly. There they fetch the same price or a higher price than orchids cultivated in the usual way. Good results have also been achieved with the soil improvement test and the adsorption test. Tests to obtain design data are being carried out on two golf courses in the Kumamoto Prefecture. 8 figs., 10 tabs., 7 photos.

  4. Optimising Ambient Setting Bayer Derived Fly Ash Geopolymers

    Directory of Open Access Journals (Sweden)

    Evan Jamieson

    2016-05-01

    Full Text Available The Bayer process utilises high concentrations of caustic and elevated temperature to liberate alumina from bauxite, for the production of aluminium and other chemicals. Within Australia, this process results in 40 million tonnes of mineral residues (Red mud each year. Over the same period, the energy production sector will produce 14 million tonnes of coal combustion products (Fly ash. Both industrial residues require impoundment storage, yet combining some of these components can produce geopolymers, an alternative to cement. Geopolymers derived from Bayer liquor and fly ash have been made successfully with a compressive strength in excess of 40 MPa after oven curing. However, any product from these industries would require large volume applications with robust operational conditions to maximise utilisation. To facilitate potential unconfined large-scale production, Bayer derived fly ash geopolymers have been optimised to achieve ambient curing. Fly ash from two different power stations have been successfully trialled showing the versatility of the Bayer liquor-ash combination for making geopolymers.

  5. Optimising Ambient Setting Bayer Derived Fly Ash Geopolymers

    Science.gov (United States)

    Jamieson, Evan; Kealley, Catherine S.; van Riessen, Arie; Hart, Robert D.

    2016-01-01

    The Bayer process utilises high concentrations of caustic and elevated temperature to liberate alumina from bauxite, for the production of aluminium and other chemicals. Within Australia, this process results in 40 million tonnes of mineral residues (Red mud) each year. Over the same period, the energy production sector will produce 14 million tonnes of coal combustion products (Fly ash). Both industrial residues require impoundment storage, yet combining some of these components can produce geopolymers, an alternative to cement. Geopolymers derived from Bayer liquor and fly ash have been made successfully with a compressive strength in excess of 40 MPa after oven curing. However, any product from these industries would require large volume applications with robust operational conditions to maximise utilisation. To facilitate potential unconfined large-scale production, Bayer derived fly ash geopolymers have been optimised to achieve ambient curing. Fly ash from two different power stations have been successfully trialled showing the versatility of the Bayer liquor-ash combination for making geopolymers. PMID:28773513

  6. Current Methods to Detoxify Fly Ash from Waste Incineration

    Energy Technology Data Exchange (ETDEWEB)

    Hallgren, Christine; Stroemberg, Birgitta [TPS Termiska Processer AB, Nykoeping (Sweden)

    2004-07-01

    Fly ash from waste incineration contains large amounts of heavy metals and dioxins, which will cause a significant disposal problem within the coming years. The amount of fly ash produced in Sweden is currently approximately 60,000 tons/y. New technological options for the decontamination and/or inertization of incinerator fly ash are being developed with the objective of rendering a product that can be reused or, at least, be deposited at standard landfill sites with no risk. Many of these technologies have been tested at industrial scale or in pilot projects. The proposed alternatives include: Thermal treatments; Immobilization/stabilization by cement based techniques; Wet chemical treatments (extractions, immobilizations); Microbiological treatments. Of these, thermal treatments are the most promising solution. Depending on the temperature thermal treatments are classified in two main types: 1) low temperature (below 600 deg C) thermal treatments and 2) high temperature (above 1200 deg C) thermal treatments (vitrification). Most dioxins can be successfully destroyed at temperatures up to 400 deg C under oxygen deficient conditions and at temperatures up to 600 deg C under oxidising conditions. However most heavy metals remain in the fly ash after low temperature treatment. At a temperature of 900 deg C most heavy metals can also be removed in a 10% HCl atmosphere by forming volatile metal chlorides (CT-Fluapur process). During vitrification processes the fly ash melts and forms an inert glassy slag. The product does not leach any significant amount of heavy metals and is free from dioxin. The volume of the fly ash is significantly reduced. The product can be land filled at low costs or used as construction material. The properties of the product depend on the cooling process and on additives such as sand, limestone or waste glass. A series of vitrification methods at industrial size or in pilot scale using different furnaces are studied. Among these, plasma

  7. Self hardening property of Botswana fly ash | Sahu | Botswana ...

    African Journals Online (AJOL)

    In the present investigation, an effort has been made to study the self hardening property of Botswana fly ash by testing penetration resistance of fly ash flowable fills and unconfined compressive strength of 3 soils mixed with fly ash and compacted to their optimum unit weight. It has been found that the strength of both ...

  8. Quality characteristics of Greek fly ashes and potential uses

    Energy Technology Data Exchange (ETDEWEB)

    Skodras, G.; Grammelis, P.; Kakaras, E. [Institute for Solid Fuels Technology and Applications, Ptolemais (Greece); Karangelos, D.; Anagnostakis, M.; Hinis, E. [Nuclear Engineering Section, Mechanical Engineering Department, National Technical University of Athens, Athens (Greece)

    2007-01-15

    The main characteristics of fly ash from Greek coal-fired boilers are presented in this paper in relation to its exploitation potential. Both fuel and fly ash samples were collected and analyzed according to the ASTM Standards. Apart from the typical analyses (proximate, ultimate, ash analysis and calorific value), an ICP-AES spectrometer was used for the analysis of heavy metals in the ash. Experimental measurements in order to determine the radioactivity content of raw fuel and the fly ash were carried out as well. A representative fly ash sample from Ptolemais power plant was evaluated and tested as filler in Self-Compacting Concrete (SCC). Ashes from the Greek brown coal are classified in type C, most of the fly ash being produced in Ptolemais of Northern Greece, while the rest in Megalopolis. Ptolemais fly ash is rich in calcium compounds, while Megalopolis fly ash contains more pyrite. Increased heavy metal concentrations are observed in the fly ash samples of Greek coal. Greek fly ash appears to have not only pozzolanic but also hydraulic behaviour. Furthermore, Greek fly ash, depending on its origin, may have relatively high natural radioactivity content, reaching in the case of Megalopolis fly ash 1 kBq kg{sup -1} of {sup 226}Ra. The laboratory results showed that fly ashes can be a competitive substitute to conventional limestone filler material in SCC. Fly ash is mostly used in Greece in cement industry replacing cement clinker and aiming to the production of special types of Portland cements. However, a more aggressive utilisation strategy should be developed, since low quantities of the total produced fly ash are currently further utilised. (author)

  9. Characterization of fly ash from bio and municipal waste

    DEFF Research Database (Denmark)

    Lima, Ana T.; Ottosen, Lisbeth M.; Pedersen, Anne Juul

    2008-01-01

    Four different fly ashes are characterized in the present paper. The ashes differ in the original fuel type and were sampled at distinct plants. The investigation includes two different ashes from municipal solid waste incineration (with and without sorbents addition), a straw ash and an ash from...... potentiality to be valorized. The main conclusion of this paper regards fly ash’s profound dissimilarity, where each ash should be studied separately....

  10. FLY ASH RECYCLE IN DRY SCRUBBING

    Science.gov (United States)

    The paper describes the effects of fly ash recycle in dry scrubbing. (Previous workers have shown that the recycle of product solids improves the utilization of slaked lime--Ca(OH)2--for sulfur dioxide (SO2) removal by spray dryers with bag filters.) In laboratory-scale experimen...

  11. Properties and application of zeolitized fly ash

    NARCIS (Netherlands)

    Steenbruggen, G.

    1999-01-01

    The combustion of coal produces large quantities of fly ash. This waste product is at present used for the production of building materials. This use may be reduced for a number of reasons, such as: stricter environmental regulations, changes in combustion techniques and competition with other

  12. FLY ASH: AN ALTERNATIVE TO POWDERED ACTIVATED ...

    African Journals Online (AJOL)

    Preferred Customer

    This paper reports the use of powdered activated carbon (PAC) and raw coal fly ash (RFA) in the removal of eosin dye from aqueous ... calculation is hereby reported to know the amount of adsorbent required for efficient removal of eosin dye. EXPERIMENTAL. Dye properties and preparation. Analytical grade eosin dye ...

  13. Possibilities of municipal solid waste incinerator fly ash utilisation.

    Science.gov (United States)

    Hartmann, Silvie; Koval, Lukáš; Škrobánková, Hana; Matýsek, Dalibor; Winter, Franz; Purgar, Amon

    2015-08-01

    Properties of the waste treatment residual fly ash generated from municipal solid waste incinerator fly ash were investigated in this study. Six different mortar blends with the addition of the municipal solid waste incinerator fly ash were evaluated. The Portland cement replacement levels of the municipal solid waste incinerator fly ash used were 25%, 30% and 50%. Both, raw and washed municipal solid waste incinerator fly ash samples were examined. According to the mineralogical composition measurements, a 22.6% increase in the pozzolanic/hydraulic properties was observed for the washed municipal solid waste incinerator fly ash sample. The maximum replacement level of 25% for the washed municipal solid waste incinerator fly ash in mortar blends was established in order to preserve the compressive strength properties. Moreover, the leaching characteristics of the crushed mortar blend was analysed in order to examine the immobilisation of its hazardous contents. © The Author(s) 2015.

  14. Alkali ash material: a novel fly ash-based cement

    Energy Technology Data Exchange (ETDEWEB)

    Hossein Rostami; William Brendley [Philadelphia University, Philadelphia, PA (United States)

    2003-08-01

    The United States generates 110 million t of coal ash annually. Approximately 70 million t of this coal ash is fly ash, of which 27% is recycled and the remaining 73% is landfilled. Disposal of such a huge quantity of ash poses a significant environmental problem. A new cementitious material has been developed, called alkali ash material (AAM), which is used to produce concrete for construction. AAM can be used to create a variety of concrete strengths and could revolutionize the concrete product manufacturing industry due to its economic advantage. AAM contains 40-95% Class F fly ash and is used as cement to bind sand, stone, and fibers creating concrete. AAM concrete has been tested for strength, durability, mechanical properties, and, most importantly, economic viability. AAM concrete is economically and technically viable for many construction applications. Some properties include rapid strength gain (90% of ultimate in 1 d), high ultimate strengths (110 MPa or 16 000 psi in 1 d), excellent acid resistance, and freeze-thaw durability. AAM's resistance to chemical attack, such as sulfuric (H{sub 2}SO{sub 4}), nitric (HNO{sub 3}), hydrochloric (HCl), and organic acids, is far better than portland cement concrete. AAM is resistant to freeze-thaw attack based on ASTM C-666 specifications. Potential immediate applications of AAM are blocks, pipe, median barriers, sound barriers, and overlaying materials. Eventual markets are high strength construction products, bridge beams, prestressed members, concrete tanks, highway appurtenances, and other concrete products. 28 refs., 7 figs., 2 tabs.

  15. Production of ceramics from coal fly ash

    Directory of Open Access Journals (Sweden)

    Angjusheva Biljana

    2012-01-01

    Full Text Available Dense ceramics are produced from fly ash from REK Bitola, Republic of Macedonia. Four types of fly ash from electro filters and one from the collected zone with particles < 0.063 mm were the subject of this research. Consolidation was achieved by pressing (P= 133 MPa and sintering (950, 1000, 1050 and 11000C and heating rates of 3 and 100/min. Densification was realized by liquid phase sintering and solid state reaction where diopside [Ca(Mg,Al(Si,Al2O6] was formed. Ceramics with optimal properties (porosity 2.96±0.5%, bending strength - 47.01±2 MPa, compressive strength - 170 ±5 MPa was produced at 1100ºC using the heating rate of 10ºC/min.

  16. Manufacture of ceramic tiles from fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Hnat, James G. (Collegeville, PA); Mathur, Akshay (Tampa, FL); Simpson, James C. (Perkiomenville, PA)

    1999-01-01

    The present invention relates to a process for forming glass-ceramic tiles. Fly ash containing organic material, metal contaminants, and glass forming materials is oxidized under conditions effective to combust the organic material and partially oxidize the metallic contaminants and the glass forming materials. The oxidized glass forming materials are vitrified to form a glass melt. This glass melt is then formed into tiles containing metallic contaminants.

  17. Manufacture of ceramic tiles from fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Hnat, J.G.; Mathur, A.; Simpson, J.C.

    1999-08-10

    The present invention relates to a process for forming glass-ceramic tiles. Fly ash containing organic material, metal contaminants, and glass forming materials is oxidized under conditions effective to combust the organic material and partially oxidize the metallic contaminants and the glass forming materials. The oxidized glass forming materials are vitrified to form a glass melt. This glass melt is then formed into tiles containing metallic contaminants. 6 figs.

  18. Treatment of fly ash from power plants using thermal plasma

    Directory of Open Access Journals (Sweden)

    Sulaiman Al-Mayman

    2017-05-01

    Full Text Available Fly ash from power plants is very toxic because it contains heavy metals. In this study fly ash was treated with a thermal plasma. Before their treatment, the fly ash was analyzed by many technics such as X-ray fluorescence, CHN elemental analysis, inductively coupled plasma atomic emission spectroscopy and scanning electron microscopy. With these technics, the composition, the chemical and physical proprieties of fly ash are determined. The results obtained by these analysis show that fly ash is mainly composed of carbon, and it contains also sulfur and metals such as V, Ca, Mg, Na, Fe, Ni, and Rh. The scanning electron microscopy analysis shows that fly ash particles are porous and have very irregular shapes with particle sizes of 20–50 μm. The treatment of fly ash was carried out in a plasma reactor and in two steps. In the first step, fly ash was treated in a pyrolysis/combustion plasma system to reduce the fraction of carbon. In the second step, the product obtained by the combustion of fly ash was vitrified in a plasma furnace. The leaching results show that the fly ash was detoxified by plasma vitrification and the produced slag is amorphous and glassy.

  19. Fly ash as a liming material for cotton.

    Science.gov (United States)

    Stevens, Gene; Dunn, David

    2004-01-01

    A field experiment was conducted to determine the effect of fly ash from a coal combustion electric power facility on soil acidity in a cotton (Gossypium hirsutum L.) field. Fresh fly ash was applied to a Bosket fine sandy loam (fine-loamy, mixed, thermic Mollic Hapludalf) soil with an initial soil pH(salt) of 4.8. The fly ash was equivalent to 42 g kg(-1) calcium carbonate with 97% passing through a 60 mesh (U.S. standard) sieve. Fly ash was applied one day before cotton planting in 1999 at 0, 3.4, 6.7, and 10.1 Mg ha(-1). No fly ash was applied in 2000. Within 60 d of fly ash application in 1999, all rates of fly ash significantly increased soil pH above 6.0. Manganese levels in cotton petioles were reduced significantly by 6.7 and 10.1 Mg ha(-1) of fly ash. Soil boron (B) and sodium (Na) concentrations were significantly increased with fly ash. In 1999, B in cotton leaves ranged from 72 to 84 mg kg(-1) in plots with fly ash applications. However, no visual symptoms of B toxicity in plants were observed. In 1999, cotton lint yield decreased on average 12 kg ha(-1) for each Mg of fly ash applied. In 2000, cotton yields were significantly greater for the residual 3.4 and 6.7 Mg fly ash ha(-1) plots than the untreated check. Due to the adverse yield effects measured in the first year following application, fly ash would not be a suitable soil amendment for cotton on this soil at this time.

  20. Electrodialytic removal of Cd from biomass combustion fly ash

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Ottosen, Lisbeth M.; Simonsen, Peter

    2004-01-01

    . The initial Cd concentration in the ashes varied between 8.8 mg Cd/kg DM (co-firing ash) and 64 mg Cd/kg DM (pre-washed straw ash), and pH varied from 3.7 to 13.3. In spite of large differences in ash characteristics, the electrodialytic remediation experiments indicated a good remediation potential for all......Due to a high concentration of Cd, biomass combustion fly ash often fails to meet the Danish legislative requirements for recycling on agricultural fields. In this work the potential of using the method Electrodialytic Remediation to reduce the concentration of Cd in different biomass combustion...... fly ashes was studied. Four fly ashes were investigated, originating from combustion of straw (two ashes), wood chips, and co-firing of wood pellets and fuel oil, respectively. One of the straw ashes had been pre-washed and was obtained suspended in water, the other ashes were obtained naturally dry...

  1. Effect of Climate Change on Service Life of High Volume Fly Ash Concrete Subjected to Carbonation—A Korean Case Study

    Directory of Open Access Journals (Sweden)

    Ki-Bong Park

    2017-01-01

    Full Text Available The increase in CO2 concentrations and global warming will increase the carbonation depth of concrete. Furthermore, temperature rise will increase the rate of corrosion of steel rebar after carbonation. On the other hand, compared with normal concrete, high volume fly ash (HVFA concrete is more vulnerable to carbonation-induced corrosion. Carbonation durability design with climate change is crucial to the rational use of HVFA concrete. This study presents a probabilistic approach that predicts the service life of HVFA concrete structures subjected to carbonation-induced corrosion resulting from increasing CO2 concentrations and temperatures. First, in the corrosion initiation stage, a hydration-carbonation integration model is used to evaluate the contents of the carbonatable material, porosity, and carbonation depth of HVFA concrete. The Monte Carlo method is adopted to determine the probability of corrosion initiation. Second, in the corrosion propagation stage, an updated model is proposed to evaluate the rate of corrosion, degree of corrosion for cover cracking of concrete, and probability of corrosion cracking. Third, the whole service life is determined considering both corrosion initiation stage and corrosion propagation stage. The analysis results show that climate change creates a significant impact on the service life of durable concrete.

  2. Electrodialytic upgrading of municipal waste incineration fly ash for reuse

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Kirkelund, Gunvor Marie; Ottosen, Lisbeth M.

    2012-01-01

    content of water soluble, mobile salts and heavy metals. It was shown that the mobility of salts and toxic elements can be significantly reduced by extraction with electrodialysis in stack [1, 2]; and that treated MSWI fly ash may potentially be utilized as a substitute for cement in concrete [3......As incineration becomes a more widespread means of waste treatment, volumes of incineration residues increase and new means of handling become a demand. Municipal Solid Waste Incineration (MSWI) fly ash is hazardous material, which is presently disposed off as such; primarily due to its high...... to investigate the leachability of salts and toxic elements as a function of treatment time and current density. Results show that a delicate balance between pH and treatment-time exist and that continuous monitoring of pH and conductivity may be used for controlling of the process at an industrial scale...

  3. Impact of fly ash composition upon shaker baghouse efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Sears, R.; Miller, S.J.

    1984-03-01

    Many parameters can have major effects on fabric filter performance. The most extensively published research in fabric filtration has concentrated on baghouse related parameters such as fabric type, cleaning mode, cleaning cycle, and air-to-cloth ratio. To a lesser extent studies have considered ash characteristics such as particle size distribution and specific filter resistance coefficient, K/sub 2/. Little research has been reported relating coal or ash properties to fabric filter performance. This paper deals with penetration from a shaker chamber with one specific fabric. The independent variable is major element concentration in fly ash. Air-to-cloth ratios varied only because combustion conditions control flue gas volumes. Results indicate that first, fabric filter performance is indeed coal specific with large differences in removal efficiency with different ashes. Second, the results reveal a definite inverse correlation between penetration and sodium concentration in the fly ash for the fabric and cleaning configuration considered. For the ashes that demonstrate poor performance in tests, careful selection of the correct fabric together with a conservative air-to-cloth ratio and the optimum cleaning cycle may all be necessary in order to maintain an adequate residual dust cake and bring the efficiency up to an acceptable level. Heavy dust cake formation may be necessary to achieve high efficiencies with these coals. Residual dust cake for the coals that showed high efficiencies in these tests may not be important, since North Dakota lignites give excellent efficiencies immediately after starting with new bags. Apparently the latter ashes build up on the woven fabric layer in such a way that openings in the weave and pinholes are immediately bridged over. These coals may then be candidates for high ratio filtration with conventional, economical woven fabric. 28 references, 10 figures, 4 tables.

  4. Assessing fly ash treatment: Remediation and stabilization of heavy metals

    DEFF Research Database (Denmark)

    Lima, A.T.; Ottosen, Lisbeth M.; Ribeiro, Alexandra B.

    2012-01-01

    Fly ashes from Municipal Solid Waste (MSW), straw (ST) and co-combustion of wood (CW) are here analyzed with the intent of reusing them. Two techniques are assessed, a remediation technique and a solidification/stabilization one. The removal of heavy metals from fly ashes through...... the electrodialytic process (EDR) has been tried out before. The goal of removing heavy metals has always been the reuse of fly ash, for instance in agricultural fields (BEK). The best removal rates are here summarized and some new results have been added. MSW fly ashes are still too hazardous after treatment to even...

  5. Application of Fly Ash from Solid Fuel Combustion in Concrete

    DEFF Research Database (Denmark)

    Pedersen, Kim Hougaard

    2008-01-01

    Application of Fly Ash from Solid Fuel Combustion in Concrete Kim H. Pedersen Abstract Industrial utilization of fly ash from pulverized coal combustion plays an important role in environmentally clean and cost effective power generation. Today, the primary market for fly ash utilization is as po......Application of Fly Ash from Solid Fuel Combustion in Concrete Kim H. Pedersen Abstract Industrial utilization of fly ash from pulverized coal combustion plays an important role in environmentally clean and cost effective power generation. Today, the primary market for fly ash utilization...... is as pozzolanic additive in the production of concrete. However, the residual carbon in fly ash can adsorb the air entraining admixtures (AEAs) added to enhance air entrainment in concrete in order to increase its workability and resistance toward freezing and thawing conditions. The problem has increased...... Nordjyllandsværket, unit 3; 3) post treatment of fly ash to lower its AEA adsorptivity. The foam index test is the method usually employed to determine the degree of fly ash interference with AEAs in concrete. The test involves the use of commercial AEAs and visual observation of foam stability. These facts reduce...

  6. The Effects of Bottom Ash on Setting Time and Compressive Strength of Fly Ash Geopolymer Paste

    Science.gov (United States)

    Affandhie, B. A.; Kurniasari, P. T.; Darmawan, M. S.; Subekti, S.; Wibowo, B.; Husin, N. A.; Bayuaji, R.; Irawan, S.

    2017-11-01

    This research is to find out the contribution of waste energy utilization of fly ash and bottom ash coal as binding agent of geopolymer concrete. This research methodology uses experimental approach in laboratory by making cylinder paste test object with dimension diameter of 2.5 cm x height 5 cm with some combination of fly ash and bottom ash mix with time setting test (ASTM C 191-04a) and compressive strength (ASTM C 39-04a). The research concludes that the effect of bottom ash on fly ash-based geopolymer paste shows good results in setting time and compressive strength.

  7. Biofuel Combustion Fly Ash Influence on the Properties of Concrete

    Directory of Open Access Journals (Sweden)

    Aurelijus Daugėla

    2016-02-01

    Full Text Available Cement as the binding agent in the production of concrete can be replaced with active mineral admixtures. Biofuel combustion fly ash is one of such admixtures. Materials used for the study: Portland cement CEM I 42.5 R, sand of 0/4 fraction, gravel of 4/16 fraction, biofuel fly ash, superplasticizer, water. Six compositions of concrete were designed by replacing 0%, 5%, 10%, 15% 20%, and 25% of cement with biofuel fly ash. The article analyses the effect of biofuel fly ash content on the properties of concrete. The tests revealed that the increase of biofuel fly ash content up to 20% increases concrete density and compressive strength after 7 and 28 days of curing and decreases water absorption, with corrected water content by using plasticizing admixture. It was found that concrete where 20% of cement is replaced by biofuel ash has higher frost resistance.

  8. A review on the effect of fly ash characteristics and their variations on the synthesis of fly ash based geopolymer

    Science.gov (United States)

    Wattimena, Oswyn K.; Antoni, Hardjito, Djwantoro

    2017-09-01

    There are more than four decades since the last 1970s where geopolymers concrete was first introduced and developed to use as a replacement to conventional concrete material which uses cement as a binder. And since the last two decades, geopolymers which utilized fly ash as aluminosilicate source material, i.e. fly ash based geopolymers, have been investigated. Many researchers present how to produce the best fly ash based geopolymer with a various source of constituent material as well as mixing formula to achieve exceptional concrete performance. Although there is a similar trend towards factors affecting the result of fly ash based geopolymer synthesis, there is still remain a wide range in mixture proportion. The considerable variation in fly ash characteristics as source material in the synthesis can very likely be one of the causes of this problem. This paper attempts to identify the effect of source material variation of geopolymer concrete, particularly which use fly ash as source material and focuses on the variation of its characteristics and the effects to properties of concrete. From the reviews it concluded that different sources (and even the same source, but different batch) of fly ash materials will give some different characteristics of the fly ash, where it would affect the synthesis process of the fly ash based geopolymer concretes.

  9. Electrodialytic removal of Cd from biomass combustion fly ash suspensions

    DEFF Research Database (Denmark)

    Kirkelund, Gunvor M.; Ottosen, Lisbeth M.; Damoe, Anne J.

    2013-01-01

    was investigated with the aim of enabling reuse of the ashes. The ashes originated from combustion of straw (two ashes), wood chips, and co-firing of wood pellets and fuel oil, respectively. A series of laboratory scale electrodialytic remediation experiments were conducted with each ash. The initial Cd...... the final Cd concentration was below 2.0. mg Cd/kg DM in at least one experiment done with each ash. This was obtained within 2 weeks of remediation and at liquid to solid (L/S) ratios of L/S 16 for the pre-washed straw ash and L/S 8 for the straw, co-firing and wood ash. © 2013 Elsevier B.V.......Due to relatively high concentrations of Cd, biomass combustion fly ashes often fail to meet Danish legislative requirements for recycling as fertilizer. In this study, the potential of using electrodialytic remediation for removal of Cd from four different biomass combustion fly ashes...

  10. Fundamental Study of Low NOx Combustion Fly Ash Utilization

    Energy Technology Data Exchange (ETDEWEB)

    E. M. Suubert; I. Kuloats; K. Smith; N. Sabanegh; R.H. Hurt; W. D. Lilly; Y. M. Gao

    1997-05-01

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over forty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  11. Fundamental Study of Low-Nox Combustion Fly Ash Utilization

    Energy Technology Data Exchange (ETDEWEB)

    E. M. Suuberg; I. Kuloats; K. Smith; N. Sabanegh; R. H. Hurt; W. D. Lilly; Y. M. Gao

    1997-11-01

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over forty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  12. Thermal stability of nano structured fly ash synthesized by high ...

    African Journals Online (AJOL)

    The size, shape and texture of the fresh as well as nano structured fly ash were studied using Scanning Electron Microscopy (SEM). The fresh ... The shape of the 30h milled particles is irregular and the surface morphology is rough. Isothermal ... Keywords: Nano materials, Particulates and Powders, XRD- analysis; Fly ash.

  13. Dynamic response of fly ash reinforced functionally graded rubber ...

    African Journals Online (AJOL)

    The dynamic analysis of jute-epoxy sandwiches with fly ash reinforced functionally gradient (FG) flexible, compliant rubber core is presented. FG samples are prepared using conventional casting technique. Presence of gradation is quantified by weight method. An attempt is made to study the influence of fly ash weight ...

  14. Surface treated fly ash filled modified epoxy composites

    Directory of Open Access Journals (Sweden)

    Uma Dharmalingam

    2015-01-01

    Full Text Available Abstract Fly ash, an inorganic alumino silicate has been used as filler in epoxy matrix, but it reduces the mechanical properties due to its poor dispersion and interfacial bonding with the epoxy matrix. To improve its interfacial bonding with epoxy matrix, surface treatment of fly ash was done using surfactant sodium lauryl sulfate and silane coupling agent glycidoxy propyl trimethoxy silane. An attempt is also made to reduce the particle size of fly ash using high pressure pulverizer. To improve fly ash dispersion in epoxy matrix, the epoxy was modified by mixing with amine containing liquid silicone rubber (ACS. The effect of surface treated fly ash with varying filler loadings from 10 to 40% weight on the mechanical, morphological and thermal properties of modified epoxy composites was investigated. The surface treated fly ash was characterized by particle size analyzer and FTIR spectra. Morphological studies of surface treated fly ash filled modified epoxy composites indicate good dispersion of fillers in the modified epoxy matrix and improves its mechanical properties. Impact strength of the surface treated fly ash filled modified epoxy composites show more improvement than unmodified composites.

  15. Kaliophilite from fly ash: synthesis, characterization and stability

    Indian Academy of Sciences (India)

    Kaliophilite was synthesized by fusion method using fly ash as starting material. In this method, at first, alkaline fusion of fly ash with KOH occurs, followed by hydrothermal treatment in KOH medium. Scanning electron microscopy (SEM) observations revealed that the synthesized kaliophilite (S-KAL) was a plate-like crystal.

  16. Speciation of arsenic and selenium during leaching of fly ash

    NARCIS (Netherlands)

    Hoek, E.E. van der

    1995-01-01

    The leaching (release) of large amounts of oxyanions, such as those of arsenic and selenium, is an major environmental problem when it comes to the disposal or use of coal fly ash. To predict environmentally safe conditions for the disposal or use of fly ash in, for example,

  17. Phosphorus removal from wastewater by fly ash ceramsite in ...

    African Journals Online (AJOL)

    Fly ash ceramsite-assisted phosphorus (P) removal from wastewater was investigated in this paper. First, the basic physical and chemical properties of two types of fly ash ceramsites were outlined. The adsorption capacity of P in wastewater was then examined by static interval experiments, in which the influence of ...

  18. Chemical and Physical Characterization of Fly Ash as Geopolymer Material

    Directory of Open Access Journals (Sweden)

    Risdanareni Puput

    2017-01-01

    Full Text Available Research on finding suitable cement substitute material becomes massive due to environmental effect. Geopolymer as inorganic material is potential to be the smart solution to overcome global warming issue. Fly ash is a waste material rich in silica and alumina becomes popular raw material to produce geopolymer. The best properties ofgeopolymer paste come from the high quality of fly ash. Therefore, it is important to investigate various types of fly ash and geopolymer properties. Their chemical and physical properties characterized by XRF, pH value, XRD and SEM. The results showed that type of fly ash depended on amount of Si-based of Ca-based compound which consisted of spherical morphology. Geopolymer paste produced from the ash with different compound has bulky and irregular shape morphology. The pH value of each ash has also a correlation with the setting time of fresh paste.

  19. Synthesis and characterization of zeolites prepared from industrial fly ash

    OpenAIRE

    Franus, Wojciech; Wdowin, Magdalena; Franus, Małgorzata

    2014-01-01

    In this paper, we present the possibility of using fly ash to produce synthetic zeolites. The synthesis class F fly ash from the Stalowa Wola SA heat and power plant was subjected to 24 h hydrothermal reaction with sodium hydroxide. Depending on the reaction conditions, three types of synthetic zeolites were formed: Na-X (20 g fly ash, 0.5 dm3 of 3 mol · dm−3 NaOH, 75 °C), Na-P1 (20 g fly ash, 0.5 dm3 of 3 mol · dm−3 NaOH, 95 °C), and sodalite (20 g fly ash, 0.8 dm3 of 5 mol · dm−3 NaOH + 0.4...

  20. Assessing fly ash treatment: Remediation and stabilization of heavy metals

    KAUST Repository

    Lima, A.T.

    2010-12-17

    Fly ashes from Municipal Solid Waste (MSW), straw (ST) and co-combustion of wood (CW) are here analyzed with the intent of reusing them. Two techniques are assessed, a remediation technique and a solidification/stabilization one. The removal of heavy metals from fly ashes through the electrodialytic process (EDR) has been tried out before. The goal of removing heavy metals has always been the reuse of fly ash, for instance in agricultural fields (BEK). The best removal rates are here summarized and some new results have been added. MSW fly ashes are still too hazardous after treatment to even consider application to the soil. ST ash is the only residue that gets concentrations low enough to be reused, but its fertilizing value might be questioned. An alternative reuse for the three ashes is here preliminary tested, the combination of fly ash with mortar. Fly ashes have been substituted by cement fraction or aggregate fraction. Surprisingly, better compressive strengths were obtained by replacing the aggregate fraction. CW ashes presented promising results for the substitution of aggregate in mortar and possibly in concrete. © 2010 Elsevier Ltd.

  1. Fluidization characteristics of power-plant fly ashes and fly ash-charcoal mixtures. [MS Thesis; 40 references

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, C.T.

    1980-03-01

    As a part of the continuing research on aluminum recovery from fly ash by HiChlor process, a plexiglass fluidization column system was constructed for measurement of fluidization parameters for power-plant fly ashes and fly ash-charcoal mixtures. Several bituminous and subbituminous coal fly ashes were tested and large differences in fluidization characteristics were observed. Fly ashes which were mechanically collected fluidized uniformly at low gas flow rates. Most fly ashes which were electrostatically precipitated exhibited channeling tendency and did not fluidize uniformly. Fluidization characteristics of electrostatically collected ashes improve when the finely divided charcoal powder is added to the mixture. The fluidization of the mixture was aided initially by a mechanical stirrer. Once the fluidization had succeeded, the beds were ready to fluidize without the assistance of a mechanical action. Smooth fluidization and large bed expansion were usually observed. The effects of charcoal size and aspect ratio on fluidization characteristics of the mixtures were also investigated. Fluidization characteristics of a fly ash-coal mixture were tested. The mixture fluidized only after being oven-dried for a few days.

  2. Fugitive particulate emission factors for dry fly ash disposal.

    Science.gov (United States)

    Mueller, Stephen F; Mallard, Jonathan W; Mao, Qi; Shaw, Stephanie L

    2013-07-01

    Dry fly ash disposal involves dropping ash from a truck and the movement of a heavy grader or similar vehicle across the ash surface. These operations are known to produce fugitive particulate emissions that are not readily quantifiable using standard emission measurement techniques. However there are numerous situations--such as applying for a source air permit--that require these emissions be quantified. Engineers traditionally use emission factors (EFs) derived from measurements of related processes to estimate fly ash disposal emissions. This study near a dry fly ash disposal site using state-of-the-art particulate monitoring equipment examines for the first time fugitive emissions specific to fly ash handling at an active disposal site. The study measured hourly airborne mass concentrations for particles smaller than 2.5 microm (PM2.5) and 10 microm (PM10) along with meteorological conditions and atmospheric turbidity at high temporal resolution to characterize and quantify fugitive fly ash emissions. Fugitive fly ash transport and dispersion were computed using the on-site meteorological data and a regulatory air pollutant dispersion model (AERMOD). Model outputs coupled with ambient measurements yielded fugitive fly ash EFs that averaged 96 g Mg(-1) (of ash processed) for the PM(c) fraction (= PM10 - PM2.5) and 18 g Mg(-1) for PM2.5. Median EFs were much lower due to the strongly skewed shape of the derived EF distributions. Fugitive EFs from nearby unpaved roads were also characterized. Our primary finding is that EFs for dry fly ash disposal are considerably less than EFs derived using US Environmental Protection Agency AP-42 Emissions Handbook formulations for generic aggregate materials. This appears to be due to a large difference (a factor of 10+) between fugitive vehicular EFs estimated using the AP-42 formulation for vehicles driving on industrial roads (in this case, heavy slow-moving grading equipment) and EFs derived by the current study. Fugitive

  3. Creep Behaviour of Fly Ash-Based Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Wallah S.E.

    2010-01-01

    Full Text Available Fly ash-based geopolymer concrete is manufactured using fly ash as its source material and does not use Portland cement at all. Beside fly ash, alkaline solution is also utilized to make geopolymer paste which binds the aggregates to form geopolymer concrete. This paper presents the study of creep behaviour of fly ash-based geopolymer concrete. Four series of specimens with various compressive strengths were prepared to study its creep behaviour for the duration of test up to one year. The test method followed the procedures applied for Ordinary Portland Cement (OPC concrete. Test results show that fly ash-based geopolymer concrete undergoes low creep which is generally less than that of OPC concrete. After one year of loading, the results for specific creep of fly ash-based geopolymer concrete in this study ranges from 15 to 29 microstrain for concrete compressive strength 67–40 MPa respectively. From the test results, it is also found out that the creep coefficient of fly ash-based geopolymer concrete is about half of that predicted using Gilbert’s Method for OPC concrete.

  4. Smelting disposal of municipal solid waste incineration fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Q.; Lu, C.; Yang, J. [Chongqing Univ., Chongqing (China); Huang, B. [Southwest Petroleum Univ., Chengdu Sichuan (China)

    2008-07-01

    Municipal solid waste (MSW) fly ash contains a significant amount of heavy metals which must be treated safely as it has a negative impact on the environment and the sustainable development of cities. The primary disposal methods used around the world are landfilling and incineration. In China, the most widely used treatment methods of MSW are open-air stacking and landfill disposal due to protected research on incineration. This paper explored the technology of the smelting operation process. It discussed the proportion of hydrated lime in the process of solidification and the effect of temperature on the separation rate of heavy metals in fly ash. The paper described the experiment and presented the physical and chemical properties of fly ash. The leaching toxicities of heavy metals in fly ash were also displayed in table format. The melting separation process of MSW incineration fly ash was discussed with particular reference to the solidification of fly ash and melting separation technology for heavy metals. It was concluded that it was feasible to use the smelting separation technology for disposal of MSW incineration fly ash as it could eliminate pollution due to heavy metals and dioxins, reduce secondary pollution, and recycle many of the heavy metals present. 9 refs., 3 tabs., 3 figs.

  5. Development of Classified Fly Ash as a Pozzolanic Material

    Science.gov (United States)

    Rukzon, Sumrerng; Chindaprasirt, Prinya

    This research studies the potential for using classified fly ash from Mae Moh power plant in Thailand as a pozzolanic material. Three different fly ash finenesses viz., coarse Original Fly Ash (OFA), Medium Fly Ash (MFA) and Fine Fly Ash (FFA) were used for the study. Ordinary Portland Cement (OPC) was partially replaced with fly ash at 20 and 40% by weight of binder. The water to binder ratio was kept constant at 0.5 and the flow of mortar was maintained at 110±5% with the aid of superplasticizer (SP). Compressive strength, carbonation depth and porosity test of mortars were determined. FFA has a high potential to be used as a good pozzolanic material. The use of FFA produces mortars with good strength and low porosity. The resistance to carbonation of mortar improves with partial replacement of FFA in comparison with the normal coarse fly ash. The use of FFA results in a strong and dense mortar which is due to better dispersion and filling effect as well as an increase in the pozzolanic reaction.

  6. Mercury Retention by Fly Ashes from Oxy-fuel Processes

    OpenAIRE

    Fernández Miranda, Nuria; Villamil Rumayor, Marta; López Antón, María Antonia; Díaz Somoano, Mercedes; Martínez Tarazona, María Rosa

    2015-01-01

    The objective of this study is to determine the mechanism of mercury retention in fly ashes, the main solid waste from coal combustion power plants, and to evaluate the interactions between the type of mercury and fly ashes. The work was based on the results of mercury speciation in the gas and the solid fly ash before and after mercury retention. The identification of the mercury species in the gas was performed using previously validated methods, but the speciation of the mercury retained i...

  7. Leaching of nutrient salts from fly ash from biomass combustion

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Vu, Duc Thuong; Stenby, Mette

    2005-01-01

    Methods to selectively leach nutrient salts from fly ash, while leaving cadmium un-dissolved were studied. Temperature, pH, water to fly ash ratio are all expected to influence the kinetics and the equilibrium boundaries for this process. Three different leaching methods were investigated...... moving bed process with agitation/centrifugation. It was found that a satisfactory leaching of the nutrient salts could be achieved with the third method using only two or three stages, depending on the water to fly ash ratio. It is an advantage to perform the process at temperatures above 50°C...

  8. Stabilize ash using Clemson`s sintering process (Part 1 -- Phase 1 results): Mixed waste fly ash stabilization. Innovative technology summary report

    Energy Technology Data Exchange (ETDEWEB)

    1998-12-01

    Incineration of applicable Department of Energy (DOE) mixed wastes has produced a secondary waste stream of radioactive and Resource Conservation and Recovery Act (RCRA) hazardous fly ash that also requires treatment before land disposal. Unlike bottom ash, fly ash usually contains constituents making efficient stabilization difficult. For example, fly ash from the DOE Waste Experimental Reduction Facility (WERF) incinerator at the Idaho National Engineering and Environmental Laboratory (INEEL) contains volatile metals, metal salts, high concentrations of zinc, and unburned organic residues. All of these constituents can effect the stabilization process. The Department of Energy, and in particular the Mixed Waste Focus Area (MWFA) of EM-50, has stated the need for improved stabilization methods would accept a higher ash waste loading while meeting waste form disposal criteria. These alternative stabilization technologies should include delivery systems to minimize worker exposure and minimize secondary waste generation, while maximizing operational flexibility and radionuclide containment. Currently, the standard practice for stabilizing ash is mixing with Portland cement at room temperature. This standard practice produces a significant increase of waste material volume or has difficulty in adequately stabilizing the components in the fly ash to ensure regulatory requirements are consistently satisfied. To address these fly ash stabilization shortcomings, the MWFA, a DOE/EM-50 program, invested in the development of several fly ash stabilization alternatives, including the Clemson University sintering method.

  9. Analysis of Content of Selected Critical Elements in Fly Ash

    Directory of Open Access Journals (Sweden)

    Makowska Dorota

    2016-03-01

    Full Text Available Pursuant to the new mineral policy of the European Union, searching for new sources of raw materials is required. Coal fly ash has long been considered as a potential source of a number of critical elements. Therefore, it is important to monitor the contents of the critical elements in fly ash from coal combustion. The paper presents the results of examinations of the contents of selected elements, i.e. beryllium, cobalt, chromium and germanium in fly ash from Polish power plants. The results of the conducted investigations indicate that the examined ash samples from bituminous coal combustion cannot be treated as a potential source of the analysed critical elements. The content of these elements in ash, though slightly higher than their average content in the sedimentary rocks, is, however, not high enough to make their recovery technologically and economically justified at this moment.

  10. Electrodialytic removal of cadmium from straw combustion fly ash

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Ottosen, Lisbeth M.; Villumsen, Arne

    2004-01-01

    Fly ash from straw combustion contains valuable nutrients when returned to agricultural soils. In many instances, however, this fly ash may contain heavy metals, such as cadmium, at levels which often exceed the limits given by the Danish legislation. Thus before utilizing the nutrients, cadmium...... must be removed from these ashes. The use of an electrodialytic remediation method to remove cadmium from fly ash arising from straw combustion and containing 11.2 mg Cd kg$+-1$/ DM (dry matter) was accessed. After 36 days of remediation at a constant current density of 5.6 mA cm$+-2$/ more than 97......% of the cadmium had been removed from around 150 g ash on a dry basis. $CPY 2004 Society of Chemical Industry....

  11. Strength properties of fly ash based controlled low strength materials.

    Science.gov (United States)

    Türkel, S

    2007-08-25

    Controlled low strength material (CLSM) is a flowable mixture that can be used as a backfill material in place of compacted soils. Flowable fill requires no tamping or compaction to achieve its strength and typically has a load carrying capacity much higher than compacted soils, but it can still be excavated easily. The selection of CLSM type should be based on technical and economical considerations for specific applications. In this study, a mixture of high volume fly ash (FA), crushed limestone powder (filler) and a low percentage of pozzolana cement have been tried in different compositions. The amount of pozzolana cement was kept constant for all mixes as, 5% of fly ash weight. The amount of mixing water was chosen in order to provide optimum pumpability by determining the spreading ratio of CLSM mixtures using flow table method. The shear strength of the material is a measure of the materials ability to support imposed stresses on the material. The shear strength properties of CLSM mixtures have been investigated by a series of laboratory tests. The direct shear test procedure was applied for determining the strength parameters Phi (angle of shearing resistance) and C(h) (cohesion intercept) of the material. The test results indicated that CLSM mixtures have superior shear strength properties compared to compacted soils. Shear strength, cohesion intercept and angle of shearing resistance values of CLSM mixtures exceeded conventional soil materials' similar properties at 7 days. These parameters proved that CLSM mixtures are suitable materials for backfill applications.

  12. Properties and Leachability of Self-Compacting Concrete Incorporated with Fly Ash and Bottom Ash

    Science.gov (United States)

    Kadir, Aeslina Abdul; Ikhmal Haqeem Hassan, Mohd; Jamaluddin, Norwati; Bakri Abdullah, Mohd Mustafa Al

    2016-06-01

    The process of combustion in coal-fired power plant generates ashes, namely fly ash and bottom ash. Besides, coal ash produced from coal combustion contains heavy metals within their compositions. These metals are toxic to the environment as well as to human health. Fortunately, treatment methods are available for these ashes, and the use of fly ash and bottom ash in the concrete mix is one of the few. Therefore, an experimental program was carried out to study the properties and determine the leachability of selfcompacting concrete incorporated with fly ash and bottom ash. For experimental study, self-compacting concrete was produced with fly ash as a replacement for Ordinary Portland Cement and bottom ash as a replacement for sand with the ratios of 10%, 20%, and 30% respectively. The fresh properties tests conducted were slump flow, t500, sieve segregation and J-ring. Meanwhile for the hardened properties, density, compressive strength and water absorption test were performed. The samples were then crushed to be extracted using Toxicity Characteristic Leaching Procedure and heavy metals content within the samples were identified accordingly using Atomic Absorption Spectrometry. The results demonstrated that both fresh and hardened properties were qualified to categorize as self-compacting concrete. Improvements in compressive strength were observed, and densities for all the samples were identified as a normal weight concrete with ranges between 2000 kg/m3 to 2600 kg/m3. Other than that, it was found that incorporation up to 30% of the ashes was safe as the leached heavy metals concentration did not exceed the regulatory levels, except for arsenic. In conclusion, this study will serve as a reference which suggests that fly ash and bottom ash are widely applicable in concrete technology, and its incorporation in self-compacting concrete constitutes a potential means of adding value to appropriate mix and design.

  13. Some studies on the reaction between fly ash and lime

    Indian Academy of Sciences (India)

    Unknown

    (1997) also studied the hydrothermal reaction of fly ash with Ca(OH)2 and CaSO4⋅2H2O. Muntcan et al (1987) studied on the autoclaved limestone materials with addi- tion of fly ash. The physico-mechanical properties of the resulting ... tate in 1 litre of alcohol. It was standardized as follows: About 0⋅1 g of freshly ignited ...

  14. Comparison of creep of the cement pastes included fly ash

    Directory of Open Access Journals (Sweden)

    Padevět Pavel

    2017-01-01

    Full Text Available The paper is devoted to comparison of creep of cement pastes containing fly ash admixture. The size of creep in time depends on the amount of components of the cement paste. Attention is paid to the content of classical fly ash in cement paste and its impact on the size of creep. The moisture of cement pastes is distinguished because it significantly affects the rheological properties of the material.

  15. KINETICS OF FLY ASH BENEFICIATION BY CARBON BURNOUT

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Joseph N.D. Dodoo; Dr. Joseph M. Okoh

    2000-11-01

    Surface area analyses performed on fly ash samples reveal that the surface area is controlled by carbon content. The higher surface areas found in large particles are due to the presence of highly porous carbonaceous particles. Adsorption-desorption isotherms and t-plots of fly ash samples indicate that fly ash is porous. BJH Adsorption/Desorption pore size analysis reveal that pore diameters are independent of sieve size. They appear to be dependent only on the nature of the material which confers porosity. Based on the results of Brown and Dykstra (41) it is reasonable to assume that calculations of reaction rates at temperatures above 550 C were confounded by weight losses from processes other than carbon oxidation and, therefore, are not useful in determination of the temperature dependence of carbon oxidation in fly ash. The results of the present study indicate that temperatures below 550 C should be used for future studies in order to satisfactorily assess the temperature dependence of carbon oxidation in fly ash. Furthermore, it is also advisable that percent carbon determinations be performed on fly ash samples after the oxidation reactions to determine whether all carbon present in fly ash is oxidized. This will ensure that reaction rates are representative of the complete oxidation of carbon. An inverse relationship was determined between reaction rates and oxygen concentration for this study. As discussed, this may be due to volatilization of volatiles from fly ash and ease of transport of products away from the reaction sites by the action of the vacuum applied to the samples. A more accurate determination of oxygen dependence of carbon oxidation can be accomplished by the use of specialty gases containing different concentrations of oxygen which could eliminate the need to apply vacuum to the samples.

  16. Pure zeolite synthesis from silica extracted from coal fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, N.; Querol, X.; Plana, F.; Andres, J.M.; Janssen, M.; Nugteren, H. [CSIC, Barcelona (Spain). Inst. Earth Science ' Jaume Almera'

    2002-07-01

    Pure zeolites can be synthesised from silica extracted from fly ash by alkaline leaching. If the process is optimised the solid residue arising from this extraction may also contain a relatively high content of zeolitic material mixed with residual fly ash components. Both the pure and the impure zeolitic material have a high potential for application in waste-water and flue gas-cleaning technologies. The silica extraction potential of 23 European coal fly ashes covering most of the possible fly ash types is investigated in this study. Optimisation of leaching processes, by varying temperature, time and alkali/fly ash rates, permitted extraction yields up to 140 g of SiO{sub 2} per kg using a single step process, but the extraction yields may reach up to 210 g kg{sup -1} by applying thermal pre-treatments prior to the extraction. The solid residue arising from the silica extraction experiments shows a high NaP1 zeolite content. A high Si/Al ratio of the glass matrix, the occurrence of easily soluble silica phases in the original fly ash and a high reactive surface area were found to be the major parameters influencing silica extraction. High purity 4A and X zeolitic material was obtained by combining the silica extracts from the Meirama fly ash and a waste solution from the Al-anodising industry. The results allowed conversion of the silica extraction yields to an equivalent 630 g of pure 4A-X zeolite per kg of fly ash with a cation exchange capacity of 4.7 meq g{sup -1}.

  17. Development of fly ash-based automotive brake lining

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, S.; Chugh, Y.P. [South Illinois University, Carbondale, IL (United States). College of Engineering

    2007-07-15

    Coal-fired power plants all over the world generate huge amounts of fly ash each year, 70 million tons of which are produced in the United States alone. Only 40% of all fly ashes generated in the USA find beneficial applications and rest have to be disposed off, which is burden for the generation industry. Fly ash particles possess certain characteristics that make them suitable for use in friction composites as a filter material. An attempt has been made through this research to incorporate more than 50wt% of fly ash particles in automotive brake lining friction composites. This paper presents the research carried out on development of friction composites, using fly ash obtained from a specific power plant in Illinois. Ingredients such as phenolic resin, aramid pulp, glass fiber, potassium titanate, graphite, aluminum fiber and copper powder were used in the composite development phase, in addition to the fly ash. The developed brake lining composites have exhibited consistent coefficients of friction in the range of 0.35-0.4, and wear rates lower than 12wt%.

  18. Suppressing Heavy Metal Leaching through Ball Milling of Fly Ash

    Directory of Open Access Journals (Sweden)

    Zhiliang Chen

    2016-07-01

    Full Text Available Ball milling is investigated as a method of reducing the leaching concentration (often termed stablilization of heavy metals in municipal solid waste incineration (MSWI fly ash. Three heavy metals (Cu, Cr, Pb loose much of their solubility in leachate by treating fly ash in a planetary ball mill, in which collisions between balls and fly ash drive various physical processes, as well as chemical reactions. The efficiency of stabilization is evaluated by analysing heavy metals in the leachable fraction from treated fly ash. Ball milling reduces the leaching concentration of Cu, Cr, and Pb, and water washing effectively promotes stabilization efficiency by removing soluble salts. Size distribution and morphology of particles were analysed by laser particle diameter analysis and scanning electron microscopy. X-ray diffraction analysis reveals significant reduction of the crystallinity of fly ash by milling. Fly ash particles can be activated through this ball milling, leading to a significant decrease in particle size, a rise in its BET-surface, and turning basic crystals therein into amorphous structures. The dissolution rate of acid buffering materials present in activated particles is enhanced, resulting in a rising pH value of the leachate, reducing the leaching out of some heavy metals.

  19. Screening coal combustion fly ashes for application in geopolymers

    NARCIS (Netherlands)

    Valcke, S.L.A.; Pipilikaki, P.; Sarabér, A.J.; Fischer, H.R.; Nugteren, H.W.

    2013-01-01

    Driven by cost and sustainability, secondary resource materials such as fly ash, blast furnace slag, and bottom ash are increasingly used for alternative types of concrete binders, such as geopolymers. Because secondary resources may be highly variable from the perspective of geopolymers, it is

  20. Adsorption of selenium using bagasse fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Wasewar, Kailas L. [Department of Chemical Engineering, Visveswarya National Institute of Technology (VNIT), Nagpur (India); Prasad, Basheshwar; Gulipalli, Sekhararao [Department of Chemical Engineering, Indian Institute of Technology (IIT), Roorkee (India)

    2009-07-15

    The present work involves the study of Se(IV) adsorption onto bagasse fly ash. The adsorbents were coated with a ferric chloride solution for the effective removal of selenium. The physico-chemical characterization of the adsorbent was carried out using standard methods, e. g., proximate analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, thermo-gravimetric analysis and differential thermal analysis. Batch experiments were carried out to determine the effect of various parameters such as adsorbent dose, initial pH, contact time, and temperature on the adsorption process. Results obtained from these studies were analyzed using various kinetic models and isotherms. Se(IV) adsorption onto adsorbent was high at low pH values, and decreased with an increase in initial pH. A temperature study showed that the uptake of Se(IV) was greatest at 293 K, within the temperature range studied. The parameters of pseudo first order, pseudo second order, and Weber-Morris intra-particle kinetic models were determined. Equilibrium isotherms were analyzed using Langmuir, Freundlich, and Temkin isotherms. Error analyses were also carried out using hybrid fractional error function and Marquardt's percent standard deviation. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  1. Reduction of metal leaching in brown coal fly ash using geopolymers.

    Science.gov (United States)

    Bankowski, P; Zou, L; Hodges, R

    2004-10-18

    Current regulations classify fly ash as a prescribed waste and prohibit its disposal in regular landfill. Treatment of the fly ash can reduce the leach rate of metals, and allow it to be disposed in less prescribed landfill. A geopolymer matrix was investigated as a potential stabilisation method for brown coal fly ash. Precipitator fly ash was obtained from electrostatic precipitators and leached fly ash was collected from ash disposal ponds, and leaching tests were conducted on both types of geopolymer stabilised fly ashes. The ratio of fly ash to geopolymer was varied to determine the effects of different compositions on leaching rates. Fourteen metals and heavy metals were targeted during the leaching tests and the results indicate that a geopolymer is effective at reducing the leach rates of many metals from the fly ash, such as calcium, arsenic, selenium, strontium and barium. The major element leachate concentrations obtained from leached fly ash were in general lower than that of precipitator fly ash. Conversely, heavy metal leachate concentrations were lower in precipitator fly ash than leached pond fly ash. The maximum addition of fly ash to this geopolymer was found to be 60wt% for fly ash obtained from the electrostatic precipitators and 70wt% for fly ash obtained from ash disposal ponds. The formation of geopolymer in the presence of fly ash was studied using 29Si MAS-NMR and showed that a geopolymer matrix was formed. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) imaging showed the interaction of the fly ash with the geopolymer, which was related to the leachate data and also the maximum percentage fly ash addition.

  2. Corrosion Studies of Fly Ash and Fly Ash-Slag Based Geopolymer

    Science.gov (United States)

    Zainal, F. F.; Amli, S. F. M.; Hussin, K.; Rahmat, A.; Abdullah, M. M. A. B.

    2017-06-01

    Abstract This paper presents the results of corrosion studies between Fly Ash Geopolymer (FG) paste and Fly Ash-Slag Geopolymer (FSG) paste. Geopolymer was made from aluminosilicate inorganic polymers mixed with the alkaline activator in order to reduce the carbon dioxide (CO2) to the ecosystem. Samples then were cured at 60ºC for 24 hours in the oven. Reinforcement bar is placed at the center of the paste. The samples were examined after 7, 14 and 28 days in terms of Open Circuit Potential (OCP) test, phase analysis and morphology analysis. The potential values regarding OCP test for FSG paste from 7 days until 28 days are 0.464 V, 0.474 V and 0.498 V more positive than FG paste which the potential values are 0.087 V, 0.133 V and 0.206 V respectively. From the Pourbaix diagram, all the potential values for FG paste and FSG paste were located in the same Fe2O3, passivity region. Passive layer which is the oxide form exists in this region to protect the reinforcement bar from corrosion agents. It can be proved from phase analysis results which iron oxide hydroxide (FeOOH), hematite (Fe2O3) and magnetite (Fe3O4) peaks exist. The differences of morphological structures of these pastes were observed by Scanning Electron Microscope (SEM). It shows that FSG paste had good corrosion resistance and low corrosion rate compared to FG paste.

  3. Producing a synthetic zeolite from secondary coal fly ash.

    Science.gov (United States)

    Zhou, Chunyu; Yan, Chunjie; Zhou, Qi; Wang, Hongquan; Luo, Wenjun

    2016-11-01

    Secondary coal fly ash is known as a by-product produced by the extracting alumina industry from high-alumina fly ash, which is always considered to be solid waste. Zeolitization of secondary coal fly ash offers an opportunity to create value-added products from this industrial solid waste. The influence of synthesis parameters on zeolite NaA such as alkalinity, the molar ratio of SiO2/Al2O3, crystallization time and temperature was investigated in this paper. It was found that the types of synthetic zeolites produced were to be highly dependent on the conditions of the crystallization process. Calcium ion exchange capacity and whiteness measurements revealed that the synthesized product meets the standard for being used as detergent, indicating a promising use as a builder in detergent, ion-exchangers or selective adsorbents. Yield of up to a maximum of 1.54 g/g of ash was produced for zeolite NaA from the secondary coal fly ash residue. This result presents a potential use of the secondary coal fly ash to obtain a high value-added product by a cheap and alternative zeolitization procedure.

  4. Availability of sulfur in fly ash to plants

    Energy Technology Data Exchange (ETDEWEB)

    Elseewi, A.A.; Bingham, F.T.; Page, A.L.

    1978-01-01

    Fly ash from a coal-fired power plant was added to soil in variable amounts and the availability of sulfur to a variety of plant species from this source was compared to that of gypsum. The study was conducted under greenhouse conditions with a calcareous and two acid soils which were low in plant-available sulfur. The fly ash used contained 0.4% S, all of which is extractable by NH/sub 4/OAc. When mixed with a calcareous and an acid soil at rates of 1 to 2% by weight, the fly ash corrected a S deficiency in the soil and maximized the yield of alfalfa (Medicago sativa L.) and bermudagrass (Cynodon dactylon L.). The increase in yield (twofold to threefold in alfalfa and 40 to 70% in bermudagrass) was accompanied by an increase in the S content of the plant tops from a deficiency level (<0.1%) to a sufficiency level (greater than or equal to 0.2%). The availability of fly ash-S and gypsum (CaSO/sub 4/ . 2H/sub 2/O)-S was compared by the addition of equal amounts of S from the two sources (25-, 50-, and 100-mg S/kg soil) to an acid soil. Yield and S content of turnip (Brassica rapa L.) and white clover (Trifolium repens L.) were equally improved, demonstrating that the availability of fly ash derived-S is equivalent to that of gympsum-S.

  5. Fly ash: Perspective resource for geo-polymer materials production

    Science.gov (United States)

    Kargin, Aleksey; Baev, Vladimir; Mashkin, Nikolay; Uglyanica, Andrey

    2016-01-01

    The present paper presents the information about the chemical and mineralogical composition of the ash and slag and their amounts at the dumps of the thermoelectric plants located in the city of Kemerovo. It is known that about 85% of ash and slag from the thermoelectric plants in Russia are removed by means of the hydraulic sluicing systems and only about 15% - by the systems of pneumatic ash handling. Currently, however, the transition from the "wet" ash removal systems to the "dry" ones is outlined. This process is quite logical since the fly ash has the higher reactivity compared with the hydraulic sluicing ash and therefore it is of the great interest for recycling and use. On the other hand, the recent trend is the increased use of fly ash in the production of geo-polymers due to their availability, workability and the increased life of the final product. The analysis is carried out to check the possibility of using the fly ash from various Kemerovo thermoelectric plants as a raw material for the production of the alkali-activated binder.

  6. Size fraction characterization of highly-calcareous fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Itskos, Grigorios; Koukouzas, Nikolaos [Institute for Solid Fuels Technology and Applications, Centre for Research and Technology Hellas, 357-359 Mesogeion Avenue, GR-152 31, Halandri, Athens (Greece); Itskos, Socrates [Department of Chemical Technology and the Environment, Steam Electric Station of Amynteon-Filotas, Public Power Corporation of Greece, GR-532 00, Amynteon (Greece)

    2010-11-15

    The chemical and mineralogical composition of lignite fly ash (FA) varies as a function of the prevalent conditions in both the processes of power production and lignite mining. The differentiation of the qualitative and quantitative composition of the highly-calcareous lignite fly ash, as a function of its particle size distribution, is verified in this paper. According to the results of the conducted research, a fine-grained fraction of considerable amount presents properties that obstruct the sustainable exploitation of calcareous lignite fly ash in cement industry applications. On the other hand, the same grain fraction (because of its hydraulic properties) can be utilized in other sort of applications, based on different criteria, i.e. in road constructions. The coarse-grained fraction (which reflects a low proportion to the total fly ash output) presents the same undesired characteristics as well. Rather, the intermediate grain fraction (75-150 {mu}m) presents the highly desirable properties when fly ash is utilized as a pozzolanic additive. In addition, the mechanism of the formation of the intermediate grain fraction strongly prevents the factors that cause the variation of fly ash-quality. It is therefore the optimum part of the whole amount of lignite FA, to be utilized as additive in cement manufacturing. The outcomes of this paper will hopefully contribute towards the crucial goal of the expansion of the utilization of calcareous lignite fly ash by proposing a more effective way of using this material, basically by taking advantage of its fundamental chemical and mineralogical properties. (author)

  7. A Comprehensive Study of the Polypropylene Fiber Reinforced Fly Ash Based Geopolymer

    DEFF Research Database (Denmark)

    Ranjbar, Navid; Mehrali, Mehdi; Behnia, Arash

    2016-01-01

    and long term impacts of different volume percentages of polypropylene fiber (PPF) reinforcement on fly ash based geopolymer composites. Different characteristics of the composite were compared at fresh state by flow measurement and hardened state by variation of shrinkage over time to assess the response...

  8. Combining sieving and washing, a way to treat MSWI boiler fly ash.

    Science.gov (United States)

    De Boom, Aurore; Degrez, Marc

    2015-05-01

    Municipal Solid Waste Incineration (MSWI) fly ashes contain some compounds that could be extracted and valorised. A process based on wet sieving and washing steps has been developed aiming to reach this objective. Such unique combination in MSWI fly ash treatment led to a non-hazardous fraction from incineration fly ashes. More specifically, MSWI Boiler Fly Ash (BFA) was separately sampled and treated. The BFA finer particles (13wt%) were found to be more contaminated in Pb and Zn than the coarser fractions. After three washing steps, the coarser fractions presented leaching concentrations acceptable to landfill for non-hazardous materials so that an eventual subsequent valorisation may be foreseen. At the contrary, too much Pb leached from the finest particles and this fraction should be further treated. Wet sieving and washing permit thus to reduce the leachability of MSWI BFA and to concentrate the Pb and Zn contamination in a small (in particle size and volume) fraction. Such combination would therefore constitute a straightforward and efficient basis to valorise coarse particles from MSWI fly ashes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Comparative study on the characteristics of fly ash and bottom ash geopolymers.

    Science.gov (United States)

    Chindaprasirt, Prinya; Jaturapitakkul, Chai; Chalee, Wichian; Rattanasak, Ubolluk

    2009-02-01

    This research was conducted to compare geopolymers made from fly ash and ground bottom ash. Sodium hydroxide (NaOH) and sodium silicate (Na(2)SiO(3)) solutions were used as activators. A mass ratio of 1.5 Na(2)SiO(3)/NaOH and three concentrations of NaOH (5, 10, and 15M) were used; the geopolymers were cured at 65 degrees C for 48 h. A Fourier transform infrared spectrometer (FT-IR), differential scanning calorimeter (DSC), and scanning electron microscope (SEM) were used on the geopolymer pastes. Geopolymer mortars were also prepared in order to investigate compressive strength. The results show that both fly ash and bottom ash can be utilized as source materials for the production of geopolymers. The properties of the geopolymers are dependent on source materials and the NaOH concentration. Fly ash is more reactive and produces a higher degree of geopolymerization in comparison with bottom ash. The moderate NaOH concentration of 10 M is found to be suitable and gives fly ash and bottom ash geopolymer mortars with compressive strengths of 35 and 18 MPa.

  10. Density and morphology studies on bottom ash and fly ash geopolymer brick

    Science.gov (United States)

    Deraman, Laila Mardiah; Abdullah, Mohd Mustafa Al Bakri; Ming, Liew Yun; Hussin, Kamarudin

    2017-04-01

    This paper studies the finding density and morphology analysis of geopolymer bricks using bottom ash and fly ash as a geopolymer raw material. The study has been conducted to produce bottom ash and fly ash geopolymer bricks by varying the ratio of fly ash/bottom ash, ratio solid/liquid and ratio sodium silicate (Na2SiO3)/ sodium hydroxide (NaOH) in the mix design. The compressive strength range between 3.8-4.5 Mpa was obtained in theprevious study [9]. The density and morphology analysis are done based on the optimum ratio selected from bottom ash/fly ash, solid/liquidand Na2SiO3/NaOH which is 1:2, 2.0 and 4.0 respectively for non-loading application brick. The morphology analysis of the bricks is closely related to the density recorded. The highest density shows the highest value of compressive strength and a denser microstructure of morphology.

  11. Hierarchical zeolites from class F coal fly ash

    Science.gov (United States)

    Chitta, Pallavi

    Fly ash, a coal combustion byproduct is classified as types class C and class F. Class C fly ash is traditionally recycled for concrete applications and Class F fly ash often disposed in landfills. Class F poses an environmental hazard due to disposal and leaching of heavy metals into ground water and is important to be recycled in order to mitigate the environmental challenges. A major recycling option is to reuse the fly ash as a low-cost raw material for the production of crystalline zeolites, which serve as catalysts, detergents and adsorbents in the chemical industry. Most of the prior literature of fly ash conversion to zeolites does not focus on creating high zeolite surface area zeolites specifically with hierarchical pore structure, which are very important properties in developing a heterogeneous catalyst for catalysis applications. This research work aids in the development of an economical process for the synthesis of high surface area hierarchical zeolites from class F coal fly ash. In this work, synthesis of zeolites from fly ash using classic hydrothermal treatment approach and fusion pretreatment approach were examined. The fusion pretreatment method led to higher extent of dissolution of silica from quartz and mullite phases, which in turn led to higher surface area and pore size of the zeolite. A qualitative kinetic model developed here attributes the difference in silica content to Si/Al ratio of the beginning fraction of fly ash. At near ambient crystallization temperatures and longer crystallization times, the zeolite formed is a hierarchical faujasite with high surface area of at least 360 m2/g. This work enables the large scale recycling of class F coal fly ash to produce zeolites and mitigate environmental concerns. Design of experiments was used to predict surface area and pore sizes of zeolites - thus obviating the need for intense experimentation. The hierarchical zeolite catalyst supports tested for CO2 conversion, yielded hydrocarbons

  12. The utilisation of fly ash in CO2 mineral carbonation

    Directory of Open Access Journals (Sweden)

    Jaschik Jolanta

    2016-03-01

    Full Text Available The fixation of CO2 in the form of inorganic carbonates, also known as mineral carbonation, is an interesting option for the removal of carbon dioxide from various gas streams. The captured CO2 is reacted with metal-oxide bearing materials, usually naturally occurring minerals. The alkaline industrial waste, such as fly ash can also be considered as a source of calcium or magnesium. In the present study the solubility of fly ash from conventional pulverised hard coal fired boilers, with and without desulphurisation products, and fly ash from lignite fluidised bed combustion, generated by Polish power stations was analysed. The principal objective was to assess the potential of fly ash used as a reactant in the process of mineral carbonation. Experiments were done in a 1 dm3 reactor equipped with a heating jacket and a stirrer. The rate of dissolution in water and in acid solutions was measured at various temperatures (20 - 80ºC, waste-to-solvent ratios (1:100 - 1:4 and stirrer speeds (300 - 1100 min-1. Results clearly show that fluidised lignite fly ash has the highest potential for carbonation due to its high content of free CaO and fast kinetics of dissolution, and can be employed in mineral carbonation of CO2.

  13. Evaluation and Treatment of Coal Fly Ash for Adsorption Application

    Directory of Open Access Journals (Sweden)

    Samson Oluwaseyi BADA

    Full Text Available Many researchers had investigated fly ash as an adsorbent for the uptake of organic compounds from petrochemical waste effluents. The availability, inexpensive and its adsorption characteristic had made it an alternative media for the removal of organic compounds from aqueous solution. The physical property of South African Coal Fly Ash (SACFA was investigated to determine its adsorption capability and how it can be improved. Chemical treatment using 1M HCl solution in the ratio of (1 g fly ash to (2 ml of acid was used and compared with untreated heat-treated samples. The chemically treated fly ash has a higher specific surface area of 5.4116 m2/g than the heat-treated fly ash with 2.9969 m2/g. More attention had to be given to the utilization of SACFA for the treatment of wastewaters containing organic compounds through the application of Liquid phase adsorption process that was considered as an inexpensive and environmentally friendly technology.

  14. Utilization of Yatagan Power Plant Fly Ash in Production of Building Bricks

    Science.gov (United States)

    Önel, Öznur; Tanriverdi, Mehmet; Cicek, Tayfun

    2017-12-01

    Fly ash is a by-product of coal combustion, which accumulates in large quantities near the coal-fired power plants as waste material. Fly ash causes serious operational and environmental problems. In this study, fly ash from Yatağgan thermal power plant was used to produce light-weight building bricks. The study aimed to reduce the problems related to fly ash by creating a new area for their use. The optimum process parameters were determined for the production of real size bricks to be used in construction industry. The commercial size bricks (200 × 200 × 90-110 mm) were manufactured using pilot size equipment. Mechanical properties, thermal conductivity coefficients, freezing and thawing strengths, water absorption rates, and unit volume weights of the bricks were determined. Etringite (Ca6Al2 (SO4)3 (OH)12 25(H2O)) and Calcium Silicate Hydrate (2CaO.SiO2.4H2O) were identified as the binding phases in the real size brick samples after 2 days of pre-curing and 28 days curing at 50° C and 95% relative moisture. The water absorption rate was found to be 27.7 % in terms of mass. The mechanical and bending strength of the brick samples with unit volume weight of 1.29 g.cm-3 were determined as 6.75 MPa and 1,56 MPa respectively. The thermal conductivity of the fly ash bricks was measured in average as 0,340 W m-1 K-1. The fly ash sample produced was subjected to toxic leaching tests (Toxic Property Leaching Procedure (EPA-TCLP 1311), Single-step BATCH Test and Method-A Disintegration Procedure (ASTM)). The results of these tests suggested that the materials could be classified as non-hazardous wastes / materials.

  15. Stability and leaching of cobalt smelter fly ash

    DEFF Research Database (Denmark)

    Vítková, Martina; Hyks, Jiri; Ettler, Vojtěch

    2013-01-01

    The leaching behaviour of fly ash from a Co smelter situated in the Zambian Copperbelt was studied as a function of pH (5–12) using the pH-static leaching test (CEN/TS 14997). Various experimental time intervals (48h and 168h) were evaluated. The leaching results were combined with the ORCHESTRA...... elements, the released concentrations were very similar after 48h and 168h, indicating near-equilibrium conditions in the system. Calcite, clinopyroxenes, quartz and amorphous phases predominated in the fly ash. Various metallic sulfides, alloys and the presence of Cu, Co and Zn in silicates and glass were...... and Cu. However, there is a high risk of Co, Cu, Pb and Zn mobility in the acidic soils around the smelter facility. Therefore, potential local options for “stabilisation” of the fly ash were evaluated on the basis of the modelling results using the PHREEQC code....

  16. Mercury capture by selected Bulgarian fly ashes: Influence of coal rank and fly ash carbon pore structure on capture efficiency

    Science.gov (United States)

    Kostova, I.J.; Hower, J.C.; Mastalerz, Maria; Vassilev, S.V.

    2011-01-01

    Mercury capture by fly ash C was investigated at five lignite- and subbituminous-coal-burning Bulgarian power plants (Republika, Bobov Dol, Maritza East 2, Maritza East 3, and Sliven). Although the C content of the ashes is low, never exceeding 1.6%, the Hg capture on a unit C basis demonstrates that the low-rank-coal-derived fly ash carbons are more efficient in capturing Hg than fly ash carbons from bituminous-fired power plants. While some low-C and low-Hg fly ashes do not reveal any trends of Hg versus C, the 2nd and, in particular, the 3rd electrostatic precipitator (ESP) rows at the Republika power plant do have sufficient fly ash C range and experience flue gas sufficiently cool to capture measurable amounts of Hg. The Republika 3rd ESP row exhibits an increase in Hg with increasing C, as observed in other power plants, for example, in Kentucky power plants burning Appalachian-sourced bituminous coals. Mercury/C decreases with an increase in fly ash C, suggesting that some of the C is isolated from the flue gas stream and does not contribute to Hg capture. Mercury capture increases with an increase in Brunauer-Emmett-Teller (BET) surface area and micropore surface area. The differences in Hg capture between the Bulgarian plants burning low-rank coal and high volatile bituminous-fed Kentucky power plants suggests that the variations in C forms resulting from the combustion of the different ranks also influence the efficiency of Hg capture. ?? 2010 Elsevier Ltd.

  17. Restoration of fly ash dump through biological interventions.

    Science.gov (United States)

    Juwarkar, Asha A; Jambhulkar, Hemlata P

    2008-04-01

    Field experiment on 10 ha area of fly ash dump was conducted to restore and revegetate it using biological interventions, which involves use of organic amendment, selection of suitable plant species along with specialized nitrogen fixing strains of biofertilizer. The results of the study indicated that amendment with farm yard manure at 50 t/ha improved the physical properties of fly ash such as maximum water holding capacity from 40.0 to 62.42% while porosity improved from 56.78 to 58.45%. The nitrogen content was increased by 4.5 times due to addition of nitrogen fixing strains of Bradyrhizobium and Azotobacter species, while phosphate content was increased by 10.0 times due to addition of VAM, which helps in phosphate immobilization. Due to biofertilizer inoculation different microbial groups such as Rhizobium, Azotobacter and VAM spores, which were practically absent in fly ash improved to 7.1 x 10(7), 9.2 x 10(7) CFU/g and 35 VAM spores/10 g of fly ash, respectively. Inoculation of biofertilizer and application of FYM helped in reducing the toxicity of heavy metals such as cadmium, copper, nickel and lead which were reduced by 25, 46, 48 and 47%, respectively, due to the increased organic matter content in the fly ash which complexes the heavy metals thereby decreasing the toxicity of metals. Amendment of fly ash with FYM and biofertilizer helped in profuse root development showing 15 times higher growth in Dendrocalamus strictus plant as compared to the control. Thus amendment and biofertilizer application provided better supportive material for anchorage and growth of the plant.

  18. Temporal and spatial variations in fly ash quality

    Energy Technology Data Exchange (ETDEWEB)

    Hower, J.C.; Trimble, A.S. [Center for Applied Energy Research, University of Kentucky, 2540 Research Park Drive, 40511 Lexington, KY (United States); Eble, C.F. [Kentucky Geological Survey, Mining and Mineral Resources Building, University of Kentucky, 40506 Lexington, KY (United States)

    2001-10-05

    Fly ash quality, both as the amount of petrographically distinguishable carbons and in chemistry, varies in both time and space. Temporal variations are a function of a number of variables. Variables can include variations in the coal blend organic petrography, mineralogy, and chemistry; variations in the pulverization of the coal, both as a function of the coal's Hardgrove grindability index and as a function of the maintenance and settings of the pulverizers; and variations in the operating conditions of the boiler, including changes in the pollution control system. Spatial variation, as an instantaneous measure of fly ash characteristics, should not involve changes in the first two sets of variables listed above. Spatial variations are a function of the gas flow within the boiler and ducts, certain flow conditions leading to a tendency for segregation of the less-dense carbons in one portion of the gas stream.Caution must be applied in sampling fly ash. Samples from a single bin, or series of bins, may not be representative of the whole fly ash, providing a biased view of the nature of the material. Further, it is generally not possible to be certain about variation until the analysis of the ash is complete.

  19. Temporal and spatial variations in fly ash quality

    Science.gov (United States)

    Hower, J.C.; Trimble, A.S.; Eble, C.F.

    2001-01-01

    Fly ash quality, both as the amount of petrographically distinguishable carbons and in chemistry, varies in both time and space. Temporal variations are a function of a number of variables. Variables can include variations in the coal blend organic petrography, mineralogy, and chemistry; variations in the pulverization of the coal, both as a function of the coal's Hardgrove grindability index and as a function of the maintenance and settings of the pulverizers; and variations in the operating conditions of the boiler, including changes in the pollution control system. Spatial variation, as an instantaneous measure of fly ash characteristics, should not involve changes in the first two sets of variables listed above. Spatial variations are a function of the gas flow within the boiler and ducts, certain flow conditions leading to a tendency for segregation of the less-dense carbons in one portion of the gas stream. Caution must be applied in sampling fly ash. Samples from a single bin, or series of bins, m ay not be representative of the whole fly ash, providing a biased view of the nature of the material. Further, it is generally not possible to be certain about variation until the analysis of the ash is complete. ?? 2001 Elsevier Science B.V. All rights reserved.

  20. Alkali-aggregate reaction in activated fly ash systems

    Energy Technology Data Exchange (ETDEWEB)

    I. Garcia-Lodeiro; A. Palomo; A. Fernandez-Jimenez [Eduardo Torroja Institute (CSIC), Madrid (Spain)

    2007-02-15

    Certain aspects of the durability of a new cementitious material, alkali activated fly ash, are addressed in this article; specifically, a series of findings relating to the alkali-silica reaction are reported. The approach adopted in the study was to compare the new cementitious systems to analogous Portland cement mortars using aggregates of differing reactivity and a procedure based on the test described in ASTM standard C 1260. The results of SEM/EDX and XRD analysis of the materials showed that activated fly ash mortars performed better than the Portland cement equivalents.

  1. BRICKS WITH TOTAL REPLACEMENT OF CLAY BY FLY ASH MIXED WITH DIFFERENT MATERIALS

    OpenAIRE

    J.N Akhtar; Alam, J; M.N Akhtar

    2011-01-01

    Fly ash is a powdery substance obtained from the dust collectors in the Thermal power plants that use coal as fuel. From the cement point of view the mineralogy of Fly ash is important as it contains 80% - 90% of glass. The impurities in coal-mostly clays, shale’s, limestone & dolomite; they cannot be burned so they turn up as ash. The Fly ash of class C category was used as a raw material to total replacement of clay for making Fly ash bricks. In present study the effect of Fly ash with high...

  2. Phenolic acids as bioindicators of fly ash deposit revegetation

    Energy Technology Data Exchange (ETDEWEB)

    L. Djurdjevic; M. Mitrovic; P. Pavlovic; G. Gajic; O. Kostic [Institute for Biological Research ' Sinisa Stankovic,' Belgrade (Serbia and Montenegro). Department of Ecology

    2006-05-15

    The floristic composition, the abundance, and the cover of pioneer plant species of spontaneously formed plant communities and the content of total phenolics and phenolic acids, as humus constituents, of an ash deposit after 7 years of recultivation were studied. The restoration of both the soil and the vegetation on the ash deposits of the 'Nikola Tesla-A' thermoelectric power plant in Obrenovac (Serbia) is an extremely slow process. Unfavorable physical and chemical characteristics, the toxicity of fly ash, and extreme microclimatic conditions prevented the development of compact plant cover. The abundance and cover of plants increased from the central part of the deposit towards its edges. Festuca rubra L., Crepis setosa Hall., Erigeron canadensis L., Cirsium arvense (L.) Scop., Calamagrostis epigeios (L.) Roth., and Tamarix gallica L. were the most abundant species, thus giving the highest cover. Humus generated during the decomposition process of plant remains represents a completely new product absent in the ash as the starting material. The amount of total phenolics and phenolic acids in fly ash increased from the center of the deposit towards its edges in correlation with the increase in plant abundance and cover. The presence of phenolic acids indicates the ongoing process of humus formation in the ash, in which the most abundant pioneer plants of spontaneously formed plant communities play the main role. Phenolic compounds can serve as reliable bioindicators in an assessment of the success of the recultivation process of thermoelectric power plants' ash deposits.

  3. Study on Strength Behavior of Organic Soil Stabilized with Fly Ash

    Directory of Open Access Journals (Sweden)

    Bayshakhi Deb Nath

    2017-01-01

    Full Text Available The aim of this study is to investigate the effect of fly ash on the consistency, compactness, acidic properties, and strength of organic soil. The presence of organic content in the soil has detrimental impacts on the physical and strength behavior of soil. To investigate the effectiveness of fly ash in the stabilization of organic soil, two types of fly ashes (Type I and Type II at different percentages were used. It is found that fly ash significantly reduces the plasticity index of the organic soil, whereas the liquid and plastic limits increase. The dry density of the fly ash-soil mixture increases significantly, while the water requirement reduces due to the addition of fly ash. The increase of dry density compromises higher strength. The increase of qu with the increase of fly ash content is mainly due to the pozzolanic reaction of fly ash, although the reduction in water content results from the addition of dry fly ash solid. Moreover, Type I fly ash contributes a higher value of qu compared to Type II fly ash. This is attributed to the characteristics of fly ash including CaO and CaO/SiO2 ratio.

  4. Effect of fly ash on sorption behavior of metribuzin in agricultural soils.

    Science.gov (United States)

    Singh, Neera; Raunaq; Singh, Shashi B

    2012-01-01

    This investigation was undertaken to determine the effect of two different fly ashes [Kota and Inderprastha (IP)] amendment on the sorption behavior of metribuzin in three Indian soil types. The IP fly ash was very effective in increasing the metribuzin sorption in the soils. The sorption with IP amendment was increased by 15-92%, whereas with the Kota fly ash an increase in sorption by 13-38% was noted. The adsorption isotherms fitted very well to the Freundlich adsorption equation and, in general, slope (1/n) values less then unity were observed. Although both the fly ashes significantly decreased metribuzin desorption, the IP fly ash was comparatively more effective in retaining metribuzin in the soils. Metribuzin sorption in the IP fly ash-amended soils showed strong correlation with the fly ash content and compared to K(f)/K(d) values, K(FA) values (sorption normalized to fly ash content) showed less variation. Metribuzin sorption-desorption did not correlate to the organic carbon content of the soil-fly ash mixture. The study demonstrates that all coal fly ashes may not be effective in enhancing the sorption of metribuzin in soils to the same extent. However, among the fly ashes used in this study, the IP fly ash was observed to be significantly effective in enhancing the sorption of metribuzin in soils. This may play an important role in reducing the run off and leaching losses of the herbicide by retaining it in the soil.

  5. Electrodialytic removal of cadmium from biomass combustion fly ashes in larger scale

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Ottosen, Lisbeth M.; Simonsen, Peter

    The paper presents results from the project: "Electrochemical removal of cadmium from biomass combustion fly ashes in larger scale and evaluation of the possibilities of reusing the treated ashes in concrete".......The paper presents results from the project: "Electrochemical removal of cadmium from biomass combustion fly ashes in larger scale and evaluation of the possibilities of reusing the treated ashes in concrete"....

  6. Development of Fly Ash Derived Sorbents to Capture CO2 from Flue Gas of Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    M. Mercedes Maroto-Valer; John M. Andresen; Yinzhi Zhang; Zhe Lu

    2003-12-31

    This research program focused on the development of fly ash derived sorbents to capture CO{sub 2} from power plant flue gas emissions. The fly ash derived sorbents developed represent an affordable alternative to existing methods using specialized activated carbons and molecular sieves, that tend to be very expensive and hinder the viability of the CO{sub 2} sorption process due to economic constraints. Under Task 1 'Procurement and characterization of a suite of fly ashes', 10 fly ash samples, named FAS-1 to -10, were collected from different combustors with different feedstocks, including bituminous coal, PRB coal and biomass. These samples presented a wide range of LOI value from 0.66-84.0%, and different burn-off profiles. The samples also spanned a wide range of total specific surface area and pore volume. These variations reflect the difference in the feedstock, types of combustors, collection hopper, and the beneficiation technologies the different fly ashes underwent. Under Task 2 'Preparation of fly ash derived sorbents', the fly ash samples were activated by steam. Nitrogen adsorption isotherms were used to characterize the resultant activated samples. The cost-saving one-step activation process applied was successfully used to increase the surface area and pore volume of all the fly ash samples. The activated samples present very different surface areas and pore volumes due to the range in physical and chemical properties of their precursors. Furthermore, one activated fly ash sample, FAS-4, was loaded with amine-containing chemicals (MEA, DEA, AMP, and MDEA). The impregnation significantly decreased the surface area and pore volume of the parent activated fly ash sample. Under Task 3 'Capture of CO{sub 2} by fly ash derived sorbents', sample FAS-10 and its deashed counterpart before and after impregnation of chemical PEI were used for the CO{sub 2} adsorption at different temperatures. The sample FAS-10 exhibited a CO{sub 2

  7. Characterization of ash cenospheres in fly ash from Australian power stations

    Energy Technology Data Exchange (ETDEWEB)

    Ling-ngee Ngu; Hongwei Wu; Dong-ke Zhang [Curtin University of Technology, Perth, WA (Australia). Centre for Fuels and Energy and Department of Chemical Engineering

    2007-12-15

    Ash cenospheres in fly ashes from five Australian power stations have been characterized. The experimental data show that ash cenosphere yield varies across the power stations. Ash partitioning occurred in the process of ash cenosphere formation during combustion. Contradictory to conclusions from the literature, iron does not seem to be essential to ash cenosphere formation in the cases examined in the present work. Further investigation was also undertaken on a series of size-fractioned ash cenosphere samples from Tarong power station. It is found that about 70 wt% of ash cenospheres in the bulk sample have sizes between 45 and 150 {mu}m. There are two different ash cenosphere structures, that is, single-ring structure and network structure. The percentage of ash cenospheres of a network structure increases with increasing ash cenosphere size. Small ash cenospheres (in the size fractions {lt}150 {mu}m) have a high SiO{sub 2}/Al{sub 2}O{sub 3} ratio, and the majority of the ash cenospheres are spherical and of a single-ring structure. Large ash cenosphere particles (in the size fractions of 150-250 {mu}m and {gt}250 {mu}m) have a low SiO{sub 2}/Al{sub 2}O{sub 3} ratio, and a high proportion of the ash cenospheres are nonspherical and of a network structure. A novel quantitative technique has been developed to measure the diameter and wall thickness of ash cenospheres on a particle-to-particle basis. A monolayer of size-fractioned ash cenospheres was dispersed on a pellet, which was then polished carefully before being examined using a scanning electron microscope and image analysis. The ash cenosphere wall thickness broadly increases with increasing ash cenosphere size. The ratios between wall thickness and diameter of ash cenospheres are limited between an upper bound of about 10.5% and a lower bound of about 2.5%, irrespective of the ash cenosphere size. 52 refs., 9 figs., 4 tabs.

  8. Aluminum recovery from coal fly ash by high temperature chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Wijatno, Hendra [Iowa State Univ., Ames, IA (United States)

    1977-10-01

    A study of aluminum recovery from power plant fly ash by high temperature chlorination was undertaken to demonstrate that fly ash could be a potential source of aluminum, iron and possibly silicon. Magnetic separation of the iron oxide served as a first step to alleviate the iron contamination problem. However, the agglomeration of some iron oxide with alumina and silica made it difficult to completely separate the iron from the fly ash. Further iron separation was achieved by chlorinating the nonmagnetic ash fraction at 550°C for 30 minutes. This reduced the iron oxide content to less than 4 percent by weight. Chlorine flow rates affected the reaction rate much more drastically than temperatures. This suggested that diffusion was the major rate-controlling step. Besides Fe2O3, Al2O3 and SiO2, other oxides such as CaO, K2O, Na2O and MgO might have complicated the alumina recovery by forming individual chlorides or complexes. Investigating methods for separating more Fe2O3, and possibly CaO, K2O, Na2O and MgO from the nonmagnetic ash fraction before chlorinating it is highly recommended.

  9. Water Diffusion Modelling of CFB Fly Ash Thermoset Composite

    Directory of Open Access Journals (Sweden)

    Villa Ralph P.

    2016-01-01

    Full Text Available The shift in coal-fired power plants from pulverized coal (PC boiler technology into the greener circulating fluidized bed (CFB boiler technology resulted into a major deviation in the properties of the waste fly ash generated making it less suitable for its previous application as additives for construction materials. A new market for CFB fly ash had to be found for it not to end up as a zero value by-product. Using CFB fly ash as filler for thermoset composites is a new and remarkable application. Only a few studies, however, have been done to characterize the properties of this new material. Further experimentation and analysis may be costly and time-consuming since common procedures are material destructive. A computer-aided modeling of the composite’s water sorption behavior was done. The effect of particle loading, size and shape were considered. These properties were varied and the resulting overall diffusivities were compared to previous experimental studies. The comparison of the model and experimental diffusivity values showed satisfactory results. This model may then provide a cheaper and more time-efficient method for the characterization of the water sorption properties of CFB fly ash thermoset composites. In the future, this may lead to further studies on its application as a green material.

  10. Studies of the Constitution of Fly Ash Using Selective Dissolution.

    Science.gov (United States)

    1983-05-01

    crystalline phase based on its single strongest XRD peak. Fly ash collected at plants where anthracite or bituminous coal is burned tends to contain small...may be graphite . (e) One or two short crystals of prismatic habit were found in this residue. They had parallel extinction, high birefringency, and

  11. Separation of ultrafine particles from class F fly ashes

    Directory of Open Access Journals (Sweden)

    Acar Ilker

    2016-01-01

    Full Text Available In this study, ultrafine particles were recovered from Çatalağzı (CFA and Sugözü (SFA thermal power plant fly ashes using a specific hydraulic classification technology. Since fly ashes have a high tendency to be flocculated in water, settling experiments were first designed to determine the more effective dispersant and the optimum dosage. Two different types of the superplasticizers (SP polymers based on sulphonate (NSF, Disal and carboxylate (Glenium 7500 were used as the dispersing agents in these settling experiments. Hydraulic classification experiments were then conducted to separate ultrafine fractions from the fly ash samples on the basis of the settling experiments. According to the settling experiments, better results were achieved with the use of Disal for both CFA and SFA. The classification experiments showed that the overflow products with average particle sizes of 5.2 μm for CFA and 4.4 μm for SFA were separated from the respective as-received samples with acceptable yields and high enough recoveries of -5 μm (ultrafine particles. Overall results pointed out that the hydraulic classification technology used provided promising results in the ultrafine particle separations from the fly ash samples.

  12. The statistical analysis of results of solidification of fly ash

    Directory of Open Access Journals (Sweden)

    Pliešovská Natália

    1996-09-01

    Full Text Available The analysis shows, that there is no statical dependence between contents of heavy metals in fly ash on one side, and contents in leaching characteristics of heavy metals from the stabilized waste and from the waste itself on the other side.

  13. Compressive strength and hydrolytic stability of fly ash based geopolymers

    Directory of Open Access Journals (Sweden)

    Nikolić Irena

    2013-01-01

    Full Text Available The process of geopolymerization involves the reaction of solid aluminosilicate materials with highly alkaline silicate solution yielding an aluminosilicate inorganic polymer named geopolymer, which may be successfully applied in civil engineering as a replacement for cement. In this paper we have investigated the influence of synthesis parameters: solid to liquid ratio, NaOH concentration and the ratio of Na2SiO3/NaOH, on the mechanical properties and hydrolytic stability of fly ash based geopolymers in distilled water, sea water and simulated acid rain. The highest value of compressive strength was obtained using 10 mol dm-3 NaOH and at the Na2SiO3/NaOH ratio of 1.5. Moreover, the results have shown that mechanical properties of fly ash based geopolymers are in correlation with their hydrolytic stability. Factors that increase the compressive strength also increase the hydrolytic stability of fly ash based geopolymers. The best hydrolytic stability of fly ash based geopolymers was shown in sea water while the lowest stability was recorded in simulated acid rain. [Projekat Ministarstva nauke Republike Srbije, br. 172054 i Nanotechnology and Functional Materials Center, funded by the European FP7 project No. 245916

  14. Upshot of Elevated Temperature on Performance Facet of Fly Ash ...

    African Journals Online (AJOL)

    This study investigates the effects of elevated temperature variation on the compressive strength of Fly Ash/Ordinary Portland Cement (OPC) Laterized concrete (LATCON). Cube specimens were cast, cured in water at ambient laboratory temperature and subjected to different temperature regimes before testing.

  15. Integrated acid mine drainage management using fly ash

    CSIR Research Space (South Africa)

    Vadapalli, VRK

    2012-01-01

    Full Text Available Fly Ash (FA) from a power station in South Africa was investigated to neutralise and remove contaminants from Acid Mine Drainage (AMD). After this primary treatment the insoluble FA residue namely solid residue (SR) was investigated as a suitable...

  16. Leaching studies of inorganic and organic compounds from fly ash

    NARCIS (Netherlands)

    Ariese, F.; Swart, K.; Morabito, R.; Brunori, C.; Balzamo, S.; Slobodnik, J.; Korenkova, E.; Janos, P.; Wildnerova, M.; Hlavay, J.; Polyak, K.; Fodor, P.; Muntau, H.

    2002-01-01

    Fly ash is produced in massive quantities by fossil fuel based power plants and waste incinerators, and contains high levels of potentially toxic chemicals. Various leaching tests exist to determine the available fractions, but the outcome is strongly dependent on the experimental conditions, and

  17. Possible Use of Fly-Ash in Road Building Industry

    Directory of Open Access Journals (Sweden)

    Krlièková Edita

    1998-09-01

    Full Text Available Problems concerning the use of waste from industrial and other productions have been dealt with at out workplace for several years. The reason is not only a lack of natural material resources but mainly economical and environmental aspects. Current research at our workplace has been aimed at finding solutions to problems concerning the use of fly-ash in road building.

  18. Native Chromium Resistant Staphylococci Species from a Fly Ash ...

    African Journals Online (AJOL)

    Sixty-six chromium-resistant Staphylococci species belonging to S. epidermidis, S. aureus, S. saprophyticus and S. arlettae were previously isolated from a chromium-polluted Fly ash (FA) dumping site in South Africa. However the genetic mechanisms responsible for chromium resistance were not known. Polymerase chain ...

  19. Process parameter optimization for fly ash brick by Taguchi method

    Directory of Open Access Journals (Sweden)

    Prabir Kumar Chaulia

    2008-06-01

    Full Text Available This paper presents the results of an experimental investigation carried out to optimize the mix proportions of the fly ash brick by Taguchi method of parameter design. The experiments have been designed using an L9 orthogonal array with four factors and three levels each. Small quantity of cement has been mixed as binding materials. Both cement and the fly ash used are indicated as binding material and water binder ratio has been considered as one of the control factors. So the effects of water/binder ratio, fly ash, coarse sand, and stone dust on the performance characteristic are analyzed using signal-to-noise ratios and mean response data. According to the results, water/binder ratio and stone dust play the significant role on the compressive strength of the brick. Furthermore, the estimated optimum values of the process parameters are corresponding to water/binder ratio of 0.4, fly ash of 39%, coarse sand of 24%, and stone dust of 30%. The mean value of optimal strength is predicted as 166.22 kg.cm-2 with a tolerance of ± 10.97 kg.cm-2. Confirmatory experimental result obtained for the optimum conditions is 160.17 kg.cm-2.

  20. Greenlandic Waste Incineration Fly And Bottom Ash As Secondary Resource In Mortar

    DEFF Research Database (Denmark)

    Kirkelund, Gunvor Marie; Ottosen, Lisbeth M.; Jensen, Pernille Erland

    2016-01-01

    , the effects on compressive strengths of mortars by substituting cement or sand by raw, washed and electrodialytically treated fly ash or bottom ash were investigated. Parts of the experimental fly ash had been pre-treated by either washing with distilled water or electro-dialytically treated to remove salts...... and by the latter method, also heavy metals. Mortar samples were cast where cement (5%–20%) or sand (5%–10%) was replaced with fly ash or bottom ash, together with references without replacements. The compressive strengths were measured after 7, 14, 28 and 42 days. Replacing cement by fly ash resulted in lower...... and cement with fly ash. Based on the compressive strength tests, it is found that using Greenlandic incineration ashes in mortar as 5% cement replacement could consume all ash instead of disposals, and could thus turn the ashes into a local resource and simultaneously reduce the import of cement....

  1. Effect of additional materials on the properties of glass-ceramic produced from incinerator fly ashes.

    Science.gov (United States)

    Cheng, T W

    2004-07-01

    There are 21 Metro-waste incinerators in Taiwan under construction and are expected to be finished at year 2003. It is estimated that these incinerators will produce about two million tons of incinerator ash. In order to reduce the volume and eliminate contamination problems, high temperature molten technology studies have been conducted. The purpose of this research was that of trying to control the chemical composition of the glass-ceramic produced from incinerator fly ash, in order to improve the characteristics of the glass-ceramic. The experimental results showed that the additional materials, Mg(OH)2 and waste glass cullet, can change glass-ceramic phases from gehlenite to augite, pigeonite, and diopside. The physical, mechanical and chemical resistance properties of the glass-ceramic also showed much better characteristics than prepared glass-ceramic using incinerator fly ash alone.

  2. Recovery of gallium and vanadium from gasification fly ash.

    Science.gov (United States)

    Font, Oriol; Querol, Xavier; Juan, Roberto; Casado, Raquel; Ruiz, Carmen R; López-Soler, Angel; Coca, Pilar; García Peña, Francisco

    2007-01-31

    The Puertollano Integrated Coal Gasification Combined Cycle (IGCC) Power Plant (Spain) fly ash is characterized by a relatively high content of Ga and V, which occurs mainly as Ga2O3 and as Ga3+ and V3+ substituting for Al3+ in the Al-Si fly ash glass matrix. Investigations focused on evaluating the potential recovery of Ga and V from these fly ashes. Several NaOH based extraction tests were performed on the IGCC fly ash, at different temperatures, NaOH/fly ash (NaOH/FA) ratios, NaOH concentrations and extraction times. The optimal Ga extraction conditions was determined as 25 degrees C, NaOH 0.7-1 M, NaOH/FA ratio of 5 L/kg and 6 h, attaining Ga extraction yields of 60-86%, equivalent to 197-275 mg of Ga/kg of fly ash. Re-circulation of leachates increased initial Ga concentrations (25-38 mg/L) to 188-215 mg/L, while reducing both content of impurities and NaOH consumption. Carbonation of concentrated Ga leachate demonstrated that 99% of the bulk Ga content in the leachate precipitates at pH 7.4. At pH 10.5 significant proportions of impurities, mainly Al (91%), co-precipitate while >98% of the bulk Ga remains in solution. A second carbonation of the remaining solution (at pH 7.5) recovers the 98.8% of the bulk Ga. Re-dissolution (at pH 0) of the precipitate increases Ga purity from 7 to 30%, this being a suitable Ga end product for further purification by electrolysis. This method produces higher recovery efficiency than currently applied for Ga on an industrial scale. In contrast, low V extraction yields (<64%) were obtained even when using extreme alkaline extraction conditions, which given the current marked price of this element, limits considerably the feasibility of V recovery from IGCC fly ash.

  3. Elastic properties of fly ash-stabilized mixes

    Directory of Open Access Journals (Sweden)

    Sanja Dimter

    2015-12-01

    Full Text Available Stabilized mixes are used in the construction of bearing layers in asphalt and concrete pavement structures. Two nondestructive methods: resonant frequency method and ultrasonic pulse velocity method, were used for estimation of elastic properties of fly ash–stabilized mixes. Stabilized mixes were designed containing sand from the river Drava and binder composed of different share of cement and fly ash. The aim of the research was to analyze the relationship between the dynamic modulus of elasticity determined by different nondestructive methods. Data showed that average value of elasticity modulus obtained by the ultrasound velocity method is lower than the values of elasticity modulus obtained by resonant frequency method. For further analysis and enhanced discussion of elastic properties of fly ash stabilized mixes, see Dimter et al. [1].

  4. Glass-ceramic from mixtures of bottom ash and fly ash.

    Science.gov (United States)

    Vu, Dinh Hieu; Wang, Kuen-Sheng; Chen, Jung-Hsing; Nam, Bui Xuan; Bac, Bui Hoang

    2012-12-01

    Along with the gradually increasing yield of the residues, appropriate management and treatment of the residues have become an urgent environmental protection problem. This work investigated the preparation of a glass-ceramic from a mixture of bottom ash and fly ash by petrurgic method. The nucleation and crystallization kinetics of the new glass-ceramic can be obtained by melting the mixture of 80% bottom ash and 20% fly ash at 950 °C, which was then cooled in the furnace for 1h. Major minerals forming in the glass-ceramics mainly are gehlenite (Ca(2)Al(2)SiO(7)) & akermanite (Ca(2)MgSiO(7)) and wollastonite (CaSiO(3)). In addition, regarding chemical/mechanical properties, the chemical resistance showing durability, and the leaching concentration of heavy metals confirmed the possibility of engineering and construction applications of the most superior glass-ceramic product. Finally, petrurgic method of a mixture of bottom ash and fly ash at 950 °C represents a simple, inexpensive, and energy saving method compared with the conventional heat treatment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. AIR ENTRAINING, AIR VOID SYSTEM AND FROST DURABILITY OF FLY ASH CONCRETE

    OpenAIRE

    千歩, 修; 濱, 幸雄

    2002-01-01

    Control of air content and resistance to frost damage are essential for fly ash concrete. This paper demonstrates a possibility of controlling the air content of fly ash concrete by the basic properties of fly ash. It also elucidates the tendencies of the effects of the presence of fly ash, mixing conditions, and type of air-entraining admixture on the air content, air void system, and air loss by agitation. The frost resistance test results of fly ash concrete slightly lower than normal conc...

  6. Fly ash zeolite catalyst support for Fischer-Tropsch synthesis

    Science.gov (United States)

    Campen, Adam

    This dissertation research aimed at evaluating a fly ash zeolite (FAZ) catalyst support for use in heterogeneous catalytic processes. Gas phase Fischer-Tropsch Synthesis (FTS) over a fixed-bed of the prepared catalyst/FAZ support was identified as an appropriate process for evaluation, by comparison with commercial catalyst supports (silica, alumina, and 13X). Fly ash, obtained from the Wabash River Generating Station, was first characterized using XRD, SEM/EDS, particle size, and nitrogen sorption techniques. Then, a parametric study of a two-step alkali fusion/hydrothermal treatment process for converting fly ash to zeolite frameworks was performed by varying the alkali fusion agent, agent:flyash ratio, fusion temperature, fused ash/water solution, aging time, and crystallization time. The optimal conditions for each were determined to be NaOH, 1.4 g NaOH: 1 g fly ash, 550 °C, 200 g/L, 12 hours, and 48 hours. This robust process was applied to the fly ash to obtain a faujasitic zeolite structure with increased crystallinity (40 %) and surface area (434 m2/g). Following the modification of fly ash to FAZ, ion exchange of H+ for Na+ and cobalt incipient wetness impregnation were used to prepare a FTS catalyst. FTS was performed on the catalysts at 250--300 °C, 300 psi, and with a syngas ratio H2:CO = 2. The HFAZ catalyst support loaded with 11 wt% cobalt resulted in a 75 % carbon selectivity for C5 -- C18 hydrocarbons, while methane and carbon dioxide were limited to 13 and 1 %, respectively. Catalyst characterization was performed by XRD, N2 sorption, TPR, and oxygen pulse titration to provide insight to the behavior of each catalyst. Overall, the HFAZ compared well with silica and 13X supports, and far exceeded the performance of the alumina support under the tested conditions. The successful completion of this research could add value to an underutilized waste product of coal combustion, in the form of catalyst supports in heterogeneous catalytic processes.

  7. Phenolic acids as bioindicators of fly ash deposit revegetation.

    Science.gov (United States)

    Djurdjević, L; Mitrović, M; Pavlović, P; Gajić, G; Kostić, O

    2006-05-01

    The floristic composition, the abundance, and the cover of pioneer plant species of spontaneously formed plant communities and the content of total phenolics and phenolic acids, as humus constituents, of an ash deposit after 7 years of recultivation were studied. The restoration of both the soil and the vegetation on the ash deposits of the "Nikola Tesla-A" thermoelectric power plant in Obrenovac (Serbia) is an extremely slow process. Unfavorable physical and chemical characteristics, the toxicity of fly ash, and extreme microclimatic conditions prevented the development of compact plant cover. The abundance and cover of plants increased from the central part of the deposit towards its edges (ranging from 1-80%). Festuca rubra L., Crepis setosa Hall., Erigeron canadensis L., Cirsium arvense (L.) Scop., Calamagrostis epigeios (L.) Roth., and Tamarix gallica L. were the most abundant species, thus giving the highest cover. Humus generated during the decomposition process of plant remains represents a completely new product absent in the ash as the starting material. The amount of total phenolics and phenolic acids (38.07-185.16 microg/g of total phenolics and 4.12-27.28 microg/g of phenolic acids) in fly ash increased from the center of the deposit towards its edges in correlation with the increase in plant abundance and cover. Ash samples contained high amounts of ferulic, vanillic, and p-coumaric acid, while the content of both p-hydroxybenzoic and syringic acid was relatively low. The presence of phenolic acids indicates the ongoing process of humus formation in the ash, in which the most abundant pioneer plants of spontaneously formed plant communities play the main role. Phenolic compounds can serve as reliable bioindicators in an assessment of the success of the recultivation process of thermoelectric power plants' ash deposits.

  8. Utilization options for fly ash, bottom ash, and slag in Eastern Europe

    Energy Technology Data Exchange (ETDEWEB)

    Manz, O.E.

    1995-12-01

    Since 1967, at least six ash utilization symposiums have been held in the United States, with papers presented by several European authors on the utilization of coal by-products in Eastern Europe. There is currently over 80,000 megawatts of installed coal-fired capacity available in that region. Unfortunately, of the 117,778,000 tonnes of fly ash, bottom ash, and slag produced in Eastern Europe in 1989, only 13% was utilized. This paper outlines the research and levels and kinds of coal by-product utilization taking place in Eastern Europe since the late 1960s.

  9. Effect of ash circulation in gasification melting system on concentration and leachability of lead in melting furnace fly ash.

    Science.gov (United States)

    Okada, Takashi; Suzuki, Masaru

    2013-11-30

    In some gasification-melting plants, generated melting furnace fly ash is returned back to the melting furnace for converting the ash to slag. This study investigated the effect of such ash circulation in the gasification-melting system on the concentration and leachability of lead in the melting furnace fly ash. The ash circulation in the melting process was simulated by a thermodynamic calculation, and an elemental analysis and leaching tests were performed on a melting furnace fly ash sample collected from the gasification-melting plant with the ash circulation. It was found that by the ash circulation in the gasification-melting, lead was highly concentrated in the melting furnace fly ash to the level equal to the fly ash from the ash-melting process. The thermodynamic calculation predicted that the lead volatilization by the chlorination is promoted by the ash circulation resulting in the high lead concentration. In addition, the lead extraction from the melting furnace fly ash into a NaOH solution was also enhanced by the ash circulation, and over 90% of lead in the fly ash was extracted in 5 min when using 0.5 mol l(-1) NaOH solution with L/S ratio of 10 at 100 °C. Based on the results, a combination of the gasification-melting with the ash circulation and the NaOH leaching method is proposed for the high efficient lead recovery. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Assessment of hardened characteristics of raw fly ash blended self-compacting concrete

    Directory of Open Access Journals (Sweden)

    B. Mahalingam

    2016-09-01

    Full Text Available Fly ash is widely used as a supplementary cementitious material in concrete. Due to the implementation of new thermal power plants as a consequence of electricity demand, generation of fly ash is noticeably increased. In addition to pozzolana blended cement production, it is very imperative to use raw fly ash in concrete. Earlier research studies investigated the performance of processed fly ash in blended cement production as well as in concrete. In general, ground fly ash is used in blended cement production. A comprehensive study on the performance evaluation of raw fly ash in self-compacting concrete is not available in the existing literature. Moreover, utilization of raw fly ash in special concrete such as self-compacting concrete is essential to comprehend the performance of raw fly ash blended concrete compared to ordinary Portland concrete. Additionally, it will help to achieve maximum utilization of raw fly ash as a supplementary cementitious material rather than disposal as a waste, which eventually leads to several environmental issues. In the study, raw fly ash was collected and is directly used in development of self-compacting concrete. Two mixes were cast and hardened characteristics of blended concrete were investigated. Results from the study showed comparable performance with control concrete. Furthermore, significant reduction in chloride permeability was observed for raw fly ash blended concrete.

  11. Effect of fly ash amendment on persistence of metribuzin in soils.

    Science.gov (United States)

    Singh, Neera; Raunaq; Singh, Shashi Bala

    2013-01-01

    This study reports the effect of fly ash amendment on persistence of metribuzin in three Indian soil types. Fly ash [Inderprastha (IP) and Kota] was amended at 1, 2 and 5% levels. Metribuzin was more persistent in the flooded soils (predominantly anaerobic) than the nonflooded (aerobic) soils. Kota fly ash amendment to nonflooded soils slightly enhanced metribuzin persistence while IP fly ash reduced the herbicide persistence in nonflooded soils. In flooded soils both types of fly ash reduced metribuzin persistence, but the extent of the effect was specific to the soil and type of fly ash. A better effect was observed in low organic matter soils and IP fly ash was more effective than the Kota fly ash. The effect of fly ash amendment on metribuzin degradation in soils was more pronounced at higher dose of fly ash. No degradation of metribuzin was observed in the sterilized soils, both without and with fly ash, suggesting that degradation of metribuzin was microbial in nature. Deaminometribuzin was recovered as the only metabolite of metribuzin degradation.

  12. Mercury in coals and fly ashes from Republika and Bobov dol thermoelectric power plants

    Science.gov (United States)

    Kostova, I.; Vassileva, C.; Hower, J.; Mastalerz, Maria; Vassilev, S.; Nikolova, N.

    2011-01-01

    Feed coal and y ash samples were collected at Republika and Bobov Dol thermoelectric power plants (TPPs). The y ashes (FAs) were collected fromthree rows of the hot-side electrostatic precipitators (ESPs) array. Each sam- ple was wet-screened at 100, 200, 325 and 500 mesh. The coals and y ashes were characterized with regard to their petrological and chemical composition (including mercury content) and to their surface area properties. The calculated enrichment factor (EF) shows that the Hg concentrations in the bulk coal samples from Republika and Bobov Dol TPPs are 2.19 and 1.41, respectively. In some coal size fractions the EF can be up to 4 times higher than the Clarke value. The calculated EF for fly ashes shows that the Hg concentrations in the bulk samples studied are lower (between 0.03 and 0.32) than the Clarke value. The most enriched in Hg are the fly ashes from the 3rd ESP row of Republika TPP. The Hg distribution in bulk FAs taken from dierent rows of the electrostatic precipitators of both TPPs studied shows well established tendency of gradual increase in the Hg content from the 1st to the 2nd and 3rd ESP rows. The correlation between Hg content and surface area, mesopore and micropore volume of y ashes was also done in the present investigation.

  13. A review of the interference of carbon containing fly ash with air entrainment in concrete

    DEFF Research Database (Denmark)

    Pedersen, Kim Hougaard; Jensen, Anker Degn; Skjøth-Rasmussen, Martin Skov

    2008-01-01

    Industrial utilization of fly ash from pulverized coal combustion plays an important role in environmentally clean and cost effective power generation. Today, the primary market for fly ash utilization is as pozzolanic additive in the production of concrete. However, the residual carbon in fly ash...... on the adsorption capacity of AEAs. The type of fuel used in the combustion process influences the amount and properties of the residual carbon. Fly ash derived from bituminous coal has generally higher carbon content compared with fly ash produced from subbituminous coal or lignite, but shows a lower AEA......-treatment methods applied to improve fly ash quality are described in the review. Ozonation, thermal treatment and physical cleaning of carbon have been found to improve the fly ash performance for concrete utilization. Ultimately, recommendations for further work are outlined in the discussion....

  14. Prediction total specific pore volume of geopolymers produced from waste ashes by fuzzy logic

    Directory of Open Access Journals (Sweden)

    Ali Nazari

    2012-04-01

    Full Text Available In the present work, total specific pore volume of inorganic polymers (geopolymers made from seeded fly ash and rice husk bark ash has been predicted by fuzzy logic. Different specimens, made from a mixture of fly ash and rice husk bark ash in fine and coarse form together with alkali activator made of water glass and NaOH solution, were subjected to porosimetry tests at 7 and 28 days of curing. The curing regime was different: one set of the specimens were cured at room temperature until reaching to 7 and 28 days and the other sets were oven cured for 36 hours at the range of 40-90 °C and then cured at room temperature until 7 and 28 days. A model based on fuzzy logic for predicting the total specific pore volume of the specimens has been presented. To build the model, training and testing using experimental results from 120 specimens were conducted. The used data as the inputs of fuzzy logic models are arranged in a format of six parameters that cover the percentage of fine fly ash in the ashes mixture, the percentage of coarse fly ash in the ashes mixture, the percentage of fine rice husk bark ash in the ashes mixture, the percentage of coarse rice husk bark ash in the ashes mixture, the temperature of curing and the time of water curing. According to the input parameters, in the fuzzy logic model, the pore volume of each specimen was predicted. The training and testing results in the fuzzy logic model have shown a strong potential for predicting the total specific pore volume of the geopolymer specimens in the considered range.

  15. Electrodialytic removal of heavy metals from different fly ashes. Influence of heavy metal speciation in the ashes

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Ottosen, Lisbeth M.; Villumsen, Arne

    2003-01-01

    in lab scale, and the results were discussed in relation to the expected heavy metal speciation in the ashes. In initial leaching experiments the pH-dependent desorption characteristics of the heavy metals Cd, Pb, Zn and Cu were analogous in the two MSWI ashes, and thus it was expected...... that the speciation of these metals was similar in the two ashes. On the other hand, the leaching behaviour (and concentration) of Cr was diverse. The apparent similar speciation of Cd, Pb, Zn and Cu was only partly confirmed in the following electrodialytic remediation experiments. Significant differences in re......Electrodialytic Remediation has recently been suggested as a potential method for removal of heavy metals from fly ashes. In this work electrodialytic remediation of three different fly ashes, i.e. two municipal solid waste incinerator (MSWI) fly ashes and one wood combustion fly ash was studied...

  16. Necessity of irrigation for revegetation on reclaimed land with fly ash. Sekitanbai umetatechi ni okeru ryokuka no tameno kangai no hitsuyosei ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Sekiyama, Tetsuo; Kozakai, Kazuki; Okabe, Katsumi.

    1989-02-01

    In view of the growing importance of revegetation measures of a reclaimed land with fly ash discharged from a coal burning thermal power plant, a study was made on necessity of irrigation in case of the positive execution of the above revegetation. This is a report of the above study. The conclusions of the study are as follows: (1) Comparing the available moisture amounts in terms of volume percentage of moisture, about 36% is for fly ash and about 34% for volcanic ash soil, but when fly ash is solidified, the above figure for fly ash becomes about 90% of that for volcanic ash soil. (2) The maximum water infiltration capacity of fly ash is 1/10-1/50 of that of volcanic ash soil and the surface run-off is much. The furrow or drip irrigation system is suitable. (3) The evaporation in fly ash is almost same as that in volcanic ash soil and the designed duty of water irrigation is considered to be 7-8mm/day (in case of cultivation of tangerine and pasture). (4) In case when the above reclaimed land is covered with volcanic ash soil, an aquifer is observed at the boundary layer between the surface soil coverage and the land. Hence draining measures such as underdrainage systems are desirable from the viewpoint of the growth of plants. 8 refs., 8 figs., 2 tabs.

  17. MSWI boiler fly ashes: magnetic separation for material recovery.

    Science.gov (United States)

    De Boom, Aurore; Degrez, Marc; Hubaux, Paul; Lucion, Christian

    2011-07-01

    Nowadays, ferrous materials are usually recovered from Municipal Solid Waste Incineration (MSWI) bottom ash by magnetic separation. To our knowledge, such a physical technique has not been applied so far to other MSWI residues. This study focuses thus on the applicability of magnetic separation on boiler fly ashes (BFA). Different types of magnet are used to extract the magnetic particles. We investigate the magnetic particle composition, as well as their leaching behaviour (EN 12457-1 leaching test). The magnetic particles present higher Cr, Fe, Mn and Ni concentration than the non-magnetic (NM) fraction. Magnetic separation does not improve the leachability of the NM fraction. To approximate industrial conditions, magnetic separation is also applied to BFA mixed with water by using a pilot. BFA magnetic separation is economically evaluated. This study globally shows that it is possible to extract some magnetic particles from MSWI boiler fly ashes. However, the magnetic particles only represent from 23 to 120 g/kg of the BFA and, though they are enriched in Fe, are composed of similar elements to the raw ashes. The industrial application of magnetic separation would only be profitable if large amounts of ashes were treated (more than 15 kt/y), and the process should be ideally completed by other recovery methods or advanced treatments. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Study on Thermal Insulation Zeolite by Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Huiping Song

    2014-01-01

    Full Text Available This paper takes the coal fly ash as the material and makes zeolite with low thermal conductivity under a two-step synthesis for the purpose of thermal insulation. It studies main factors affecting zeolite such as the different concentration of NaOH, the solid-liquid ratio, the silica-alumina ratio, and the crystallization temperature. The optimal conditions were obtained that the NaOH concentration was 3 mol/L, the solid-liquid ratio was 10 : 1, the silica-alumina ratio was 2, and the crystallization temperature was 12°C. Zeolites have multiple pores and skeletal structures under SEM observation. The mean particle size was 2.78 um of concentrated distribution. The pore volume was 0.148 m3/g measured by BET analysis, the specific surface was 118.6 m2/g, and the thermal conductivity was 0.153 W/(m·K. Zeolite was proved to be a qualified insulation material which can be used in thermal insulation coating as a new material of energy conservation.

  19. Microstructure Development and Transport Properties of Portland Cement-fly Ash Binary Systems : In view of service life predictions

    NARCIS (Netherlands)

    Yu, Z.

    2015-01-01

    Fly ash is a by-product of burning coal in electric power generating plants. It is commonly known that owing to its pozzolanic properties fly ash is widely used as a partial replacement for Portland cement in concrete. The use of fly ash in concrete not only reduces the landfill costs of fly ash,

  20. Silica Fume and Fly Ash Admixed Can Help to Improve the PRC Durability Combine Microscopic Analysis

    Directory of Open Access Journals (Sweden)

    Xiao Li-guang

    2016-01-01

    Full Text Available Silica fume/Fly ash RPC can greatly improve durability. When Silica fume to replace the same amount of 8% of the proportion of cement, re-mixed 15min of mechanically activated Fly ash content of 10%, by chloride ion flux detector measuring, complex doped than the reference RPC impermeability improved significantly; In addition, by using static nitrogen adsorption method showed, RPC internal pore structure determination, the hole integral volume was lower than the reference admixed RPC integral pore volume significantly; And combined SEM microscopic experimental methods, mixed of RPC internal structure and the formation mechanism analysis showed that, SF/FA complex fully embodies the synergy doped composites “Synergistic” principle.

  1. Fly Ash as a Time Marker for Anthropocene Alluvial Sedimentation

    Science.gov (United States)

    Bettis, E. A., III; Grimley, D. A.; Anders, A. M.; Bates, B.; Hannan, E.

    2014-12-01

    Human land use has transformed the landscapes, ecosystems and hydrology of the North American Midcontinent. One widespread impact of this transformation is increased runoff and accelerated soil erosion, which, along with direct human channel modifications and artificial drainage, have dramatically altered hydrologic and ecological conditions in streams and rivers with far-reaching results. A legacy of this change in streams and rivers is preserved on floodplains throughout the region in sediment known as post-settlement alluvium (PSA). Documenting the spatial and temporal pattern of historic floodplain sedimentation in the drainage network is part of a larger effort to understand decadal and century-scale sediment routing through the drainage system and the role of floodplain sedimentation in carbon sequestration. Fly ash, a product of high-temperature coal combustion, began to accumulate on the landscape in the early historic period (c.a.1840-1850 in Iowa and Illinois) as coal-burning technology such as steam engines came into use after 1850; prior to which no source of fly ash was present. Release of fly ash from coal burning in power plants and steam locomotives likely peaked in the early-mid 20th century. Fly ash particles (~ 1 to 10 % magnetic) are identified by their spheroidal shape and range in size from coarse clay to silt (~1-63µ). By identifying the percentage of fly ash spheroids in the magnetic separate (10 - 60µ size range) of a soil or sediment profile, the pre-fly ash Historic surface could be discerned. Application of this technique in selected localities in eastern Iowa (Clear Creek drainage) and central Illinois (Sangamon River drainage) resulted in successful demarcation of the PSA contact in areas where the boundary was physically evident. Bolstered by this success we were able to confidently demark the PSA contact in other settings where the boundary was not as physically evident. This relatively easy to implement, inexpensive tool will

  2. Studies on Carbon-Fly Ash Composites with Chopped PANOX Fibers

    OpenAIRE

    Patel,Rakesh V; Manocha, S.

    2013-01-01

    Chemical analysis and morphological studies of fly ash reveals the complex chemical constituents present as spherical particles with diameter of less than 25 μm. The constituents of fly ash are silica, alumina, iron oxide, titanium dioxide, calcium and magnesium oxide, and other trace elements. The use of thermosetting as well thermoplastic polymer matrix has been made by several workers to develop polymer matrix fly ash particulate composites by using the hard and abrasive properties of fly ...

  3. Utilization of blended fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash in geopolymer.

    Science.gov (United States)

    Chindaprasirt, Prinya; Rattanasak, Ubolluk

    2010-04-01

    In this paper, synthesis of geopolymer from fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash was studied in order to effectively utilize both ashes. FBC-fly ash and bottom ash were inter-ground to three different finenesses. The ashes were mixed with as-received PCC-fly ash in various proportions and used as source material for synthesis of geopolymer. Sodium silicate (Na(2)SiO(3)) and 10M sodium hydroxide (NaOH) solutions at mass ratio of Na(2)SiO(3)/NaOH of 1.5 and curing temperature of 65 degrees C for 48h were used for making geopolymer. X-ray diffraction (XRD), scanning electron microscopy (SEM), degree of reaction, and thermal gravimetric analysis (TGA) were performed on the geopolymer pastes. Compressive strength was also tested on geopolymer mortars. The results show that high strength geopolymer mortars of 35.0-44.0MPa can be produced using mixture of ground FBC ash and as-received PCC-fly ash. Fine FBC ash is more reactive and results in higher degree of reaction and higher strength geopolymer as compared to the use of coarser FBC ash. Grinding increases reactivity of ash by means of increasing surface area and the amount of reactive phase of the ash. In addition, the packing effect due to fine particles also contributed to increase in strength of geopolymers. Copyright 2009 Elsevier Ltd. All rights reserved.

  4. The effect of fly ashes in the corrosion and durability in concretes; Efecto de las Cenizas Volantes en la Durabilidad y en la Corrosion en Armaduras del Hormigon

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    From the beginning of this century, fly ashes have been the object of a variety of studies and research-looking for different ways of application. The construction industry reuses the highest volume of the fly ash actually produced. Researches carried out on the behaviour of hydraulic blended materials mixed with fly ash have supported the progressive use of these by-products, and simultaneously have opened new ways of application. Spanish fly ash producers together with research centers, as IETcc, have been involved in investigations since 70`s. The last important research carried out has been the one dealing with the durability of concrete made with fly ash and its interaction with the corrosion of reinforcements. In this work five fly ashes of silicon-aluminous type were mixed with portland cement containing low alkali and aluminates in order to enhance the effect of those components from the fly ash. The main goal was to study the degradation mechanisms of concretes made with fly ashes, substituting partially the cement (15 and 35%) in several aggressive media: containing sulfates, chlorides or sea water. The effect to these aggressive media on the durability has also been considered regarding reinforcements. Different type of tests were carried out in laboratory and under natural exposure. In the case of laboratory studies the objectives were: 1) to stablish the mechanisms of hardening. The effect of fly ashes in pozolanic reaction and in the microstructure of the material. 2) Resistance of the addition of fly ashes against chloride and sulfates. Definition of the deterioration mechanisms. 3) Effect of fly ashes on the corrosion of reinforcements. Influence on the passivation process. Resistance against carbonation and chloride attack. (Author)

  5. Determination of anisotropy and multimorphology in fly ash based geopolymers

    Science.gov (United States)

    Khan, M. Irfan; Azizli, Khairun; Sufian, Suriati; Man, Zakaria; Siyal, Ahmer Ali; Ullah, Hafeez

    2015-07-01

    In this study, Malaysian coal fly ash-based geopolymers were investigated for its morphology and chemical composition using scanning electron microscopy coupled with energy dispersive X-rays (SEM-EDX). Geopolymer was synthesized using sodium hydroxide as activator. SEM studies revealed multiphasous structure of the material, composed of geopolymeric gel, partially reacted fly ashparticles and selectively leached particles. EDX analysis confirmed the chemical composition of different regions. Infra red spectroscopic studies supported the SEM-EDX analysis by confirming presence of unreacted quartzite and mullite in geopolymers. It is concluded that geopolymers possese a non uniform chemistry through out the structure.

  6. Determination of anisotropy and multimorphology in fly ash based geopolymers

    Energy Technology Data Exchange (ETDEWEB)

    Khan, M. Irfan, E-mail: mirfanwazir@gmail.com; Azizli, Khairun, E-mail: khairun-azizli@petronas.com.my; Sufian, Suriati, E-mail: suriati@petronas.com.my; Man, Zakaria, E-mail: zakaman@petronas.com.my; Siyal, Ahmer Ali, E-mail: ahmersiyal@gmail.com; Ullah, Hafeez, E-mail: Hafeez-wazir@yahoo.com [Department of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750, Tronoh, Perak (Malaysia)

    2015-07-22

    In this study, Malaysian coal fly ash-based geopolymers were investigated for its morphology and chemical composition using scanning electron microscopy coupled with energy dispersive X-rays (SEM-EDX). Geopolymer was synthesized using sodium hydroxide as activator. SEM studies revealed multiphasous structure of the material, composed of geopolymeric gel, partially reacted fly ashparticles and selectively leached particles. EDX analysis confirmed the chemical composition of different regions. Infra red spectroscopic studies supported the SEM-EDX analysis by confirming presence of unreacted quartzite and mullite in geopolymers. It is concluded that geopolymers possese a non uniform chemistry through out the structure.

  7. Seeding effect on cocomposting wastewater biosolids with coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Fang, M.; Wong, J.W.C. [Hong Kong Baptist University, Hong Kong (China). Dept. of Biology

    2001-10-01

    The seeding effect on fly ash-amended biosolids composting was evaluated by inoculating a mixture of ash and biosolids with seeding materials before composting. These inocula included thermophilic bacteria (Bacillus. brevis, B. coagulans, and B. licheniformis) isolated from the ash-biosolids compost, a commercial decomposter, and recycled biosolids compost. Although the addition of these microbial additives to the ash-biosolids compost improved the population of thermophilic bacteria at the early stage of composting, the improvement was negligible after 4 days of composting. Inoculation with isolated bacterial culture, milk powder, or the decomposter, only, did not effectively improve the decomposition of organic matter compared with those receiving inoculation of both microbial additives and milk powder together. The isolated Bacillus species was as efficient as the commercial decomposter in accelerating the decomposition rate during ash-amended biosolids composting as indicated by the high amounts of carbon dioxide evolved and cumulative weight loss. Taking into consideration the lower operating cost and acceptable decomposition efficiency, recycled biosolids compost seemed to be a promising additive to ash-amended biosolids compost to improve composting efficiency.

  8. Performance of Fly ash Based Geopolymer Mortars in Sulphate Solution

    Directory of Open Access Journals (Sweden)

    P. Ghosh

    2010-01-01

    Full Text Available An experimental investigation was conducted to study the performance of fly ash based geopolymer mortar specimens inMagnesium Sulphate solution. Specimens were manufactured from low calcium fly ash by activation with a mixture of SodiumHydroxide and Sodium Silicate solution and cured thermally. 10% by weight Magnesium Sulphate solution was usedto soak the specimen up to 24 weeks. Performance of the specimens was evaluated in terms of visual appearance, variationof pH of solution, change in weight, and change in compressive strength over the exposure period. White deposits occurredon the surface of specimen which was initially soft but later converted to hard crystals. pH of solution increased noticeablyduring the initial weeks which indicate migration of alkalis from mortar specimens. At the end of 24 weeks samples experiencedvery little weight gain and recorded a loss of compressive strength by up to 56%.

  9. Geopolymer lightweight bricks manufactured from fly ash and foaming agent

    Science.gov (United States)

    Ibrahim, Wan Mastura Wan; Hussin, Kamarudin; Abdullah, Mohd Mustafa Al Bakri; Kadir, Aeslina Abdul

    2017-04-01

    This paper deals with the development of lightweight geopolymer bricks by using foaming agent and fly ash. The mix parameters analysed through a laboratory experiment with fix ratio of sodium silicate/sodium hydroxide solution mass ratio 2.5, fly ash/alkaline activator solution mass ratio 2.0, foaming agent/paste mass ratio 1:2 and molarity of sodium hydroxide solution used was 12M. Different curing temperature (Room Temperature, 60, 80) and foaming agent/water mass ratio (1:10 and 1:20) were studied. Compressive strength, density analysis, and water absorption has been investigated. The results show that the foamed geopolymer bricks with a lower foam/water mass ratio (1:10)and high curing temperature (80°C) leading to a better properties. Mixtures with a low density of around 1420 kg/m3 and a compressive strength of around 10 MPa were achieved.

  10. Post-treatment of Fly Ash by Ozone in a Fixed Bed Reactor

    DEFF Research Database (Denmark)

    Pedersen, Kim Hougaard; Melia, M. C.; Jensen, Anker Degn

    2009-01-01

    The residual carbon in fly ash produced from pulverized coal combustion can adsorb the air-entraining admixtures (AEAs) added to enhance air entrainment in concrete. This behavior of the ash can be suppressed by exposing the fly ash to oxidizing species, which oxidizes the carbon surface and thus...... prevents the AEA to be adsorbed. In the present work, two fly ashes have been ozonated in a fixed bed reactor and the results showed that ozonation is a potential post-treatment method that can lower the AEA requirements of a fly ash up to 6 times. The kinetics of the carbon oxidation by ozone was found...

  11. Optimising Ambient Setting Bayer Derived Fly Ash Geopolymers

    OpenAIRE

    Evan Jamieson; Catherine S. Kealley; Arie van Riessen; Hart, Robert D

    2016-01-01

    The Bayer process utilises high concentrations of caustic and elevated temperature to liberate alumina from bauxite, for the production of aluminium and other chemicals. Within Australia, this process results in 40 million tonnes of mineral residues (Red mud) each year. Over the same period, the energy production sector will produce 14 million tonnes of coal combustion products (Fly ash). Both industrial residues require impoundment storage, yet combining some of these components can produce ...

  12. Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses

    OpenAIRE

    Heah Cheng-Yong; Liew Yun-Ming; Mohd Mustafa Al Bakri Abdullah; Kamarudin Hussin

    2017-01-01

    This paper presents a comparative study of the characteristic of unfoamed and foamed geopolymers after exposure to elevated temperatures (200?800??C). Unfoamed geopolymers were produced with Class F fly ash and sodium hydroxide and liquid sodium silicate. Porous geopolymers were prepared by foaming with hydrogen peroxide. Unfoamed geopolymers possessed excellent strength of 44.2?MPa and degraded 34% to 15?MPa in foamed geopolymers. The strength of unfoamed geopolymers decreased to 5?MPa with ...

  13. Flocculation of cyanobacterial cells using coal fly ash modified chitosan

    OpenAIRE

    Yuan, Y.; Zhang, H; Pan, G.

    2016-01-01

    Harmful algal blooms (HABs) have increasingly occurred worldwide, which pose serious threats to water environment safety. In this study, a compound flocculant (CFAL-Chitosan) was developed for HABs mitigation where chitosan was modified by coal fly ash leachate (CFAL). When using optimized dosage of CFAL-Chitosan flocculant, the zeta potential of Microcystis aeruginosa (M.A.) flocs stayed close to zero and the algal removal efficiency plateaued over 95 % in a wide dosage range from 3 to 6 mg/...

  14. Solidification of coal mining wastes using pozzolanic fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Laczny, J.M.; Dabrowska, L. [Inst. for Ecology of Industrial Areas, Katowice (Poland)

    2001-07-01

    A detailed analysis of chemical composition of porous waters in coal mining wastes and fly ashes has shown that there is a possibility of such alternate disposal which would facilitate forming a protective barrier, which due to reactions undergoing between chemical compounds of both phases would result in forming the so called 'reactive barrier'. This new solution is under patent procedure. 6 refs.

  15. Incorporation of treated straw and wood fly ash into clay building brick

    DEFF Research Database (Denmark)

    Chen, Wan; Ottosen, Lisbeth M.; Jensen, Pernille Erland

    2016-01-01

    in the treated ash, suggests the possibility of the ash reuse in sintered clay bricks. In this study, the straw and wood fly ash treated by washing and EDR was incorporated into yellow clay bricks at different substitution rates. The properties of the clay-ash bricks were studied in terms of shrinkage, water......High Cd content in straw and wood fly ash, generated from biomass-fired power plants, prohibits its recycling as fertilizer spreading on the landfilled. To improve and alter the current mainstream of fly ash treatment by landfilling, different approaches were tried for treatment of straw and wood...

  16. DETERMINING THE ROLE OF INDIVIDUAL FLY ASH PARTICLES IN INFLUENCING THE VARIATION IN THE OVERALL PHYSICAL, MORPHOLOGICAL, AND CHEMICAL PROPERTIES OF FLY ASH

    Directory of Open Access Journals (Sweden)

    Usman Haider

    2016-08-01

    Full Text Available The properties of fly ashes vary because of the differences in the properties of their individual particles, and the determination of variation in these properties is of interest to the industries which use pulverized raw fly ash in applications, such as in cementitious materials and in the recovery of certain rare elements from raw fly ash. To investigate the differences in individual particles, four pulverized raw fly ashes from thermal power plants of the Czech Republic were used in this research. It was observed from FE-SEM that all four fly ashes consist of glassy hollow spherical, solid spherical, porous spherical, bright spherical, porous slaggy and compact slaggy particles. Box and whisker diagrams were plotted from the data of EDX individual particle analyses, which showed that the data of percentages for the Si, Al, and Fe elements is more scattered as compared to other elements. It was further observed from ternary phase diagrams and pseudo coloured images, that nature of fly ash particles changes from alumino silicate glassy to alumino silicate calcite metallic to pure ferro-metallic,where glassy particles showed high percentages and pure calcite particles were absent in fly ashes. Furthermore, a comparison between the XRF, the EDX total area analyses, showed that the EDX individual particle analysis gives more realistic and reliable data with median, mean, and the standard deviation for percentages of each element present in the fly ashes.

  17. Geopolymerisation of fly ashes with waste aluminium anodising etching solutions.

    Science.gov (United States)

    Ogundiran, M B; Nugteren, H W; Witkamp, G J

    2016-10-01

    Combined management of coal combustion fly ash and waste aluminium anodising etching solutions using geopolymerisation presents economic and environmental benefits. The possibility of using waste aluminium anodising etching solution (AES) as activator to produce fly ash geopolymers in place of the commonly used silicate solutions was explored in this study. Geopolymerisation capacities of five European fly ashes with AES and the leaching of elements from their corresponding geopolymers were studied. Conventional commercial potassium silicate activator-based geopolymers were used as a reference. The geopolymers produced were subjected to physical, mechanical and leaching tests. The leaching of elements was tested on 28 days cured and crushed geopolymers using NEN 12457-4, NEN 7375, SPLP and TCLP leaching tests. After 28 days ambient curing, the geopolymers based on the etching solution activator showed compressive strength values between 51 and 84 MPa, whereas the commercial potassium silicate based geopolymers gave compressive strength values between 89 and 115 MPa. Based on the regulatory limits currently associated with the used leaching tests, all except one of the produced geopolymers (with above threshold leaching of As and Se) passed the recommended limits. The AES-geopolymer geopolymers demonstrated excellent compressive strength, although less than geopolymers made from commercial activator. Additionally, they demonstrated low element leaching potentials and therefore can be suitable for use in construction works. Copyright © 2016. Published by Elsevier Ltd.

  18. Phosphate removal from water by fly ash: factorial experimental design.

    Science.gov (United States)

    Can, Mevra Yalvac; Yildiz, Ergun

    2006-07-31

    The influence of three variables (phophate concentration, initial pH of solution (pH(0)) and the fly ash dosage) on the removal efficiency of phosphate (% E) and equilibrium pH of solution (pH(eq)) by using fly ash was studied by means of 2(3) full factorial experimental designs. The parameters coded as x(1), x(2) and x(3), consecutively(,) were used. The parameters were investigated at two levels (-1 and 1). The effects of these factors on dependent variables, namely, % E and pH(eq) were investigated. To determine the significance of effects, the analysis of variance with 95% confidence limits was used. It was shown that % E and pH(eq) obtained in this study were found to be 99.6% and 11.16, corresponding to the operating condition of 25 mg l(-1), 2 g l(-1) and 5.5 for the phosphate concentration, fly ash dosage and pH(0), respectively.

  19. Coal fly ash as a resource for rare earth elements.

    Science.gov (United States)

    Franus, Wojciech; Wiatros-Motyka, Małgorzata M; Wdowin, Magdalena

    2015-06-01

    Rare earth elements (REE) have been recognised as critical raw materials, crucial for many clean technologies. As the gap between their global demand and supply increases, the search for their alternative resources becomes more and more important, especially for the countries which depend highly on their import. Coal fly ash (CFA), which when not utilised is considered waste, has been regarded as the possible source of many elements, including REE. Due to the increase in the energy demand, CFA production is expected to grow, making research into the use of this material a necessity. As Poland is the second biggest coal consumer in the European Union, the authors have studied different coal fly ashes from ten Polish power plants for their rare earth element content. All the fly ashes have a broadly similar distribution of rear earth elements, with light REE being dominant. Most of the samples have REE content relatively high and according to Seredin and Dai (Int J Coal Geol 94: 67-93, 2012) classification can be considered promising REE raw materials.

  20. Utilization of coal fly ash in solidification of liquid radioactive waste from research reactor.

    Science.gov (United States)

    Osmanlioglu, Ahmet Erdal

    2014-05-01

    In this study, the potential utilization of fly ash was investigated as an additive in solidification process of radioactive waste sludge from research reactor. Coal formations include various percentages of natural radioactive elements; therefore, coal fly ash includes various levels of radioactivity. For this reason, fly ashes have to be evaluated for potential environmental implications in case of further usage in any construction material. But for use in solidification of radioactive sludge, the radiological effects of fly ash are in the range of radioactive waste management limits. The results show that fly ash has a strong fixing capacity for radioactive isotopes. Specimens with addition of 5-15% fly ash to concrete was observed to be sufficient to achieve the target compressive strength of 20 MPa required for near-surface disposal. An optimum mixture comprising 15% fly ash, 35% cement, and 50% radioactive waste sludge could provide the solidification required for long-term storage and disposal. The codisposal of radioactive fly ash with radioactive sludge by solidification decreases the usage of cement in solidification process. By this method, radioactive fly ash can become a valuable additive instead of industrial waste. This study supports the utilization of fly ash in industry and the solidification of radioactive waste in the nuclear industry.

  1. Illinois basin coal fly ashes. 2. Equilibria relationships and qualitative modeling of ash-water reactions

    Science.gov (United States)

    Roy, W.R.; Griffin, R.A.

    1984-01-01

    Alkaline and acidic Illinois Basin coal fly ash samples were each mixed with deionized water and equilibrated for about 140 days to simulate ash ponding environments. Common to both equilibrated solutions, anhydrite solubility dominated Ca2+ activities, and Al3+ activities were in equilibrium with both matrix mullite and insoluble aluminum hydroxide phases. Aqueous silica activities were controlled by both mullite and matrix silicates. The pH of the extract of the acidic fly ash was 4.1 after 24 h but increased to a pH value of 6.4 as the H2SO4, assumed to be adsorbed to the particle surfaces, was exhausted by the dissolution of matrix iron oxides and aluminosilicates. The activities of aqueous Al3+ and iron, initially at high levels during the early stages of equilibration, decreased to below analytical detection limits as the result of the formation of insoluble Fe and Al hydroxide phases. The pH of the extract of the alkaline fly ash remained above a pH value of 10 during the entire equilibration interval as a result of the hydrolysis of matrix oxides. As with the acidic system, Al3+ activities were controlled by amorphous aluminum hydroxide phases that began to form after about 7 days of equilibration. The proposed mechanisms and their interrelations are discussed in addition to the solubility diagrams used to deduce these relationships. ?? 1984 American Chemical Society.

  2. Synthesis and characterization of zeolites prepared from industrial fly ash.

    Science.gov (United States)

    Franus, Wojciech; Wdowin, Magdalena; Franus, Małgorzata

    2014-09-01

    In this paper, we present the possibility of using fly ash to produce synthetic zeolites. The synthesis class F fly ash from the Stalowa Wola SA heat and power plant was subjected to 24 h hydrothermal reaction with sodium hydroxide. Depending on the reaction conditions, three types of synthetic zeolites were formed: Na-X (20 g fly ash, 0.5 dm(3) of 3 mol · dm(-3) NaOH, 75 °C), Na-P1 (20 g fly ash, 0.5 dm(3) of 3 mol · dm(-3) NaOH, 95 °C), and sodalite (20 g fly ash, 0.8 dm(3) of 5 mol · dm(-3) NaOH + 0.4 dm(3) of 3 mol · dm(-3) NaCl, 95 °C). As synthesized materials were characterized to obtain mineral composition (X-ray diffractometry, Scanning electron microscopy-energy dispersive spectrometry), adsorption properties (Brunauer-Emmett-Teller surface area, N2 isotherm adsorption/desorption), and ion exchange capacity. The most effective reaction for zeolite preparation was when sodalite was formed and the quantitative content of zeolite from X-ray diffractometry was 90 wt%, compared with 70 wt% for the Na-X and 75 wt% for the Na-P1. Residues from each synthesis reaction were the following: mullite, quartz, and the remains of amorphous aluminosilicate glass. The best zeolitic material as characterized by highest specific surface area was Na-X at almost 166 m(2) · g(-1), while for the Na-P1 and sodalite it was 71 and 33 m(2) · g(-1), respectively. The ion exchange capacity decreased in the following order: Na-X at 1.8 meq · g(-1), Na-P1 at 0.72 meq · g(-1), and sodalite at 0.56 meq · g(-1). The resulting zeolites are competitive for commercially available materials and are used as ion exchangers in industrial wastewater and soil decontamination.

  3. The High Teperature Influence on Geopolymer Fly Ash Mixture’s Compressisive Strength with Insudtrial Waste Material Substitution

    Science.gov (United States)

    Bayuaji, R.; Wibowo, B.; Subekti, S.; Santoso, S. E.; Hardiyanto, E.; Kaelani, Y.; Mallu, L. L.

    2017-11-01

    This research aimed to figure out the influence of fly ash mixture from the industrial waste at the temperatures of 150°C, 450°C, 750°C viewed from the strength and resistance of geopolymer paste. As a result, cement will be substituted by industrial waste like fly ash. This experimental research was conducted on the mix design of geopolymer concrete which was made by dimension with 2.5 cm in diameter and 5 cm in height from four mixture composition of fly ash and industrial waste i.e. 100% fly ash, 50% fly ash+50% bottom ash, 50% fly ash+50% sandblast, and 50% fly ash+50% carbide waste. Each mixture was tested in terms of porosity and compressive strength. In conclusion, in the mixture of 50% fly ash+50% Sandblast and 50% fly ash+50% bottom ash in 12 molars, 1.5 activator comparison can be used to substitute fly ash at high temperature. Meanwhile, the mixture of 50% fly ash+50% carbide waste in 8 molars, 0.5 activator comparison has very small strength remaining if it is compared to the mixture of fly ash and other industrial waste (Bottom ash and Sandblast). The performance of mixture paste of 50% fly ash+50% carbide waste was very vulnerable after being burnt. Consequently, it cannot be used as the main structure at high temperature.

  4. Effect of Grinding Fineness of Fly Ash on the Properties of Geopolymer Foam

    Directory of Open Access Journals (Sweden)

    Szabó R.

    2017-06-01

    Full Text Available Present paper deals with the development of geopolymer foam prepared from ground F class power station fly ash. The effect of the fly ash fineness on the rheology of the geopolymer paste and the foam properties have been investigated. The raw fly ash was ground in a ball mill for various duration, 5, 10, 20, 30, 60 and 120 min. Geopolymer paste was prepared from the raw and ground fly ash with NaOH – sodium silicate mixture as alkaline activator. Geopolymer foam production was made using H2O2 as foaming agent. Additionally, the geopolymer material structure was investigated by Fourier transform infrared spectrometer, the foam cell structure was monitored using optical microscopy. The rheological behaviour of the geopolymer paste changed due to the grinding of fly ash (from Bingham plastic to Newtonian liquid. Grinding of fly ash has a significant effect on the physical properties as well as on the cell structure of the geopolymer foam.

  5. Physical and Chemical Character of Fly Ash of Coal Fired Power Plant in Java

    Science.gov (United States)

    Triwulan; Priadana, K. A.; Ekaputri, J. J.; Bayuaji, R.

    2017-11-01

    Quality of fly ash is varying widely in the field, it depends on the combustion process and the quality of the basic ingredients, namely coal. It will affect the physical and mechanical properties of the concrete mixtures used. This study used 12 samples of fly ash. The physical and chemical properties and finesse modulus were analyzed. The fly ash was mixed with OPC (Ordinary Portland Cement) with the proportion of 20% fly ash and 80% OPC. The specimens were form with mortar dimension of 5cm x 5 cm. The test was affected by the correlation of fly ash fineness modulus to compressive strength, correlation density of fly ash to compressive strength, and correlation of carbon content to the compressive strength.

  6. Study on Type C Coal Fly ash as an Additive to Molding Sand for Steel Casting

    Science.gov (United States)

    Palaniappan, Jayanthi

    2017-04-01

    Study of physio-chemical properties studies such as granulometric analysis, moisture, X ray fluorescence etc. were performed with Type C coal—combustion fly ash to investigate their potential as a distinct option for molding sand in foundry, thereby reducing the dependency on latter. Technological properties study such as compressive strength, tensile strength, permeability and compaction of various compositions of fly ash molding sand (10, 20 and 30 % fly ash substitute to chemically bonded sand) were performed and compared with silica molding sand. Steel casting production using this fly ash molding sand was done and the casting surface finish and typical casting parameters were assessed. It was noted that a good quality steel casting could be produced using type C fly ash molding sand, which effectively replaced 20 % of traditional molding sand and binders thereby providing greater financial profits to the foundry and an effective way of fly ash utilization (waste management).

  7. Effect of fly ash preliminary calcination on the properties of geopolymer.

    Science.gov (United States)

    Temuujin, J; van Riessen, A

    2009-05-30

    The influence of preliminary calcination of fly ashes on the geopolymerisation process has been studied. Preliminary calcination at 500 and 800 degrees C causes decarbonation of the fly ash while it also leads to a decrease of the amorphous content of the fly ashes from 60 to 57%. Geopolymer prepared using raw fly ash exhibited a compressive strength 55.7(9.2)MPa, while for 500 and 800 degrees C calcined samples it reduced to 54(5.8) and 44.4(5.4)MPa, respectively. The decrease in compressive strength of the geopolymers is discussed in terms of partial surface crystallisation of the fly ash particles. Reactivity of the fly ash also has been correlated with the shrinkage rate and presence of efflorescence on the surface of geopolymers.

  8. Development of a standard operating procedure for analysis of ammonia concentrations in coal fly ash.

    Science.gov (United States)

    2015-04-01

    Research was performed to support the development and recommendation of a standard operating : procedure (SOP) for analyzing the ammonia content in fly ash intended for use in concrete. A review : of existing ash producers found that several differen...

  9. Thermal treatment of ashes[Fly Ash from Municipal Waste Incineration]; Termisk rening av askor

    Energy Technology Data Exchange (ETDEWEB)

    Wikman, Karin; Berg, Magnus; Bjurstroem, Henrik [AaF-Energi och Miljoe AB, Stockholm (Sweden); Nordin, Anders [Umeaa Univ. (Sweden). Dept. of Applied Physics and Electronics

    2003-04-01

    In this project descriptions of different processes for thermal treatment of ashes have been compiled. A technical and economic evaluation of the processes has been done to identify possibilities and problems. The focus in the project lays on treatment of fly ash from municipal waste incineration but the processes can also be used to treat other ashes. When the ash is heated in the thermal treatment reactor, with or without additives, the material is sintered or vitrified and at the same time volatile substances (Zn, Pb, Cd, Hg etc.) are separated. In general the separation is more effective in processes with reducing conditions compared to oxidizing conditions. Oxidizing processes have both worse separation capacity and require more energy. The oxidizing processes are mainly used to stabilize the ash through vitrification and they are in some cases developed for management of municipal sewage sludge and bottom ash. However, these processes are often not as complex as for example an electric arc melting furnace with reducing conditions. The research today aim to develop more effective electrical melting systems with reducing conditions such as plasma melting furnaces, electric resistance melting furnaces and low frequency induction furnaces. A central question in the evaluation of different thermal treatment processes for ash is how the residues from the treatment can be used. It is not certain that the vitrified material is stable enough to get a high economic value, but it can probably be used as construction material. How the remaining metals in the ash are bound is very important in a long-time perspective. Further studies with leaching tests are necessary to clarify this issue. The heavy metal concentrate from the processes contains impurities, such as chlorine, which makes it unprofitable to obtain the metals. Instead the heavy metal concentrate has to be land filled. However, the amount of material for land filling will be much smaller if only the heavy

  10. Evaluating the possibilities of obtaining initial concentrates of rare earth elements (REEs from fly ashes

    Directory of Open Access Journals (Sweden)

    J. Całus Moszko

    2016-10-01

    Full Text Available The article presents the results of initial laboratory research into the possibilities of obtaining REE from fly ash from one of Polish powerhouses. In the work the authors have presented the results of investigations into the obtaining of initial REEs concentrations from fly ashes by physicochemical and hydrometallurgical methods. These investigations provide a basis for developing a technology of RRE recovery from fly ashes produced in the process of hard coals combustion.

  11. Production of cenospheres from coal fly ash through vertical thermal flame (VTF) process

    OpenAIRE

    Soh, WM; J. Tan; Heng, JYY; Cheeseman, C

    2016-01-01

    Coal fly ash is a complex mixture of anthropogenic materials produced during the combustion of pulverised coal in coal fired power plants. They pose environmental concerns that lead to air and water pollution. Effort has been done to reduce the production of coal fly ash or to extract potentially valuable products from coal fly ash, such as cenospheres. Cenospheres are light, low density, thin-walled hollow ceramic microsphere with unique properties. Conventional cenosphere production methods...

  12. Mineralogy and microstructure of sintered lignite coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Marina Ilic; Christopher Cheeseman; Christopher Sollars; Jonathan Knight [Faculty of Technology and Metallurgy, Belgrade (Yugoslavia)

    2003-02-01

    Lignite coal fly ash from the 'Nikola Tesla' power plant in Yugoslavia has been characterised, milled, compacted and sintered to form monolithic ceramic materials. The effect of firing at temperatures between 1130 and 1190{sup o}C on the density, water accessible porosity, mineralogy and microstructure of sintered samples is reported. This class C fly ash has an initial average particle size of 82 {mu}m and contains siliceous glass together with the crystalline phases quartz, anorthite, gehlenite, hematite and mullite. Milling the ash to an average particle size of 5.6 m, compacting and firing at 1170{sup o}C for 1 h produces materials with densities similar to clay-based ceramics that exhibit low water absorption. Sintering reduces the amount of glass, quartz, gehlenite and anhydrite, but increases formation of anorthite, mullite, hematite and cristobalite. SEM confirms the formation of a dense ceramic at 1170{sup o}C and indicates that pyroplastic effects cause pore formation and bloating at 1190{sup o}C. 23 refs., 6 figs., 2 tabs.

  13. Direct Quantitative Analysis of Arsenic in Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Sri Hartuti

    2012-01-01

    Full Text Available A rapid, simple method based on graphite furnace atomic absorption spectrometry is described for the direct determination of arsenic in coal fly ash. Solid samples were directly introduced into the atomizer without preliminary treatment. The direct analysis method was not always free of spectral matrix interference, but the stabilization of arsenic by adding palladium nitrate (chemical modifier and the optimization of the parameters in the furnace program (temperature, rate of temperature increase, hold time, and argon gas flow gave good results for the total arsenic determination. The optimal furnace program was determined by analyzing different concentrations of a reference material (NIST1633b, which showed the best linearity for calibration. The optimized parameters for the furnace programs for the ashing and atomization steps were as follows: temperatures of 500–1200 and 2150°C, heating rates of 100 and 500°C s−1, hold times of 90 and 7 s, and medium then maximum and medium argon gas flows, respectively. The calibration plots were linear with a correlation coefficient of 0.9699. This method was validated using arsenic-containing raw coal samples in accordance with the requirements of the mass balance calculation; the distribution rate of As in the fly ashes ranged from 101 to 119%.

  14. Environmental impact of manganese due to its leaching from coal fly ash.

    Science.gov (United States)

    Prasad, Bably; Mondal, Kajal K R

    2009-01-01

    In India, so far not much efforts have been made to use coal ash as backfill material in underground/ open cast mines and to predict its subsequent effect on ground water quality. One of the main problems in disposing of big quantities of coal ash is the possible leaching of different pollutants, including manganese. A thorough investigation regarding leaching of manganese from different fly ashes is required to know the impact of manganese due to its leaching from fly ash to ground water as well as surface water. In the present study, short term and long term leaching studies have been carried out on fly ash, bottom ash, pond ash and weathered ash of Chandrapura thermal power plant, Bokaro, Jharkhand and Ramagundam thermal power plant, Ramagundam, Andhra Pradesh. The amount of manganese released in different experiments has been evaluated. The leachate of Chandrapura fly ash has more manganese concentration (0.2001 mg/L) than the leachate of bottom ash, pond ash and weathered ash. A field investigation at Damoda abandoned open cast mine, filled with pond ash of Chandrapura thermal power plant revealed that concentration of manganese in ground water beneath the ash filled mine has been found very high (maximum up to 6.0 mg/L). But its migration to a long distance has not been seen. Remedial measures for coal ash disposal have also been formulated.

  15. Micromorphology use for visualization of fly-ash distribution in sandy material

    Science.gov (United States)

    Kodesova, R.; Kapicka, A.

    2009-04-01

    Fly-ash migration in three sands of various particle size distributions and consequently various porosities, was studied in the laboratory. The fly-ash was applied on the top of all sands packed in plastic cylinders followed by pulse infiltrations. Water regime was monitored using the soil water content sensors and tensiometers. Kappameter SM400 (Petrovský at al., 2004) was used to monitor migration of ferrimagnetic particles-tracers presented in the fly-ash. Undisturbed samples of sands polluted by fly-ash were taken at the end of the experiments to study final fly-ash distribution in thin sections. Images showed that while fly-ash migrates freely thought the course sandy material, in the other two sands fly-ash is accumulated in few bottle neck pores. However, fly-ash mobility was documented in both cases. Information about image porosities and pore blocking will be used as input data for numerical simulation of observed fly-ash transport. Acknowledgement: Authors acknowledge the financial support of the Grant Agency of Academy of Sciences of the Czech Republic grant No. A300120701, and the Ministry of Education, Youth and Sports grant No. MSM 6046070901.

  16. Preparation of Fly ash Based Adsorbents for Removal Active Red X-3B from Dying Wastewater

    Directory of Open Access Journals (Sweden)

    Li Jinping

    2016-01-01

    Full Text Available Fly ash with a large number of active sites can occur with the adsorbent chemical and physical adsorption, and therefore have a strong adsorption capacity. The original fly ash and raw fly ash compared to the physical and chemical properties to a significant change. On the fly ash in industrial water treatment application were outlined. The purpose is to focus on the modification methods of fly ash and comparison of raw fly ash and fly ash in the effect of dyeing wastewater. Single factor test method; select the appropriate modifier to study the dosage, pH, stirring time on the modification of adsorption properties of fly ash before and after. The results showed that the modified fly ash was better than the adsorption. Greatly improves on active red X-3B dye wastewater removal capacity, pH = 5, 6, dosage is 5g / L, the mixing time is 30min, COD removal rate reached 73.07%. This modified material can be used as adsorbent for pre-treating dying wastewater.

  17. PENGARUH KOMPOSISI KAOLIN TERHADAP DENSITAS DAN KEKUATAN BENDING PADA KOMPOSIT FLY ASH-KAOLIN

    Directory of Open Access Journals (Sweden)

    Rahmat Doni W

    2011-02-01

    Full Text Available Tujuan penelitian ini adalah untuk mengetahui pengaruh suhu sinter terhadap densitas komposit keramik fly ash/Kaolin, mendapatkan suhu sinter terbaik pada komposit keramik fly ash/Kaolin, mengetahui pengaruh penambahan komposisi Kaolin sebesar 0 %, 5 %, 10 %, 15 % dan 20 % berat terhadap kekuatan bending pada komposit keramik fly ash/Kaolin. Penelitian ini menggunakan bahan dasar fly ash dan Kaolin (teknis dengan variasi penambahan Kaolin sebesar 0%, 5%, 10%, 15% dan 20% berat. Pencetakan dilakukan dengan beban kompaksi sebesar 3000 kgf atau sama dengan tekanan kompaksi 166,42 MPa untuk spesimen silinder (d = 15 mm dan t = 8 mm dan 58,84 MPa untuk spesimen balok (B = 10mm, W = 8 mm, dan L = 50mm. Dilanjutkan proses sintering pada suhu 1100, 1150 dan 1200 oC yang kemudian diambil suhu sinter terbaik. Pengujian meliputi uji komposisi fly ash dan Kaolin, uji densitas dengan metode Archimedes, dan uji kekuatan bending dengan four point bending test. Hasil penelitian ini menunjukkan bahwa densitas komposit keramik fly ash/ Kaolin meningkat pada suhu sinter 1100-1150oC dan turun kembali pada suhu sinter 1150-1200oC. Suhu sinter optimum komposit keramik fly ash/Kaolin adalah 1150oC. Kekuatan komposit keramik fly ash/Kaolin paling tinggi yaitu pada komposisi 95% fly ash dan 15% Kaolin sebesar 16,20 Mpa.

  18. Metallothionein response in earthworms Lampito mauritii (Kinberg) exposed to fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Maity, S.; Hattacharya, S.; Chaudhury, S. [Visva Bharati, Santini Ketan (India)

    2009-10-15

    Among pollutants, the coal fly ash occupies a significant position in industrial wastes. The fly ash matrix is a complex mixture of various organic (polyhalogenated compounds) and inorganic (Si, Al, Fe, As, Cd, Bi, Hg, etc.) chemicals. The application of fly ash for agricultural purposes and as landfills may lead to the contamination of the land with some of the toxic chemical compounds present in fly ash. Thus prior to the application of fly ash for developmental activities, it requires bio-monitoring and risk characterization. In order to achieve this objective adult Lampito mauritii were exposed to different proportions of fly ash in soil for 30 d and the concentrations of metallothionein in earthworm were assessed. The results revealed that up to 50% of fly ash amendment does not apparently harm the earthworm in respect of their survival and growth. A significant increase in tissue metallothionein level was recorded in L mauritii exposed to fly ash amended soil without tissue metal accumulation indicating that metallothionein is involved in scavenging of free radicals and reactive oxygen species metabolites. It is concluded that this biochemical response observed in L mauritii exposed to fly ash amended soil could be used in ecotoxicological field monitoring.

  19. [Effect of desilication treatment using silicate bacteria on the bioleaching efficiency of municipal solid waste incineration fly ash].

    Science.gov (United States)

    Yang, Jie; Wang, Qun-Hui; Luo, Qi-Shi; Wang, Qi; Wu, Ting-Ji

    2010-01-01

    One silicate bacteria strain SDB6 with good performance in silicon removal was isolated and screened from soil. Based on the morphological, physiological, biochemical characteristics and 16S rDNA sequence analysis, SDB6 was identified as Bacillus mucilaginosus strain. The effects of nitrogen source, pH, temperature, rotate speed and medium volume on the growth of SDB6 were investigated. The above factors were optimized using the orthogonal design. The optimized condition was described as follows: 10 g/L yeast, 250 mL flask with 50 mL culture medium, pH 7.5, 30 degrees C, 180 r/min. The bioleaching of un-desilicated and desilicated fly ash using the adapted Aspergillus niger AS 3.879M strain was carried out for 20d. The results indicated that the metal extraction yield in bioleaching increased obviously with desilication treatment comparing to that without desilication treatment. The extraction yield of Cu, Mn, Cr, Zn and Fe from desilicated fly ash was 31%, 75%, 60%, 60% and 48%, respectively. The total metals extraction yield of desilicated fly ash increased to 50%. The TCLP results of the fly ash after bioleaching indicated that the leaching toxicities of the treated fly ash were far lower than the regulated levels of China and permitted to the further landfill or reuse.

  20. Recycling of Pre-Washed Municipal Solid Waste Incinerator Fly Ash in the Manufacturing of Low Temperature Setting Geopolymer Materials

    Directory of Open Access Journals (Sweden)

    Raffaele Cioffi

    2013-08-01

    Full Text Available In this work, three samples of municipal solid waste incinerators fly ash (MSWI-FA have been stabilized in systems containing coal fly ash to create geopolymers through a polycondensation reaction. Monolithic products have been obtained with both MSWI fly ash as received and after the partial removal of chloride and sulfate by water washing. The polycondensation products have been characterized qualitatively by means of Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy and quantitatively, through the determination of the volume of reacted water and silicate. Furthermore, the heavy metals and chloride releases together with the physico-mechanical properties have been evaluated on the hardened products. In conclusion, considering the technological and environmental performances of the obtained geopolymers, they could be suitable for many non-structural applications, such as backfilling of abandoned quarries, decorative materials or brick fireplaces, hearths, patios, etc.

  1. Recycling of Pre-Washed Municipal Solid Waste Incinerator Fly Ash in the Manufacturing of Low Temperature Setting Geopolymer Materials.

    Science.gov (United States)

    Ferone, Claudio; Colangelo, Francesco; Messina, Francesco; Santoro, Luciano; Cioffi, Raffaele

    2013-08-12

    In this work, three samples of municipal solid waste incinerators fly ash (MSWI-FA) have been stabilized in systems containing coal fly ash to create geopolymers through a polycondensation reaction. Monolithic products have been obtained with both MSWI fly ash as received and after the partial removal of chloride and sulfate by water washing. The polycondensation products have been characterized qualitatively by means of Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy and quantitatively, through the determination of the volume of reacted water and silicate. Furthermore, the heavy metals and chloride releases together with the physico-mechanical properties have been evaluated on the hardened products. In conclusion, considering the technological and environmental performances of the obtained geopolymers, they could be suitable for many non-structural applications, such as backfilling of abandoned quarries, decorative materials or brick fireplaces, hearths, patios, etc.

  2. Properties of concrete made with alkali-activated fly ash lightweight aggregate (AFLA)

    Energy Technology Data Exchange (ETDEWEB)

    Byung-wan Jo; Seung-kook Park; Jong-bin Park [Hanyang University, Seoul (Republic of Korea). Structural Engineering Lab., Department of Civil Engineering

    2007-02-15

    An experiment was performed to investigate the properties of the hardened paste of fly ash by alkali activation and to determine the possible use of the paste in the production of lightweight aggregates. The highest compressive strength was 33.9 MPa, for paste with 10% NaOH, 15% sodium silicate, and 5% MnO{sub 2}, cured at room temperature after 24 h of moisture curing at 50{sup o}C. The hardened paste of fly ash was granulated to produce AFLA (alkali-activated fly ash lightweight aggregate). AFLA exhibited specific gravity (SSD, OD), water absorption, unit weight, and solid volume percentages of 1.85 (SSD), 1.66 (OD), 11.8%, 972 kg/m{sup 3}, and 58.6%, respectively. The results of the heavy metals leaching test met US EPA regulations. The concrete using AFLA exhibited a compressive strength of 26.47 MPa and good freeze-thaw resistance at 6.0% entrained air content.

  3. Chlorides behavior in raw fly ash washing experiments

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Fenfen, E-mail: zhu@hse.gcoe.kyoto-u.ac.jp [Department of Urban and Environmental Engineering, Graduate School of Engineering, Katsura Campus, Kyoto University, Nishikyo-ku, Kyoto 615-8540 (Japan); Takaoka, Masaki; Oshita, Kazuyuki [Department of Urban and Environmental Engineering, Graduate School of Engineering, Katsura Campus, Kyoto University, Nishikyo-ku, Kyoto 615-8540 (Japan); Kitajima, Yoshinori; Inada, Yasuhiro [High Energy Accelerator Research Organization (KEK), Institute of Material Structure Science (IMSS), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Morisawa, Shinsuke; Tsuno, Hiroshi [Department of Urban and Environmental Engineering, Graduate School of Engineering, Katsura Campus, Kyoto University, Nishikyo-ku, Kyoto 615-8540 (Japan)

    2010-06-15

    Chloride in fly ash from municipal solid waste incinerators (MSWIs) is one of the obstructive substances in recycling fly ash as building materials. As a result, we have to understand the behavior of chlorides in recycling process, such as washing. In this study, we used X-ray absorption near edge structure (XANES) and X-ray diffraction (XRD) to study the chloride behavior in washed residue of raw fly ash (RFA). We found that a combination of XRD and XANES, which is to use XRD to identify the situation of some compounds first and then process XANES data, was an effective way to explain the chlorides behavior in washing process. Approximately 15% of the chlorine in RFA was in the form of NaCl, 10% was in the form of KCl, 51% was CaCl{sub 2}, and the remainder was in the form of Friedel's salt. In washing experiments not only the mole percentage but also the amount of soluble chlorides including NaCl, KCl and CaCl{sub 2} decreases quickly with the increase of liquid to solid (L/S) ratio or washing frequency. However, those of insoluble chlorides decrease slower. Moreover, Friedel's salt and its related compound (11CaO.7Al{sub 2}O{sub 3}.CaCl{sub 2}) were reliable standards for the insoluble chlorides in RFA, which are strongly related to CaCl{sub 2}. Washing of RFA promoted the release of insoluble chlorides, most of which were in the form of CaCl{sub 2}.

  4. Fire Related Temperature Resistance of Fly Ash Based Geopolymer Mortar

    Directory of Open Access Journals (Sweden)

    Jeyalakshmi R.

    2017-01-01

    Full Text Available The study presented in this paper is on the effect of heat treatment on fly ash based geopolymer mortar synthesized from fly ash (Class F –Low lime using alkaline binary activator solution containing sodium hydroxide (18 M and sodium silicate solution (MR 2.0, cured at 80oC for 24 h. 7 days aged specimen heated at elevated temperature (200°C, 400°C, 600°C and 800°C for the sustained period of 2hrs. The TGA/DTA analysis and thermal conductivity measurement as per ASTM C113 were carried out besides the compressive strengths. The thermal stability of the fly ash mortar at elevated temperature was found to be high as reflected in the observed value of f800°C/f30°C being more than 1 and this ratio was raised to about 1.3 with the addition of 2% Zirconium di oxide (ZrO2. No visible cracks were found on the specimens with and without ZrO2 when 800°C was sustained for 4 hrs in smaller specimens of size: 50 mm diameter x 100 mm height and in also bigger size specimens: 22 cm × 11 cm × 7 cm specimens. TGA/DTA analysis of the geopolymer paste showed that the retention of mass was around 90%. The addition of ZrO2 improved thermal resistance. The micro structure of the matrix found to be intact even at elevated temperature that was evident from the FESEM studies.

  5. Statistical Approach to the Transformation of Fly Ash into Zeolites

    Science.gov (United States)

    Derkowski, Arkadiusz; Michalik, Marek

    2007-01-01

    The experimental conversion of F-class fly ash into zeolites is described. The ash, composed mainly of aluminosilicate glass, mullite and quartz, was collected in the Cracow power plant (southern Poland). The experiments involved the heating of fly ash samples in PTFE vessels. Time, temperature and solution composition were the reaction parameters considered in the experiments and in the subsequent modeling. A series of reactions with 0.5, 3 and 5M NaOH solutions (and some with additional 3M NaCl) were carried out at 70°, 100° and 150°C for 12-48 hours under autogenic pressure (not measured) and at a constant ash-to-solution ratio of 33.3 g/l. The following zeolite phases were synthesized: sodalite (SOD structure), hydroxysodalite (SOD), CAN type phases, Na-X (FAU), and NaP1 (GIS). Statistically calculated relationships based on the mineral- and chemical compositions of the reaction products support the conclusion that the type of zeolite phase that crystallizes depends on the concentration of OH- and Cl- in solution and on the temperature of the reaction. The duration of reaction, if on the order of tens of hours, is of less significance. The nature of the zeolite phase that crystalises is controlled by the intensity and selectivity of the substrate dissolution. That dissolution can favour, in sequence, one or other of the components in the substrate, resulting in Si/Al variation in the reaction solutions. Mullite dissolution (decreasing solution Si/Al) characterizes the most advanced reaction stages. The sequence of crystallization of the zeolite phases mirrors the sequential dissolution of substrate components, and the composition of the crystallizing zeolite crystals reflects the changes in the solution Si/Al.

  6. The production and properties of fly ash containing aluminum matrix composite materials; Herstellung und Eigenschaften von flugaschehaltigen Aluminium-Matrix-Verbundwerkstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Kolukisa, S.; Topuz, A.; Sagin, A. [Metallurgical and Materials Eng. Dep., Yildiz Technical Univ., Yildiz-Istanbul (Turkey)

    2003-07-01

    Cost saving in composite materials is very important. Therefore fly ash particles, which are a waste product of coal combustion, can be used as reinforcement in aluminum matrix composite materials. Aluminum matrix composite materials (AMC) fabricated from A360 and 443 aluminum alloys and Tuncbilek, Yatagan fly ashes were used as reinforcement with volume fractions 5%, 10%, 15%, 20%. Stir mixing and casting process were used for the production of fly ash containing aluminum-matrix composites (AMC's). Specially designed and ceramic covered mixers were used for stirring of melted aluminum alloy at 750, 850, 950 C temperatures and 400, 560, 750 rpm rotation rates. It has been observed that, with applied production process, maximum 20% (volume fraction) fly ash can be added to aluminum alloy matrix. Referring to the experimental data, optimum properties were achieved at 850 C stirring temperature and 560 rpm mixer rotation rates. (orig.)

  7. Waste Minimization Protocols for the Process of Synthesizing Zeolites from South African Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Leslie F. Petrik

    2013-04-01

    Full Text Available Production of a high value zeolite from fly ash has been shown to be an avenue for the utilization of South African fly ash which presently constitutes a huge disposal problem. The synthesis of zeolites Na-P1 and analcime on a micro-scale has been successful and preliminary investigation shows that scale-up synthesis is promising. However, the post-synthesis supernatant waste generated contains high levels of NaOH that may constitute a secondary disposal problem. A waste minimization protocol was developed to reduce the volume of waste generated with a view to enhancing the feasibility of the scale synthesis. Series of experiments were conducted in 100 mL jacketed batch reactors. Fly ash was reacted with 5 Mol NaOH on a 1:1 mass basis during the aging step, followed by hydrothermal treatment in which ultrapure water was added to the slurry. This study shows that by re-introducing the supernatant waste into the experiments in such a way that it supplies the required reagent (NaOH for the zeolite synthesis, zeolite Na-P1 and analcime can be synthesized. It also shows that the synthesis process can be altered to allow up to 100% re-use of the supernatant waste to yield high value zeolitic products. This study effectively constructed two protocols for the minimization of waste generated during the synthesis of zeolites from South African coal fly ash. This result could be used to establish a basis for legal and environmental aspects involved in the commission of a full-scale plant synthesizing zeolites NaP1 and analcime.

  8. Waste Minimization Protocols for the Process of Synthesizing Zeolites from South African Coal Fly Ash.

    Science.gov (United States)

    Plessis, Pieter W Du; Ojumu, Tunde V; Petrik, Leslie F

    2013-04-29

    Production of a high value zeolite from fly ash has been shown to be an avenue for the utilization of South African fly ash which presently constitutes a huge disposal problem. The synthesis of zeolites Na-P1 and analcime on a micro-scale has been successful and preliminary investigation shows that scale-up synthesis is promising. However, the post-synthesis supernatant waste generated contains high levels of NaOH that may constitute a secondary disposal problem. A waste minimization protocol was developed to reduce the volume of waste generated with a view to enhancing the feasibility of the scale synthesis. Series of experiments were conducted in 100 mL jacketed batch reactors. Fly ash was reacted with 5 Mol NaOH on a 1:1 mass basis during the aging step, followed by hydrothermal treatment in which ultrapure water was added to the slurry. This study shows that by re-introducing the supernatant waste into the experiments in such a way that it supplies the required reagent (NaOH) for the zeolite synthesis, zeolite Na-P1 and analcime can be synthesized. It also shows that the synthesis process can be altered to allow up to 100% re-use of the supernatant waste to yield high value zeolitic products. This study effectively constructed two protocols for the minimization of waste generated during the synthesis of zeolites from South African coal fly ash. This result could be used to establish a basis for legal and environmental aspects involved in the commission of a full-scale plant synthesizing zeolites NaP1 and analcime.

  9. Study on Thermal Insulation Zeolite by Coal Fly Ash

    OpenAIRE

    Huiping Song; Nan Zheng; Fangbin Xue; Fangqin Cheng

    2014-01-01

    This paper takes the coal fly ash as the material and makes zeolite with low thermal conductivity under a two-step synthesis for the purpose of thermal insulation. It studies main factors affecting zeolite such as the different concentration of NaOH, the solid-liquid ratio, the silica-alumina ratio, and the crystallization temperature. The optimal conditions were obtained that the NaOH concentration was 3 mol/L, the solid-liquid ratio was 10 : 1, the silica-alumina ratio was 2, and the crysta...

  10. PENGGUNAAN FLY ASH DAN VISCOCRETE PADA SELF COMPACTING CONCRETE

    Directory of Open Access Journals (Sweden)

    Handoko Sugiharto

    2001-01-01

    Full Text Available Self Compacting Concrete (SCC gives a new solution in concrete technology, since SCC does not need vibrator for compacting. SCC has been used and developed abroad, however in Indonesia SCC is not used because there is no research about SCC yet. In this preliminary research, trial mix is performed to understand the characteristics and to calculate the materials composition to be used in SCC. From this trial mix, some variables are fixed and others are varied. This variable is examined further in the next trial mix. The workability is examined using slump cone method and flowability using L-shaped box. From this test, it is found out that to get the condition of self compactibility, viscocrete must be used. The binder (cement-fly ash composition, is examined using 10:0, 8:2, 7:3, 6:4 cement to fly ash ratio, until the maximum of flowability and workability, which is 5:5. Viscocrete dose 1.5 % and 2 % did not show a significant difference for all binder composition. From the workability, flowability and strength point of view, binder composition 6:4 and viscocrete dose 1.5 % gives the optimal condition. Abstract in Bahasa Indonesia : Self Compacting Concrete (SCC memberikan solusi baru dalam dunia teknologi beton karena tidak memerlukan vibrator untuk pemadatannya. SCC telah digunakan dan dikembangkan di luar negeri, tetapi di Indonesia belum begitu dikenal, dikarenakan belum adanya penelitian tentang SCC di Indonesia. Pada penelitian awal ini dilakukan trial mix untuk mengetahui karakteristik dan memperkirakan komposisi bahan yang dibutuhkan untuk SCC. Kemudian dari trial mix tersebut ditetapkan variabel-variabel berubah dan variabel-variabel tetap yang akan diuji pada trial mix selanjutnya. Pengujian workability dilakukan dengan alat slump cone sedangkan pengujian flowability dilakukan dengan alat L-shaped box. Dari hasil pengujian yang telah dilakukan, ternyata harus digunakan viscocrete untuk mendapatkan kondisi self compactibility. Untuk

  11. Defluoridation of water by adsorption on fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Chaturvedi, A.K.; Yadava, K.P.; Pathak, K.C.; Singh, V.N. (Banaras Hindu University, Varanasi (India). Dept. of Applied Chemistry, Inst. of Technology)

    1990-01-01

    The ability of fly ash to remove fluoride from water and wastewaters has been studied at different concentrations, times, temperatures and pH of the solution. The rate constants of adsorption, intraparticle transport, mass transfer coefficients and thermodynamic parameters have been calculated at 30, 40, and 50{degree}C. The empirical model has been tested at various concentrations for the present system. The removal of fluoride is favourable at low concentration, high temperature and acidic pH. 18 refs., 9 figs., 3 tabs.

  12. The Effect of Different Ratio Bottom Ash and Fly Ash Geopolymer Brick on Mechanical Properties for Non-loading Application

    Directory of Open Access Journals (Sweden)

    Mardiah Deraman Laila

    2017-01-01

    Full Text Available This paper studies the finding of strength and water absorption of geopolymer bricks using bottom ash and fly ash as a geopolymer raw material for non-loading application with minimum strength. The study has been conducted to produce bottom ash and fly ash geopolymer bricks by varying the ratio of fly ash-to-bottom ash, solid-to-liquid and sodium silicate (Na2SiO3-to-sodium hydroxide (NaOH in the mixing process. The compressive strength range between 3.8-4.5 MPa was obtained due to the minimum strength of non-loading application with 70°C curing temperature within 24 hours at 7 days of ageing. The optimum ratio selected of bottom ash-to-fly ash, solid-to-liquid and Na2SiO3-to-NaOH are 1:2, 2.0 and 4.0 respectively. The water absorption result is closely related to the amount of bottom ash used in the mix design.

  13. Evaluation of Greek type Portland cement based on Megalopolis fly ash addition

    Energy Technology Data Exchange (ETDEWEB)

    Stivanakis, V.; Papamantellos, D. [University of Patras (Greece). Department of Chemical Engineering, Laboratory of Metallurgy; Galanoulis, E. [Titan Cement Company S.A., Drepano, Achaias (Greece)

    2003-04-01

    Fly-ash is considered as a fine material which is produced during firing of powdered solid fuels in steam generating plants. It is contained in the output exhaust gases and collected in the electrostatic filters. In the lignite fired power plants of Public Power Corporation in the regions of Ptolemais-Amynteon and Megalopolis 65 . 10 t/a of lignite are consumed nowadays with a corresponding fly ash production of about 13 . 10{sup 6} t/a. The utilisation of fly ash generated in Megalopolis plant ({proportional_to} 3.5 . 106 t/a) in cement industry has been investigated by the Laboratory of Metallurgy (METLAB) in collaboration with the cement company Titan and the Greek P.P.C. since 1979. The primary target of this research and development work, was to investigate the addition of Megalopolis fly ash in the manufacturing process of cement, in quantities around 10%, replacing the so-called Volcanic Rock (Santorini's earth), which was used as a pozzolanic material. Megalopolis fly ash was considered to be unsuitable for use as hydraulic powder due to its high SiO{sub 2} content ({proportional_to}50%), in contrast to Ptolemais-Amynteon fly ash, which contains high percentages of CaO (30 - 40%). The first results were very encouraging as they proved that addition of blended fly ash could be added up to 50% without considerable reduction in the compressive strength of cement. Consequently, exploitation of Megalopolis fly ash by Titan cement industry began in 1982, with the production of Greek type Portland cement that contains 15 - 20% of Megalopolis fly ash. The annual consumption of Megalopolis fly ash since 1982 is in the range of 300.000 - 500.000 t/a. In the years following 1983, a systematic investigation of the influence of Megalopolis fly ash addition, up to a content of 80% upon the technological properties of cement and concrete was carried out. The workability, compressive strength (2, 7, 28 days), long-term compressive strength (up to 180 days) and the

  14. Characterization of municipal solid waste incineration fly ash before and after electrodialytic treatment

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Gardner, Kevin H.

    2003-01-01

    Municipal solid waste incineration (MSWI) fly ash, which has been treated electrodialytically for the removal of heavy metals, may have changed characteristics compared to untreated fly ash. In this study, MSWI fly ash was characterized with respect to leaching properties (pH static leaching...... metals had been removed from the ash during the electrodialytic treatment, the leachability of several of the residual metals had actually increased. The increased leachability was most probably caused by mineral dissolution and chelating of metals by residual citrate in the ash. Ammonium citrate had...... been added to the ash before and during electrodialytic treatment to increase the heavy metal desorption. The morphology and mineralogy of the ash was also altered as a result of the treatment. XRPD ex-aminations revealed that a severe depletion of Cl, Na and K in the treated ashes was due to wash out...

  15. APC fly ashes stabilized with Portland cement for further development of road sub-base aggregates

    Science.gov (United States)

    Formosa, J.; Giro-Paloma, J.; Maldonado-Alameda, A.; Huete-Hernández, S.; Chimenos, J. M.

    2017-10-01

    Although waste-to-energy plants allow reducing the mass and volume of municipal solid waste (MSW) incinerated, an average around 30 % of the total content remains as bottom ash (BA) and air pollution control (APC) ashes at the end of combustion process. While weathered bottom ash (WBA) is considered a non-hazardous residue that can be revalorized as a secondary aggregate, APC fly ashes generated during the flue gas treatment are classified as hazardous waste and are handled in landfill disposal after stabilization, usually with Portland cement (OPC). However, taking into account the amount of APC residues produced and the disposing cost in landfill, their revalorization is an important issue that could be effectively addressed. As MSW can be incinerated producing bottom ashes (BA) or air pollutant control (APC) residues, the development of a mortar formulated with APC fly ash as secondary building material is a significant risk to the environment for their content of heavy metals. In this way, Design of Experiment (DoE) was used for the improvement of granular material (GM) formulation composed by APC and OPC for further uses as road sub-base aggregate. DoE analysis was successful in the modelling and optimization the formulation as function of the mechanical properties and APC amount. Consequently, an optimal mortar formulation (OMF) of around 50 wt.% APC and 50 wt.% OPC was considered. The OMF leachates and abrasion resistance have been analyzed. These results have demonstrated the viability of OMF as non-hazardous material feasible to be used as secondary aggregate. Moreover, it would be possible to consider the environmental assessment of a GM composed by ≈20 wt.% of OMF and ≈80 wt.% of WBA in order to improve mechanical properties and heavy metals stabilization.

  16. Carbon in Fly Ash Analysis Using Photoacoustic Spectroscopy.

    Science.gov (United States)

    Dykstra, Jeffrey Raymond

    Photoacoustic absorption spectroscopy (PAS) was investigated as a method for on-line monitoring of carbon in fly ash from coal-fired boilers. PAS is based on the periodic heating of a gas when amplitude-modulated radiation is absorbed by the gas or by particles suspended in the gas. This periodic heating produces an acoustical wave that can be detected by a microphone. Because the PAS signal is based solely on the absorption of radiation (by carbon) and not scattering of radiation (by mineral matter), it has the potential for distinguishing unburned carbon from mineral matter suspended in the flue gas. Two radiation sources were studied: helium-neon laser and microwaves. The helium-neon source produces a large mass specific absorption coefficient for the carbon in the fly ash. Although the optical PAS system uses less than one forty thousandths of the power as the microwave system, it still has twice the sensitivity (D etam) and the microwave source (lambda = 12.24 cm). It may be possible to find a source that has all the positive characteristics with manageable drawbacks.

  17. Abatement of organic pollutants using fly ash based adsorbents.

    Science.gov (United States)

    Adegoke, Kayode Adesina; Oyewole, Rhoda Oyeladun; Lasisi, Bukola Morenike; Bello, Olugbenga Solomon

    2017-11-01

    The presence of organic pollutants in the environment is of major concern because of their toxicity, bio-accumulating tendency, threat to human life and the environment. It is a well-known fact that, these pollutants can damage nerves, liver, and bones and could also block functional groups of essential enzymes. Conventional methods for removing dissolved pollutants include chemical precipitation, chemical oxidation or reduction, filtration, ion-exchange, electrochemical treatment, application of membrane technology, evaporation recovery and biological treatment. Although all the pollutant treatment techniques can be employed, they have their inherent advantages and limitations. Among all these methods, adsorption process is considered better than other methods because of convenience, easy operation and simplicity of design. A fundamentally important characteristic of good adsorbents is their high porosity and consequent larger surface area with more specific adsorption sites. This paper presents a review of adsorption of different pollutants using activated carbon prepared from fly ash sources and the attendant environmental implications. Also, the ways of overcoming barriers to fly ash utilization together with regeneration studies are also discussed.

  18. Pb-free Radiation Shielding Glass Using Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Watcharin Rachniyom

    2015-12-01

    Full Text Available In this work, Pb-free shielding glass samples were prepared by the melt quenching technique using subbituminous fly ash (SFA composed of xBi2O3 : (60-xB2O3 : 10Na2O : 30SFA (where x = 10, 15, 20, 25, 30 and 35 by wt%. The samples were investigated for their physical and radiation shielding properties. The density and hardness were measured. The results showed that the density increased with the increase of Bi2O3 content. The highest value of hardness was observed for glass sample with 30 wt% of Bi2O3 concentration. The samples were investigated under 662 keV gamma ray and the results were compared with theoretical calculations. The values of the mass attenuation coefficient (μm, the atomic cross section (σe and the effective atomic number (Zeff were found to increase with an increase of the Bi2O3 concentration and were in good agreement with the theoretical calculations. The best results for the half-value layer (HVL were observed in the sample with 35 wt% of Bi2O3 concentration, better than the values of barite concrete. These results demonstrate the viability of using coal fly ash waste for radiation shielding glass without PbO in the glass matrices.

  19. Flexural Test of Fly Ash based Geopolimer Concrete Beams

    Directory of Open Access Journals (Sweden)

    Nindyawati

    2017-01-01

    Full Text Available Fly ash is a by-product from the coal industry, which is widely available in Indonesia. Fly ash contains quite high silicate and alumina. Silica and alumina reacts with alkaline solution to produce alumina silicate gel which binds the aggregate to produce geopolymer concrete. Geopolymer concrete is introduced as an environmental concrete with high compressive strength. The use of geopolymer concrete beams is a solution to reduce the effects of greenhouse gases. This research uses experimental designs. The data are obtained from the testing of 4 pieces of reinforced geopolymer concrete beams and reinforced ordinary concrete beams with a / d of 1.11 and 2.24. The results are obtained from the maximum load that can be accepted by the beam. The results of this study are: (1 Geopolymer concrete cylinder has 26.78% higher compressive strength than ordinary concrete cylinders (2 Ordinary concrete beams can withstand 34.8% load higher compared to the geopolymer concrete beam (3 Reinforced ordinary concrete beams experience bending shear collapse while reinforced geopolymer concrete beam experience pure bending collapse.

  20. Sulfate resistance of fly ash-based geopolymer mortar

    Science.gov (United States)

    Saloma, Iqbal, Maulid Muhammad; Aqil, Ibnu

    2017-09-01

    This paper presents sulfuric acid attack of fly ash-based geopolymer mortar. Precursor used in this study was fly ash, and activator used was NaOH and Na2SiO3. The ratio of activator/precursor, ratio of Na2SiO3/NaOH, and ratio of fine aggregate/precursor is 0.42, 2.00, and 2.00, respectively. The molar concentration of NaOH which was used were 8, 10, 12, 14, and 16 M. This study used cube specimen with 5 cm x 5 cm x 5 cm. The results showed that the higher the molar concentration of NaOH, the lower the weight loss. Maximum percentage of weight loss is 3.54% occured for the specimen with molar concentration of NaOH 8 M. The compressive strength for all specimens decreased due to the longer duration of immersion in sulfuric acid solution. However, this percentage of decreasing for compressive strength will be as lower as increasing the molar concentration of NaOH used. The maximum percentage of decreasing is 35.49% for specimen with NaOH 8 M with 90 days of immersion.

  1. Improvements of nano-SiO2 on sludge/fly ash mortar.

    Science.gov (United States)

    Lin, D F; Lin, K L; Chang, W C; Luo, H L; Cai, M Q

    2008-01-01

    Sewage sludge ash has been widely applied to cementitious materials. In this study, in order to determine effects of nano-SiO(2) additives on properties of sludge/fly ash mortar, different amounts of nano-SiO(2) were added to sludge/fly ash mortar specimens to investigate their physical properties and micro-structures. A water-binding ratio of 0.7 was assigned to the mix. Substitution amounts of 0%, 10%, 20%, and 30% of sludge/fly ash (1:1 ratio) were proposed. Moreover, 0%, 1%, 2%, and 3% of nano-SiO(2) was added to the mix. Tests, including SEM and compressive strength, were carried out on mortar specimens cured at 3, 7, and 28 days. Results showed that sludge/fly ash can make the crystals of cement hydration product finer. Moreover, crystals increased after nano-SiO(2) was added. Hence, nano-SiO(2) can improve the effects of sludge/fly ash on the hydration of mortar. Further, due to the low pozzolanic reaction active index of sludge ash, early compressive strengths of sludge/fly ash mortar were decreased. Yet, nano-SiO(2) could help produce hydration crystals, which implies that the addition of nano-SiO(2) to mortar can improve the influence of sludge/fly ash on the development of the early strength of the mortar.

  2. The influence of salinity of fly ash mixtures on energy looses during flow in pipelines

    Directory of Open Access Journals (Sweden)

    И. Собота

    2017-06-01

    Full Text Available In Polish mining for backfilling the fly ash mixtures are used. Last time for fly ash mixtures preparation the saline water from mine have been used, to thanks to that the saline water missing the surface waters. Usage of saline water for fly ash mixture preparation causes the changes in energy looses during the flow in pipelines. The paper presents the results of energy looses measurement іn laboratory pipeline installation with diameter D =50 mm. The measurements have been performed for different fly ash – saline water proportions. Tested fly-ash from Siersza power plant has typical properties (grain size distribution curve, density for ashes used for backfilling mixtures preparation. Increase of fluid (water salinity modifies fluid viscosity. Brine in comparison with pure water retains as liquid with increased viscosity. Increased viscosity can influence on the mixture ash-brine properties for example causing flocculation effect. Also changeable salinity has an influence on proper determination of resistance (frictional coefficient λ during mixtures flow in pipelines because it depends on Reynolds number which depends on liquid viscosity. Increase of fly-ash concentrations in fly-ash – brine mixtures cause increase of energy losses.

  3. Influence of fly ash fineness on water requirement and shrinkage of blended cement mortars

    Directory of Open Access Journals (Sweden)

    Vanissorn Vimonsatit

    2015-12-01

    Full Text Available In this paper, the influence of fly ash fineness on water requirement and shrinkage of blended cement mortar was studied. The results indicate that the water requirement and shrinkage characteristic of the blended cement mortar are dependent on fly ash fineness and replacement level. The use of coarse fly ash slightly reduces the water requirement but greatly reduced the drying and the autogenous shrinkage of the blended cement mortars and the reduction is more with an increase in the fly ash replacement level. The finer fly ashes further reduce the water requirement, but increase the drying and the autogenous shrinkages as compared with coarser fly ash. The incorporation of superplasticizer drastically reduces the water requirement, but the effect on the drying and autogenous shrinkages of the normal Portland cement mortar is small. However, for the fly ash mortar, the use of superplasticizer results in a decrease in drying shrinkage and in a substantial increase in the autogenous shrinkage particularly for the fine fly ash at a high replacement level.

  4. Effect of class F fly ash on the durability properties of concrete

    Directory of Open Access Journals (Sweden)

    Ashish Kumer Saha

    2018-01-01

    Full Text Available The present study evaluates the application of class F fly ash as a partial replacement of binder in concrete. The compressive strength of the fly ash samples showed low early compressive strength comparing to the control samples. However, due to pozzolanic reaction strength was improved gradually over a longer period of time, whereas control samples stopped the strength growth after 56-d of curing. The drying shrinkage was reduced with the increment of fly ash content in the mix. The inclusion of fly ash as a binder reduced the porosity of the concrete. As a result, the fly ash concrete exhibited lower water sorptivity and chloride permeability. Furthermore, a significant drop of sorptivity and chloride permeability was observed for fly ash concrete between the curing period of 28–180 days. Microstructural morphology of fly ash samples was investigated to evaluate the reason behind the improved durability characteristics. Keywords: Fly ash, Compressive strength, Drying shrinkage, Permeable void, Water sorptivity, Chloride permeability

  5. Permeation Properties and Pore Structure of Surface Layer of Fly Ash Concrete

    Directory of Open Access Journals (Sweden)

    Jun Liu

    2014-05-01

    Full Text Available This paper presents an experimental study on the nature of permeation properties and pore structure of concrete surface layers containing fly ash. Concretes containing different dosages of fly ash as a replacement for cement (15% and 30% by weight of total cement materials, respectively were investigated. Concrete without any fly ash added was also employed as the reference specimen. Laboratory tests were conducted to determine the surface layer properties of concrete including chloride transport, apparent water permeability and pore structure. The results demonstrate that incorporation of fly ash, for the early test period, promotes the chloride ingress at the surface layer of concrete but substituting proportions of fly ash may have little impact on it. With the process of chloride immersion, the chloride concentration at the surface layer of concrete with or without fly ash was found to be nearly the same. In addition, it is suggested that the water permeability at the concrete surface area is closely related to the fly ash contents as well as the chloride exposure time. Pore structure was characterized by means of mercury intrusion porosimetry (MIP test and the scanning electron microscopy (SEM images. The modification of pore structure of concrete submersed in distilled water is determined by the pozzolanic reaction of fly ash and the calcium leaching effect. The pozzolanic reaction was more dominant at the immersion time of 180 days while the calcium leaching effect became more evident after 270 days.

  6. Permeation Properties and Pore Structure of Surface Layer of Fly Ash Concrete.

    Science.gov (United States)

    Liu, Jun; Qiu, Qiwen; Xing, Feng; Pan, Dong

    2014-05-30

    This paper presents an experimental study on the nature of permeation properties and pore structure of concrete surface layers containing fly ash. Concretes containing different dosages of fly ash as a replacement for cement (15% and 30% by weight of total cement materials, respectively) were investigated. Concrete without any fly ash added was also employed as the reference specimen. Laboratory tests were conducted to determine the surface layer properties of concrete including chloride transport, apparent water permeability and pore structure. The results demonstrate that incorporation of fly ash, for the early test period, promotes the chloride ingress at the surface layer of concrete but substituting proportions of fly ash may have little impact on it. With the process of chloride immersion, the chloride concentration at the surface layer of concrete with or without fly ash was found to be nearly the same. In addition, it is suggested that the water permeability at the concrete surface area is closely related to the fly ash contents as well as the chloride exposure time. Pore structure was characterized by means of mercury intrusion porosimetry (MIP) test and the scanning electron microscopy (SEM) images. The modification of pore structure of concrete submersed in distilled water is determined by the pozzolanic reaction of fly ash and the calcium leaching effect. The pozzolanic reaction was more dominant at the immersion time of 180 days while the calcium leaching effect became more evident after 270 days.

  7. Influence Of Trace Metal Distribution On Its Leachability From Coal Fly Ash

    Science.gov (United States)

    The risks associated with the reuse of coal fly ash in natural environmental settings in terms of their mobility and ecotoxicological significance is largely determined by: (1) the physicochemical conditions the fly ash is placed under; (2) the total leachable metal content in fl...

  8. Research on the denitration mechanism of fly ash catalysts modified by low-temperature plasma technology

    Science.gov (United States)

    Nie, Wen-jie; Sha, Xiang-ling; Zhang, Lei; Wang, Yu-su; Wen, Xin; Li, Yong-hui

    2017-08-01

    There are three different fly ashes mixed with bentonite respectively as raw material to preparation of denitration catalyst. Then the catalyst combined with the low temperature plasma for denitration. The different mixing ratio, drying temperature and drying time of catalyst preparation were studied. The denitration mechanism of fly ash catalyst modified with different gases (O2, N2, Ar, and hydrocarbon gas) by low-temperature plasma technology was studied. The compositions of fly ash were detected by element analysis, ICP analysis, Boehm analysis, and Infrared spectral analysis which affected the denitration performance of fly ash catalyst. And we discussed the effect of denitration performance with different types of fly ash and plasma power. The results shown that: fly ash mixed with bentonite for 2:1, drying temperature is 100°C and drying time is 30 min are the optimal preparation conditions; The denitration performance is best of the catalyst which produced by circulating fluidized bed when the plasma power is 30 W. And Oxygen can be used as the modification gas for preparing the fly-ash catalyst. There are more basic functional groups on the surface of fly ash catalyst modified with oxygen atmosphere and the N=O plays a main role.

  9. Research on the denitration mechanism of fly ash catalysts modified by low-temperature plasma technology

    Directory of Open Access Journals (Sweden)

    Wen-jie Nie

    2017-08-01

    Full Text Available There are three different fly ashes mixed with bentonite respectively as raw material to preparation of denitration catalyst. Then the catalyst combined with the low temperature plasma for denitration. The different mixing ratio, drying temperature and drying time of catalyst preparation were studied. The denitration mechanism of fly ash catalyst modified with different gases (O2, N2, Ar, and hydrocarbon gas by low-temperature plasma technology was studied. The compositions of fly ash were detected by element analysis, ICP analysis, Boehm analysis, and Infrared spectral analysis which affected the denitration performance of fly ash catalyst. And we discussed the effect of denitration performance with different types of fly ash and plasma power. The results shown that: fly ash mixed with bentonite for 2:1, drying temperature is 100°C and drying time is 30 min are the optimal preparation conditions; The denitration performance is best of the catalyst which produced by circulating fluidized bed when the plasma power is 30 W. And Oxygen can be used as the modification gas for preparing the fly-ash catalyst. There are more basic functional groups on the surface of fly ash catalyst modified with oxygen atmosphere and the N=O plays a main role.

  10. Experimental investigation of clay fly ash bricks for gamma-ray shielding

    Energy Technology Data Exchange (ETDEWEB)

    Mann Harjinder Singh; Mudahar, Gumel Singh [Dept. of Physics, Punjabi University, Patiala (India); Brar, Gurdarshan Singh [Dept. of Higher Education, Additional Project Director, Chandigarh (India); Mann, Kulwinder Singh [Dept. of Applied Sciences, I.K. Gujral Punjab Technical University, Jalandhar (India)

    2016-10-15

    This study aims to determine the effect of fly ash with a high replacing ratio of clay on the radiation shielding properties of bricks. Some interaction parameters (mass attenuation coefficients, half value layer, effective atomic number, effective electron density, and absorption efficiency) of clay fly ash bricks were measured with a NaI(Tl) detector at 661.6 keV, 1,173.2 keV, and 1,332.5 keV. For the investigation of their shielding behavior, fly ash bricks were molded using an admixture to clay. A narrow beam transmission geometry condition was used for the measurements. The measured values of these parameters were found in good agreement with the theoretical calculations. The elemental compositions of the clay fly ash bricks were analyzed by using an energy dispersive X-ray fluorescence spectrometer. At selected energies the values of the effective atomic numbers and effective electron densities showed a very modest variation with the composition of the fly ash. This seems to be due to the similarity of their elemental compositions. The obtained results were also compared with concrete, in order to study the effect of fly ash content on the radiation shielding properties of clay fly ash bricks. The clay fly ash bricks showed good shielding properties for moderate energy gamma rays. Therefore, these bricks are feasible and eco-friendly compared with traditional clay bricks used for construction.

  11. Environmental-benign utilisation of fly ash as low-cost adsorbents.

    Science.gov (United States)

    Wang, Shaobin; Wu, Hongwei

    2006-08-25

    Fly ash is a waste substance from thermal power plants, steel mills, etc. that is found in abundance in the world. In recent years, utilisation of fly ash has gained much attention in public and industry, which will help reduce the environmental burden and enhance economic benefit. In this paper, the technical feasibility of utilisation of fly ash as a low-cost adsorbent for various adsorption processes for removal of pollutants in air and water systems has been reviewed. Instead of using commercial activated carbon or zeolites, a lot of researches have been conducted using fly ash for adsorption of NO(x), SO(x), organic compounds, and mercury in air, and cations, anions, dyes and other organic matters in waters. It is recognised that fly ash is a promising adsorbent for removal of various pollutants. Chemical treatment of fly ash will make conversion of fly ash into a more efficient adsorbent for gas and water cleaning. Investigations also revealed that unburned carbon component in fly ash plays an important role in adsorption capacity. Directions for future research are also discussed.

  12. Experimental Study on Durability Improvement of Fly Ash Concrete with Durability Improving Admixture

    Directory of Open Access Journals (Sweden)

    Hong-zhu Quan

    2014-01-01

    Full Text Available In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete, the compressive strength of fly ash concrete can be improved by 10%–20%, and the drying shrinkage is reduced by 60%. Carbonation resistance of concrete is roughly proportional to water-cement ratio regardless of water-binder ratio and fly ash replacement ratio. For the specimens cured in air for 2 weeks, the freezing-thawing resistance is improved. In addition, by making use of durability improving admixture, it is easier to control the air content and make fly ash concrete into nonair-entraining one. The quality of fly ash concrete is thereby optimized.

  13. Fly ash from coal and biomass for use in concrete : Origin, properties and performance

    NARCIS (Netherlands)

    Saraber, A.J.

    2017-01-01

    Coal fly ash is widely used in as raw material in concrete industry because it can replace part of the cement and fly ash contributes to improve certain properties of concrete. As a way to reduce the contribution of coal fired power plants to the climate change, more and more coal is replaced by

  14. Gravel road stabilisation of Ehnsjoevaegen, Hallstavik[Using fly ash]; Skogsbilvaegsrenovering av Ehnsjoevaegen, Hallstavik

    Energy Technology Data Exchange (ETDEWEB)

    Macsik, Josef; Svedberg, Bo [Ecoloop, Stockholm (Sweden)

    2006-03-15

    Fly ash in geotechnical applications has stabilising, isolating, low permeability and hardening effect. Fly ash can be used in road constructions with low bearing capacity, as well as on top cover material on landfills. The aim of the project was to build a road section with fly ash stabilised gravel, based on laboratory studies, and follow up technical and environmental aspect during the first year after stabilisation. The overall aim of this project was to evaluate fly ash from Holmen Paper, Hallstavik, from technical and environmental point of view in a gravel road construction. A gravel road, Ehnsjoevaegen, was stabilised with fly ash during autumn 2004. This road was a low priority road. The fly ash stabilised road section was 1300 m long. Gravel from the road Ehnsjoevaegen was stabilised and investigated in a laboratory study. Leachability of metals and geotechnical aspects were investigated. The laboratory study showed that fly ash stabilised gravel has high shear strength, however its thawing resistance is not fully acceptable. Additives of cement or merit are needed in order to increase its thawing resistance. The actual road section is not going to be used during thawing period and no additives were used. The test road is divided into different sections including a reference section. The road stabilisation work was conducted with gravel transported to Ehnsjoevaegen from off site and not with gravel from the site. Fly ash was tipped off on a levelled road, followed by tipping of gravel. Mixing fly ash and gravel was done on site by a road scraper. After the mixing the road was gravelled with 0,1 m graded gravel. In this project the fly ash had low water content. In order to get optimal compaction water was added from a tanker supplying water before compacted with a compactor. Results from the pilot test shows that fly ash stabilised gravel can be tipped, mixed and compacted effectively. Tipping can be optimised if fly ash and gravel is mixed in a mixer

  15. Recycling of MSWI fly ash in clay bricks-effect of washing and electrodialytic treatment

    DEFF Research Database (Denmark)

    Chen, Wan; Klupsch, Ewa; Kirkelund, Gunvor Marie

    2017-01-01

    Fly ash generated from municipal solid waste incineration (MSWI) is a hazardous waste due to presence and leachability of heavy metals and organic pollutants (e.g. dioxins and polycyclic aromatic hydrocarbons). In 2000, approximately 25 Mt/year of fly ash was generated in USA, Japan and EU...... (Reijnders 2005). Electrodialytic remediation (EDR) is one technique for MSWI fly ash treatment (Ferreira et al. 2005), where an electric DC field is applied to an ash-water suspension to extract and separate heavy metal by migration towards anode or cathode through ion exchange membranes. Ferreira et al....... (2008) observed that in MSWI ash treated by water washing and EDR, metals were mainly in the strongly bonded and residual phases, indicating a reduction in the ash’s environmental risk. Belmonte et al. (2016) made Greenlandic bricks (∼2 g discs) containing 20% and 40% of EDR treated MSWI fly ash...

  16. Treatment and toxicity evaluation of methylene blue using electrochemical oxidation, fly ash adsorption and combined electrochemical oxidation-fly ash adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Kai-sung Wang; Ming-Chi Wei; Tzu-Huan Peng; Heng-Ching Li; Shu-Ju Chao; Tzu-Fang Hsu; Hong-Shen Lee; Shih-Hsien Chang [Chung-Shan Medical University, Taichung (Taiwan)

    2010-08-15

    Treatment of a basic dye, methylene blue, by electrochemical oxidation, fly ash adsorption, and combined electrochemical oxidation-fly ash adsorption was compared. Methylene blue at 100 mg L{sup -1} was used in this study. The toxicity was also monitored by the Vibrio fischeri light inhibition test. When electrochemical oxidation was used, 99% color and 84% COD were removed from the methylene blue solution in 20 min at a current density of 428 A m{sup -2}, NaCl of 1000 mg L{sup -1}, and pH{sub 0} of 7. However, the decolorized solution showed high toxicity (100% light inhibition). For fly ash adsorption, a high dose of fly ash (>20,000 mg L{sup -1}) was needed to remove methylene blue, and the Freundlich isotherm described the adsorption behavior well. In the combined electrochemical oxidation-fly ash adsorption treatment, the addition of 4000 mg L{sup -1} fly ash effectively reduced intermediate toxicity and decreased the COD of the electrochemical oxidation-treated methylene blue solution. The results indicated that the combined process effectively removed color, COD, and intermediate toxicity of the methylene blue solution.

  17. Investigation of the possibility of binding fly ash particles by elemental sulphur

    Directory of Open Access Journals (Sweden)

    Vidojković V.

    2006-01-01

    Full Text Available Thermal power plants in Serbia use lignite for electrical power production The secondary product of coal combustion is fly ash in the amount of 17%. Fly ash causes the pollution of air, water and soil, and also cause many human, especially lung diseases. Secondary sulphur is a product of crude oil refining. The aim of this study was to investigate the use of sulphur as a bonding material in ultra fine particle agglomeration (smaller than 63 μm in fly ash. The agglomeration should make the ash particles larger and heavy enough to fall without flying fractions. The experiments showed that during the homogenization of the ashes and sulphur from 150 to 170 °C in a reactor with intensive mixing, an amount of 15% sulphur was sufficient to bond particles and cause agglomeration without visible flying fractions.

  18. Influence of alkali cation on the mechanical properties and durability of fly ash based geopolymers.

    Science.gov (United States)

    Nikolić, Irena; Zejak, Radomir; Jankovič-Častvan, Ivona; Karanović, Ljiljana; Radmilović, Vuk; Radmilović, Velimir

    2013-01-01

    This research has provided information about the influence of alkali cations (Na+ and K+) on the mechanical properties and durability of fly ash based geopolymers. The results have shown that alkali cations have a strong influence on the mechanical properties of fly ash based geopolymers. K-geopolymers generally reach a higher value of compressive strength in comparison to Na- geopolymers. On the other hand, microstructure and phase composition of fly ash based geopolymers are not influenced by the nature of alkali cations. The ratio of main gel structure forming elements is practically not affected by the nature of alkali cations. Durability of fly ash based geopolymers in different aquatic environments is greatly dependent on the choice of alkali cations. Na- geopolymers are generally more resistant in water and aggressive environments than the K-geopolymers. The best durability of fly ash based geopolymers was observed in sea water.

  19. Strength and workability characteristics of fly ash-based natural fibre reinforced mortar

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrisha, G.; Sundararajan, T. [Pondicherry Engineering College, Pondicherry (India). Dept. of Civil Engineering

    2003-07-01

    Fly ash from Neyveli thermal power station was used as replacement for ordinary Portland cement in high-volumes in coir fibre reinforced mortar to study its influence on the modification of the matrix, improvement in workability and strength characteristics. Four aspect ratios (15, 30, 50 and 70); four levels of fibre contents (0.2%, 0.3%, 0.4%, 0.5% - by weight of cement) were considered to highlight the positive influence of flyash in improving the workability and strength characteristics of flyash based coir fibre reinforced mortar. 3 refs., 9 tabs.

  20. The use of a modified fly ash as an adsorbent for lead

    Energy Technology Data Exchange (ETDEWEB)

    Woolard, C.D.; Petrus, K.; van der Horst, M. [University of Port Elizabeth, Port Elizabeth (South Africa). Dept. of Chemistry

    2000-07-01

    Coal fly ash was modified by hydrothermal treatment with NaOH solutions of varying concentrations. During the modification the zeolites, NaP1 and hydroxysodalite, were synthesised. Increasing base concentration led to hydroxysodalite being the preferred product. Elemental analysis revealed that the modification treatment preferentially leached Si from the fly ash at low base concentrations. Elevated base concentrations, however, resulted in Al being leached as well as the inclusion of Na in the zeolite product. The modification activated the fly ash significantly with respect to specific surface area and cation exchange capacity. Lead sorption studies were performed. Adsorption experiments at pH = 5, revealed that all modified ash samples adsorbed significantly more Pb than the raw ash. The best adsorption was obtained for ash, modified with 3M NaOH. 3M NaOH-modified ash also proved the most effective sorbent when adsorption was determined as a function of pH.

  1. Coal Fly Ash Ceramics: Preparation, Characterization, and Use in the Hydrolysis of Sucrose

    OpenAIRE

    Ricardo Pires dos Santos; Jorge Martins; Carlos Gadelha; Benildo Cavada; Alessandro Victor Albertini; Francisco Arruda; Mayron Vasconcelos; Edson Teixeira; Francisca Alves; José Lima Filho; Valder Freire

    2014-01-01

    Coal ash is a byproduct of mineral coal combustion in thermal power plants. This residue is responsible for many environmental problems because it pollutes soil, water, and air. Thus, it is important to find ways to reuse it. In this study, coal fly ash, obtained from the Presidente Médici Thermal Power Plant, was utilized in the preparation of ceramic supports for the immobilization of the enzyme invertase and subsequent hydrolysis of sucrose. Coal fly ash supports were prepared at several c...

  2. Effect of fly ash amendment on metolachlor and atrazine degradation and microbial activity in two soils.

    Science.gov (United States)

    Ghosh, Rakesh Kumar; Singh, Neera; Singh, Shashi Bala

    2016-08-01

    The study reports the effect of Inderprastha (IP) and Badarpur (BP) fly ashes on degradation of metolachlor and atrazine in Inceptisol and Alfisol soils. Metolachlor dissipated at faster rate in Alfisol (t1/2 8.2-8.6 days) than in Inceptisol (t1/2 13.2-14.3 days). The fly ashes enhanced the persistence of metolachlor in both the soils; however, the extent of effect was more in Inceptisol (t1/2 16.6-33.8 days) than Alfisol (t1/2 8.4-12 days) and effect increased with fly ash dose. 2-Ethyl-6-methylacetanilide was detected as the only metabolite of metolachlor. Atrazine was more persistent in flooded soils (t1/2 10.8-20.3 days) than nonflooded soils (t1/2 3.7-12.6 days) and fly ash increased its persistence, but effect was more pronounced in the flooded Inceptisol (t1/2 23.7-31 days) and nonflooded Alfisol (t1/2 6.3-10.1 days). Increased herbicide sorption in the fly ash-amended soils might have contributed to the increased pesticide persistence. The IP fly ash inhibited microbial biomass carbon at 5 % amendment levels in both the soils, while BP fly ash slightly increased microbial biomass carbon (MBC) content. Dehydrogenase activity was inhibited by both fly ashes in both the soils with maximum inhibition observed in the IP fly ash-amended Alfisol. No significant effect of fly ash amendment was observed on the fluorescein diacetate activity.

  3. Superior photocatalytic, electrocatalytic, and self-cleaning applications of Fly ash supported ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Thirumalai, Kuppulingam; Balachandran, Subramanian [Department of Chemistry, Annamalai University, Annamalainagar, 608 002, Tamil Nadu (India); Swaminathan, Meenakshisundaram, E-mail: chemres50@gmail.com [Department of Chemistry, Annamalai University, Annamalainagar, 608 002, Tamil Nadu (India); Nanomaterials Laboratory, International Research Centre, Kalasalingam Universty, Krihnankoil, 626126 (India)

    2016-11-01

    Ever growing research on modified semiconductor oxides made a significant progress in catalytic functional materials. In this article, we report the modification of ZnO photocatalyst by a simple hydrothermal decomposition method utilizing the cheaply available industrial waste fly ash. This modified Fly ash-ZnO photocatalyst was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), high resolution transmission electron microscopy (HR-TEM), Atomic force microscopy (AFM), photoluminescence spectroscopy (PL) and diffuse reflectance spectroscopy (DRS). The XRD pattern indicates the presence of fly ash components and the hexagonal wurtzite structured ZnO. TEM images reveal well defined nanorod like structure. Reduction of photoluminescence intensity of Fly ash-ZnO at 418 nm, when compared to, prepared ZnO, indicates the suppression of recombination of the photogenerated electron–hole pair by loaded Fly ash on ZnO. Fly ash-ZnO exhibits enhanced photocatalytic activity for the degradation of azo dyes Reactive Orange 4, Rhodamine-B and Trypan Blue. This catalyst shows higher electrocatalytic activity than ZnO in the oxidation of methanol. Significant hydrophobicity of Fly ash-ZnO reveals its self cleaning property. - Highlights: • The degradation efficiency of Fly ash-ZnO under UV and Solar irradiation is greater than prepared ZnO and TiO{sub 2}‒P25. • Electrocatalytic activity of Fly ash-ZnO exhibits enhanced current production by methanol oxidation. • Fly ash-ZnO shows the high hydrophobicity than ZnO, it can be used as a self cleaning material for industrial applications.

  4. Fly ash application in nutrient poor agriculture soils: impact on methanotrophs population dynamics and paddy yields.

    Science.gov (United States)

    Singh, Jay Shankar; Pandey, Vimal Chandra

    2013-03-01

    There are reports that the application of fly ash, compost and press mud or a combination thereof, improves plant growth, soil microbial communities etc. Also, fly ash in combination with farmyard manure or other organic amendments improves soil physico-chemical characteristics, rice yield and microbial processes in paddy fields. However, the knowledge about the impact of fly ash inputs alone or in combination with other organic amendments on soil methanotrophs number in paddy soils is almost lacking. We hypothesized that fly ash application at lower doses in paddy agriculture soil could be a potential amendment to elevate the paddy yields and methanotrophs number. Here we demonstrate the impact of fly ash and press mud inputs on number of methanotrophs, antioxidants, antioxidative enzymatic activities and paddy yields at agriculture farm. The impact of amendments was significant for methanotrophs number, heavy metal concentration, antioxidant contents, antioxidant enzymatic activities and paddy yields. A negative correlation was existed between higher doses of fly ash-treatments and methanotrophs number (R(2)=0.833). The content of antioxidants and enzymatic activities in leaves of higher doses fly ash-treated rice plants increased in response to stresses due to heavy metal toxicity, which was negatively correlated with rice grain yield (R(2)=0.944) and paddy straw yield (R(2)=0.934). A positive correlation was noted between heavy metals concentrations and different antioxidant and enzymatic activities across different fly ash treated plots.The data of this study indicate that heavy metal toxicity of fly ash may cause oxidative stress in the paddy crop and the antioxidants and related enzymes could play a defensive role against phytotoxic damages. We concluded that fly ash at lower doses with press mud seems to offer the potential amendments to improving soil methanotrophs population and paddy crop yields for the nutrient poor agriculture soils. Copyright © 2012

  5. Effect of Fly-ash on The Performance of Asphalt Concrete Mixes

    Directory of Open Access Journals (Sweden)

    Aliaa Faleh Al.ani

    2017-08-01

    Full Text Available At last year, effectively fly ash has been used in producing high performance concrete mixes with limited used in asphalt pavements. This is possibly due to the performance advantage that fly ash equipped to asphalt mixes in now days. A bituminous paving mixture is a mix of coarse aggregate, fine aggregate and bitumen mixed in suitable proportion to result strong and durable mix to bear traffic load. In this paving mix, normally limestone and fly ash are used as filler material. In this research , the performance of asphalt concrete mixes modified with fly ash as a partial replacement of limestone dust mineral filler were evaluated. Four replacement rates were used; 0, 1, 2, and 3 percent by weight of aggregate. Asphalt concrete mixes were prepared at their optimum asphalt content and then tested to evaluate their engineering properties which include moisture damage, resilient modulus, permanent deformation and fatigue characteristics. These properties have been evaluated using indirect tensile strength, uniaxial repeated loading and repeated flexural beam tests. Mixes modified with fly ash were found to have improved fatigue and permanent deformation characteristics, also showed lower moisture susceptibility and high resilient modulus. the result showed that a rate changed from 1 to 3 percent has shown an increase in resilient modulus for addition of fly ash as a filler substitute and the resilient modulus for mixes with 3 percent fly ash was 1.31 times that for mixes with 0 percent fly ash. The altering of fly ash as a filler substitute from a range (1-3 percent has modified the fatigue property of the asphalt concrete mixes as determined by flexural test, Significantly, to modify the asphalt concrete manner taken the percent of fly ash 2, and to produce the mixes more durable , higher resistance to distresses by adding the local knowledge.

  6. Evaluation of Changes in Index Properties of Lateritic Soil Stabilized with Fly Ash

    Directory of Open Access Journals (Sweden)

    Agapitus AMADI

    2010-12-01

    Full Text Available For soils to be suitable in civil engineering projects, they must meet existing local requirements for index properties in addition to certain strength criteria. Typically, specifications limit these properties to some threshold values which in most cases are project specific. Some lateritic soils in their natural state need some treatment/modification to meet these specification requirements. The objective of this study was to evaluate changes in the index properties (i.e., particle size distribution, Atterberg limits and compaction characteristics of a residually derived lateritic soil following fly ash application. Lateritic soil – fly ash mixtures with up to 20% fly ash by dry weight of soil were tested and specimens for compaction characteristics were prepared at different compaction states (optimum, dry and wet of optimum moisture content and compacted using British Standard Light (BSL compactive effort. While soil – fly ash mixtures containing up to 15% fly ash classify as CL according to USCS classification system and plotted above A-line in the plasticity chart, it was observed that changes in the gradation characteristics of soil sample treated with 20% fly ash resulted in the alteration of its classification to ML as well as the crossing of the A- line to the silty region. The liquid limit (LL varied from 42.2 to 29.53% representing 70% reduction while the plasticity index (PI of specimen treated with 20% fly ash was 16% lower than that of natural soil. The optimum moisture content (OMC ranged from 17.36% for the natural soil to 18.34% for soil mixtures containing 20% fly ash which yielded dry unit weight of 17.2kN/m3 for the natural soil and 16.1kN/m3 for samples treated with 20% fly ash. From the study, useful data were obtained showing substantial and desirable changes in the properties of lateritic soil as a civil engineering material on application of fly ash.

  7. Examination of the possibilities of the application of waste materials (gypsum, fly ash and bottom ash in construction

    Directory of Open Access Journals (Sweden)

    Trifunović Prvoslav

    2014-01-01

    Full Text Available The possibilities of the application of waste gypsum (citrogypsum, nitrogyosum and sulphogypsum, fly ash and bottom ash in construction: for production of gypsum binders (a-calcium sulphate hemihydrate, b-calcium sulphata hemihydrate and b-anhydrite, for obtaining construction products (bricks and blocks and as component materials for road layers were presented in this work. Also, the possibilities of the application of sulphogypsum (or FGD gypsum for solidification and stabilization of fly ash were presented. The obtained results could have great importance in both ecological and economic views (elimination of important pollutants of water, air and soil, replacement of natural by waste materials, reduction of waste disposal cost.

  8. Chemical properties of fly ashes produced in the Arcelor Mittal power station and the Třinec ironworks power station

    Science.gov (United States)

    Bulikova, L.

    2017-10-01

    Fly ash is an inorganic secondary material coming from combustion of coal in power stations. Tested fly ashes were produced by different processes. Therefore they have different parameters. Their chemical properties were determined using chemical analyzes and compared. Results of laboratory tests show possibility to use of fly ashes in road construction as binder for soil treatment.

  9. Selenium in pollen gathered by bees foraging on fly ash-grown plants

    Energy Technology Data Exchange (ETDEWEB)

    De Jong, D.; Morse, R.A.; Gutenmann, W.H.; Lisk, D.J.

    1977-10-01

    Fly ash is the material collected in the stacks of coal burning electric power-generating plants by electrostatic precipitators. About 26 million metric tons of fly ash was estimated to have been produced in 1975 (BRACKETT, 1970). Aside from a small percentage of the material which is used as a base material for roads and in concrete, the bulk of it is deposited in landfills. It was first reported by Gutenmann et al. (1976) that sweet clover, found voluntarily growing on a fly ash landfill site, contained up to 200 ppM of selenium. Fly ashes from 21 states were found to contain the element. Cabbage grown on each of these fly ashes added (7 percent w/w) to soil was shown to absorb selenium in proportion to its concentration in the particular ash (GUTENMANN et al., 1976). The percentage of fly ash in soil was also shown to dictate the extent of selenium absorption by a variety of plants (FURR et al., 1976). In the work reported, pollen collected by honey bees foraging on plants growing on a fly ash landfill was analyzed for selenium and compared with that collected by bees from the same plants growing on soil.

  10. Steel Fibre Reinforcing Characteristics on the Size Reduction of Fly Ash Based Concrete

    Directory of Open Access Journals (Sweden)

    Sounthararajan Vallarasu Manoharan

    2014-01-01

    Full Text Available The behavior of glued steel fibres in high strength concrete with size reduction properties of concrete has been attempted. Glued steel fibres with both ends hooked having length to diameter ratio of 70 was added at a dosage level of 0.5% to 1.5% by volume fraction. The study was carried out to analyze the effects of fibre addition on the thickness reduction of concrete element. A high strength concrete mixture was designed and various thicknesses of concrete prisms were casted for different volume fraction of steel fibres. The hardened concrete properties were determined based on the mix constituents such as water to binder ratio 0.3 (w/b, superplasticizer dosage, fine to coarse aggregate ratio 0.6 (F/c, and fly ash replacement level at 25% and 50% by weight of binder content. The experimental test results showed that the flexural strength varies with respect to the depth of concrete specimen. It can be observed that the reduction in size up to 10% size containing 25% fly ash with 1.5% steel fibres showed better strength enhancement of 4.70 MPa and 6.69 MPa for 7 days and 28 days, respectively. Also, the addition of steel fibres at higher percentage of fly ash containing 50% showed better improvement in the flexural strength for the size reduction at 5%, when compared to plain concrete beam which exhibited higher stress carrying capacity of 6.08 MPa at 28 days and showed an increase of 7.99%.

  11. Biological and chemical interactions excelerating the removal of impurities from fly ashes

    Directory of Open Access Journals (Sweden)

    Štyriaková Iveta

    2002-03-01

    Full Text Available The mesophilic bacteria were isolated from the deposit of fly ash in Chalmová (Slovakia and identified using the BBL identification system. Bacillus cereus was the dominant species in this deposit of aluminosilicate minerals. Under laboratory conditions , Bacillus cereus accelerated the extraction of major and trace impurities in fly ash during bioleaching processes. This process was dependent on bacterial adhesion and production of organic acids. The effect of organic acids produced by bacteria was detected especially in sites where impregnated metals were found in the aluminosilicate structure. Amorphous spherical aluminosilicate particles in allotriomorphic aluminosilicate grains represent a main mineral component of fly-ash in which also elements such as Fe, Ti, Mn, As are bound. The rate of mobilization of Al, Si and Ti from coal fly ash under biochemically relevant conditions in vitro was previously shown to depend on the quantity of the ash microspheres. The qualitative EDS analyse of leachates confirmed the extraction of toxic elements (As and Mn from the initial sample of fly ash.Heterotrophic bacteria of Bacillus genus are capable to remove impurities from deposited fly-ash. A long-term deposition of energy fly-ash causes chemical and mineralogical changes as a result of weathering processes. Depending on the composition of coal concentrate containing SiO2, Al2O3, Fe2O3, CaO, MgO and other oxides, fly ash can provide a useful preliminary batch for the preparation of glass-ceramics or zeolite after extracting of bacterially dissolved elements from it. The mobility of major impurities (Ca and Fe and heavy metals, caused by biochemical leaching of fly ash, suggests the possibility of the development of an alternative way of this raw material treatment. The advantage of bioleaching is relatively low cost and the subsequent low demand for energy compared with conventional technologies.

  12. Characteristics of SCC with Fly Ash and Manufactured Sand

    Science.gov (United States)

    Praveen Kumar, K.; Radhakrishna

    2016-09-01

    Self compacting concrete (SCC) of M40 grade was designed. The binder in SCC consists of OPC and fly ash in the ratio of 65:35. River sand was replaced by manufactured sand (M-sand) at replacement levels of 20,40,60,80 and 100%. An attempt was made to evaluate the workability and strength characteristics of self compacting concrete with river sand and manufactured sand as fine aggregates. For each replacement level, constant workability was maintained by varying the dosage of superplasticizer. T50 flow time, V Funnel time, V-funnel T5 time as well as compressive, split tensile and flexural strength of SCC were found at each replacement level of M-sand. They were compared to SCC with river sand. Results indicate favourable use of M-sand in preparation of Self Compacting Concrete.

  13. Electroless Ag coating of fly ash cenospheres using polyaniline activator

    Science.gov (United States)

    Wang, Wei; Li, Qin; Li, Ying; Xu, Hui; Zhai, Jianping

    2009-11-01

    The electroless Ag coating of fly ash cenospheres employing polyaniline activator was investigated after polyaniline activator was coated on the surfaces of the cenosphere particles by in situ chemical polymerization. The composites were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, UV-visible absorption spectroscopy, x-ray diffraction and thermogravimetric analysis (TGA). The results indicate that a small amount of polyaniline activator was deposited in a discontinuous way on the surfaces of the cenosphere particles. Due to the activation of polyaniline, relatively compact and continuous Ag layer with a thickness of about 4 µm was obtained under the given electroless plating condition. The possible interaction between polyaniline and silver ions and the mechanism of Ag deposition were also investigated by the x-ray photoelectron spectroscopy technique.

  14. Electroless Ag coating of fly ash cenospheres using polyaniline activator

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wei; Li Qin; Li Ying; Xu Hui; Zhai Jianping, E-mail: jpzhai@nju.edu.c [State Key Laboratory of Pollution Control and Resource Reuse, and School of the Environment, Nanjing University, Nanjing 210093 (China)

    2009-11-07

    The electroless Ag coating of fly ash cenospheres employing polyaniline activator was investigated after polyaniline activator was coated on the surfaces of the cenosphere particles by in situ chemical polymerization. The composites were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, UV-visible absorption spectroscopy, x-ray diffraction and thermogravimetric analysis (TGA). The results indicate that a small amount of polyaniline activator was deposited in a discontinuous way on the surfaces of the cenosphere particles. Due to the activation of polyaniline, relatively compact and continuous Ag layer with a thickness of about 4 {mu}m was obtained under the given electroless plating condition. The possible interaction between polyaniline and silver ions and the mechanism of Ag deposition were also investigated by the x-ray photoelectron spectroscopy technique.

  15. Floating cultivation of marine cyanobacteria using coal fly ash.

    Science.gov (United States)

    Matsumoto, M; Yoshida, E; Takeyama, H; Matsunaga, T

    2000-01-01

    The aim of this study was to develop improved methodologies for bulk culturing of biotechnologically useful marine cyanobacteria in the open ocean. We have investigated the viability of using coal fly ash (CFA) blocks as the support medium in a novel floating culture system for marine micro-algae. The marine cyanobacterium Synechococcus sp. NKBG 040607 was found to adhere to floating CFA blocks in liquid culture medium. Maximum density of attached cells of 2.0 x 10(8) cells/cm2 was achieved using seawater. The marine cyanobacterium Synechococcus sp. NKBG 042902 weakly adhered to floating CFA blocks in BG-11 medium. Increasing the concentration of calcium ion in the culture medium enhanced adherence to CFA blocks.

  16. Resource recovery from coal fly ash waste: an overview study

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V.; Matsuda, M.; Miyake, M. [Okayama University, Okayama (Japan). Graduate School of Environmental Science

    2008-02-15

    Coal fly ash (CFA) is a useful byproduct of the combustion of coal. It is composed primarily of almost perfectly spherical aluminosilicate glass particles. This spherical characteristic and other characteristics of CFA should be exploited, rather than simply using CFA as inert filler for construction. Unfortunately, the presence of carbon residues and high levels of heavy metals has so far limited the uses of CFA. Forced leaching methods have been used to improve the technical and environmentally friendly qualities of CFA, but these processes do not seem to be economically viable. Actually, CFA is a major source of Si and Al for the synthesis of industrial minerals. Potential novel uses of CFA, e.g., for the synthesis of ceramic materials, ceramic membrane filters, zeolites, and geopolymers, are reviewed in this article with the intention of exploring new areas that will

  17. Optimizing and Characterizing Geopolymers from Ternary Blend of Philippine Coal Fly Ash, Coal Bottom Ash and Rice Hull Ash

    Directory of Open Access Journals (Sweden)

    Martin Ernesto Kalaw

    2016-07-01

    Full Text Available Geopolymers are inorganic polymers formed from the alkaline activation of amorphous alumino-silicate materials resulting in a three-dimensional polymeric network. As a class of materials, it is seen to have the potential of replacing ordinary Portland cement (OPC, which for more than a hundred years has been the binder of choice for structural and building applications. Geopolymers have emerged as a sustainable option vis-à-vis OPC for three reasons: (1 their technical properties are comparable if not better; (2 they can be produced from industrial wastes; and (3 within reasonable constraints, their production requires less energy and emits significantly less CO2. In the Philippines, the use of coal ash, as the alumina- and silica- rich geopolymer precursor, is being considered as one of the options for sustainable management of coal ash generation from coal-fired power plants. However, most geopolymer mixes (and the prevalent blended OPC use only coal fly ash. The coal bottom ash, having very few applications, remains relegated to dumpsites. Rice hull ash, from biomass-fired plants, is another silica-rich geopolymer precursor material from another significantly produced waste in the country with only minimal utilization. In this study, geopolymer samples were formed from the mixture of coal ash, using both coal fly ash (CFA and coal bottom ash (CBA, and rice hull ash (RHA. The raw materials used for the geopolymerization process were characterized using X-ray fluorescence spectroscopy (XRF for elemental and X-ray diffraction (XRD for mineralogical composition. The raw materials’ thermal stability and loss on ignition (LOI were determined using thermogravimetric analysis (TGA and reactivity via dissolution tests and inductively-coupled plasma mass spectrometry (ICP analysis. The mechanical, thermal and microstructural properties of the geopolymers formed were analyzed using compression tests, Fourier transform infra-red spectroscopy (FTIR

  18. Optimizing and Characterizing Geopolymers from Ternary Blend of Philippine Coal Fly Ash, Coal Bottom Ash and Rice Hull Ash

    Science.gov (United States)

    Kalaw, Martin Ernesto; Culaba, Alvin; Hinode, Hirofumi; Kurniawan, Winarto; Gallardo, Susan; Promentilla, Michael Angelo

    2016-01-01

    Geopolymers are inorganic polymers formed from the alkaline activation of amorphous alumino-silicate materials resulting in a three-dimensional polymeric network. As a class of materials, it is seen to have the potential of replacing ordinary Portland cement (OPC), which for more than a hundred years has been the binder of choice for structural and building applications. Geopolymers have emerged as a sustainable option vis-à-vis OPC for three reasons: (1) their technical properties are comparable if not better; (2) they can be produced from industrial wastes; and (3) within reasonable constraints, their production requires less energy and emits significantly less CO2. In the Philippines, the use of coal ash, as the alumina- and silica- rich geopolymer precursor, is being considered as one of the options for sustainable management of coal ash generation from coal-fired power plants. However, most geopolymer mixes (and the prevalent blended OPC) use only coal fly ash. The coal bottom ash, having very few applications, remains relegated to dumpsites. Rice hull ash, from biomass-fired plants, is another silica-rich geopolymer precursor material from another significantly produced waste in the country with only minimal utilization. In this study, geopolymer samples were formed from the mixture of coal ash, using both coal fly ash (CFA) and coal bottom ash (CBA), and rice hull ash (RHA). The raw materials used for the geopolymerization process were characterized using X-ray fluorescence spectroscopy (XRF) for elemental and X-ray diffraction (XRD) for mineralogical composition. The raw materials’ thermal stability and loss on ignition (LOI) were determined using thermogravimetric analysis (TGA) and reactivity via dissolution tests and inductively-coupled plasma mass spectrometry (ICP) analysis. The mechanical, thermal and microstructural properties of the geopolymers formed were analyzed using compression tests, Fourier transform infra-red spectroscopy (FTIR), scanning

  19. Optimizing and Characterizing Geopolymers from Ternary Blend of Philippine Coal Fly Ash, Coal Bottom Ash and Rice Hull Ash.

    Science.gov (United States)

    Kalaw, Martin Ernesto; Culaba, Alvin; Hinode, Hirofumi; Kurniawan, Winarto; Gallardo, Susan; Promentilla, Michael Angelo

    2016-07-15

    Geopolymers are inorganic polymers formed from the alkaline activation of amorphous alumino-silicate materials resulting in a three-dimensional polymeric network. As a class of materials, it is seen to have the potential of replacing ordinary Portland cement (OPC), which for more than a hundred years has been the binder of choice for structural and building applications. Geopolymers have emerged as a sustainable option vis-à-vis OPC for three reasons: (1) their technical properties are comparable if not better; (2) they can be produced from industrial wastes; and (3) within reasonable constraints, their production requires less energy and emits significantly less CO₂. In the Philippines, the use of coal ash, as the alumina- and silica- rich geopolymer precursor, is being considered as one of the options for sustainable management of coal ash generation from coal-fired power plants. However, most geopolymer mixes (and the prevalent blended OPC) use only coal fly ash. The coal bottom ash, having very few applications, remains relegated to dumpsites. Rice hull ash, from biomass-fired plants, is another silica-rich geopolymer precursor material from another significantly produced waste in the country with only minimal utilization. In this study, geopolymer samples were formed from the mixture of coal ash, using both coal fly ash (CFA) and coal bottom ash (CBA), and rice hull ash (RHA). The raw materials used for the geopolymerization process were characterized using X-ray fluorescence spectroscopy (XRF) for elemental and X-ray diffraction (XRD) for mineralogical composition. The raw materials' thermal stability and loss on ignition (LOI) were determined using thermogravimetric analysis (TGA) and reactivity via dissolution tests and inductively-coupled plasma mass spectrometry (ICP) analysis. The mechanical, thermal and microstructural properties of the geopolymers formed were analyzed using compression tests, Fourier transform infra-red spectroscopy (FTIR), scanning

  20. Management of root-knot disease of tomato by the application of fly ash in soil

    Energy Technology Data Exchange (ETDEWEB)

    Khan, M.R.; Khan, M.W.; Sigh, K. [Aligarh Muslim University, Aligarh (India). Inst. of Agriculture

    1997-02-01

    The effects of fly ash at different concentrations (0, 10, 20, 30... 100% vol./vol. in soil) on plant growth and yield were investigated in tomato plants infected or noninfected with root-knot nematode, Meloidogyne incognita (2000 juveniles per plant) in clay pots. Ash application enhanced plant growth, leaf pigment concentrations, fruit production, weight of fruit/plant and mean fruit weight of both nematode-infected and noninfected tomato plants, being maximum in the soil containing 50 or 60% fly ash. Fly ash treatments adversely affected root invasion by juveniles, disease intensity and reproduction of the nematodes. Linear regression suggested 40% fly ash as the most economic level, enhancing yield of infected plants by 96% and suppressing the nematode disease and reproduction by 63 and 76% respectively.

  1. Novel materials based on microspheres from coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    A.G. Anshits; T.A. Vereshchagina; O.M. Sharonova; N.N. Anshits; E.V. Rabchevskii; O.A. Bayukov; S.V. Podoinitsyn [Institute of Chemistry and Chemical Technology (Russian Federation)

    2003-07-01

    Several morphological types of microspheres, comparable with synthetic ones by the composition and the properties, are generated during high-temperature thermochemical transformations while burning coal at the power plants. The three-step process for separation of ashes formed as a result of burning three different types of coals, including magnetic separation, hydrodynamic separation and granulometric classification, enabled us to obtain a wide range of stabilized products of magnetic microspheres and cenospheres with purity of 96-99% by the magnetic component. The physical and chemical properties as well as the morphology of the products obtained have been studied in detail by the methods of scanning electron microscopy (SEM), X-ray diffraction, Moessbauer and ESR spectroscopies. The general regularities of microsphere generation from a ferrosilicate melt in burning of coals of different types and the areas of application for the microspheres of different morphological types have been analyzed. The report describes the results of work in the following directions: Recovery of close-cut fractions of microspheres of stabilized composition from fly ashes of three power-generating coals of Russia. Morphological features of magnetic microspheres and cenospheres. Composition and physicochemical properties of close-cut fractions of microspheres of stabilized composition. Application areas of glass crystalline microspheres: catalysts of oxidative conversion of methane; microspherical porous glasses and sorbents on the basis of cenospheres; porous matrices for high-toxic waste disposal, in particular, for liquid radioactive waste. 15 refs., 6 figs., 1 tab.

  2. Natural radioactivity of coal and fly ash at the Nikola Tesla B TPP

    Directory of Open Access Journals (Sweden)

    Kisić Dragica M.

    2013-01-01

    Full Text Available Serbian thermal power plants (TPPs produce siliceous fly ash from lignite in the quantity of approximately 6 million tons per year. The potential market for the use of fly ash is operational, but for the time being, only used by cement producers. Fly ash radioactivity could be one of the major points of concern when larger use of fly ash is planned, particularly in the Serbian construction industry. Radioactivity measurements have been conducted regularly for decades. This paper presents the results of a ten-year fly ash radioactivity measurements at the Nikola Tesla B TPP located in Obrenovac. In addition, the paper compares the natural radionuclides coal content data combusted by the Nikola Tesla B TPP boilers coming from the Kolubara Basin and ash created during coal combustion. Fly ash created in the Nikola Tesla TPPs boilers is characterised by the increased concentration of the natural radionuclides content compared to coal. This is the so-called technologically enhanced natural radioactivity (Technologically Enhanced Occurring Radioactive Material - TENORM of industrial waste, whereas the average specific activities: 232Th in coal amount to 25.2 Bq/kg, and in fly ash and coal 84.2 Bq/kg and 238U 38.3 Bq/kg, respectively. Following the obtained natural radionuclides content results it may be concluded that the Nikola Tesla B TPP ash may be disposed into the environment. Ash may be used also in the construction industry (civil engineering. In building construction applications, ash share as the additive to other building materials depends from its physical and chemical characteristics, as well as from the radionuclides activity: 266Ra, 232Th and 40K. Unlike the thermal power plants regularly (once a year testing the specific natural radionuclides activity in the combusted coal and boiler fly ash, Electric Power Industry of Serbia has not performed large-scale investigations of the natural radionuclides content in coal within the Kolubara

  3. Technical note: Vetiver can grow on coal fly ash without DNA damage.

    Science.gov (United States)

    Chakraborty, Rajarshi; Mukherjee, Anita

    2011-02-01

    Fly ash is a by-product of coal-fired electricity generation plants. The prevalent practice of disposal is as slurry of ash and water to open lands or ash ponds located near power plants and this has lain to waste thousands of hectares all over the world. Wind and leaching are often the causes of off-site contamination from fly ash dumpsites. Vetiver (Vetiveria zizanioides) grown on fly ash for three months showed massive, mesh-like growth of roots which could have a phytostabilizing effect. The plant achieved this without any damage to its nuclear DNA as shown by comet assay done on the root nuclei, which implies the long-term survival of the plant on the remediation site. Also, when Vetiver is used for phytoremediation of coal fly ash, its shoots can be safely grazed by animals as very little of heavy metals in fly ash were found to be translocated to the shoots. These features make planting of Vetiver a practical and environmentally compatible method for restoration of fly ash dumpsites. Lack of DNA damage in Vetiver has been compared to that in a sensitive plant i.e. Allium cepa. Our results suggested that apart from traditional end-points viz. growth parameters like root length, shoot length and dry weight, comet assay could also be included in a battery of tests for initial, rapid and effective selection of plants for restoration and phytoremediation of polluted sites.

  4. Effects of soil application of fly ash on the fusarial wilt on tomato cultivars

    Energy Technology Data Exchange (ETDEWEB)

    Khan, M.R.; Singh, W.N. [Aligarh Muslim University, Aligarh (India). Dept. of Plant Protection, Rafi Ahmad Kidwai Institute of Agricultural Science

    2001-07-01

    A study was carried out in microplots to evaluate the effect of fly ash on the plant growth and yield of tomato cultivars, Pusa Ruby, Pusa Early Dwarf and New Uday, and on wilt disease caused by Fusarium oxysporum f. sp. lycopersici. Fly ash was applied to soil by broadcast or in rows at the rate of 1, 2, 3 and 4 kg ash m{sup -2} in place of inorganic fertilizers. In control plots, NPK (about 40 : 20 : 20 kg acre{sup -1}) and compost were added in place of fly ash. Ash application greatly increased the soil contents of P, K, B, Ca, Mg, Mn, Zn, carbonates, bicarbonates and sulphates. Plants grown in the ash-treated plots, especially at 3 or 4 kg dose, showed luxuriant growth and greener foliage, and plant growth and yield of the three cultivars were significantly increased in comparison with the plants grown in plots without fly ash. The wilt fungus, F. oxysporum f. sp. lycopersiciat the inoculum level of 2 g plant{sup -1} caused significant suppression of growth and yield in all three cultivars. Application of fly ash, however, checked the suppressive effect of the fungus, leading to a significant increase in the considered variables compared with the inoculated control. Soil population of the fungus gradually decreased with an increase in ash dose. Row application was found to be relatively more effective in enhancing the yield of tomato cultivars and suppressing the wilt disease.

  5. Implications of fly ash application to soil for plant growth and feed quality

    Energy Technology Data Exchange (ETDEWEB)

    Hammermeister, A.M.; Naeth, M.A.; Chanasyk, D.S. [University of Alberta, Edmonton, AB (Canada). Dept. of Renewable Resources

    1998-02-01

    Fly ash has shown potential as a soil amendment and a source of trace elements beneficial to plants. However, agricultural utilization of fly ash has been restricted due to variability in chemical composition, elemental toxicity, induced nutrient imbalances in plants and inconsistent response of vegetation to fly ash amendment. Fly ash was applied to reclaimed mine soil near Edmonton, Alberta, at rates of 0, 25, 50, 100, 200 and 400 t ha{sup -1}. Total and water soluble concentrations of selected elements were determined from soil samples collected at 0 to 15 cm. Growth, development, and elemental uptake of barley (Hordeum vulgare, L., Jackson cv.), brome (Bromus inermis, Leyss), and alfalfa (Medicago sativa, L., Beaver cv.) were measured at selected stages of development. Water soluble concentrations of B, Mo, Ca, Cr, K, Mg, Mo, Na, P, Se and Sr variably increased with increasing fly ash rate. Boron concentration in plant tissue increased significantly to toxic levels with symptoms evident at early stages of barley development and increasingly severe at later stages. Toxicity symptoms were less severe for brome and alfalfa. The Cu:Mo ratio of vegetation decreased with increased fly ash rate to levels which could cause Cu deficiency in livestock. Yield of barley silage was significantly increased at intermediate rates of fly ash application, but significantly reduced at 400 t ha{sup -1}.

  6. Studies on Carbon-Fly Ash Composites with Chopped PANOX Fibers

    Directory of Open Access Journals (Sweden)

    Rakesh V. Patel

    2013-01-01

    Full Text Available Chemical analysis and morphological studies of fly ash reveals the complex chemical constituents present as spherical particles with diameter of less than 25 μm. The constituents of fly ash are silica, alumina, iron oxide, titanium dioxide, calcium and magnesium oxide, and other trace elements. The use of thermosetting as well thermoplastic polymer matrix has been made by several workers to develop polymer matrix fly ash particulate composites by using the hard and abrasive properties of fly ash and lightweight of polymers. Such composites have poor mechanical strength, fracture toughness, and thermal stability. To overcome these shortcomings, in carbonaceous matrix, the carbon fibers were added as additional reinforcement along with the fly ash. The composites were developed with two different methods known as Dry method and Wet method. The processing parameters such as temperature and pressure were optimized in establishing the carbon matrix. Physical, thermal, and mechanical characteristics were studied. The microstructures of composites show good compatibility between fly ash and fibers with the carbon matrix. These composites have higher strength, thermal stability, and toughness as compared to polymer matrix fly ash particulate composites.

  7. [Fly ash-catalyzed oxidation of p-nitro phenol with H2O2].

    Science.gov (United States)

    Zhang, Ai-Li; Deng, Fang-Fang; Zhou, Ji-Ti; Jin, Ruo-Fei; Liang, Li-Li; Zhang, Guo-Liang

    2009-07-15

    Fly ash was investigated as a catalyst in the oxidation of p-nitro phenol (PNP) with H2O2 at ambient temperature and pressure. The physical and chemical properties of fly ash were analyzed. The effects of fly ash composition, pretreatment methods and other parameters (such as dosage, pH, reaction time and oxidant concentration) on PNP removal rate were studied. It was found that fly ash with larger specific surface area and higher carbon content demonstrated higher catalytic activity. Heat treatment (350 degrees C) on fly ash could effectively improve the PNP removal rate. With an initial H2O2 concentration of 200 mg/L, 60 g/L heat-treated fly ash could remove 62.38% PNP at 25 degrees C, pH = 2. Specific surface area, carbon and metal oxide contents of fly ash play an important role in the catalysis process. The adsorption control experiment showed that adsorption was the main effect (65.97%) in the catalysis process. The activity of the catalyst gradually increased during its reuse. The PNP removal rate could reach 82.47% and 98.72% in the second and third rounds of reuse, respectively. The removal rate remained at about 99% in the rest 9 rounds of reuse. And the catalytic properties decreased after 12 times uses.

  8. Mechanical and Durability Properties of Fly Ash Based Concrete Exposed to Marine Environment

    Science.gov (United States)

    Kagadgar, Sarfaraz Ahmed; Saha, Suman; Rajasekaran, C.

    2017-06-01

    Efforts over the past few years for improving the performance of concrete suggest that cement replacement with mineral admixtures can enhance the strength and durability of concrete. Feasibility of producing good quality concrete by using alccofine and fly ash replacements is investigated and also the potential benefits from their incorporation were looked into. In this study, an attempt has been made to assess the performance of concrete in severe marine conditions exposed upto a period of 150 days. This work investigates the influence of alccofine and fly ash as partial replacement of cement in various percentages (Alccofine - 5% replacement to cement content) and (fly ash - 0%, 15%, 30%, 50% & 60% to total cementitious content) on mechanical and durability properties (Permit ion permeability test and corrosion current density) of concrete. Usage of alccofine and high quantity of fly ash as additional cementitious materials in concrete has resulted in higher workability of concrete. Inclusion of alccofine shows an early strength gaining property whereas fly ash results in gaining strength at later stage. Concrete mixes containing 5% alccofine with 15% fly ash replacement reported greater compressive strength than the other concrete mixes cured in both curing conditions. Durability test conducted at 56 and 150 days indicated that concrete containing higher percentages of fly ash resulted in lower permeability as well lesser corrosion density.

  9. Reduced downward mobility of metribuzin in fly ash-amended soils.

    Science.gov (United States)

    Singh, Neera; Raunaq; Singh, Shashi Bala

    2013-01-01

    Metribuzin, a triazine herbicide, is poorly sorbed in the soils, therefore leaches to lower soil profile. Fly ash amendment, which enhanced metribuzin sorption in soils, may play a significant role in reducing the downward mobility of herbicide. Therefore, the present study reports the effect of Inderprastha fly ash amendment on metribuzin leaching in three soil types. Fly ash was amended at 1, 2 and 5% levels in the upper 15 cm of 30 cm long packed soil columns. Results suggested a significant reduction in the leaching losses of metribuzin in fly ash-amended columns of all the three soil types and effect increased with increase in the level of fly ash. Even after percolating water equivalent to 362 mm rainfall no metribuzin was recovered in the leachate of 5% fly ash-amended columns. Fly ash application affected both metribuzin breakthrough time and its maximum concentration in the leachate. Further, it resulted in greater retention of metribuzin in the application zone and better effect was observed in the organic carbon poor soils.

  10. Growth and elemental accumulation by canola on soil amended with coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Yunusa, I.A.M.; Manoharan, V.; DeSilva, D.L.; Eamus, D.; Murray, B.R.; Nissanka, S.P. [University of Technology Sydney, Sydney, NSW (Australia)

    2008-05-15

    To explore the agronomic potential of an Australian coal fly ash, we conducted two glasshouse experiments in which we measured chlorophyll fluorescence, CO{sub 2} assimilation (A), transpiration, stomatal conductance, biomass accumulation, seed yield, and elemental uptake for canola (Brassica napus) grown on soil amended with an alkaline fly ash. In Experiment 1, application of up to 25 Mg/ha of fly ash increased A and plant weight early in the season before flowering and seed yield by up to 21%. However, at larger rates of ash application A, plant growth, chlorophyll concentration, and yield were all reduced. Increases in early vigor and seed yield were associated with enhanced uptake of phosphorus (P) by the plants treated with fly ash. Fly ash application did not influence accumulation of B, Cu, Mo, or Zn in the stems at any stage of plant growth or in the seed at harvest, except Mo concentration, which was elevated in the seed. Accumulation of these elements was mostly in the leaves, where concentrations of Cu and Mo increased with any amount of ash applied while that of B occurred only with ash applied at 625 Mg/ha. In Experiment 2, fly ash applied at 500 Mg/ha and mixed into the whole 30 cm soil core was detrimental to growth and yield of canola, compared with restricting mixing to 5 or 15 cm depth. In contrast, application of ash at 250 Mg/ha with increasing depth of mixing increased A and seed yield. We concluded that fly ash applied at not more than 25 Mg/ha and mixed into the top 10 to 15 cm of soil is sufficient to obtain yield benefits.

  11. Growth and elemental accumulation by canola on soil amended with coal fly ash.

    Science.gov (United States)

    Yunusa, I A M; Manoharan, V; DeSilva, D L; Eamus, D; Murray, B R; Nissanka, S P

    2008-01-01

    To explore the agronomic potential of an Australian coal fly ash, we conducted two glasshouse experiments in which we measured chlorophyll fluorescence, CO2 assimilation (A), transpiration, stomatal conductance, biomass accumulation, seed yield, and elemental uptake for canola (Brassica napus) grown on soil amended with an alkaline fly ash. In Experiment 1, application of up to 25 Mg/ha of fly ash increased A and plant weight early in the season before flowering and seed yield by up to 21%. However, at larger rates of ash application A, plant growth, chlorophyll concentration, and yield were all reduced. Increases in early vigor and seed yield were associated with enhanced uptake of phosphorus (P) by the plants treated with fly ash. Fly ash application did not influence accumulation of B, Cu, Mo, or Zn in the stems at any stage of plant growth or in the seed at harvest, except Mo concentration, which was elevated in the seed. Accumulation of these elements was mostly in the leaves, where concentrations of Cu and Mo increased with any amount of ash applied while that of B occurred only with ash applied at 625 Mg/ha. In Experiment 2, fly ash applied at 500 Mg/ha and mixed into the whole 30 cm soil core was detrimental to growth and yield of canola, compared with restricting mixing to 5 or 15 cm depth. In contrast, application of ash at 250 Mg/ha with increasing depth of mixing increased A and seed yield. We concluded that fly ash applied at not more than 25 Mg/ha and mixed into the top 10 to 15 cm of soil is sufficient to obtain yield benefits.

  12. Mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor.

    Science.gov (United States)

    Zhang, Yongsheng; Zhao, Lilin; Guo, Ruitao; Song, Na; Wang, Jiawei; Cao, Yan; Orndorff, William; Pan, Wei-ping

    2015-07-01

    In this study, the mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor were investigated through thermal decomposition methods. The results show that the mercury adsorption performance of the HBr-modified fly ash was enhanced significantly. The mercury species adsorbed by unmodified fly ash were HgCl2, HgS and HgO. The mercury adsorbed by HBr-modified fly ash, in the entrained-flow reactor, existed in two forms, HgBr2 and HgO, and the HBr was the dominant factor promoting oxidation of elemental mercury in the entrained-flow reactor. In the current study, the concentration of HgBr2 and HgO in ash from the fine ash vessel was 4.6 times greater than for ash from the coarse ash vessel. The fine ash had better mercury adsorption performance than coarse ash, which is most likely due to the higher specific surface area and longer residence time. Copyright © 2015. Published by Elsevier B.V.

  13. Sintering of MSW fly ash for reuse as a concrete aggregate.

    Science.gov (United States)

    Mangialardi, T

    2001-10-12

    The sintering process of municipal solid waste (MSW) fly ash was investigated in order to manufacture sintered products for reuse as concrete aggregates. Four types of fly ash resulting from different Italian MSW incineration plants were tested in this study. A modification of the chemical composition of MSW fly ash--through a preliminary four-stage washing treatment of this material with water--was attempted to improve the chemical and mechanical characteristics of sintered products.The sintering treatment of untreated or washed fly ash was performed on cylindrical compact specimens (15 mm in diameter and 20mm in height) at different compact pressures, sintering temperatures and times.The sintering process of untreated MSW fly ashes proved to be ineffective for manufacturing sintered products for reuse as a construction material, because of the adverse chemical characteristics of these fly ashes in terms of sulfate, chloride, and vitrifying oxide contents.A preliminary washing treatment of MSW fly ash with water greatly improved the chemical and mechanical characteristics of sintered products and, for all the types of fly ash tested, the sintered products satisfied the Italian requirements for normal weight aggregates for use in concretes having a specified strength not greater than 12 and 15N/mm(2), when measured on cylindrical and cubic specimens, respectively.A compact pressure of 28 N/mm(2), a sintering temperature of 1140 degrees C, and a sintering time of 60 min were the best operating conditions for manufacturing sintered products of washed MSW fly ash.

  14. Integrated acid mine drainage management using fly ash.

    Science.gov (United States)

    Vadapalli, Viswanath R K; Gitari, Mugera W; Petrik, Leslie F; Etchebers, Olivier; Ellendt, Annabelle

    2012-01-01

    Fly Ash (FA) from a power station in South Africa was investigated to neutralise and remove contaminants from Acid Mine Drainage (AMD). After this primary treatment the insoluble FA residue namely solid residue (SR) was investigated as a suitable mine backfill material by means of strength testing. Moreover, SR was used to synthesise zeolite-P using a two-step synthesis procedure. Furthermore, the zeolite-P was investigated to polish process water from the primary FA-AMD reaction. The main objective of this series of investigations is to achieve zero waste and to propose an integrated AMD management using FA. Fly Ash was mixed with AMD at various predetermined FA-AMD ratios until the mixtures achieved circumneutral pH or higher. The supernatants were then analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Ion Chromatography (IC) for cations and anions respectively. The physical strength testing of SR was carried out by mixing it with 3% Ordinary Portland Cement (OPC) and curing for 410 days. Synthesis of zeolite-P using SR was carried out by two step synthesis procedure: ageing for 24 hours followed by a mild hydrothermal synthesis at 100°C for 4 days. The polishing of process water from primary AMD treatment using FA was ascertained by mixing the process water with zeolite at a liquid to solid ratio of 100:1 for 1 hour. The results indicated that FA can be successfully used to ameliorate AMD. High removal of major AMD contaminants Fe, Al, Mg, Mn and sulphate was achieved with the ash treatment and trace elements such as Zn, Ni, Cu and Pb were also removed by the FA. Strength testing over 410 days indicated that the material gained strength over the testing period. The maximum unconfined compressive strength and elastic modulus was observed to be approximately 0.3 MPa and 150 Mpa respectively. The X-ray diffraction (XRD) analysis of the synthesized product indicated that SR was successfully converted into zeolite-P with some mullite phase

  15. Electrodialytic removal of cadmium from biomass combustion fly ash in larger scale

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Ottosen, Lisbeth M.; Simonsen, Peter

    2005-01-01

    Due to a high concentration of the toxic heavy metal cadmium (Cd), biomass combustion fly ash often fails to meet the Danish legislative requirements for recycling on agricultural fields. It has previously been shown that it is possible to reduce the concentration of Cd in different bio ashes......). The experimental ash was a straw combustion fly ash suspended in water. Within 4 days of remediation, Cd concentrations below the limiting concentration of 5.0 mg Cd/kg DM for straw ash were reached. On the basis of these results, the energy costs for remediation of ash in industrial scale have been estimated...... significantly by using electrodialytic remediation, an electrochemically assisted extraction method. In this work the potential of the method was demonstrated in larger scale. Three different experimental set-ups were used, ranging from bench-scale (25 L ash suspension) to pilot scale (0.3 - 3 m3...

  16. MANUAL. Fly ash in civil engineering, Gravel roads; HANDBOK. Flygaska i mark- och vaegbyggnad, Grusvaegar

    Energy Technology Data Exchange (ETDEWEB)

    Munde, Hanna; Svedberg, Bo; Macsik, Josef; Maijala, Aino; Lahtinen, Pentti; Ekdahl, Peter; Neren, Jens [Vattenfall AB, Stockholm (Sweden). Vaerme Norden

    2006-01-15

    Fly ash based on biofuels or coal has been used as construction material for a long time in roads and other civil engineering applications. Some example, where it has been used in roadbase and subbase of gravel roads, are in the counties of Uppsala, Soedermanland, Vaestmanland and in Finland. The use of fly ash has contributed to good function for example as bearing capacity, thaw and frost capacity and good durability. This has also reduced costs for maintenance. The objective of this project was to develop a manual to provide a base for contemporary use of fly ash in road constructions. In the manual experience from studies, field tests and regulations has been compiled. The manual handles fly ash as base for products to be used in base and subbase in gravel roads. Future user of the guidelines are mainly consultant engineers and contractors. However the aim of the manual is to also support road administrators, environmental authorities and industry. The project has been carried out parallel to another ongoing national project titled 'Guidelines, Use of alternative materials in civil engineering'. The objective of that project is to establish a base for handling of alternative materials in Sweden. Fly ash in gravel roads are mainly used in two typical applications, one without any additive in a single layer and one with fly ash mixed with gravel. The use of flyash provides functional properties such as increased stiffness, stability and enhanced frost and thaw capacity for the road construction in total. Furthermore the products based on fly ash will have low permeability and good frost and thaw durability. These properties are for example related to fly ash quality, design and construction and are in general expected to be better than for traditional constructions using, for example, sand or gravel. The properties can be enhanced further by using binders such as cement and Merit. Fly ash should always be used above the ground water table with

  17. Effects of fly-ash treatment of soil on yields and chemical composition of chicory

    Energy Technology Data Exchange (ETDEWEB)

    Scotti, I.A.; Lombi, E.; Carini, F.; Silva, S. [Universita Cattolica Sacro Cuore, Piacenza (Italy). Ist. di Chimica Agraria e Ambientale

    1996-09-01

    In pot trials, chicory (Cichorium intybus) was grown on two soils with and without two levels (3% and 10%) of fly ash. It was observed that the addition of 3% fly ash gives rise to a significant increase in the yield and in Mg content, compared to a traditional dressing; all the other elements taken into account (Ca, S, Zn, Mn, Co, Pb, Ni, Cu and B) show positive or negative changes which, in most cases are not significant. With the addition of 10% fly ash the yield decreased, while the concentrations of all the elements, except Mn whose concentration in an acid soil undergoes a reduction, in general show significant increases.

  18. Synthesis of zeolites using fly ash and their application in removing heavy metals from waters

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.X.; Guo, Y.L.; Yang, Z.H.; Cai, H.S.; Querol, X. [China University of Geoscience, Wuhan (China)

    2003-09-01

    Three types of zeolite (NaP1 zeolite, analcime and chabazite) were hydrothermally synthesized by reacting fly ash with NaOH solution. The maximum conversion rate from fly ash to single zeolite is about 40%-75%, and the total conversion rate 60%-80%. The synthesis experimental results indicate that factors including vortex, viscosity, temperature, reaction time, and NaOH concentration in the reaction system strongly affect the type and conversion rate of zeolites. The batch experiments of removing Cu{sup 2+}, Pb{sup 2+} and Cd{sup 2+} from wastewaters show that the adsorption capacity of zeolites synthesized is higher than that of fly ash.

  19. Preliminary treatment of MSW fly ash as a way of improving electrodialytic remediation

    DEFF Research Database (Denmark)

    Ferreira, Célia Maria Dias; Jensen, Pernille Erland; Ottosen, Lisbeth M.

    2008-01-01

    In the current work electrodialytic remediation (EDR) was applied to remove heavy metals from municipal solid waste (MSW) fly ash, a hazardous waste collected during flue gas treatment. Tests were conducted to evaluate if EDR could be improved by introducing a preliminary treatment in which very...... to the fly ash. It was seen that at the end metals are mainly found in the strongly bonded and residual phases. This indicates that the combined treatment (washing + EDR) is successful in reducing the environmental risk posed by fly ash....

  20. Synthesis of hydroxy sodalite from coal fly ash using waste industrial brine solution.

    Science.gov (United States)

    Musyoka, Nicholas M; Petrik, Leslie F; Balfour, Gillian; Gitari, Wilson M; Hums, Eric

    2011-01-01

    The effect of using industrial waste brine solution instead of ultra pure water was investigated during the synthesis of zeolites using three South African coal fly ashes as Si feedstock. The high halide brine was obtained from the retentate effluent of a reverse osmosis mine water treatment plant. Synthesis conditions applied were; ageing of fly ash was at 47 ° C for 48 hours, and while the hydrothermal treatment temperature was set at 140 ° C for 48 hours. The use of brine as a solvent resulted in the formation of hydroxy sodalite zeolite although unconverted mullite and hematite from the fly ash feedstock was also found in the synthesis product.

  1. Geotechnical and Physico-Chemical Characterization of Low Lime Fly Ashes

    Directory of Open Access Journals (Sweden)

    Arif Ali Baig Moghal

    2013-01-01

    Full Text Available In order to explore the possibility of using low-lime fly ashes, the physical and chemical properties which have a direct bearing on their geotechnical and geoenvironmental behaviors have been investigated. In this paper, two types of low-lime fly ashes, originating from India, have been used. A brief account of various methods adopted in characterizing their physical, chemical, and geotechnical properties is presented. The relative importance of each of these properties in enhancing the bulk applicability of fly ashes has been brought out.

  2. Electrodialytic remediation of fly ash from co-combustion of wood and straw

    DEFF Research Database (Denmark)

    Chen, Wan; Jensen, Pernille Erland; Ottosen, Lisbeth M.

    2015-01-01

    The heavy metal content in fly ash from biomass combustion, such as straw, wood and sludge, often needs reducing before the ash can be used as fertilizer for agricultural land or as a component in the production of construction materials. In this study, fly ash from a boiler fueled with wood chips....... The two-compartment EDR cell probably performed better due to a fast acidification process. In addition, this process was less energy-consuming. However, the fast acidification did in turn affect the leaching property of the treated ash, such as As and Ni, exceeding the limiting concentrations. The EDR...

  3. Root penetration of sealing layers made of fly ash and sewage sludge.

    Science.gov (United States)

    Neuschütz, Clara; Stoltz, Eva; Greger, Maria

    2006-01-01

    Fly ash and sewage sludge are suggested materials for constructing sealing layers covering mine tailings impoundments. Little is known, however, of their effect on vegetation or resistance to root penetration. We investigate: (i) the ability of different plant species to grow in sealing layers comprising fly ash and sewage sludge, (ii) the impact on plant growth of freshly hardened fly ash compared to aged and leached ash, and (iii) the plant stress response to fly ashes of different properties. A 6-mo greenhouse study using birch (Betula pendula Roth.), Scots pine (Pinus sylvestris L.), Kentucky bluegrass (Poa pratensis L.), and willow (Salix viminalis L.) demonstrated that no roots could grow into a compacted layer consisting only of ash, while a 6:4, ash-sludge mixture admitted roots into the upper part and a 1:9, ash-sludge mixture was totally penetrated (to 15 cm in depth) by roots of willow and Scots pine. Freshly hardened ash prevented root growth more effectively than aged ash did, as was observed in tests using reed canarygrass (Phalaris arundinacea L.) and pea (Pisum sativum L.). Furthermore, extracts of highly alkaline ash were more toxic to pea in a 48-h toxicity test than less alkaline ash was. However, stress responses to diluted ash extracts of lower pH, measured as enzyme capacities in dwarf bean (Phaseolus vulgaris L.), were more related to the metal and ion contents. Root penetration of sealing layers is most effectively prevented if little sewage sludge is added, and if ash of high alkalinity is chosen.

  4. Activated Carbon-Fly Ash-Nanometal Oxide Composite Materials: Preparation, Characterization, and Tributyltin Removal Efficiency

    Directory of Open Access Journals (Sweden)

    Olushola S. Ayanda

    2013-01-01

    Full Text Available The physicochemical properties, nature, and morphology of composite materials involving activated carbon, fly ash, nFe3O4, nSiO2, and nZnO were investigated and compared. Nature and morphology characterizations were carried out by means of scanning electron and transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Other physicochemical characterizations undertaken were CNH analysis, ash content, pH, point of zero charge, and surface area and porosity determination by BET. Experimental results obtained revealed that activated carbon, nSiO2, activated carbon-fly ash, activated carbon-fly ash-nFe3O4, activated carbon-fly ash-nSiO2, and activated carbon-fly ash-nZnO composite materials exhibited net negative charge on their surfaces while fly ash, nFe3O4, and nZnO possessed net positive charge on their surfaces. Relatively higher removal efficiency (>99% of TBT was obtained for all the composite materials compared to their respective precursors except for activated carbon. These composite materials therefore offer great potential for the remediation of TBT in wastewaters.

  5. Contribution of Fineness Level of Fly Ash to the Compressive Strength of Geopolymer Mortar

    Directory of Open Access Journals (Sweden)

    Firdaus

    2017-01-01

    Full Text Available The development of geopolymers has allowed the flash as the substitution of cement in the application of concrete. Therefore, this will be very useful considering the quite abundant by-product materials from power plants burning coal in South Sumatera. However, the untreated fly ash from the source caused its fineness level unpredictable, whereas the fineness of binder in cementitious material significantly affects the mechanical properties of the harden. Therefore, this study aims to determine the contribution of the fineness level of fly ash to the compressive strength of geopolymer mortar, as well as its excellent composition. Type F fly ash from Tanjung Enim Power Plant was treated by filtering to obtain different fineness levels based on the fall zones of the ash. Activators used in geopolymer mixing were sodium hydroxide (NaOH and sodium silicate (Na2SiO3 with three activator/fly ash ratios which was 0.25, 0.35 and 0.45. The results showed that the fineness level based on fall zone as well as the activator to fly ash ratio significantly influenced the compressive strength of the geopolymer mortar. The compressive strength of the F4-P4 specimen of geopolymer mortar with zone-4 fly ash and an activator ratio of 0.45 achieved 28.2 MPa at 28 days.

  6. Fly ash-airborne particles from Ptolemais-Kozani area, northern Greece, as determined by ESEM-EDX

    Energy Technology Data Exchange (ETDEWEB)

    Iordanidis, A.; Triantafyllou, A.G.; Asvesta, A. [Department of Geotechnology and Environmental Engineering, Technological Educational Institute of Western Macedonia, Kila, 50100 Kozani (Greece); Buckman, J. [Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh Campus, EH14 4AS, Scotland (United Kingdom)

    2008-01-07

    The aim of this study is to investigate the contribution of fly ash from lignite-fired power stations to the air pollution of the Western Macedonia region of northern Greece. Several filters that capture airborne particles were collected over a year's period (March 2003 to February 2004), from seven sampling sites spread throughout the area. In addition, fly ash was collected from two power plants in this area along with stack ash (fly ash that escaped the electrostatic precipitators and trapped at the stack's exit). Both fly ash and filters were analysed with the help of Environmental Scanning Electron Microscopy (ESEM), coupled with energy dispersive X-ray analysis (EDX) in order to determine the morphological, mineralogical and chemical characteristics of fly ash particles. Cenospheres, vesicular spheres, spheroids, dense spheres and chars were the main recognized fly ash particles. Similar airborne particles were also present in almost every filter collected in the area. Sampling sites situated nearby power plants had apparently more fly ash particles. Fine fly ash particles (< 5 {mu}m) were transported to distant sites, while larger fly ash particles ({>=} 10 {mu}m) were mostly recorded in the vicinity of power stations. The analysis also revealed the presence of potential toxic elements in the fly ash, a fact with important environmental implications. (author)

  7. Fly ash stabilisation of gravel roads; Flygaska som foerstaerkningslager i grusvaeg

    Energy Technology Data Exchange (ETDEWEB)

    Macsik, Josef

    2006-01-15

    Majority of the existing gravel roads have low bearing capacity during spring and autumn, due to thaw and/or rain. Low bearing capacity leads often to bad road conditions. This situation results in higher costs for the lumber industry and the public. Management of gravel roads all the year around would traditionally require excavation of frost susceptible soils and replacement with natural materials. Fly ash (from bio fuels) has good technical properties as bearing layer in road constructions. Fly ash stabilised gravel roads have better function and longer life span with less maintenance than traditional gravel roads. The aim of this project is to show how fly ash stabilisation of gravel roads can increase bearing capacity and what its environmental impact is. The overall aim is to make it easier for entrepreneurs and consulting companies to use fly ash during gravel road renovation and/or constructing new gravel roads. This report targets fly ash producers and road constructors as well as environmental agencies. Two different pilot tests were investigated in this study, Norberg with fly ash from Stora Enso Fors AB, and Boerje (Uppsala) with fly ash from Vattenfall Uppsala AB. Both road sections with related reference section were investigated during a two year period. Only fly ash was used in the bearing layer at Norberg and fly ash gravel was used at Boerje. Bearing capacity was investigated twice, for both locations, November 2003 one month after the road renovation and during thawing, April 2004. Water samples from lysimeters, ground water and surface water were only collected and analysed from Norberg. Experience from the fly ash stabilised road sections show that curing and traffic load can with time compensate for less compaction. The same is noticed at Boerje, although deflection measurements show that there are small differences. Stabilisation of gravel roads increases the roads bearing capacity. Two years after stabilisation 90 timber loads were

  8. Fractionation of Heavy Metals in Fly Ash from Wood Biomass Using the BCR Sequential Extraction Procedure.

    Science.gov (United States)

    Jukić, Mirela; Ćurković, Lidija; Šabarić, Jasenka; Kerolli-Mustafa, Mihone

    2017-10-01

    The aim of this study was to extract the wood biomass fly ash fractions by a three-stage sequential extraction method for acetic acid and ion exchangeable (BCR 1), hydroxylamine hydrochloride reduction (BCR 2), and hydrogen peroxide oxidation (BCR 3) fractions in order to access the leaching behavior of this residue. The fly ash was collected as a by-product from the processing of mixed wood biomass in Udbina combustion facility, Croatia. Concentrations of several elements (As, Cd, Cr, Cu, Ni, Pb and Zn) in all extracts were determined by inductively coupled plasma atomic emission spectrometry. The acidic exchangeable form of the metals was used to evaluate the potential ecological risk of biomass fly ash. According to calculated potential ecological risk index, it is confirmed that mobility of Ni and As has major environmental impact. However the results of potential ecological risk show that biomass fly ash had a low risk.

  9. The high strain rate compressive response of Mg-Al alloy/fly Ash cenosphere composites

    Science.gov (United States)

    Luong, Dung D.; Gupta, Nikhil; Rohatgi, Pradeep K.

    2011-02-01

    The strain rate dependence of mechanical properties of AZ91D alloy composites filled with 5 wt.% hollow fly ash cenosphere is examined in the strain rate range of 630-1,203 s-1 using a split-Hopkinson pressure bar system. In addition, a test scheme is designed to study the intermediate strain rate response of the material. Addition of fly ash caused grain refinement and finer precipitates in the matrix alloy. Compared to the matrix alloy, the energy absorption is higher in AZ91D/fly ash cenosphere composites at comparable strain rates. In addition, the yield strength is found to be about 19-41% higher in the composites containing fly ash cenospheres.

  10. Factors affecting the suitability of fly ash as source material for geopolymers

    Energy Technology Data Exchange (ETDEWEB)

    E.I. Diaz; E.N. Allouche; S. Eklund [Louisiana Tech University, Ruston, LA (United States). Department of Civil Engineering

    2010-05-15

    The suitability of fly ash stock piles for geopolymer manufacturing was studied. The results of chemical analyses, X-ray diffraction (XRD) and particle size distribution (PSD) of five sources of fly ash obtained from coal-fired power generating plants in the US are presented. Geopolymer paste and concrete specimens were prepared from each stock pile. The specimens were subjected to an array of chemical and mechanical tests including XRD, RAMAN spectroscopy, setting time and compressive strength. A correlation study was undertaken comparing the fly ash precursor chemical and crystallographic compositions as well as particle size distribution, with the mechanical and chemical characteristics of the resulting geopolymer. Factors inherent to the fly ash stockpile such as particle size distribution, degree of vitrification and location of the glass diffraction maximum were found to play an important role in the fresh and hardened properties of the resulting geopolymer. 26 refs., 7 figs., 2 tabs.

  11. Identification of potential concerns associated with FDOT use of ammoniated coal fly ash.

    Science.gov (United States)

    2012-12-01

    The objectives of this project include a careful examination of the issues surrounding high ammonia content in cement due to the use of ammoniated fly ash. The researchers will gather information from published material and consider policies and prac...

  12. Natural radioactivity of coal and fly ash at the Nikola Tesla B TPP

    National Research Council Canada - National Science Library

    Kisić Dragica M; Miletić Saša R; Radonjić Vladimir D; Radanović Sanja B; Filipovic Jelena Z; Gržetić Ivan A

    2013-01-01

    .... Radioactivity measurements have been conducted regularly for decades. This paper presents the results of a ten-year fly ash radioactivity measurements at the Nikola Tesla B TPP located in Obrenovac...

  13. Phase transformations in synthesis technologies and sorption properties of zeolites from coal fly ash

    Directory of Open Access Journals (Sweden)

    О. Б. Котова

    2016-08-01

    Full Text Available Coal fly ash is generated in the course of combustion of coal at thermal power plants. Environmental problems increase sharply without disposing that industrial waste. Technologies were tested of hydrothermal synthesis of zeolites from fly ash forming during combustion of coal at thermal power plants of the Pechora coal basin and dependences were identified of the experiment conditions on physical and chemical properties of the end product. It is demonstrated that synthesizing zeolites from fly ash is the first stage of forming ceramic materials (ceramic membranes, which defines the fundamental character (importance of that area of studies. It was for the first time that sorption and structural characteristics and cation-exchange properties of fly ash from the Pechora basin coals were studied with respect to, Ba2+ and Sr2+.

  14. MICROSTRUCTURE, MINERALOGY AND PHYSICAL PROPERTIES OF GROUND FLY ASH BASED GEOPOLYMERS

    National Research Council Canada - National Science Library

    Ferenc Madai; Ferenc Kristaly; Mucsi Gabor

    2015-01-01

    ...). Compressive strength was determined on cilindrical specimens. Finally, samples of the ground fly ash based geopolymer specimens were analyzed by X-ray diffraction, optical and scanning electron microscopy...

  15. Synthesis of geopolymer composites from a mixture of ferronickel slag and fly ash

    Science.gov (United States)

    Liu, Yun; Zhang, Kang; Feng, Enjuan; Zhao, Hongyi; Liu, Futian

    2017-03-01

    The synthesis of geopolymers using ferronickel slag and fly ash under alkaline activation was studied. In order to study the effects of different fly ash content on the mechanical properties of the geopolymers produced, the compressive strength of samples was tested at 3, 7, 28 days. The results showed that when the fly ash content was 40%, the compressive strength reached the highest (110.32MPa) at 28 days. XRD analysis showed that the ferronickel slag geopolymers had amorphous aluminosilicate phase formation, indicating that the hydration reaction occurred. FTIR analysis showed the reaction of the geopolymers generated at Si-O-T (Si, Al) and Al-O-Si three-dimensional network. In SEM images, the structure of the geopolymers with 40% fly ash was more compact and cohesive.

  16. Preparation and Characterization of Manganese Slag and Fly Ash-based Geopolymer

    Directory of Open Access Journals (Sweden)

    Wang Ya-guang

    2017-01-01

    Full Text Available In this study, a series of manganese slag and fly ash-based geopolymers were prepared though alkali activation by varing the amount of manganese slag. The 3-day, 7-day and 14-day compressive strengths of these samples were tested. The maximum strength of 42.78 MPa was obtained at 14th days of testing when 455 g of fly ash, 195g of manganese slag, 20% of the alkali content , the curing temperature of 100°C, the curing time of 12h were used. XRD and FTIR characterization results shown that the polymerization reaction occurs between the glassiness in the manganese slag and the fly ash while adding alkali activator, and the main structure formed was Ca-A-S-H, which contributed the major strength in manganese slag and fly ash-based geopolymer.

  17. Synthesis of Zeolite from Fly Ash and Removal of Heavy Metal Ions from Newly Synthesized Zeolite

    OpenAIRE

    Solanki, Parag; Gupta, Vikal; Kulshrestha, Ruchi

    2010-01-01

    Coal fly ash was used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. Characteristics of the various Fly ash samples were carried out. Coal proximate analysis was done. Batch experiment was carried out for the adsorption of some heavy metal ions on to synthesized Zeolite. The cost of synthesized zeolite was estimated to be almost one-fifth of that of commercial 13X zeolite available in the market.

  18. Design of a leaching test framework for coal fly ash accounting for environmental conditions.

    Science.gov (United States)

    Zandi, Mohammad; Russell, Nigel V

    2007-08-01

    Fly ash from coal combustion contains trace elements which, on disposal or utilisation, may leach out, and therefore be a potential environmental hazard. Environmental conditions have a great impact on the mobility of fly ash constituents as well as the physical and chemical properties of the fly ash. Existing standard leaching methods have been shown to be inadequate by not representing possible disposal or utilisation scenarios. These tests are often criticised on the grounds that the results estimated are not reliable as they are not able to be extrapolated to the application scenario. In order to simulate leaching behaviour of fly ash in different environmental conditions and to reduce deviation between measurements in the fields and the laboratories, it is vital to study sensitivity of the fly ash constituents of interest to major factors controlling leachability. pH, liquid-to-solid ratio, leaching time, leachant type and redox potential are parameters affecting stability of elements in the fly ash. Sensitivity of trace elements to pH and liquid to solid ratio (as two major overriding factors) has been examined. Elements have been classified on the basis of their leaching behaviour under different conditions. Results from this study have been used to identify leaching mechanisms. Also the fly ash has been examined under different standard batch leaching tests in order to evaluate and to compare these tests. A Leaching Test Framework has been devised for assessing the stability of trace elements from fly ashes in different environments. This Framework assists in designing more realistic batch leaching tests appropriate to field conditions and can support the development of regulations and protocols for the management and disposal of coal combustion by-products or other solid wastes of environmental concern.

  19. Chemical modification of coal fly ash for the removal of phosphate from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    P. Pengthamkeerati; T. Satapanajaru; P. Chularuengoaksorn [Kasetsart University, Bangkok (Thailand). Environmental Technology Research Unit (EnviTech), Department of Environmental Science

    2008-09-15

    This study investigated the chemical modifications of coal fly ash treated with HCl and NaOH. Sorption behavior of phosphate from water solution on treated fly ash was examined. Results showed that the HCl-treated fly ash (TFA-HCl) had a greater specific surface area (SSA) than the NaOH-treated fly ash (TFA-NaOH) and untreated fly ash (FA). The XRF, XRD patterns, and SEM images revealed the decreased CaO content in the TFA-HCl and observed the presence of NaP1 and sodalite zeolites in the TFA-NaOH. The P sorption capacity of all studied fly ashes increased with increasing initial P concentration and mechanisms of P sorption were influenced by the equilibrium pH. Maximum phosphate immobilization capacity obtained from Langmuir model was in the following manner, TFA-NaOH > FA > TFA-HCl (57.14, 23.20, and 6.90 mg P g{sup -1}, respectively). The decreased CaO content and acidic pH in the TFA-HCl were responsible for the lowest capacity of phosphate immobilization, because of unfavorable condition for calcium phosphate precipitation. In contrast, due to alkaline condition and relatively high calcium content, the precipitation of calcium phosphate was a key mechanism for phosphate removal in the FA and TFA-NaOH. The TFA-NaOH had a greatest phosphate immobilization, due to high CaO content and an increased SSA after the conversion of fly ash to zeolite. Both Langmuir and Freundlich models were good fitted for the TFA-NaOH, while was only Langmuir model for the FA and Freundlich model for the TFA-HCl. Results suggested that treating fly ash with alkaline solution was a promising way to enhance phosphate immobilization. 23 refs., 7 figs., 2 tabs.

  20. MICROSTRUCTURE, MINERALOGY AND PHYSICAL PROPERTIES OF GROUND FLY ASH BASED GEOPOLYMERS

    OpenAIRE

    Ferenc Madai; Ferenc Kristaly; Mucsi Gabor

    2015-01-01

    This paper is focused on the utilization of deposited fly ash as a main component of geopolymer. After determination of particle size distribution, moisture content, real and bulk density and specific surface area of the raw fly ash, mechanical activation was performed by laboratory scale ball mill. This step is introduced for improving the reactivity of raw material. Then test specimens were produced by geopoliomerisation using a caustic spent liquor (NaOH). Compressive strength was determin...

  1. Synthesis of Zeolite from Fly Ash and Removal of Heavy Metal Ions from Newly Synthesized Zeolite

    Directory of Open Access Journals (Sweden)

    Parag Solanki

    2010-01-01

    Full Text Available Coal fly ash was used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. Characteristics of the various Fly ash samples were carried out. Coal proximate analysis was done. Batch experiment was carried out for the adsorption of some heavy metal ions on to synthesized Zeolite. The cost of synthesized zeolite was estimated to be almost one-fifth of that of commercial 13X zeolite available in the market.

  2. Evaluating the Effects of the Kingston Fly Ash Release on Fish Reproduction: Spring 2009 - 2010 Studies

    Energy Technology Data Exchange (ETDEWEB)

    Greeley Jr, Mark Stephen [ORNL; Adams, Marshall [ORNL; McCracken, Kitty [ORNL

    2012-05-01

    On December 22, 2008, a dike containing fly ash and bottom ash at the Tennessee Valley Authority's (TVA) Kingston Fossil Plant in East Tennessee failed and released a large quantity of ash into the adjacent Emory River. Ash deposits from the spill extended 4 miles upstream of the facility to Emory River mile 6 and downstream to Tennessee River mile 564 ({approx}8.5 miles downstream of the confluence of the Emory River with the Clinch River, and {approx}4 miles downstream of the confluence of the Clinch River with the Tennessee River). A byproduct of coal combustion, fly ash contains a variety of metals and other elements which, at sufficient concentrations and in specific forms, can be harmful to biological systems. The ecological effects of fly ash contamination on exposed fish populations depend on the magnitude and duration of exposure, with the most significant risk considered to come from elevated levels of certain metals in the ash, particularly selenium, on fish reproduction and fish early life stages (Lemly 1993; Besser and others 1996). The ovaries of adult female fish in a lake contaminated by coal ash were reported to have an increased frequency of atretic oocytes (dead or damaged immature eggs) and reductions in the overall numbers of developing oocytes (Sorensen 1988) associated with elevated body burdens of selenium. Larval fish exposed to selenium through maternal transfer of contaminants to developing eggs in either contaminated bodies of water (Lemly 1999) or in experimental laboratory exposures (Woock and others 1987, Jezierska and others 2009) have significantly increased incidences of developmental abnormalities. Contact of fertilized eggs and developing embryos to ash in water and sediments may also pose an additional risk to the early life stages of exposed fish populations through direct uptake of metals and other ash constituents (Jezierska and others 2009). The establishment and maintenance of fish populations is intimately associated

  3. Characteristic fly-ash particles from oil-shale combustion found in lake sediments

    Energy Technology Data Exchange (ETDEWEB)

    Alliksaar, T.; Hoerstedt, P.; Renberg, I. [Estonian Academy of Sciences, Tallinn (Estonia). Dept. of Geoecology

    1998-05-01

    Fly-ash particles accumulate in sediments and can be used to assess spatial distribution and temporal trends of atmospheric deposition of pollutants derived from high temperature combustion of fossil fuels. Previous work has concerned fly-ash derived from oil and coal. Oil-shale is the main fossil fuel used in Estonia and a major source of atmospheric pollution in the Baltic states. To assess if oil-shale power plants produce specific fly-ash particles scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were used to compare fly-ash particles from oil-shale combustion with particles from oil and coal combustion. Two types were analysed, large black (10-30{mu}m) and small glassy ({lt} 5 {mu}m) spheroidal particles. Although article morphology to some extent is indicative of the fuel burnt, morphological characters are not sufficient to differentiate between particles of different origin. However, the results indicate that with EDX analysis the fly-ash from oil-shale can be distinguished form oil and coal derived particles in environmental samples. Concentrations of large black and small glassy spheroidal fly-ash particles in a sediment core from an Estonian lake showed similar trends to oil-shale combustion statistics from Estonian power plants. 27 refs., 6 figs., 2 tabs.

  4. Experimental Study of Beam-Column Joints Reinforced Concrete with Fiber Concrete and Fly-Ash

    Directory of Open Access Journals (Sweden)

    Purwanto Edy

    2017-01-01

    Full Text Available Reinforced concrete elements in the beam - column joint (HBK plays a very important role for maintaining the structure when subjected to the lateral load, despite the presence of many bars in the area often results in imperfections implementation. The use of fly-ash and fiber in the area of HBK can be one of available solutions; both can increase the strength of concrete and reduce the reinforcement. This study discusses the usage of fly-ash in concrete with proportion of 25% by weight of cement and dramix steel fibers and 10 kg for one m3 of concrete. This study uses the specimens of HBK with a variation of the concrete at age of 28 and 90 days. The analysis of 28 days HBK results: specimen with normal and with fly ash have average load of 10.53 kN and 6.97 kN where specimen with Fly-ash + additive has 12.65 kN (20.13% higher than normal specimen. At the age of 90 days, HBK with normal concrete, fly ash and fiber concrete can withstand load at 12.73 kN, 10.87 kN, and 13.15 kN respectively, where HBK with fiber + fly-ash reaches at 13.38 kN or has 5.00% more than HBK with normal concrete.

  5. Acidification - neutralization processes in a lignite mine spoil amended with fly ash or limestone

    Energy Technology Data Exchange (ETDEWEB)

    Seoane, S.; Leiros, M.C. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain). Dept. de Edafologia y Quimica Agricola

    2001-08-01

    A laboratory experiment was conducted to investigate the long-term effects of amending sulfide-rich lignite mine spoil with fly ash (originating from a coal-fired power station and largely comprised of aluminosilicates) and/or agricultural limestone. The experiment was carried out with soil moisture maintained at field capacity or alternate cycles of wetting and drying. Results obtained suggest that the principal acidification processes were oxidation of sulfide and formation of hydroxysulfate (FeOHSO{sub 4}), whereas the main neutralization processes were weathering of aluminosilicates in fly ash-treated samples. The highest dose of limestone rapidly raised the pH of the spoil, but this increase was not maintained throughout the one-year experiment. In contrast, fly ash-treated samples showed a more sustained increase in pH, attributable to the gradual weathering of aluminosilicates. The best results (i.e., good short- and long-term neutralization) were obtained in samples treated with both fly ash and limestone. The low liming capacity of the fly ash (47.85 cmol kg{sup -1}) means that it must be used in large quantities, an advantage in achieving the further aim of disposing of the fly ash. 33 refs., 5 figs., 4 tabs.

  6. Removal of trivalent chromium from aqueous solution by zeolite synthesized from coal fly ash.

    Science.gov (United States)

    Wu, Deyi; Sui, Yanming; He, Shengbing; Wang, Xinze; Li, Chunjie; Kong, Hainan

    2008-07-15

    The capability of 14 zeolites synthesized from different fly ashes (ZFAs) to sequestrate Cr(III) from aqueous solutions was investigated in a batch mode. The influence of pH on the sorption of Cr(III) was examined. ZFAs had a much greater ability than fly ash to remove Cr(III), due to the high cation exchange capacity (CEC) and the high acid neutralizing capacity (ANC) of ZFAs. The mechanism of Cr(III) removal by ZFAs involved ion exchange and precipitation. A high-calcium content in both the fly ashes and ZFAs resulted in a high ANC value and, as a result, a high immobilization capacity for Cr(III). The pH strongly influenced Cr(III) removal by ZFAs. Inside the solubility range, removal of chromium increased with increasing pH. Hydroxysodalite made from a high-calcium fly ash had a higher sorptive capacity for Cr(III) than the NaP1 zeolite from medium- and low-calcium fly ashes. On the other hand, at pH values above the solubility range, the efficiency of chromium removal by the ZFAs approached 100% due to the precipitation of Cr(OH)3 on the sorbent surfaces. It is concluded that ZFAs and high-calcium fly ashes may be promising materials for the purification of Cr(III) from water/wastewater.

  7. Geopolymeric adsorbents from fly ash for dye removal from aqueous solution.

    Science.gov (United States)

    Li, Lin; Wang, Shaobin; Zhu, Zhonghua

    2006-08-01

    Adsorbents from coal fly ash treated by a solid-state fusion method using NaOH were prepared. It was found that amorphous aluminosilicate geopolymers would be formed. These fly ash-derived inorganic polymers were assessed as potential adsorbents for removal of some basic dyes, methylene blue and crystal violet, from aqueous solution. It was found that the adsorption capacity of the synthesised adsorbents depends on the preparation conditions such as NaOH:fly-ash ratio and fusion temperature with the optimal conditions being at 1.2:1 weight ratio of Na:fly-ash at 250-350 degrees C. The synthesised materials exhibit much higher adsorption capacity than fly ash itself and natural zeolite. The adsorption isotherm can be fitted by Langmuir and Freundlich models while the two-site Langmuir model producing the best results. It was also found that the fly ash derived geopolymeric adsorbents show higher adsorption capacity for crystal violet than methylene blue and the adsorption temperature influences the adsorption capacity. Kinetic studies show that the adsorption process follows the pseudo second-order kinetics.

  8. Hydration of Hybrid Alkaline Cement Containing a Very Large Proportion of Fly Ash: A Descriptive Model

    Directory of Open Access Journals (Sweden)

    Inés Garcia-Lodeiro

    2016-07-01

    Full Text Available In hybrid alkaline fly ash cements, a new generation of binders, hydration, is characterized by features found in both ordinary portland cement (OPC hydration and the alkali activation of fly ash (AAFA. Hybrid alkaline fly ash cements typically have a high fly ash (70 wt % to 80 wt % and low clinker (20 wt % to 30 wt % content. The clinker component favors curing at ambient temperature. A hydration mechanism is proposed based on the authors’ research on these hybrid binders over the last five years. The mechanisms for OPC hydration and FA alkaline activation are summarized by way of reference. In hybrid systems, fly ash activity is visible at very early ages, when two types of gel are formed: C–S–H from the OPC and N–A–S–H from the fly ash. In their mutual presence, these gels tend to evolve, respectively, into C–A–S–H and (N,C–A–S–H. The use of activators with different degrees of alkalinity has a direct impact on reaction kinetics but does not modify the main final products, a mixture of C–A–S–H and (N,C–A–S–H gels. The proportion of each gel in the mix does, however, depend on the alkalinity generated in the medium.

  9. Rheology of fly ashes from coal and biomass co-combustion

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Frandsen, Flemming

    2010-01-01

    The presence of large amounts of alkali metals, chlorine and sulphur in most biomass fuels - compared to coal - can create serious ash-related problems such as deposition, agglomeration and/or corrosion. This paper discusses the viscosity characteristics of fly ash from the co-combustion of vario...

  10. A review: Fly ash and deposit formation in PF fired biomass boilers

    DEFF Research Database (Denmark)

    Jensen, Peter Arendt; Jappe Frandsen, Flemming; Wu, Hao

    2016-01-01

    to the commercialization of the suspension biomass firing technology a range of research studies have improved our understanding of the formation of fly ash and the impact on deposit formation and corrosion in such boilers. In this paper a review of the present knowledge with respect to ash and deposit formation...... in biomass suspension fired boilers is provided. Furthermore the influence of co-firing and use of additives on ash chemistry, deposit properties and boiler operation is discussed....

  11. Preparation and characterization of carbon-enriched coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Rubio, B.; Izquierdo, M.T.; Mayoral, M.C.; Bona, M.T.; Martinez-Tarazona, R.M. [CSIC, Zaragoza (Spain)

    2008-09-15

    Carbon-enriched fractions have been obtained from two coal fly ash (FA) samples. The FA came from two pulverized-coal fired power stations (Lada and Escucha, Spain) and were collected from baghouse filters. Sieving was used to obtain carbon-enriched fractions, which were further subjected to two beneficiation processes: acid demineralization using HCl and HF, and oil agglomeration using soya oil-water. Yield in weight after sieving, unburned carbon content, and several physicochemical characteristics, of the obtained fractions were used to compare the performance of the beneficiation methods. Low carbon concentration was obtained by sieving. particularly in the case of Escucha FA. However, after acid demineralization or oil agglomeration, fractions containing unburned carbon in a range of 63% to 68% were obtained. These fractions showed differences in mineral phase composition and distribution depending on the FA and oil the beneficiation method used. The textural properties of the obtained fractions varied as a function of their carbon content and the beneficiation method used. However, no significant differences in morphology of the carbonaceous particles were found

  12. Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Ganesan Lavanya

    2015-01-01

    Full Text Available This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study is the combination of sodium silicate and sodium hydroxide solution with the ratio of 2.50. The molarity of sodium hydroxide was fixed as 12. The test specimens were 150×150×150 mm cubes, 100×200 mm cylinders, and 100×50 mm discs cured at ambient temperature. Surface deterioration, density, and strength over a period of 14, 28, and 45 days were observed. The results of geopolymer and ordinary Portland cement concrete were compared and discussed. After 45 days of exposure to the magnesium sulfate solution, the reduction in strength was up to 12% for geopolymer concrete and up to 25% for ordinary Portland cement concrete. After the same period of exposure to the sulphuric acid solution, the compressive strength decrease was up to 20% for geopolymer concrete and up to 28% for ordinary Portland cement concrete.

  13. Zeolite formation from coal fly ash and its adsorption potential.

    Science.gov (United States)

    Ruen-ngam, Duangkamol; Rungsuk, Doungmanee; Apiratikul, Ronbanchob; Pavasant, Prasert

    2009-10-01

    The possibility in converting coal fly ash (CFA) to zeolite was evaluated. CFA samples from the local power plant in Prachinburi province, Thailand, were collected during a 3-month time span to account for the inconsistency of the CFA quality, and it was evident that the deviation of the quality of the raw material did not have significant effects on the synthesis. The zeolite product was found to be type X. The most suitable weight ratio of sodium hydroxide (NaOH) to CFA was approximately 2.25, because this gave reasonably high zeolite yield with good cation exchange capacity (CEC). The silica (Si)-to-aluminum (Al) molar ratio of 4.06 yielded the highest crystallinity level for zeolite X at 79% with a CEC of 240 meq/100 g and a surface area of 325 m2/g. Optimal crystallization temperature and time were 90 degrees C and 4 hr, respectively, which gave the highest CEC of approximately 305 meq/100 g. Yields obtained from all experiments were in the range of 50-72%.

  14. Fly ash-based geopolymer lightweight concrete using foaming agent.

    Science.gov (United States)

    Al Bakri Abdullah, Mohd Mustafa; Hussin, Kamarudin; Bnhussain, Mohamed; Ismail, Khairul Nizar; Yahya, Zarina; Razak, Rafiza Abdul

    2012-01-01

    In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature), for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2) produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa) for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity.

  15. Compressive and bonding strength of fly ash based geopolymer mortar

    Science.gov (United States)

    Zailani, Warid Wazien Ahmad; Abdullah, Mohd Mustafa Al Bakri; Zainol, Mohd Remy Rozainy Mohd Arif; Razak, Rafiza Abd.; Tahir, Muhammad Faheem Mohd

    2017-09-01

    Geopolymer which is produced by synthesizing aluminosilicate source materials with an alkaline activator solution promotes sustainable and excellent properties of binder. The purpose of this paper is to determine the optimum binder to sand ratio of geopolymer mortars based on mechanical properties. In order to optimize the formulation of geopolymer mortar, various binder to sand ratios (0.25, 0.33, 0.5, 1.0, 2.0, 3.0, and 4.0) are prepared. The investigation on the effect of sand inclusion to the compressive and bonding strength of geopolymer mortar is approached. The experimental results show that the bonding strength performance of geopolymer is also depends on the various binder to sand ratio, where the optimum ratio 0.5 gives a highest strength of 12.73 MPa followed by 12.35 MPa, which corresponds the ratio 1.0 for geopolymer, while the compared value of OPC bonding strength is given by 9.3 MPa. The morphological structure at the interface zone is determined by Scanning Electron Microscope (SEM) and the homogenous bonding between geopolymer and substrate can be observed. Fly ash based geopolymers reveal a new category of mortar which has high potential to be used in the field of concrete repair and rehabilitation.

  16. Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses

    Science.gov (United States)

    Cheng-Yong, Heah; Yun-Ming, Liew; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin

    2017-03-01

    This paper presents a comparative study of the characteristic of unfoamed and foamed geopolymers after exposure to elevated temperatures (200-800 °C). Unfoamed geopolymers were produced with Class F fly ash and sodium hydroxide and liquid sodium silicate. Porous geopolymers were prepared by foaming with hydrogen peroxide. Unfoamed geopolymers possessed excellent strength of 44.2 MPa and degraded 34% to 15 MPa in foamed geopolymers. The strength of unfoamed geopolymers decreased to 5 MPa with increasing temperature up to 800 °C. Foamed geopolymers behaved differently whereby they deteriorated to 3 MPa at 400 °C and increased up to 11 MPa at 800 °C. Even so, the geopolymers could withstand high temperature without any disintegration and spalling up to 800 °C. The formation of crystalline phases at higher temperature was observed deteriorating the strength of unfoamed geopolymers but enhance the strength of foamed geopolymers. In comparison, foamed geopolymer had better thermal resistance than unfoamed geopolymers as pores provide rooms to counteract the internal damage.

  17. Workability and strength of coarse high calcium fly ash geopolymer

    Energy Technology Data Exchange (ETDEWEB)

    P. Chindaprasirt; T. Chareerat; V. Sirivivatnanon [Khon Kaen University, Khon Kaen (Thailand). Department of Civil Engineering

    2007-03-15

    In this paper, the basic properties viz., workability and strength of geopolymer mortar made from coarse lignite high calcium fly ash were investigated. The geopolymer was activated with sodium hydroxide (NaOH), sodium silicate and heat. The results revealed that the workable flow of geopolymer mortar was in the range of 110 {+-}5%-135 {+-}5% and was dependent on the ratio by mass of sodium silicate to NaOH and the concentration of NaOH. The obtained compressive strength was in the range of 10-65 MPa. The optimum sodium silicate to NaOH ratio to produce high strength geopolymer was 0.67-1.0. The concentration variation of NaOH between 10 M and 20 M was found to have a small effect on the strength. The geopolymer samples with high strength were obtained with the following practices: the delay time after moulding and before subjecting the sample to heat was 1 h and the optimum curing temperature in the oven was 75{sup o}C with the curing duration of not less than two days.

  18. Amelioration of soil PAH and heavy metals by combined application of fly ash and biochar

    Science.gov (United States)

    Masto, Reginald; George, Joshy; Ansari, Md; Ram, Lal

    2016-04-01

    Generation of electricity through coal combustion produces huge quantities of fly ash. Sustainable disposal and utilization of these fly ash is a major challenge. Fly ash along with other amendments like biochar could be used for amelioration of soil. In this study, fly ash and biochar were used together for amelioration of polycyclic aromatic hydrocarbon (PAH) contaminated soil. Field experiment was conducted to investigate the effects of fly ash and biochar on the amelioration of soil PAH, and the yield of Zea mays. The treatments were control, biochar (4 t/ha), fly ash (4 t/ha), ash + biochar ( 2 + 2 t/ha). Soil samples were collected after the harvest of maize crop and analysed for chemical and biological parameters. Thirteen PAHs were analysed in the postharvest soil samples. Soil PAHs were extracted in a microwave oven at 120 °C using hexane : acetone (1:1) mixture. The extracted solutions were concentrated, cleaned and the 13 PAHs [Acenaphthene (Ace), fluorene (Flr), phenanthrene (Phn), anthracene(Ant), pyrene(Pyr), benz(a)anthracene (BaA), chrysene (Chy), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF), benzo(a)pyrene, benzo(g,h,i)perylene (BghiP), dibenzo(a,h)anthracene, and indeno(1,2,3-cd)pyrene)(Inp)] were analysed using GC-MS. The mean pH increased from 6.09 in control to 6.64 and 6.58 at biochar and fly ash treated soils, respectively. N content was not affected, whereas addition of biochar alone and in combination with fly ash, has significantly increased the soil organic carbon content. P content was almost double in combined (9.06 mg/kg) treatment as compared to control (4.32 mg/kg). The increase in K due to biochar was 118%, whereas char + ash increased soil K by 64%. Soil heavy metals were decreased: Zn (-48.4%), Ni (-41.4%), Co (-36.9%), Cu (-35.7%), Mn (-34.3%), Cd (-33.2%), and Pb (-30.4%). Soil dehydrogenase activity was significantly increased by ash and biochar treatments and the maximum activity was observed for the combined

  19. Mechanical and durability properties of fly ash geopolymer concrete containing recycled coarse aggregates

    Directory of Open Access Journals (Sweden)

    Faiz Uddin Ahmed Shaikh

    2016-12-01

    Full Text Available This paper presents mechanical and durability properties of geopolymer concrete containing recycled coarse aggregate (RCA. The RCA is sourced from local construction and demolition (C&D waste in Perth, Australia. The RCA is used as a partial replacement of natural coarse aggregate (NCA in geopolymer concrete at 15%, 30% and 50% by wt. which corresponds to series two, three and four, respectively, while the geopolymer concrete containing 100% NCA is control and is considered as the first series. Class F fly ash is used as the source material for the geopolymer and 8 M sodium hydroxide and sodium silicate alkali activators are used to synthesise the fly ash geopolymer in this study. In all four series a constant alkali activator to fly ash ratio is used. Compressive strength, indirect tensile strength and elastic modulus of above geopolymer concrete are measured at 7 and 28 days, while sorptivity, immersed water absorption and volume of permeable voids of above geopolymer concrete are measured at 28 days. Relevant Australian standards are used to measure all the above properties except the sorptivity which is measured according to ASTM standard. Results show that the compressive strength, indirect tensile strength and elastic modulus of geopolymer concrete decrease with an increase in RCA contents, which is also true for both 7 and 28 days. Excellent correlations of compressive strength with indirect tensile strength and elastic modulus are also observed in geopolymer concrete containing RCA. Existing empirical models for cement concrete and geopolymer concrete containing NCA underestimate and overestimate the indirect tensile strength and elastic modulus, respectively of geopolymer concrete containing RCA. The measured durability properties such as sorptivity, water absorption and volume of permeable voids of geopolymer concrete were also adversely affected by the incorporation of RCA and these properties increase with an increase in RCA

  20. Effect of curing conditions and ionic additives on properties of fly ash ...

    Indian Academy of Sciences (India)

    In the present work the reaction between fly ash and lime in fly ash–lime compacts under water curing and steam curing conditions was studied thoroughly in ... and Materials Engineering Department, College of Engineering and Computing, Florida International University, Miami, Fl 33174, USA; Chemical Engineering ...

  1. Characterization of flue gas, fly ash, aerosol and deposit compositions as a function of waste composition and grate operation

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Zeuthen, Frederik Jacob; Frandsen, Flemming

    2007-01-01

    The Danish strategy for waste management is still to increase recycling and on the same time to reduce the volume of land-filled waste, in order to avoid loss of resources, and waste incineration is an important part of this strategy. In 2004, 26 % of the total reported Danish waste production...... metals, was then mixed with the reference fuel in the individual test runs. The dedicated waste fractions comprised NaCl (road salt), batteries, automotive shredder waste, CCA (Copper-Chromate-Arsenate)-impregnated wood, PVC plastics, and (leather) shoes. Test runs with varying operational parameters, e...... elements Pb, Zn, Cd and Cu was found in the fly ash fractions sampled at app. 175oC, but not in the deposits sampled at 400oC. This indicated condensation of metal chlorides at lower temperatures. It was concluded that the composition of the input waste affected the composition of the fly ash and deposits...

  2. Electrochemical treatment of wood combustion fly ash for the removal of cadmium

    DEFF Research Database (Denmark)

    Damø, Anne Juul

    2002-01-01

    Due to a high content of macronutrients and a potential liming capacity, recycling of ashes from biomass combustion to agricultural fields as fertilisers and/or for soil improvement is considered in Denmark and other countries utilising biomass as an energy source. However, especially the fly ash...... fractions contain amounts of the toxic heavy metal Cd that may exceed the limiting values for agricultural utilisation given by the Danish EPA. In this work the advances of using an electrochemical remediation method to reduce the Cd content in wood combustion fly ash - for the aim of recycling...

  3. Study of Interaction between Fly Ash-cement and Bentonite Matrices

    Directory of Open Access Journals (Sweden)

    Daněk Tomáš

    2015-01-01

    Full Text Available Among the important factors characterizing the quality of sealing mixtures is strength, durability, compatibility and permeability. Experimental work was therefore conducted to assess the use of cement, fly ash, gravel and bentonite in the form of artificial self-hardening sealing mixture. The results of the work show a good compatibility between the bentonite and cement during its fly ash replacement. Compactness of the structure was confirmed by studying of permeability and SEM microscopy, which in the system of ash-cement-bentonite matrix allowed assessing successive microstructure development of hydrating gel.

  4. Partial oxidation of methane to methanol over catalyst ZSM-5 from coal fly ash and rice husk ash

    Directory of Open Access Journals (Sweden)

    Mirda Yanti Fusia

    2017-01-01

    Full Text Available Methane is one of the greenhouse gases that can be converted into liquid fuels such as methanol to retain most of the energy of methane and produce a cleaner environment. The conversion of methane to methanol using ZMS-5 represents a breakthrough in the utilization of methane. However, material sources for zeolite synthesis as catalyst usually are pro-analysis grade materials, which are expensive. Therefore, in this research, coal fly ash and rice husk ash were used as raw materials for mesoporous ZSM-5 zeolite synthesis. First, coal fly ash and rice husk were subjected to pre-treatment to extract silicate (SiO44− and aluminate (AlO45− and impurities separation. The ZSM-5 zeolite was synthesized through hydrothermal treatment using two types of templates. After ZSM-5 was synthesized, it was modified with Cobalt through impregnation method. The catalytic activity of both ZSM-5 and Co/ZSM-5 zeolites as heterogeneous catalysts in partial oxidation of methane were preliminary tested and compared with that commercial one. The result showed that the zeolite catalyst ZSM-5 from fly ash coal and rice husk ash has the potential to be used as catalysts in the partial oxidation of methane to methanol.

  5. Evaluation of Fly Ash Quality Control Tools : Technical Summary

    Science.gov (United States)

    2010-06-01

    Many entities currently use fl y ash in portland cement concrete (PCC) pavements and structures. Although : the body of knowledge is great concerning the use of fl y ash, several projects per year are subject to poor : performance where fl y ash is n...

  6. Evaluation of fly ash quality control tools : tech summary.

    Science.gov (United States)

    2010-06-01

    Many entities currently use fl y ash in portland cement concrete (PCC) pavements and structures. Although : the body of knowledge is great concerning the use of fl y ash, several projects per year are subject to poor : performance where fl y ash is n...

  7. Rheology of Fly Ash Mixed Tailings Slurries and Applicability of Prediction Models

    Directory of Open Access Journals (Sweden)

    Joon Kyu Lee

    2017-09-01

    Full Text Available Coal fly ash has potential applications in the management of reactive mine tailings. The shear stress versus shear rate curves obtained during viscometer tests are presented to describe the rheological behaviors of tailings slurries mixed with fly ash. The investigation was conducted on specimens prepared with different fly ash additions as well as prepared at variable conditions of temperature, mixing time, and CaCl2 solution. It was observed that the rheological properties of ash-tailings slurry mixtures are influenced by the hydration of fly ash as well as the particle packing and arrangement. Rheological properties of specimen mixtures were determined from the resulting flow curves using the existing rheological models. The performance of prediction models in calculating the rheological properties of the mixed specimens, as quantified by the root mean square error (RMSE, varied with the mixture constituents, temperature, and time. In general, the Papanastasion, Herschel-Bulkley, Sisko, and Robertson-Stiff models were found to be favorable for use with mixtures of fly ash and tailings slurries, compared to the Bingham, Modified Bingham, Casson, and De Kee models.

  8. Beyond waste: new sustainable fillers from fly ashes stabilization, obtained by low cost raw materials

    Directory of Open Access Journals (Sweden)

    N. Rodella

    2016-09-01

    Full Text Available A sustainable economy can be achieved only by assessing processes finalized to optimize the use of resources. Waste can be a relevant source of energy thanks to energy-from-waste processes. Concerns regarding the toxic fly ashes can be solved by transforming them into resource as recycled materials. The commitment to recycle is driven by the need to conserve natural resources, reduce imports of raw materials, save landfill space and reduce pollution. A new method to stabilize fly ash from Municipal Solid Waste Incinerator (MSWI at room temperature has been developed thanks to COSMOS-RICE LIFE+ project (www.cosmos-rice.csmt.eu. This process is based on a chemical reaction that occurs properly mixing three waste fly ashes with rice husk ash, an agricultural by-product. COSMOS inert can replace critical raw materials (i.e. silica, fluorspar, clays, bentonite, antimony and alumina as filler. Moreover the materials employed in the stabilization procedure may be not available in all areas. This paper investigates the possibility of substituting silica fume with corresponding condensed silica fume and to substitute flue-gas desulfurization (FGD residues with low-cost calcium hydroxide powder. The removal of coal fly ash was also considered. The results will be presented and a possible substitution of the materials to stabilize fly ash will be discussed.

  9. Stabilization and separation of heavy metals in incineration fly ash during the hydrothermal treatment process.

    Science.gov (United States)

    Hu, Yuyan; Zhang, Pengfei; Li, Jianping; Chen, Dezhen

    2015-12-15

    In the paper, hydrothermal treatment (HT) of MSWI fly ashes was performed to stabilize and separate heavy metals. Influences of pre-treatment, types of ferric and/or ferrous additives, and subsequent heavy metal stabilization procedure by adding phosphate were investigated. The chemical stability of hydrothermal products was examined by solid waste extraction procedure with acetic acid buffer solution. Mineralogical investigation of selected hydrothermal product was carried out by XRD. FEGE SEM- -EDX was used to study the morphology and surface compositions of the ash particles. Experimental results revealed that HT process facilitated heavy metal exposure to leaching solution. FEGE SEM-EDX images revealed that fly ash particles were re-organized during hydrothermal process and that the minerals with special shapes and containing high levels of heavy metals were formed. A mild acid washing treatment with final pH around 6.20 could remove soluble heavy metals. Therefore, it may be a proper pre- or post-treatment method for fly ash particles for the purpose of reducing heavy metal contents. For the purpose of stabilizing heavy metals, the addition of ferric/ferrous salts in the HT process or phosphate stabilization after HT is recommended. The HT process may be applied to realize the environmentally sound management of MSWI fly ash or to recover and utilize MSWI fly ash. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Fly-ash products from biomass co-combustion for VOC control.

    Science.gov (United States)

    Kwong, C W; Chao, C Y H

    2010-02-01

    Experiments were conducted in a continuous flow reactor at room temperature to evaluate the elimination of low-concentration toluene in the gas phase to verify if fly-ash products from biomass combustion in an ozonation system could be used in the removal of volatile organic compounds. The fly-ash products from pure biomass combustion (Ash(100)) demonstrated the highest ozonation activities upon the removal of low-concentration toluene (1.5 ppmv), followed by the fly-ash products from co-combustion (Ash(30)) and the coal combustion (Ash(0)). Kinetic experiments showed that the activation energy of the toluene elimination process was substantially reduced with the use of ozone and the reaction intermediates, such as formic acids, aldehydes, etc. Results also showed that the intermediates were reduced with increasing humidity level. The combined use of fly-ash products and zeolite 13X enhanced the removal of toluene to above 90% and suppressed the release of residual ozone and intermediates by holding them in the adsorbed phase.

  11. Structural and Mechanical Characterization of Sustainable Composites Based on Recycled and Stabilized Fly Ash

    Directory of Open Access Journals (Sweden)

    Stefano Besco

    2014-08-01

    Full Text Available This paper reports the results on the use of an innovative inert, based on stabilized fly ash from municipal solid waste incineration as a filler for polypropylene. The starting material, which contains large quantities of leachable Pb and Zn, was stabilized by means of an innovative process using rice husk ash as a waste silica source, together with other fly ashes, such as coal fly ash and flue gas desulfurization residues. The use of all waste materials to obtain a new filler makes the proposed technology extremely sustainable and competitive. The new composites, obtained by using the stabilized material as a filler for polypropylene, were characterized and their mechanical properties were also investigated. A comparison with a traditional polypropylene and calcium carbonate based compound was also done. This research activity was realized in the frame of the COSMOS-RICE project, financed by the EU Commission.

  12. Study on Reactivity of Circulating Fluidized Bed Combustion Fly Ashes in the Presence of Water

    Directory of Open Access Journals (Sweden)

    Salain I.M.A.K.

    2010-01-01

    Full Text Available A study on reactivity of four different Circulating Fluidized Bed Combustion (CFBC fly ashes has been realized in the presence of water. Paste of each ash was prepared and analyzed for its setting time, expansion and strength. The products of hydration, and their evolutions over a period of time were identified by X-ray diffraction and differential thermal analysis. The results of this study show that the reactivity of the CFBC fly ashes is strongly related to their chemical composition, essentially to their quantity of silica, alumina, lime and sulfate, which promote principally the formation of ettringite, gypsum and C-S-H. It is further noted that the intensity and the proportion of these phases determine the hydration behavior of the CFBC fly ashes.

  13. Application of dry separative methods for decreasing content the residues unburned coal and separation Fe from black coal flies ash

    Directory of Open Access Journals (Sweden)

    František Kaľavský

    2008-06-01

    Full Text Available Main obstacle using of fly ashes in building, that is its main consumer, is the residue of unburned coal; it is expressed of loss onignition - LOI. In present, the valid STN and EU standard limits the content of LOI to 3 – 5 %, in national conditions maximum 7 %.Application of processing technologies also has to assure utilization of fly ash that provides a possibility of complex utilizationof individual products obtained by modification.By means of corona separation, based on different conductivity of individual fly ash elements, it is possible to separate unburnedcoal particles. The fly ash sample from black coal burning in melting boiler that was deposited on fly ash deposit, content of LOIof dielectric particle 6,45 % at 61 % weight yield was achieved. In the samples taken from dry taking of fly ash the non-conductingproduct contained 7,72 % of LOI at 73 % of weight yield.

  14. Characterization and electrodialytic treatment of wood combustion fly ash for removal of cadmium

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul

    2003-01-01

    -for the aim of recycling-was described. Initial characterisation of the experimental ash showed that the Cd content exceeded the limiting values for agricultural use and therefore needed treatment before being recycled. The pH in the ash was very high (13.3), and the Cd was not soluble at these alkaline......Due to a high content of macronutrients and a potential liming capacity, recycling of ashes from biomass combustion to agricultural fields as fertilisers and/or for soil improvement is considered in Denmark and other countries utilising biomass as an energy source. However, the fly ash fractions...... especially contain amounts of the toxic heavy metal cadmium that may exceed the limiting values for agricultural utilisation given by the Danish Environmental Protection Agency.In this work the advances of using an electrodialytic remediation method to reduce the Cd content in wood combustion fly ash...

  15. Thermal and hydrometallurgical recovery methods of heavy metals from municipal solid waste fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Kuboňová, L., E-mail: lenka.kubonova@vsb.cz [VSB – Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava (Czech Republic); Langová, Š. [VSB – Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava (Czech Republic); Nowak, B.; Winter, F. [Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9/166, A-1060 Vienna (Austria)

    2013-11-15

    Highlights: • MSW fly ash was thermally and hydrometallurgically treated to remove heavy metals. • More than 90% of easy volatile heavy metals (Cd and Pb) were removed thermally. • More than 90% of Cd, Cr, Cu an Zn were removed by alkaline – acid leaching. • The best results were obtained for the solution of 3 M NaOH and 2 M H{sub 2}SO{sub 4}. - Abstract: Heavy metals in fly ash from municipal solid waste incinerators are present in high concentrations. Therefore fly ash must be treated as a hazardous material. On the other hand, it may be a potential source of heavy metals. Zinc, lead, cadmium, and copper can be relatively easily removed during the thermal treatment of fly ash, e.g. in the form of chlorides. In return, wet extraction methods could provide promising results for these elements including chromium and nickel. The aim of this study was to investigate and compare thermal and hydrometallurgical treatment of municipal solid waste fly ash. Thermal treatment of fly ash was performed in a rotary reactor at temperatures between 950 and 1050 °C and in a muffle oven at temperatures from 500 to 1200 °C. The removal more than 90% was reached by easy volatile heavy metals such as cadmium and lead and also by copper, however at higher temperature in the muffle oven. The alkaline (sodium hydroxide) and acid (sulphuric acid) leaching of the fly ash was carried out while the influence of temperature, time, concentration, and liquid/solid ratio were investigated. The combination of alkaline-acidic leaching enhanced the removal of, namely, zinc, chromium and nickel.

  16. Performance evaluation of cement stabilized fly ash-GBFS mixes as a highway construction material.

    Science.gov (United States)

    Singh, S P; Tripathy, D P; Ranjith, P G

    2008-01-01

    Fly ash and granulated blast furnace slag (GBFS) are major by-products of thermal and steel plants, respectively. These materials often cause disposal problems and environmental pollution. Detailed laboratory investigations were carried out on cement stabilized fly ash-(GBFS) mixes in order to find out its suitability for road embankments, and for base and sub-base courses of highway pavements. Proctor compaction test, unconfined compressive strength (UCS) test and California Bearing Ratio (CBR) test were conducted on cement stabilized fly ash-GBFS mixes as per the Indian Standard Code of Practice. Cement content in the mix was varied from 0% to 8% at 2% intervals, whereas the slag content was varied as 0%, 10%, 20%, 30% and 40%. Test results show that an increase of either cement or GBFS content in the mixture, results in increase of maximum dry density (MDD) and decrease of optimum moisture content (OMC) of the compacted mixture. The MDD of the cement stabilized fly ash-GBFS mixture is comparably lower than that of similarly graded natural inorganic soil of sand to silt size. This is advantageous in constructing lightweight embankments over soft, compressible soils. An increase in percentage of cement in the fly ash-GBFS mix increases enormously the CBR value. Also an increase of the amount of GBFS in the fly ash sample with fixed cement content improves the CBR value of the stabilized mix. In the present study, the maximum CBR value of compacted fly ash-GBFS-cement (52:40:8) mixture obtained was 105%, indicating its suitability for use in base and sub-base courses in highway pavements with proper combinations of raw materials.

  17. Chemical associations and mobilization of heavy metals in fly ash from municipal solid waste incineration.

    Science.gov (United States)

    Weibel, Gisela; Eggenberger, Urs; Schlumberger, Stefan; Mäder, Urs K

    2017-04-01

    This study focusses on chemical and mineralogical characterization of fly ash and leached filter cake and on the determination of parameters influencing metal mobilization by leaching. Three different leaching processes of fly ash from municipal solid waste incineration (MSWI) plants in Switzerland comprise neutral, acidic and optimized acidic (+ oxidizing agent) fly ash leaching have been investigated. Fly ash is characterized by refractory particles (Al-foil, unburnt carbon, quartz, feldspar) and newly formed high-temperature phases (glass, gehlenite, wollastonite) surrounded by characteristic dust rims. Metals are carried along with the flue gas (Fe-oxides, brass) and are enriched in mineral aggregates (quartz, feldspar, wollastonite, glass) or vaporized and condensed as chlorides or sulphates. Parameters controlling the mobilization of neutral and acidic fly ash leaching are pH and redox conditions, liquid to solid ratio, extraction time and temperature. Almost no depletion for Zn, Pb, Cu and Cd is achieved by performing neutral leaching. Acidic fly ash leaching results in depletion factors of 40% for Zn, 53% for Cd, 8% for Pb and 6% for Cu. The extraction of Pb and Cu are mainly limited due to a cementation process and the formation of a PbCu 0 -alloy-phase and to a minor degree due to secondary precipitation (PbCl 2 ). The addition of hydrogen peroxide during acidic fly ash leaching (optimized acidic leaching) prevents this reduction through oxidation of metallic components and thus significantly higher depletion factors for Pb (57%), Cu (30%) and Cd (92%) are achieved. The elevated metal depletion using acidic leaching in combination with hydrogen peroxide justifies the extra effort not only by reduced metal loads to the environment but also by reduced deposition costs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Fly Ash-based Geopolymer Lightweight Concrete Using Foaming Agent

    Directory of Open Access Journals (Sweden)

    Rafiza Abdul Razak

    2012-06-01

    Full Text Available In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH, and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature, for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2 produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity.

  19. Composition and morphology of fly ash glass-crystalline microspheres

    Energy Technology Data Exchange (ETDEWEB)

    A.G. Anshits; N.N. Anshits; O.A. Bayukov; A.N. Salanov [Institute of Chemistry and Chemical Technology SB RAS, Krasnoyarsk (Russian Federation)

    2005-07-01

    There has been obtained two series of narrow fractions of cenospheres from coal fly ash with the use of different separation methods. The content of Fe{sub 2}O{sub 3} in magnetic cenospheres varies in the interval of 3.1-21.0 wt. %. For narrow fractions of cenospheres, distinguished on the size, at close content of Fe{sub 2}O{sub 3} (2.6-3.1 wt. %) the content of Al{sub 2}O{sub 3} varies in the interval of 19.6-25.0 wt. %. The influence of the chemical composition of cenospheres on their morphology, composition of spinel phase and the size of its crystallites was studied by the methods of Moessbauer spectroscopy, SEM and the thermodynamic analysis of multicomponent silicate systems. It was shown, that at decrease in the content of aluminium in cenospheres the thickness and porosity of the shell is increased. The external and internal surface of the shell is covered with the nanosized film. At high content of Al{sub 2}O{sub 3} in cenospheres the solid solution of the spinel phase on the basis of MgAl{sub 2}O{sub 4} is formed. In magnetic microspheres with increase in Fe{sub 2}O{sub 3} content and decrease in the melt viscosity the thickness of the shell is increased and its porosity is reduced. The solid solution of spinel phase is formed on the basis of magnetite. At low content of Fe{sub 2}O{sub 3} (less than 4.5 wt. %) spinel phase is nanosized (3-10 nm) and is preferably located in a film on the external surface of cenospheres. 25 refs., 4 figs., 4 tabs.

  20. Fabrication and adsorption properties of hybrid fly ash composites

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Mengfan [Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi' an710119, Shaanxi (China); Ma, Qingliang, E-mail: maqingliang@tyut.edu.cn [Key Laboratory of Coal Science and Technology, Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan, 030024 (China); Lin, Qingwen; Chang, Jiali [Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi' an710119, Shaanxi (China); Ma, Hongzhu, E-mail: hzmachem@snnu.edu.cn [Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi' an710119, Shaanxi (China)

    2017-02-28

    Highlights: • Hybrid hydrophilic/hydrophobic FA composites was constructed. • 99.2% O-II removal was obtained with MF/P(DMDAAC-co-AAM). • MF/KH-570 showed better hydrophobic property. • The possible mechanism of FA composite fabrication was studied. • The Freundlich isotherm and pseudo-second-order kinetic model fit better with kerosene adsorption. - Abstract: In order to realize the utilization of fly ash (FA) as industrial solid waste better, high-efficient inorganic/organic hybrid composite adsorbents derived from (Ca(OH){sub 2}/Na{sub 2}FeO{sub 4}) modified FA (MF) was fabricated. The hydrophilic cationic polymer (P(DMDAAC-co-AAM) or hydrophobic modifier (calcium-570) were used. The prepared composites were characterized by X-ray fluorescence spectroscopy, energy dispersive spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller, Fourier transform infrared spectroscopy, thermogravimetry, and contact angle test. The adsorption of cationic composites MF/P(DMDAAC-co-AAM) towards Orange II in wastewater was investigated. The results show that: adsorption amount of 24.8 mg/g with 2000 mg/L of composites, 50 mg/L Orange II, original pH (6–8), at 40 min and room temperature, was obtained. Meanwhile, oil adsorption ratio Q(g/g) of hydrophobic composites MF/KH-570 was also evaluated. The maximum Q of 17.2 g/g to kerosene was obtained at 40 min. The isotherm and kinetics of these two adsorption processes were also studied. The results showed that the fabricated MF composites modified with hydrophilic or hydrophobic group can be used to adsorb dye in wastewater or oil effectively.

  1. A study on fiy ash: ballistic separation of a fly ash

    Directory of Open Access Journals (Sweden)

    Peris Mora, Eduardo

    1991-09-01

    Full Text Available The object of this study is the characterization of several sized fractions from a "spanish fly ash" originating in the thermoelectric power plant in Andorra (Teruel. Physical (size distributions, densities chemical (chemical composition and mineralogical characteristics (X-ray diffractograms and infrared spectra for those sized fractions have been analyzed. Initial fly ash was ballistically separated (horizontal draft into four fractions using an aerodynamic tunnel with horizontal air current The separation effectivity was adapted for our later studies. The results obtained were interesting: in the first case, the simplicity of the separation method, by this way we will be able to use it for further studies on sized fractions. On the other hand, differences on granulometric distributions and vitreous nature will allow us to study the effect of several fractions on mechanic properties of concrete with them.

    El objeto de este estudio es la caracterización de las diferentes fracciones de distintas granulometrías y tamaños obtenidas de una ceniza volante española producida en la central termoeléctrica de Andorra (Teruel. Se han estudiado las propiedades físicas (distribución granulométrica, densidad químicas (composición química y mineralógicas (difracción de rayos X y espectroscopia infrarroja de dichas fracciones. La técnica de separación aplicada es la "balística" (tiro horizontal, de la que se obtienen cuatro fracciones. Se usó un túnel aerodinámico con corriente horizontal de aire. La efectividad de la separación conseguida fue satisfactoria para nuestros objetivos. Los resultados obtenidos son interesantes desde dos puntos de vista: Por una parte, la simplicidad del método permite aplicarlo para posteriores estudios en cantidades importantes. Por otra parte, las diferencias en las distribuciones granulométricas y su naturaleza vitrea nos permitirá diseñar un estudio posterior acerca de la influencia

  2. Effects of different surface modification and contents on municipal solid waste incineration fly ash/epoxy composites.

    Science.gov (United States)

    Goh, C K; Valavan, S E; Low, T K; Tang, L H

    2016-12-01

    Incineration fly ash, a waste from municipal solid waste incineration plant can be used to replace conventional filler as reinforcing filler to enhance the mechanical strength of a composite. Surface modification was performed on the incineration fly ash before mixing into the soft polymer matrix so as to improve interfacial bond of the filler and epoxy resin. In this study, detailed characterisation of mechanical, morphological and leaching behaviours of municipal solid waste incineration (MSWI) fly ash infused composite has been carried out. Flexural and tensile test was conducted to determine the effect on mechanical properties of the composite by varying the concentration of incineration fly ash filler added into polymer matrix and surface modification of incineration fly ash filler using silane coupling agent and colloidal mesoporous silica (CMS). The results indicated that composite infused with incineration fly ash filler surface treated with CMS shown improvement on the tensile and flexural strengths. In addition, SEM images showed that surface modification of incineration fly ash with colloidal mesoporous silica enhanced the interfacial bonding with polymer resin which explained the improvement of mechanical strength. Leaching test showed result of toxic metals such as Pb, Zn, Fe, Cu, Cr, Cd and Rb immobilised in the polymer matrix of the composite. Hence, the use of MSWI fly ash as reinforcing filler in the composite appears green and sustainable because this approach is a promising opportunity to substitute valuable raw material with MSWI fly ash. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Investigation on the fly ash thermal treatment on the performance of Lithium Ferriphosphate (LiFePO{sub 4}) battery

    Energy Technology Data Exchange (ETDEWEB)

    Febiolita, Bella; Khoirunnissak, Dewi; Purwanto, Agus, E-mail: aguspurw@gmail.com [Research Group of Battery & Advanced Material, Department of Chemical Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A Kentingan, Surakarta Indonesia 57126 (Indonesia)

    2016-02-08

    Addition of the fly ash can be used to improve the capacity of LiFePO{sub 4} battery. Fly ash was added in Acethylene Black (AB) as 2% of the total weight of Acetylene Black (AB). The effects of temperature variation and fly ash characteristics were analyzed. Fly ash was prepared by heating at 50, 100, 150, and 250°C in muffle furnace for 5 hours and passed in 200 mesh screen prior to mixing it with other compounds. Lithium Ferriphospat (LiFePO{sub 4}), fly ash, Acethylene Black (AB), Polyvinylidene Fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to be slurry. The slurry were coated, dried and hot pressed to make a cathode film. The performance of battery lithium was examined by eight channel battery analyzer. The composition of the fly ash was examined by X-ray fluorescence spectrometry (XRF) and Fourier Tansform Infrared Spectroscopy (FTIR). The excellent performance was shown in the fly ash addition which were treated by heating at 150°C. The capacity of fly ash added LiFePO{sub 4} battery is 94.373 mAh/g, which is higher than that of without fly ash addition, i.e. 67.998 mAh/g.

  4. Electrodialytic extraction of Cu, Pb and Cl from municipal solid waste incineration fly ash suspended in water

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Lima, Ana Teresa; Pedersen, Anne Juul

    2006-01-01

    The possibility of using fly ash from municipal solid waste incineration (MSWI) in, for example, concrete is considered. MSWI fly ash, however, has too high a concentration of heavy metals, which may cause leaching problems during use or problems with waste handling at the end of the lifetime...... of the concrete. The Cl content in MSWI fly ash is also too high and will cause corrosion problems in reinforced concrete. The possibility of removing some of the unwanted heavy metals (Cu and Pb) together with Cl from an MSWI fly ash suspended in water using an electrodialytic separation method was investigated...

  5. Effect of adding acid solution on setting time and compressive strength of high calcium fly ash based geopolymer

    Science.gov (United States)

    Antoni, Herianto, Jason Ghorman; Anastasia, Evelin; Hardjito, Djwantoro

    2017-09-01

    Fly ash with high calcium oxide content when used as the base material in geopolymer concrete could cause flash setting or rapid hardening. However, it might increase the compressive strength of geopolymer concrete. This rapid hardening could cause problems if the geopolymer concrete is used on a large scale casting that requires a long setting time. CaO content can be indicated by pH values of the fly ash, while higher pH is correlated with the rapid setting time of fly ash-based geopolymer. This study investigates the addition of acid solution to reduce the initial pH of the fly ash and to prolong the setting time of the mixture. The acids used in this study are hydrochloric acid (HCl), sulfuric acid (H2 SO4), nitric acid (HNO3) and acetic acid (CH3 COOH). It was found that the addition of acid solution in fly ash was able to decrease the initial pH of fly ash, however, the initial setting time of geopolymer was not reduced. It was even faster than that of the control mixture. The acid type causes various influence, depending on the fly ash properties. In addition, the use of acid solution in fly ash reduces the compressive strength of geopolymer mortar. It is concluded that the addition of acid solution cannot prolong the rapid hardening of high calcium fly ash geopolymer, and it causes adverse effect on the compressive strength.

  6. Impact of coal fly ash addition on ash transformation and deposition in a full-scale wood suspension-firing boiler

    DEFF Research Database (Denmark)

    Wu, Hao; Bashir, Muhammad Shafique; Jensen, Peter Arendt

    2013-01-01

    Ash transformation and deposition during pulverized wood combustion in a full-scale power plant boiler of 800 MWth were studied with and without the addition of coal fly ash. The transient ash deposition behavior was characterized by using an advanced deposit probe system at two boiler locations...... with flue gas temperatures of about 1300 C and 800 C, respectively. The mechanisms of ash transformation and deposit formation were elaborated through a detailed characterization of the collected deposits and fly ashes. The results implied that during pulverized wood combustion, the formation of deposits...... constant after a few hours. The formed deposits, especially those at the location with low flue gas temperatures, contained a considerable amount of K2SO4, KCl, and KOH/K2CO3. With the addition of a large amount (about 4 times of the mass flow of wood ash) of coal fly ash to the boiler, these alkali...

  7. Effect Of Fly Ash Filler To Dielectric Properties Of The Insulator Material Of Silicone Rubber And Epoxy Resin

    Directory of Open Access Journals (Sweden)

    Ikhlas Kitta

    2015-08-01

    Full Text Available Currently many operated the coal fired power plant to meet the energy needs of the worlds electricity. But the coal fired power plant produces waste that can pollute the environment such as fly ash and bottom ash so requires management to not cause environmental problems because coal fly ash classified as a hazardous waste. Fly ash has a particle size that is very smooth and of some literature research done previously fly ash coal containing silica SiO2 alumina Al2O3 titanium dioxide TiO2 magnesium oxide MgO and zinc oxide ZnO are potentially as filler that are likely to be used as a mixture of silicone rubber and epoxy resin for electrical insulators. So this research theme was engineering insulation materials by utilizing waste coal fly ash. The purpose of this study was to obtain performance characteristics of waste coal fly ash as filler in silicon rubber and epoxy resin. To achieve these objectives the activities that have been done is examined the effects of the use of fly ash as filler in silicone rubber material and epoxy resin. Parameters measured were dielectric strength and relative permittivity. The result of this research is the dielectric strength of silicone rubber rose with increasing quantity of fly ash. Conversely in epoxy resin dielectric strength decreases with increasing quantity of fly ash. Furthermore the measurement results relative permittivity where the value of the relative permittivity of silicon rubber swell if it is filled with fly ash as well as epoxy resin which has a value of permittivity relative to the concentration of fly ash filler material is linear.

  8. Heavy metal migration during electroremediation of fly ash from different wastes--modelling.

    Science.gov (United States)

    Lima, A T; Rodrigues, P C; Mexia, J T

    2010-03-15

    Fly ash is an airborne material which is considered hazardous waste due to its enrichment on heavy metals. Depending on the waste from which they are originated, fly ash may be further valorised, e.g. as soil amendment or concrete and ceramics adjuvant, or landfilled, when defined as hazardous material. In any case, heavy metal content has to be decreased either for fly ash valorisation or for complying with landfill criteria. The electrodialytic (EDR) process is a remediation technique based on the principle of electrokinetics and dialysis, having the aim to remove heavy metals from contaminated solid media. EDR was here applied to fly ashes from the combustion of straw (ST), from the incineration of municipal solid waste (DK and PT) and from the co-combustion of wood (CW). A statistical study, using F tests, Bonferroni multiple comparison method and a categorical regression, was carried out to determine which variables ("Ash type", "Duration", "Initial pH", "Final pH", "Acidification" and "Dissolution") were the most significant for EDR efficiency. After establishing these, the selected variables were then used to characterize some kinetic parameters, from metals migration during EDR, using a biregressional design. Cd, Cr, Cu, Ca and Zn migration velocity and acceleration to the electrodes (anode and cathode) were then considered. Cd and Cu migration to the cathode were found to be significantly influenced by "Ash type", "Duration", "Final pH" and "Dissolution". (c) 2009 Elsevier B.V. All rights reserved.

  9. Mineralogy, geochemistry and physical properties of fly ash from the Megalopolis lignite fields, Peloponnese, southern Greece

    Energy Technology Data Exchange (ETDEWEB)

    Sakorafa, V.; Michailidis, K.; Burragato, F. [Universita degli Studi di Roma `La Sapienza`, Rome (Italy). Dipt. di Scienze della Terra

    1996-03-01

    Results are given on the mineralogy, morphology, geochemistry and physical characteristics of fly ash from the Megalopolis lignite fields, Peloponnese (S. Greece). The main mineral species present are quartz, anhydride, plagioclase, haematite, gehlenite and calcite. Also present, in minor and trace amounts, are lime, alkali feldspars, bassanite, gypsum, mica and unburnt lignite. Morphologically, fly ash consists of irregularly shaped, oval and spherical particles, of widely varying sizes. Chemically, the fly ash samples examined fall in the pozzolan field in the triangular diagram CaO-SiO{sub 2}-Al{sub 2}O{sub 3}. The trace elements As, Cd, Mo and Se, and Ni, V, and Zn of great and moderate environmental concern respectively, occur in concentrations higher than the respective Clarke values. Ash fusion temperatures vary within the range 1257{degree}C (initial deformation temperature) to 1339{degree}C (flow temperature) on average. Fouling and slagging parameters of the ash are within the preferred ranges of empirical practice. The chemistry of the fly ash reveals properties of concern to the construction industry, to the prediction of lignite-fired boiler performance and to health and environment. 21 refs., 4 figs., 3 tabs.

  10. Effect of curing and drying on strength and absorption of concretes containing fly ash and silica fume

    Energy Technology Data Exchange (ETDEWEB)

    Saricimen, H.; Maslehuddin, M.; Shameem, M.; Al-Ghamdi, A. J.; Barry, M. S. [King Fahd Univ. of Petroleum and Minerals, Research Inst., Dhahran, (Saudi Arabia)

    2000-07-01

    The effects of curing and drying on the strength and absorption of plain and pozzolanic (i.e. containing finely ground clay or volcanic material) cement concretes are evaluated. Curing was carried out over a range of days ranging from one day to 60 days. At each testing period specimens were oven-dried at 70 degrees C for periods ranging from two hours to 24 hours, and the effect of curing and drying was evaluated by measuring 48-hour absorption and volume of permeable voids. Results showed an increase in compressive strength with increased curing and drying, with maximum increase occurring in fly-ash cement concrete specimens. There was a decrease in absorption with time of curing and an increase with drying period. Absorption capacity of fly-ash and silica-fume cements concrete specimens showed a significant decrease after three to seven days of curing. Absorption of pozzolanic cement concretes appeared unaffected especially after seven days of curing. Permeable voids decreased with curing. This characteristic was most evident in the case of fly-ash cement concrete specimens.25 refs., 14 tabs., 3 figs.

  11. Experimental investigation in separating the heavy metal elements of refuse incineration fly ashes by using molten iron

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J. [Chongqing Univ., Chongqing (China)]|[CPI-Yuanda Environmental-protection Engineering Co. Ltd., Chongqing (China); Liu, Q.; Dong, L. [Chongqing Univ., Chongqing (China); Du, Y. [CPI-Yuanda Environmental-protection Engineering Co. Ltd., Chongqing (China)

    2008-07-01

    One of the main waste treatment methods in the world for municipal solid waste (MSW) is incineration. It is effective in toxic substance destruction, waste volume reduction, and energy recovery. Some chemical substances are accumulated during incineration, most notably lead, zinc, chromium and cadmium, as well as other heavy metals. Untreated fly ash disposed in landfills can pollute the soil, surface water and groundwater because of the high levels of hazardous heavy metals and high salt concentration that can be leached out. This paper presented an experiment that melt-separated the heavy metal elements from fly ash generated during refuse incineration. Molted iron, was used as resolvent to dissolve the heavy metal elements in it. The paper described the materials and methods as well as the results of the study. It was concluded that using molted iron to separate the heavy metal elements from MSW incineration fly ash was feasible. The removal ratio of the main heavy metal elements was above 80 per cent, and some of it was above 99 per cent. 5 refs., 7 tabs., 1 fig.

  12. Aqueous extraction of anions from coal and fly ash followed by ion-chromatographic determination

    Directory of Open Access Journals (Sweden)

    Tasić Aleksandra M.

    2016-01-01

    Full Text Available Three different techniques were applied for the aqueous extraction of anions from coal and fly ash: rotary mixer- and ultrasonic-assisted extraction with different duration time, and microwave-assisted extraction at different temperatures. Validation showed that the ion-chromatographic method was suitable for the analysis of anions in coal and fly ash extracts. The variations in the amounts of anions using different extraction times during rotary-assisted extraction were minimal for all investigated anions. The efficiency of ultrasound-assisted extraction of anions from coal depended on the sonication time and was highest at 30 min. The ultrasound-assisted extraction was less efficient for the extraction of anions from fly ash than rotary-assisted extraction. Increase of temperature in the microwave-assisted extraction had a positive effect on the amounts of all anions extracted from coal and sulphate from fly ash, while the amounts of fluoride and chloride in fly ash extracts decreased. The microwave-assisted extraction of coal at 150°C was compared with standard ASTM methods, and results were in good agreement only for chloride. Changes in the pH value and conductivity during ultrasound-assisted extraction were measured in order to explain changes on the surface of coal particles in contact with water and different processes that occur under environmental conditions. [Projekat Ministarstva nauke Republike Srbije, br. 172030, br. 176006 i br. III43009

  13. Utilization of fly ash as partial sand replacement in oil palm shell lightweight aggregate concrete

    Science.gov (United States)

    Nazrin Akmal, A. Z. Muhammad; Muthusamy, K.; Mat Yahaya, F.; Hanafi, H. Mohd; Nur Azzimah, Z.

    2017-11-01

    Realization on the increasing demand for river sand supply in construction sector has inspired the current research to find alternative material to reduce the use of natural sand in oil palm shell lightweight aggregate concrete (OPS LWAC) production. The existence of fly ash, a by-product generated from coal power plant, which pose negative impact to the environment when it is disposed as waste, were used in this research. The effect of fly ash content as partial sand replacement towards workability and compressive strength of OPS lightweight aggregate concrete were investigated. Four concrete mixes containing various percentage of fly ash that are 0%, 10%, 20% and 30% by weight of sand were used in the experimental work. All mixes were cast in form of cubes before subjected to water curing until the testing age. Compressive strength test were conducted at 1, 3, 7 and 28 days. The finding shows that the workability of the OPS LWAC decreases when more fly ash are used as sand replacement. It was found that adding of 10% fly ash as sand replacement content resulted in better compressive strength of OPS LWAC, which is higher than the control mix.

  14. Air pollution-associated fly ash particles induce fibrotic mechanisms in primary fibroblasts.

    Science.gov (United States)

    Gursinsky, Torsten; Ruhs, Stefanie; Friess, Ulrich; Diabaté, Silvia; Krug, Harald F; Silber, Rolf-Edgar; Simm, Andreas

    2006-01-01

    Air pollution is associated with a variety of respiratory and cardiovascular disorders, including fibrosis. To understand the possible molecular mechanisms underlying this observation, we examined the effect of particulate matter on primary fibroblasts, the key regulators of the extracellular matrix. Fly ash collected in an experimental waste incinerator was used as model particles for fine and ultrafine pollution components. Brief treatment of fibroblasts isolated from adult male Wistar rat hearts with fly ash triggered the immediate formation of intracellular reactive oxygen species (ROS). Using phospho-specific antibodies we observed activation of p38 MAP kinase, p44/42 MAP kinase (ERK1/2) and p70(S6) kinase. Prolonged incubation with fly ash increased the expression of collagen 1 and TGF-beta1, but decreased mRNA levels of MMP9 and TNF-alpha. Cell proliferation was inhibited at high concentrations of fly ash. An increase in the level of advanced glycation endproduct (AGE) modification of various cellular proteins after long-term treatment of cultured fibroblasts with fly ash was observed. The results of our study demonstrate that direct activation of fibroblasts by combustion-derived particles is a mechanism that may contribute to the adverse health effects of particulate air pollution.

  15. Influence of NaOH solution on the synthesis of fly ash geopolymer

    Energy Technology Data Exchange (ETDEWEB)

    Ubolluk Rattanasak; Prinya Chindaprasirt [Burapha University, Chonburi (Thailand). Department of Chemistry

    2009-10-15

    A study was conducted on leaching of fly ash mixed with NaOH solution and on mixing procedure for preparing geopolymer. Leaching of SiO{sub 2} and Al{sub 2}O{sub 3} was investigated by mixing fly ash with NaOH solution for different time intervals and leachates were analyzed in terms of silica and alumina contents. To make geopolymer paste, separate mixing and normal mixing were used. For separate mixing, NaOH solution was mixed with fly ash for the first 10 min; subsequently sodium silicate solution was added into the mixture. For normal mixing, fly ash, sodium hydroxide and sodium silicate solution were incorporated and mixed at the same time. Geopolymers were cured at 65{sup o}C for 48 h. Microstructure of paste and compressive strength of mortar were investigated. Results revealed that solubility of fly ash depended on concentration of NaOH and duration of mixing with NaOH. For mixing procedure, separate mixing gave slightly better strength mortar than normal mixing. High strength geopolymer mortar up to 70.0 MPa was obtained when the mixture was formulated with 10 M NaOH and sodium silicate to NaOH ratio of 1.0, and the separate mixing sequence was used.

  16. Determination of the elastic modulus of fly ash-based stabilizer applied in the trackbed

    Science.gov (United States)

    Lojda, Vít; Lidmila, Martin; Pýcha, Marek

    2017-09-01

    This paper describes a unique application of a fly ash-based stabilizer in the trackbed of a railway main line. The key goals of the stabilizer application are to protect the subgrade against the ingress of rain water, to increase the frost resistance and to remediate the natural ground constituted of weathered rock. The stabilizer was designed as a mixture of fly ash, generated as a waste material from coal plants, gypsum, calcium oxide and water. The mixture recipe was developed in a laboratory over several years. In 2005, a trial section of a railway line with subgrade consisting of clay limestone (weathered marlite) was built in the municipality of Smiřice. Since then, periodical measurements including collection of samples for laboratory evaluation of the fly ash-based stabilizer have taken place. Over the time span of the measurements, changes in mineral composition and development of fly ash transforming structures leading to the formation of C-A-S-H gel were detected. This paper describes the experimental laboratory investigation of the influence of dynamic loading on the elastic modulus of fly ash stabilizer samples and the development of permanent deformation of the samples with increasing number of loading cycles.

  17. Synergetic use of lignite fly ash and metallurgical converter slag in geopolymer concrete

    Directory of Open Access Journals (Sweden)

    Gábor Mucsi

    2014-08-01

    Full Text Available The application and utilization of the industrial wastes and by-products in the construction industry is a key issue from an environmental and economic point of view. The increased use of lignite has substantially increased the available quantities of lignite fired power plant fly ash, which can be mainly classified as class C fly ash. The utilization of such raw material however has some difficulties. In the present paper lignite fired power station fly ash and metallurgical converter slag were used for the production of geopolymer concrete. The fly ash was used as a geopolymer based binder material, and a converter slag as aggregate, thus created a geopolymer concrete which contains mainly industrial wastes. As preliminary test experimental series were carried out using andesite as aggregate. The optimal aggregate/binder ratio was determined. The effect of the amount of alkaline activator solution in the binder, the aggregate type on the geopolymer concretes’ compressive strength and density was investigated. Furthermore, the physical properties - freeze-thaw resistance and particle size distribution - of the applied aggregates were measured as well. As a result of the experiments it was found that physical properties of the andesite and converter slag aggregate was close. Therefore andesite can be replaced by converter slag in the concrete mixture. Additionally, geopolymer concrete with nearly 20 MPa compressive strength was produced from class C fly ash and converter slag.

  18. Fly Ash and Composted Biosolids as a Source of Fe for Hybrid Poplar: A Greenhouse Study

    Directory of Open Access Journals (Sweden)

    Kevin Lombard

    2011-01-01

    Full Text Available Soils of northwest New Mexico have an elevated pH and CaCO3 content that reduces Fe solubility, causes chlorosis, and reduces crop yields. Could biosolids and fly ash, enriched with Fe, provide safe alternatives to expensive Fe EDDHA (sodium ferric ethylenediamine di-(o-hydroxyphenyl-acetate fertilizers applied to Populus hybrid plots? Hybrid OP-367 was cultivated on a Doak sandy loam soil amended with composted biosolids or fly ash at three agricultural rates. Fly ash and Fe EDDHA treatments received urea ammonium nitrate (UAN, biosolids, enriched with N, did not. Both amendments improved soil and plant Fe. Heavy metals were below EPA regulations, but high B levels were noted in leaves of trees treated at the highest fly ash rate. pH increased in fly ash soil while salinity increased in biosolids-treated soil. Chlorosis rankings improved in poplars amended with both byproducts, although composted biosolids offered the most potential at improving Fe/tree growth cheaply without the need for synthetic inputs.

  19. Studies on synthesis and characteristics of zeolite prepared from Indian fly ash.

    Science.gov (United States)

    Prasad, Bably; Maity, Sudip; Sangita, Kumari; Mahato, Arun Kumar; Mortimer, Robert J G

    2012-01-01

    In the present study, samples of coal fly ash were obtained from seven major Indian thermal power plants. These samples were transformed into fly ash zeolite (FAZ) using hydrothermal activation by treatment with NaOH. All experiments were carried out at 100 degrees C, but with different solid:liquid ratios, different concentrations of alkali and different incubation times. The chemical composition, mineralogy and morphology of the fly ash and FAZ were determined by wet chemical method after Na2CO3 fusion, x-ray diffraction and scanning electron microscopy. The cation exchange capacity of fly ash and FAZ was determined using the ammonium acetate method (IS:2720). The ammonium exchange capacity was determined by the titrimetric method. The experiments demonstrate that zeolite can be synthesized at 100 degrees C using alkali. The cation exchange capacity and ammonium adsorption capacity of FAZ (up to 250 meq/100 g and 22.93 mg NH4+/g respectively) indicate that the FAZ may be potentially useful to reduce heavy metals and other pollutants from contaminated environments. Therefore, zeolitization at low temperature potentially allows waste fly ash to be used in an economically advantageous way.

  20. Effects of ultrasonic treatment on zeolite synthesized from coal fly ash.

    Science.gov (United States)

    Belviso, Claudia; Cavalcante, Francesco; Lettino, Antonio; Fiore, Saverio

    2011-03-01

    The synthesis of zeolites from three samples of fly ash was carried out through a low-temperature (25-60°C) hydrothermal process with a NaOH pre-fusion treatment preceded by sonication. The results were compared with those of conventional hydrothermal syntheses. XRD and SEM investigations demonstrate that the application of ultrasonic treatment facilitates the formation of zeolites at a lower-temperature (25°C) than syntheses not preceded by sonication. No significant difference in type, temperature of crystallization, or amount of zeolites synthesized was noted between the three different samples of fly ash, implying that the chemical composition of fly ash had little influence on the zeolite product within the compositional range of these fly ash precursors. Although there appears to be a correlation between the SiO(2)/Al(2)O(3) ratio of the fly ash and the temperature of zeolite formation by conventional synthesis, no correlation was apparent when ultrasonic pre-treatment was used at low-temperatures. Copyright © 2010 Elsevier B.V. All rights reserved.

  1. MICROSTRUCTURE, MINERALOGY AND PHYSICAL PROPERTIES OF GROUND FLY ASH BASED GEOPOLYMERS

    Directory of Open Access Journals (Sweden)

    Ferenc Madai

    2015-03-01

    Full Text Available This paper is focused on the utilization of deposited fly ash as a main component of geopolymer. After determination of particle size distribution, moisture content, real and bulk density and specific surface area of the raw fly ash, mechanical activation was performed by laboratory scale ball mill. This step is introduced for improving the reactivity of raw material. Then test specimens were produced by geopoliomerisation using a caustic spent liquor (NaOH. Compressive strength was determined on cilindrical specimens. Finally, samples of the ground fly ash based geopolymer specimens were analyzed by X-ray diffraction, optical and scanning electron microscopy. Results prove that geopolymer production with proper strength from the investigated F-type deposited fly ash is possible. The uniaxial compressive strength of obtained composites strongly depends on the fineness of the ground fly ash. XRD results show that comparing the crystalline components for different geopolymer samples, zeolite-A appears and its amount increases gradually from 0T sample till 30T and then decreases for 60T sample. The same trend holds for sodalite type structure phases, however its amount is much lower than for zeolite-A. SEM+EDS investigation revealed that Na-content is elevated in the interstitial fine-grained matrix, especially for the 30T sample when highest strength was observed. Si and Al are abundant mainly in anhedral and spherical grains and in rarely occurring grains resembling some crystal shape.

  2. Beneficial use of fly ash and red mud in geopolymer concrete

    Energy Technology Data Exchange (ETDEWEB)

    Duchesne [Laval Univ., Quebec City, PQ (Canada)

    2009-07-01

    Coal-fired power plants generate millions of tons of fly ash on a yearly basis. Fly ash is a fine particulate aluminosilicate residue mainly composed of spherical micron-sized particles collected from dust collection systems. The management of fly ash is a significant area of concern because only 20 to 30 per cent of the generated fly ash is utilized, primarily in cement and concrete and as filling material, while a much larger portion is deposited in landfills. Red mud is an alkaline industrial residue generated during the Bayer process for alumina production. This paper exhaustively characterized the chemical and mineralogical properties of solid-waste materials. The study investigated the behaviour of geopolymer pastes made using sodium hydroxide and sodium silicate activators. The paper presented the materials and methods as well as results and discussion of x-ray diffraction, scanning electron microscopy, setting time and other early age properties of concrete. It was concluded that fly ash and red mud can be used as the main raw material for the making of geopolymer, a new generation of binder. 10 refs., 1 tab., 6 figs.

  3. Reburning Characteristics of Residual Carbon in Fly Ash from CFB Boilers

    Science.gov (United States)

    Zhang, S. H.; Luo, H. H.; Chen, H. P.; Yang, H. P.; Wang, X. H.

    The content of residual carbon in fly ash of CFB boilers is a litter high especially when low-grade coal, such as lean coal, anthracite coal, gangue, etc. is in service, which greatly influences the efficiency of boilers and fly ash further disposal. Reburn of fly ash through collection, recirculation in CFB furnace or external combustor is a possibly effective strategy to decrease the carbon content, mainly depending on the residual carbon reactivity. In this work, the combustion properties of residual carbon in fly ash and corresponding original coal from large commercial CFB boilers (Kaifeng (440t/h), and Fenyi (410t/h), all in china) are comparably investigated through experiments. The residual carbon involved was firstly extracted and enriched from fly ash by means of floating elutriation to mitigate the influence of ash and minerals on the combustion behavior of residual carbon. Then, the combustion characteristic of two residual carbons and the original coal particles was analyzed with thermogravimetric analyzer (TGA, STA409C from Nestch, Germany). It was observed that the ignition temperature of the residual carbon is much higher than that of original coal sample, and the combustion reactivity of residual carbon is not only dependent on the original coal property, but also the operating conditions. The influence of oxygen content and heating rate was also studied in TGA. The O2 concentration is set as 20%, 30%, 40% and 70% respectively in O2/N2 gas mixture with the flow rate of 100ml/min. It was found that higher oxygen content is favor for decreasing ignition temperature, accelerating the combustion rate of residual carbon. And about 40% of oxygen concentration is experimentally suggested as an optimal value when oxygen-enriched combustion is put into practice for decreasing residual carbon content of fly ash in CFB boilers.

  4. Environmentally-Friendly Dense and Porous Geopolymers Using Fly Ash and Rice Husk Ash as Raw Materials

    Directory of Open Access Journals (Sweden)

    Daniele Ziegler

    2016-06-01

    Full Text Available This paper assesses the feasibility of two industrial wastes, fly ash (FA and rice husk ash (RHA, as raw materials for the production of geopolymeric pastes. Three typologies of samples were thus produced: (i halloysite activated with potassium hydroxide and nanosilica, used as the reference sample (HL-S; (ii halloysite activated with rice husk ash dissolved into KOH solution (HL-R; (iii FA activated with the alkaline solution realized with the rice husk ash (FA-R. Dense and porous samples were produced and characterized in terms of mechanical properties and environmental impact. The flexural and compressive strength of HL-R reached about 9 and 43 MPa, respectively. On the contrary, the compressive strength of FA-R is significantly lower than the HL-R one, in spite of a comparable flexural strength being reached. However, when porous samples are concerned, FA-R shows comparable or even higher strength than HL-R. Thus, the current results show that RHA is a valuable alternative to silica nanopowder to prepare the activator solution, to be used either with calcined clay and fly ash feedstock materials. Finally, a preliminary evaluation of the global warming potential (GWP was performed for the three investigated formulations. With the mix containing FA and RHA-based silica solution, a reduction of about 90% of GWP was achieved with respect to the values obtained for the reference formulation.

  5. The Effect of Alkaline Activator Ratio on the Compressive Strength of Fly Ash-Based Geopolymer Paste

    Science.gov (United States)

    Lăzărescu, A. V.; Szilagyi, H.; Baeră, C.; Ioani, A.

    2017-06-01

    Alkaline activation of fly ash is a particular procedure in which ash resulting from a power plant combined with a specific alkaline activator creates a solid material when dried at a certain temperature. In order to obtain desirable compressive strengths, the mix design of fly ash based geopolymer pastes should be explored comprehensively. To determine the preliminary compressive strength for fly ash based geopolymer paste using Romanian material source, various ratios of Na2SiO3 solution/ NaOH solution were produced, keeping the fly ash/alkaline activator ratio constant. All the mixes were then cured at 70 °C for 24 hours and tested at 2 and 7 days, respectively. The aim of this paper is to present the preliminary compressive strength results for producing fly ash based geopolymer paste using Romanian material sources, the effect of alkaline activators ratio on the compressive strength and studying the directions for future research.

  6. Utilize Cementitious High Carbon Fly Ash (CHCFA) to Stabilize Cold In-Place Recycled (CIR) Asphalt Pavement as Base Coarse

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Haifang; Li, Xiaojun; Edil, Tuncer; O' Donnell, Jonathan; Danda, Swapna

    2011-02-05

    The purpose of this study was to evaluate the performance of cementitious high carbon fly ash (CHCFA) stabilized recycled asphalt pavement as a base course material in a real world setting. Three test road cells were built at MnROAD facility in Minnesota. These cells have the same asphalt surface layers, subbases, and subgrades, but three different base courses: conventional crushed aggregates, untreated recycled pavement materials (RPM), and CHCFA stabilized RPM materials. During and after the construction of the three cells, laboratory and field tests were carried out to characterize the material properties. The test results were used in the mechanistic-empirical pavement design guide (MEPDG) to predict the pavement performance. Based on the performance prediction, the life cycle analyses of cost, energy consumption, and greenhouse gasses were performed. The leaching impacts of these three types of base materials were compared. The laboratory and field tests showed that fly ash stabilized RPM had higher modulus than crushed aggregate and RPM did. Based on the MEPDG performance prediction, the service life of the Cell 79 containing fly ash stabilized RPM, is 23.5 years, which is about twice the service life (11 years) of the Cell 77 with RPM base, and about three times the service life (7.5 years) of the Cell 78 with crushed aggregate base. The life cycle analysis indicated that the usage of the fly ash stabilized RPM as the base of the flexible pavement can significantly reduce the life cycle cost, the energy consumption, the greenhouse gases emission. Concentrations of many trace elements, particularly those with relatively low water quality standards, diminish over time as water flows through the pavement profile. For many elements, concentrations below US water drinking water quality standards are attained at the bottom of the pavement profile within 2-4 pore volumes of flow.

  7. Rhizofiltration of Heavy Metals (Cadmium, Lead and Zinc From Fly Ash Leachates Using Water Hyacinth (Eichhornia Crassipes

    Directory of Open Access Journals (Sweden)

    Amit Kumar Yadav

    2015-02-01

    Full Text Available Fly ashes are usually contaminated with toxic heavy metals. These metals are leaching out aftercontact with water during wet disposal system, thus polluting the soil, surface and groundwater. In the present study, a hydroponics experiment was conducted to examine the removalof heavy metals Cd, Pb and Zn by Eichhornia crassipes grown at various concentration of fly ash ranging from 10, 20 and 40 percent over a period of 30 days.After 30 days, the plants were separately harvested, dried and weighedfor biomass of the roots and shoots. The uptake of each metalwas studied in the root and shoot separately, to determine the bioaccumulation of metals in Eichhornia crasspies.The translocation factor was calculated to study the efficiency of the plants forbioaccumulation of each metal in roots and shoot. The results showed that maximum uptake of metals Cd, Pb and Zn by plantwasfoundat the higher concentration (40% of fly ash.The metals uptake found was 99.16, 166.52 and 741.04 μg g-1 tissues in the roots, respectively and 33.46, 41.33 and 255.90 μgg-1 tissues in the shoots, respectively and successfullyremoved up to 78% of Cd, 82% of Pb and 70% of Zn.The maximum removal efficiency by plant for Cd, Pb and Zn at lower concentration (10% of fly ash was 84%, 86% and 75%, respectively.The heavy metals accumulated more in roots than in the shoots by Eichhornia crassipes. The maximum bioconcentration factor and translocation factor value of Eichhornia crappies for Cd, Pb and Zn were calculated as 705.55, 705.55 and 614.51 and 41.86, 47.18 and 34.53 respectively. The high removal efficiencies of heavy metals Cd, Pb and Zn was find without toxic effect by this aquatic macrophyte, thisplant can be recommended for the actual treatment of fly ash leachatesin ash pond to clean up the aquatic environment.DOI: http://dx.doi.org/10.3126/ije.v4i1.12187International Journal of Environment Volume-4, Issue-1, Dec-Feb 2014/15, page : 179-196   

  8. Coal fly ash-containing sprayed mortar for passive fire protection of steel sections

    Directory of Open Access Journals (Sweden)

    Vilches, L. F.

    2005-09-01

    Full Text Available The present article addresses the possible use of coal fly ash as the chief component of sprayed mortars to fireproof steel structures. A pilot wet-mix gunning rig was specifically designed and built to spray different pastes on to sheet steel and sections with different surface/volume ratios. After gunning, the specimens were placed in a furnace and subjected to standard fire resistance testing. Product fire resistance was calculated from the test results. The mortar used in this study, with a high fly ash content, was found to have acceptable mechanical properties as well as afire resistance potential comparable to those of commercial passive fire protection products.

    En este artículo se estudia el posible uso de las cenizas volantes procedentes de la combustión del carbón como constituyente principal de morteros que pueden ser proyectados sobre estructuras metálicas, para protegerlas contra el fuego. Con objeto de estudiar el proceso de proyección, se ha construido una planta piloto de gunitado por vía húmeda. La pasta se ha proyectado sobre placas metálicas y perfiles metálicos con diferentes relaciones superficie/volumen. Tras el gunitado, las probetas proyectadas se colocan en un horno y se someten a un programa de calentamiento según la norma de resistencia al fuego. A partir de los datos obtenidos se ha podido realizar una estimación de la resistencia al fuego del producto. Los resultados muestran que el material proyectado usado en este estudio, que contiene una alta proporción de cenizas volantes, tiene unas propiedades mecánicas aceptables y unas características potenciales de resistencia al fuego comparables a las de otros productos comerciales utilizados en la protección pasiva contra el fuego.

  9. Characterization of upgraded hydrogel biochar from blended rice husk with coal fly ash

    Science.gov (United States)

    Ahmad, Nurul Farhana; Alias, Azil Bahari; Talib, Norhayati; Rashid, Zulkifli Abd; Ghani, Wan Azlina Wan Ab Karim

    2017-12-01

    Rice husk biochar (RB) blended with coal fly ash (CFA) is used as a material to develop hydrogel for heavy metal removal. This combination, namely hydrogel rice husk biochar-coal fly ash (HRB-CFA) composite is synthesized by embedding the biochar into acrylamide (AAM) as monomer, with N,N'-Methylenebisacrylamide (MBA) as crosslinker and ammonium persulfate (APS) as initiator. While activated carbon (AC) remains an expensive material, HRB-CFA is attracting great interest for its use in the absorption of organic contaminants due to its low material cost and importance as renewable source for securing future energy supply in the environmental system. Although the CFA does not have the surface area as high as AC, certain metallic components that are naturally present in the CFA can play the catalytic role in the removal of heavy metal from wastewater. The percentage of heavy metal removal is depends on the parameters that influence the sorption process; the effect of pH solution, dosage of adsorbent, initial concentration of solution, and contact time. The aim of this study is to characterize HRB-CFA by performing several analyses such as the Brunauer-Emmett-Teller (BET), thermogravimetric (TGA) and field emission scanning electron microscopy (FESEM) methods. The results obtained revealed that the best hydrogel ratio is 0.5:0.5 of blended RB and CFA, as proven by BET surface area, pore volume and pore size of 3.5392 m2/g, 0.00849 cm3/g and 90.566 Å, and the surface morphology showed an increase in porosity size.

  10. Dry Sliding Friction and Wear Studies of Fly Ash Reinforced AA-6351 Metal Matrix Composites

    Directory of Open Access Journals (Sweden)

    M. Uthayakumar

    2013-01-01

    Full Text Available Fly ash particles are potentially used in metal matrix composites due to their low cost, low density, and availability in large quantities as waste by-products in thermal power plants. This study describes multifactor-based experiments that were applied to research and investigation on dry sliding wear system of stir-cast aluminum alloy 6351 with 5, 10, and 15 wt.% fly ash reinforced metal matrix composites (MMCs. The effects of parameters such as load, sliding speed, and percentage of fly ash on the sliding wear, specific wear rate, and friction coefficient were analyzed using Grey relational analysis on a pin-on-disc machine. Analysis of variance (ANOVA was also employed to investigate which design parameters significantly affect the wear behavior of the composite. The results showed that the applied load exerted the greatest effect on the dry sliding wear followed by the sliding velocity.

  11. Properies of binder systems containing cement, fly ash, and limestone powder

    Directory of Open Access Journals (Sweden)

    Krittiya Kaewmanee

    2014-10-01

    Full Text Available Fly ash and limestone powder are two major widely available cement replacing materials in Thailand. However, the current utilization of these materials is still not optimized due to limited information on properties of multi-binder systems. This paper reports on the mechanical and durability properties of mixtures containing cement, fly ash, and limestone powder as single, binary, and ternary binder systems. The results showed that a single binder system consisting of only cement gave the best carbonation resistance. A binary binder system with fly ash exhibited superior performances in long-term compressive strength and many durability properties except carbonation and magnesium sulfate resistances, while early compressive strength of a binary binder system with limestone powder was excellent. The ternary binder system, taking the most benefit of selective cement replacing materials, yielded, though not the best, satisfactory performances in almost all properties. Thus, the optimization of binders can be achieved through a multi-binder system.

  12. Prediction of the Chloride Resistance of Concrete Modified with High Calcium Fly Ash Using Machine Learning.

    Science.gov (United States)

    Marks, Michał; Glinicki, Michał A; Gibas, Karolina

    2015-12-11

    The aim of the study was to generate rules for the prediction of the chloride resistance of concrete modified with high calcium fly ash using machine learning methods. The rapid chloride permeability test, according to the Nordtest Method Build 492, was used for determining the chloride ions' penetration in concrete containing high calcium fly ash (HCFA) for partial replacement of Portland cement. The results of the performed tests were used as the training set to generate rules describing the relation between material composition and the chloride resistance. Multiple methods for rule generation were applied and compared. The rules generated by algorithm J48 from the Weka workbench provided the means for adequate classification of plain concretes and concretes modified with high calcium fly ash as materials of good, acceptable or unacceptable resistance to chloride penetration.

  13. A high unburned carbon fly ash concrete’s performance characteristics

    Directory of Open Access Journals (Sweden)

    Claudia Patricia Valderrama

    2011-01-01

    Full Text Available Engineering today requires that structures are strong and durable; the latter concept is a decisive factor in their design and construction. The scientific community continues developing new cementitious materials and improving tra-ditional concrete’s properties, specifically reducing permeability by incorporating materials such as pozzolans. This paper analyses the effect of fly ash (FA added to concrete on mechanical strength regarding compression, capillary absorption and chloride permeability and their behaviour compared to concrete containing silica fume (SF. An optimum 10% mechanical strength was found for fly ash; however, this increased with addition, resulting in positive effects on durability. Fly ash had lower performance for all properties evaluated when compared to silica fume.

  14. Influence of several experimental parameters on As and Se leaching from coal fly ash samples

    Energy Technology Data Exchange (ETDEWEB)

    Otero-Rey, Jose R. [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Mato-Fernandez, Maria J. [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Moreda-Pineiro, Jorge [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Alonso-Rodriguez, Elia [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain)]. E-mail: elia@udc.es; Muniategui-Lorenzo, Soledad [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Lopez-Mahia, Purificacion [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Prada-Rodriguez, Dario [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain)

    2005-02-28

    Coal fly ash leaching process for As and Se is studied. Environmental parameters such as pH, temperature, solid-liquid ratio, particle size and leaching time are taken into account in order to simulate As and Se leaching process for disposal coal fly ash. Analysis of reference materials was carried out by using of hydride generation coupled to atomic fluorescence spectrometry. Plackett-Burman experimental design is used to know the significative parameters, and Box-Behnken experimental design is used to refine the results obtained for these significative parameters. pH and temperature shown a hardly influence in leaching process. Furthermore, leaching time was also significative. According our results, it may be assumed that percentage of As and Se leaching in experimental conditions tested is relatively low for acidic fly ashes.

  15. Fly ash porous material using geopolymerization process for high temperature exposure.

    Science.gov (United States)

    Abdullah, Mohd Mustafa Al Bakri; Jamaludin, Liyana; Hussin, Kamarudin; Bnhussain, Mohamed; Ghazali, Che Mohd Ruzaidi; Ahmad, Mohd Izzat

    2012-01-01

    This paper presents the results of a study on the effect of temperature on geopolymers manufactured using pozzolanic materials (fly ash). In this paper, we report on our investigation of the performance of porous geopolymers made with fly ash after exposure to temperatures from 600 °C up to 1000 °C. The research methodology consisted of pozzolanic materials (fly ash) synthesized with a mixture of sodium hydroxide and sodium silicate solution as an alkaline activator. Foaming agent solution was added to geopolymer paste. The geopolymer paste samples were cured at 60 °C for one day and the geopolymers samples were sintered from 600 °C to 1000 °C to evaluate strength loss due to thermal damage. We also studied their phase formation and microstructure. The heated geopolymers samples were tested by compressive strength after three days. The results showed that the porous geopolymers exhibited strength increases after temperature exposure.

  16. Fly Ash Porous Material using Geopolymerization Process for High Temperature Exposure

    Directory of Open Access Journals (Sweden)

    Mohd Izzat Ahmad

    2012-04-01

    Full Text Available This paper presents the results of a study on the effect of temperature on geopolymers manufactured using pozzolanic materials (fly ash. In this paper, we report on our investigation of the performance of porous geopolymers made with fly ash after exposure to temperatures from 600 °C up to 1000 °C. The research methodology consisted of pozzolanic materials (fly ash synthesized with a mixture of sodium hydroxide and sodium silicate solution as an alkaline activator. Foaming agent solution was added to geopolymer paste. The geopolymer paste samples were cured at 60 °C for one day and the geopolymers samples were sintered from 600 °C to 1000 °C to evaluate strength loss due to thermal damage. We also studied their phase formation and microstructure. The heated geopolymers samples were tested by compressive strength after three days. The results showed that the porous geopolymers exhibited strength increases after temperature exposure.

  17. Zeolite synthesis from a high Si-Al fly ash from East China

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, R.; Umana, J.C.; Querol, X.; Lopez-Soler, A.; Plana, F.; Zhuang, X. [CAS, Beijing (China). Inst. of Geology & Geophysics

    2002-07-01

    A high Al-Si Chinese fly ash from Dou He power plant (Tangshan city, Hebei Province, Eastern China) was selected as starting material of the zeolitisation process. Zeolitic material was obtained by conventional alkaline activation using NaOH and KOH solutions. The process of synthesis was optimised by applying a wide range of reaction temperature, time and activation reagent concentrations. A high solution/fly ash ratio was used in order to dissolve highly resistant Al-Si phases such as mullite. High yields were obtained with both KOH and NaOH solutions. Final products reached a cation exchange capacity (CEC) of up to 2.3 meq g{sup 3}. Major zeolites obtained with a high CEC were: NaP1, KM and F-linde zeolite. The low contents of major impurities of this fly ash enhance the potential application for the synthesis of zeolites for waste-water treatment.

  18. Chromium determination in fly ash by slurry-sampling electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Baralkiewicz, D; Lamont, S.; Stemerowicz, M. [Adam Mickiewicz University of Poznan, Poznan (Poland). Dept. of Water & Soil Analysis

    2002-07-01

    The paper reports analytical conditions for determination of chromium in fly ash by slurry sampling electrothermal atomic absorption spectrometry (SS ETAAS). Stability test for slurries have been carried out. Triton X-100 was used as a stabilizing agent. The procedure was validated by analysis of certified reference coal fly ash material SRM 1633B. The results of determination of chromium by SS ETAAS in three real fly ash samples from Poland (Szczecin area) and Canada (Sydney, Nova Scotia area) were compared with the results of these samples analysed by the wet digestion method. The detection limit calculated to 0.077 mg/kg and relative standard deviation (RSD) of measurements for the slurry sampling method was 3.5-5.2% for SRM 1633B.

  19. Influence of ammonia on leaching behaviors of incineration fly ash and its geochemical modeling

    DEFF Research Database (Denmark)

    Astrup, Thomas Fruergaard; Guan, Zhen Zhen; Chen, De Zhen

    2013-01-01

    Incineration fly ash could be contaminated with NH3 that was slipped from the ammonia-based selective non-catalytic reduction(SNCR) process and from evaporation of municipal solid wastes' leachate involved in the wastes. This research was conducted to investigate the impacts of ammonia on leaching...... of dissolved organic carbon (DOC) and metals from incineration fly ash in the pH range of 3.66-12.44 with an active ammonia spike. A geochemical modeling software Visual MINTEQ was adopted to calculate the chemical speciation of metals under the leaching conditions to reveal the mechanism behind the impacts...... by precipitation/dissolution and surface complexation/precipitation processes; Visual MINTEQ modeling could well describe the leaching behaviors of Al, Cu, Pb and Zn from incineration fly ash....

  20. Influence of fly ash added to a ceramic body on its thermophysical properties

    Directory of Open Access Journals (Sweden)

    Kováč Jozef

    2016-01-01

    Full Text Available We study thermal expansion, mass changes, heat capacity, and thermal diffusivity and conductivity for a ceramic body with 20 mass% and without fly ash content, using the TDA, TG, DTA, DSC, and flash method. The measurements were performed (a for green samples either isothermally or by a linear heating up to a temperature 600°C, 1050°C, or 1100°C, depending on the measurement method; (b at the room temperature for samples preheated at 100°C, 200°C, ..., 1100°C. In case (a addition of fly ash changes the final contraction only above ~900°C, while the thermal properties remain almost unchanged. In case (b the final contraction of samples at 1100°C is the same. The thermal diffusivity is nearly identical up to 700°C, and fly ash causes the diffusivity to stay almost constant up to 1000°C.

  1. Influence of calcium compounds on the mechanical properties of fly ash geopolymer pastes.

    Science.gov (United States)

    Temuujin, J; van Riessen, A; Williams, R

    2009-08-15

    The influence of calcium compounds (CaO and Ca(OH)(2)) on the mechanical properties of fly ash based geopolymers has been studied. Calcium compounds were substituted in fly ash at 1, 2 and 3 wt%, respectively. Curing of the geopolymers was performed at ambient temperature (20 degrees C) and 70 degrees C. Addition of calcium compounds as a fly ash substitute improved mechanical properties for the ambient temperature cured samples while decreasing properties for the 70 degrees C cured samples. Seven days compressive strength of the ambient temperature cured samples increased from 11.8 (2.9) to 22.8 (3.8)MPa and 29.2 (1.1)MPa for 3% CaO and 3% Ca(OH)(2) additions, respectively.

  2. Coal fly ash-slag-based geopolymers: microstructure and metal leaching.

    Science.gov (United States)

    Izquierdo, Maria; Querol, Xavier; Davidovits, Joseph; Antenucci, Diano; Nugteren, Henk; Fernández-Pereira, Constantino

    2009-07-15

    This study deals with the use of fly ash as a starting material for geopolymeric matrices. The leachable concentrations of geopolymers were compared with those of the starting fly ash to evaluate the retention of potentially harmful elements within the geopolymer matrix. Geopolymer matrices give rise to a leaching scenario characterised by a highly alkaline environment, which inhibits the leaching of heavy metals but may enhance the mobilization of certain oxyanionic species. Thus, fly ash-based geopolymers were found to immobilize a number of trace pollutants such as Be, Bi, Cd, Co, Cr, Cu, Nb, Ni, Pb, Sn, Th, U, Y, Zr and rare earth elements. However, the leachable levels of elements occurring in their oxyanionic form such as As, B, Mo, Se, V and W were increased after geopolymerization. This suggests that an optimal dosage, synthesis and curing conditions are essential in order to obtain a long-term stable final product that ensures an efficient physical encapsulation.

  3. Coal fly ash-slag-based geopolymers: Microstructure and metal leaching

    Energy Technology Data Exchange (ETDEWEB)

    Izquierdo, Maria, E-mail: mariaizq@ija.csic.es [Institute of Earth Sciences ' Jaume Almera' -CSIC, Lluis Sole Sabaris s/n 08028 Barcelona (Spain); Querol, Xavier [Institute of Earth Sciences ' Jaume Almera' -CSIC, Lluis Sole Sabaris s/n 08028 Barcelona (Spain); Davidovits, Joseph [Cordi-Geopolymere, Espace Creatis, Z.A. Bois de la Chocque 02100 Saint-Quentin (France); Antenucci, Diano [Institut Scientifique de Service Public (ISSeP) 200, rue du Chera, B-4000 Liege (Belgium); Nugteren, Henk [Delft University of Technology, Faculty of Applied Sciences, DelftChemTech, Particle Technology Group, Julianalaan 136, 2628 BL Delft (Netherlands); Fernandez-Pereira, Constantino [University of Seville, School of Industrial Engineering, Department of Chemical and Environmental Engineering, Camino de los Descubrimientos s/n, 41092 Seville (Spain)

    2009-07-15

    This study deals with the use of fly ash as a starting material for geopolymeric matrices. The leachable concentrations of geopolymers were compared with those of the starting fly ash to evaluate the retention of potentially harmful elements within the geopolymer matrix. Geopolymer matrices give rise to a leaching scenario characterised by a highly alkaline environment, which inhibits the leaching of heavy metals but may enhance the mobilization of certain oxyanionic species. Thus, fly ash-based geopolymers were found to immobilise a number of trace pollutants such as Be, Bi, Cd, Co, Cr, Cu, Nb, Ni, Pb, Sn, Th, U, Y, Zr and rare earth elements. However, the leachable levels of elements occurring in their oxyanionic form such as As, B, Mo, Se, V and W were increased after geopolymerization. This suggests that an optimal dosage, synthesis and curing conditions are essential in order to obtain a long-term stable final product that ensures an efficient physical encapsulation.

  4. Risk ranking of bioaccessible metals from fly ash dissolved in simulated lung and gut fluids

    Energy Technology Data Exchange (ETDEWEB)

    John Twining; Peter McGlinn; Elaine Loi; Kath Smith; Reto Giere [Australian Nuclear Science and Technology Organisation, Menai, NSW (Australia)

    2005-10-01

    Power plant fly ash from two fuels, coal and a mixture of coal and shredded tires were evaluated for trace metal solubility in simulated human lung and gut fluids (SLF and SGF, respectively) to estimate bioaccessibility. The proportion of bioaccessible to total metal ranged from zero (V) to 80% (Zn) for coal-derived ash in SLF and from 2 (Th) to 100% (Cu) for tire-derived fly ash in SGF. The tire-derived ash contained much more Zn. However, Zn ranked only 5th of the various toxic metals in SGF compared with international regulations for ingestion. On the basis of total concentrations, the metals closest to exceeding limits based on international regulations for inhalation were Cr, Pb, and Al. On dissolution in SLF, the most limiting metals were Pb, Cu, and Zn. For metals exposed to SGF there was no relative change in the top metal, Al, before and after dissolution but the second-ranked metal shifted from Pb to Ni. In most cases only a proportion of the total metal concentrations in either fly ash was soluble, and hence bioaccessible, in either biofluid. When considering the regulatory limits for inhalation of particulates, none of the metal concentrations measured were as hazardous as the fly ash particulates themselves. However, on the basis of the international ingestion regulations for Al, the maximum mass of fly ash that could be ingested is only 1 mg per day (10 mg based on bioaccessibility). It is possible that such a small mass could be consumed by exposed individuals or groups. 39 refs., 1 fig., 3 tabs.

  5. Synthesis of a nano-crystalline solid acid catalyst from fly ash and its catalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Chitralekha Khatri; Ashu Rani [Government P.G. College, Kota (India). Environmental Chemistry Laboratory

    2008-10-15

    The synthesis of nano-crystalline activated fly ash catalyst (AFAC) with crystallite size of 12 nm was carried out by chemical and thermal treatment of fly ash, a waste material generated from coal-burning power plants. Fly ash was chemically activated using sulfuric acid followed by thermal activation at 600{sup o}C. The variation of surface and physico-chemical properties of the fly ash by activation methods resulted in improved acidity and therefore, catalytic activity for acid catalyzed reactions. The AFAC was characterized by X-ray diffraction, FT-IR spectroscopy, N{sub 2}-adsorption-desorption isotherm, scanning electron microscopy, flame atomic absorption spectrophotometry and sulfur content by CHNS/O elemental analysis. It showed amorphous nature due to high silica content (81%) and possessed high BET surface area (120 m{sup 2}/g). The catalyst was found to be highly active solid acid catalyst for liquid phase esterification of salicylic acid with acetic anhydride and methanol giving acetylsalicylic acid and methyl salicylate respectively. A maximum yield of 97% with high purity of acetylsalicylic acid (aspirin) and a very high conversion 87% of salicylic acid to methyl salicylate (oil of wintergreen) was obtained with AFAC. The surface acidity and therefore, catalytic activity in AFAC was originated by increased silica content, hydroxyl content and higher surface area as compared to fly ash. The study shows that coal generated fly ash can be converted into potential solid acid catalyst for acid catalyzed reactions. Furthermore, this catalyst may replace conventional environmentally hazardous homogeneous liquid acids making an ecofriendly; solvent free, atom efficient, solid acid based catalytic process. 27 refs., 5 figs., 2 tabs.

  6. The effect of water binder ratio and fly ash on the properties of foamed concrete

    Science.gov (United States)

    Saloma, Hanafiah, Urmila, Dea

    2017-11-01

    Foamed concrete is a lightweight concrete composed by cement, water, fine aggregate and evenly distributed foam. Foamed concrete is produced by adding foam to the mixture. The function of foam is to create air voids in the mixture, so the weight of the concrete becomes lighter. The foaming agent is diluted in water then given air pressure by foam generator to produce foam. This research utilizes coal combustion, which is fly ash as cementitious material with a percentage of 0%, 10%, 15%, and 20%. The purpose of the research is to examine the effect of water binder ratio 0.425, 0.450, 0.475, and 0.500 using fly ash on the properties of foamed concrete. Fresh concrete tests include slump flow and setting time test while hardened concrete tests include density and compressive strength. The maximum value of slump flow test result is 59.50 cm on FC-20-0.500 mixture with w/b = 0.500 and 20% of fly ash percentage. The results of the setting time tests indicate the fastest initial and final time are 335 and 720 minutes, respectively on FC-0-0.425 mixture with w/b = 0.425 without fly ash. The lowest density is 978.344 kg/m3 on FC-20-0.500 mixture with w/b = 0.500 and 20% of fly ash percentage. The maximum compressive strength value is 4.510 MPa at 28 days on FC-10-0.450 mixture with w/b = 0.450 and 10% of fly ash percentage.

  7. Aggregation experiments on fine fly ash particles in uniform magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.W.; Zhao, C.S.; Wu, X.; Lu, D.F.; Han, S. [Southeast University, Nanjing (China)

    2007-05-15

    Aggregation experiments on three fly ash samples in the size range of 0.023-9.314 {mu} m were conducted in a uniform magnetic field. The fly ash particles were produced from combustion of three different bituminous coals. The coals were originated Dongshen, Datong and Xuzhou of China, respectively. A fluidized bed aerosol generator was used to disperse the fly ash particles to generate a constant aerosol. The aerosol particles aggregated when passing through the magnetic field. The variation of particle number concentration caused by particle aggregation was measured in real time by an Electrical Low Pressure Impactor (ELPI). The effects of several parameters, such as particle size, magnetic flux density, particle residence time in the magnetic field, total particle mass concentration and average gas velocity, on particle aggregation were examined. Experimental results indicated that removal efficiencies are the highest for particles with sizes in the middle of the size ranges tested. Increasing magnetic flux density, total particle mass concentration, particle residence time in the magnetic field or by reducing average gas velocity can increase removal efficiencies of single-sized and total fly ash particles. The single-sized and total particle removal efficiencies of the three fly ashes are different under the same operating conditions. The model prediction of particle aggregation under high total particle mass concentrations conditions indicated that the single-sized and total particle removal efficiencies will increase greatly with the increase in total particle mass concentration. The model predicted total removal efficiencies of the three fly ash particles are 53%, 43% and 14%, for Dongshen, Datong and Xuzhou coals respectively when total particle mass concentration is 40 g/m{sup 3}.

  8. Effect of mixes made of coal bottom ash and fly ash on the mechanical strength and porosity of Portland cement

    Directory of Open Access Journals (Sweden)

    Argiz, C.

    2013-03-01

    Full Text Available New additions to the cement are needed to achieve a more sustainable and durable construction material. Within this context, bottom ashes can be used as a main constituent of Portland cements when it is mixed in an optimized proportion with fly ashes. The mechanical characteristics of standarized mortars made of mixes of pulverized coal combustion bottom and fly ashes are studied. The mortars were made of ordinary Portland cement (CEM I 42.5 N and mixes of bottom ashes with fly ashes in similar proportions to those of CEM II/A-V, CEM II/B-V and CEM IV/A (V. Summing up, it can be said that the utilization of bottom ashes mixed with fly ashes in replacement levels from 0% to 100% do not affect significantively on the mechanical caracteristics of the mortars considered in the present study which had an addition maximum content of 35%.

    La utilización de nuevas adiciones en el cemento es necesaria con el fin de obtener un material más sostenible y durable. En este sentido, las cenizas de fondo o cenicero de las centrales termoeléctricas de carbón se podrían reciclar siendo empleadas como un componente principal de los cementos Portland. Se han estudiado las propiedades mecánicas de unos morteros normalizados elaborados con mezclas de cenizas volantes con cenizas de fondo fabricados con unos porcentajes similares a los correspondientes de los CEM II/A-V, CEM II/B-V y CEM IV/A (V. En conclusión, la utilización de mezclas de cenizas de fondo o cenicero con cenizas volantes sustituyendo a éstas últimas entre el 0% y el 100%, no influye significativamente en el comportamiento mecánico de los morteros estudiados en los que el contenido máximo de adición ha sido del 35%, si bien afecta a determinados aspectos microestructurales, como la cantidad y distribución de poros capilares.

  9. Application of injection material for rehabilitation of underground pipeline using fly ash surfactant mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Hideki Shimada; Yasuhiro Yoshida; Jiro Oya; Takashi Sasaoka; Kikuo Matsui; Hideaki Nakagawa; Jan Gottfried [Kyushu University, Fukuoka (Japan). Earth Resources Engineering Department

    2010-03-15

    A large amount of waste is produced at coal preparation plants. The properties of the waste vary depending on the mineralogical content of the mother rock in which the coal is embedded. The quality of the waste depends on the method of mining and cleaning, but it consists mostly of clays, quartz, carbonaceous materials, mica, pyrites and so on. About 80% of coal-ash is now utilised in Japan, and the remaining is disposed of at disposal sites. However, the life span of each disposal site is limited and it is difficult to find new disposal sites. It is therefore desirable that the percentage of utilisation of fly ash be increased in every possible way in Japan. One way of achieving this goal is to incorporate more fly ash in cement mixes that can be applied as the injection material for natural/artificial openings. In this study, different combinations of fly ash, surfactants and water were investigated to determine the influence of surfactants on the properties of fly ash mixtures used in slurry pipe jacking.

  10. Application of Anova on Fly Ash Leaching Kinetics for Value Addition

    Science.gov (United States)

    Swain, Ranjita; Mohapatro, Rudra Narayana; Bhima Rao, Raghupatruni

    2016-04-01

    Fly ash is a major problem in power plant sectors as it is dumped at the plant site. Fly ash generation increases day to day due to rapid growth of steel industries. Ceramic/refractory industries are growing rapidly because of more number of steel industries. The natural resources of the ceramic/refractory raw materials are depleting with time due to its consumption. In view of this, fly ash from thermal power plant has been identified for use in the ceramic/refractory industries after suitable beneficiation. In this paper, sample was collected from the ash pond of Vedanta. Particle size (d80 passing size) of the sample is around 150 micron. The chemical analysis of the sample shows that 3.9 % of Fe2O3 and CaO is more than 10 %. XRD patterns show that the fly ash samples consist predominantly of the crystalline phases of quartz, hematite and magnetite in a matrix of aluminosilicate glass. Leaching of iron oxide is 98.3 % at 3 M HCl concentration at 90 °C for 270 min of leaching time. Kinetic study on leaching experiment was carried out. ANOVA software is utilized for curve fitting and the process is optimized using MATLAB 7.1. The detailed study of properties for ceramic material is compared with the standard ceramic materials. The product contains 0.3 % of iron. The other properties of the product have established the fact that the product obtained can be a raw material for ceramic industries.

  11. Attenuation of trace elements in coal fly ash leachates by surfactant-modified zeolite.

    Science.gov (United States)

    Neupane, Ghanashyam; Donahoe, Rona J

    2012-08-30

    Potential leaching of trace elements from older, unlined fly ash disposal facilities is a serious threat to groundwater and surface water contamination. Therefore, effective methods for containing the pollutant elements within the unlined coal combustion products (CCPs) disposal facilities are required to minimize any potential impact of leachate emanating from such facilities into the nearby environment. Because surfactant-modified zeolite (SMZ) has the potential to sequester both cationic and anionic trace elements from aqueous solutions, bench-scale batch and column experiments were performed to test its ability to remediate trace elements in leachates generated from both alkaline and acidic fly ash samples. Fly ash leachate treatment results showed the potential application of SMZ as an effective permeable reactive barrier (PRB) material to control the dispersion of heavy metals and metalloids from ash disposal sites. Quantitative comparison of the elemental composition of SMZ-treated and untreated leachates indicated that SMZ was effective in decreasing the concentrations of trace elements in fly ash leachates. Similarly, SMZ treatment column experiments showed the delayed peak leaching events and overall reductions in leachate concentrations of trace elements. The effectiveness of SMZ column treatments, however, decreased with time potentially due to the saturation of sorption sites. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Waste Minimization Protocols for the Process of Synthesizing Zeolites from South African Coal Fly Ash

    OpenAIRE

    Petrik, Leslie F.; Tunde V. Ojumu; Du Plessis, Pieter W.

    2013-01-01

    Production of a high value zeolite from fly ash has been shown to be an avenue for the utilization of South African fly ash which presently constitutes a huge disposal problem. The synthesis of zeolites Na-P1 and analcime on a micro-scale has been successful and preliminary investigation shows that scale-up synthesis is promising. However, the post-synthesis supernatant waste generated contains high levels of NaOH that may constitute a secondary disposal problem. A waste minimization protocol...

  13. Detrimental effects of cement mortar and fly ash mortar on asthma progression.

    Science.gov (United States)

    Cho, Ara; Jang, Hong-Seok; Roh, Yoon Seok; Park, Hee Jin; Talha, A F S M; So, Seung-Young; Lim, Chae Woong; Kim, Bumseok

    2013-11-01

    Currently, concrete additive materials are used worldwide to improve properties of concrete production and to reduce the total cost of the materials used in the concrete. However, the effects of exposure to various gases emitted from mortar mixed with additive materials are poorly understood. To evaluate the pattern of gas emission from cement mortar and additives, the emission levels of gas including ammonia (NH3) and volatile organic compounds (VOCs) were measured from two different mortar types, Ordinary Portland Cement (OPC), and OPC with fly ash on various time points after manufacture. On days 1, 3, 10 and 30 after manufacture, moderate concentrations of NH3 (4, 9, 12 and 5 ppm) were measured in OPC mortar (24h, 150 mm × 150 mm × 50 mm), whereas higher concentrations of NH3 (73, 55, 20 and 5 ppm) were measured in OPC mortar with fly ash (24h, 150 mm × 150 mm × 50 mm). Furthermore, the concentration of VOCs was more than 10 ppm on 1, 3, and 10 days of age in OPC and OPC with fly ash mortars. To examine the mortars' allergic effects on the respiratory system, mice were sensitized with ovalbumin (OVA) and divided into four groups: normal, asthma control, OPC mortar and OPC mortar with fly ash. The mice were housed in corresponding group cage for 10 days with OVA challenges to induce asthma. Histopathologically, increased infiltration of lymphocytes was observed in the lung perivascular area of mice housed in OPC mortar and OPC mortar with fly ash cages compared to lungs of asthma control mice. Moreover, severe bronchial lumen obstruction and increased hypertrophy of bronchial epithelial cells (pmortar with fly ash group compared to OPC mortar or asthma control groups. Lungs of the two mortar groups generally expressed higher levels of genes related with asthma, including IL-4, eotaxin and epidermal growth factor (EGF) compared to lungs of asthma control mice. Additionally, the OPC mortar with fly ash group showed higher expression of IL-5, 13 and monocyte

  14. Study on the Disposition of Water in Fly Ash-Based Geopolymers Using ATR–IR

    OpenAIRE

    Liu, Jian; Fang, Yuan; Kayali, Obada

    2016-01-01

    This paper addresses the question of whether the main product of low calcium fly ash-based geopolymer is a hydrate, namely, sodium aluminosilicate hydrate (N-A-S-H). The answer to this question is important for understanding geopolymer characteristics. One of these is its fire resistance. In this study, fly ash-based geopolymers were synthesized using the combination of Na2CO3 and Ca(OH)2. Samples were cured at ambient temperature for 7 days, then placed in the oven at 105°C for 24 h, and the...

  15. Elemental analysis of trace elements in fly ash sample of Yatagan thermal power plants using EDXRF

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, O.; Kobya, M. [Selcuk University, Meram (Turkey). Faculty of Education

    2006-09-15

    Fly ash samples collected by means of an electrostatic precipitator from the lignite-fired Yatagan Power Plants of the located in Turkey was analysed using X-ray fluorescence technique. Five trace elements, namely Nd, Ba, Sr, Mo and As were quantified using XRF. These concentration values can be helpful in developing an environmental pollution abatement approach for various applications of fly ash such as cement manufacture, wastewater treatment, lightweight contraction aggregate, ceramic production, and secondary source in recovery of valuable elements. Present results compared with results of the Kemerkoy thermal power plants.

  16. Using cement, lignite fly ash and baghouse filter waste for solidification of chromium electroplating treatment sludge

    OpenAIRE

    Wantawin, C.; Chobthiangtham, P.

    2004-01-01

    The objective of the study is to use baghouse filter waste as a binder mixed with cement and lignite fly ash to solidify sludge from chromium electroplating wastewater treatment. To save cost of solidification, reducing cement in binder and increasing sludge in the cube were focused on. Minimum percent cement in binder of 20 for solidification of chromium sludge was found when controlling lignite fly ash to baghouse filter waste at the ratio of 30:70, sludge to binder ratio of 0.5, water to m...

  17. Waste Water Treatment-Bed of Coal Fly Ash for Dyes and Pigments Industry

    Directory of Open Access Journals (Sweden)

    Syed Farman Ali Shah

    2015-12-01

    Full Text Available The highly porous power plant waste ashes have been utilized to treat toxic effluent of a dyes manufacturing plant. An attempt has been made for the first time in Pakistan, to generate an effective and economically sound treatment facility for the toxic effluent of a dyes manufacturing plant. This is an indigenous bed which could replace expensive treatment facilities, such as reverse osmosis (RO, granulated activated carbon (GAC bed, etc. The treatment efficiency was improved by coupling coagulants with fly ash adsorbent bed. The ash was collected from coal fired boilers of power plant at Lakhra Power Generation Company, Jamshoro, Pakistan. The use of this ash resolved the disposal and environmental issues by treating wastewater of chemical, dyes and pigment industry. The treatment bed comprised of briquettes of coal fly ash coupled with commercial coagulant ferrous sulfate-lime reduced COD, color, turbidity and TSS of effluent remarkably. An adsorption capacity and chemical behavior of fly ash bed was also studied. In coagulation treatment, coagulant FeSO4-lime influenced reduction of COD, color, turbidity and TSS by 32%, 48%, 50% and 51%, respectively. The CFAB coupled with coagulant, resulted an excessive removal of color, TSS, COD, and turbidity by 88%, 92%, 67% and89%, respectively.

  18. Microstructure and Mechanical Properties of Fly Ash Particulate Reinforced in LM6 for Energy Enhancement in Automotive Applications

    Science.gov (United States)

    Ervina Efzan, M. N.; Siti Syazwani, N.; Bakri Abdullah, Mohd Mustafa Al

    2016-06-01

    Fly ash has gathered widespread attention as a potential reinforcement for aluminium matrix composites (AMCs) to enhance the properties and reduce the cost of production. Aluminium alloy LM6 reinforced with three different amounts (0, 4, 5 and 6 wt. %) of fly ash particle that were prepared by compo-casting method. The fly ash particles were incorporated into semi-solid state of LM6 melt. In this study, the microstructure of prepared AMCs with the homogenous distribution of fly ash was analysed using optical microscope. The microstructure having refinement of structure with the decreasing of Si-needle structure and increasing the area of eutectic a-Al matrix as shown in figure. Besides, as the increasing amount of fly ash incorporated, there are more petal-like dark structure existed in the microstructure. The density of the AMCs decreased as the incorporation of fly ash increased. While the hardness and ultimate tensile strength of the AMCs increased with the incorporation of fly ash. The addition of fly ash particles improved the physical and mechanical properties of the AMCs. Thus lead to improve the energy consumption in automotive parts.

  19. Studying the melting behaviour of fly ash from the incineration of MSW using viscosity and heated stage XRD data

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Folkedahl, B.; Frandsen, F. J.

    2008-01-01

    The purpose of the present study has been to investigate the melting behaviour of fly ashes from the incineration of MSW (municipal solid waste). Four fly ash samples from the Svendborg WtE (waste-to-energy) plant (2nd-3rd pass, super-heater, economizer, ESP), in Denmark, have been investigated...

  20. Electrodialytic removal of heavy metals from municipal solid waste incineration fly ash using ammonium citrate as assisting agent

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Ottosen, Lisbeth M.; Villumsen, Arne

    2005-01-01

    Electrodialytic remediation, an electrochemically assisted separation method, has previ-ously shown potential for removal of heavy metals from municipal solid waste incineration (MSWI) fly ashes. In this work electrodialytic remediation of MSWI fly ash using ammonium citrate as assisting agent...

  1. Fly ash classification efficiency of electrostatic precipitators in fluidized bed combustion of peat, wood, and forest residues.

    Science.gov (United States)

    Ohenoja, Katja; Körkkö, Mika; Wigren, Valter; Österbacka, Jan; Illikainen, Mirja

    2018-01-15

    The increasing use of biomasses in the production of electricity and heat results in an increased amount of burning residue, fly ash which disposal is becoming more and more restricted and expensive. Therefore, there is a great interest in utilizing fly ashes instead of just disposing of it. This study aimed to establish whether the utilization of fly ash from the fluidized bed combustion of peat, wood, and forest residues can be improved by electrostatic precipitator separation of sulfate, chloride, and some detrimental metals. Classification selectivity calculations of electrostatic precipitators for three different fuel mixtures from two different power plants were performed by using Nelson's and Karnis's selectivity indices. Results showed that all fly ashes behaved similarly in the electrostatic separation process SiO 2 resulted in coarse fractions with Nelson's selectivity of 0.2 or more, while sulfate, chloride, and the studied detrimental metals (arsenic, cadmium, and lead) enriched into fine fractions with varying selectivity from 0.2 to 0.65. Overall, the results of this study suggest that it is possible to improve the utilization potential of fly ashes from fluidized bed combustion in concrete, fertilizer, and earth construction applications by using electrostatic precipitators for the fractionating of fly ashes in addition to their initial function of collecting fly ash particles from flue gases. The separation of the finer fractions (ESP 2 and 3) from ESP 1 field fly ash is recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Effect of fly ash on persistence, mobility and bio-efficacy of metribuzin and metsulfuron-methyl in crop fields.

    Science.gov (United States)

    Singh, Neera; Bala Singh, Shashi; Raunaq; Das, T K

    2013-11-01

    Field evaluation of two fly ashes (40t/ha) on persistence, mobility and bioactivity of metribuzin and metsulfuron-methyl was studied in soybean and wheat crops, respectively. Metribuzin was applied as pre-emergence at 0.5kg/ha, while metsulfuron-methyl was applied post-emergence at 8g/ha. Results suggested that metribuzin in surface (0-15cm) soil of fly ash unamended plots reached below detectable limit in 60 days, while herbicide persisted till 112 days in surface soil of fly ash amended plots. No metribuzin leached down to subsurface (15-30cm) soil in fly ash amended plots, while traces of metribuzin (0.6-1.2μg/kg) were recovered in subsurface soil of fly ash unamended plot. Metsulfuron-methyl in surface soil persisted till 15 days in control and 20 days in fly ash amended plots and no metsulfuron-methyl leached down to subsurface soil. Fly ash amendment had no adverse effect on the bioactivity of herbicides and yield of soybean and wheat. The study suggested that fly ash amendment to soil can be exploited to retain applied herbicides in surface soil. © 2013 Elsevier Inc. All rights reserved.

  3. Relation between leaching characteristics of heavy metals and physical properties of fly ashes from typical municipal solid waste incinerators.

    Science.gov (United States)

    Ni, Peng; Li, Hailong; Zhao, Yongchun; Zhang, Junying; Zheng, Chuguang

    2017-09-01

    Due to the alkalinity and high concentration of potentially hazardous heavy metals, fly ash from a municipal solid waste (MSW) incinerator is classified as hazardous waste, which should be of particular concern. Physical and chemical characterizations of the contrasted fly ashes were investigated to explore the relation between leaching characteristics of heavy metals and physical properties of fly ashes. The results showed that CaClOH, NaCl, Ca(OH)2, KCl and SiO2 were primary mineral compositions in the MSWI fly ashes, and the particle size distribution of fly ash ranged between 10 μm and 300 μm. The smaller the particle size distribution of fly ash, the larger the BET-specific surface area, which was beneficial to the leaching of heavy metals. As a result of various pores, it easily accumulated heavy metals as well. The leaching tests exhibited a high leachability of heavy metals and the leaching concentration of Pb in almost all of the fly ash samples went far beyond the Standard for Pollution Control on the Landfill Site of Municipal Solid Waste. Thereupon, it is necessary to establish proper disposal systems and management strategies for environmental protection based on the characteristics of MSW incineration (MSWI) fly ash in China.

  4. Microstructure and Engineering Properties of Alkali Activated Fly Ash -as an environment friendly alternative to Portland cement

    NARCIS (Netherlands)

    Ma, Y.

    2013-01-01

    Alkali activated fly ash (AAFA), also named “geopolymer”, has emerged as a novel engineering material in the construction industry. This material is normally formed by the reaction between fly ash and aqueous hydroxide or alkali silicate solution. With proper mix design, AAFA can present comparable

  5. Evaluation of metal mobility/immobility in fly ash induced by bacterial strains isolated from the rhizospheric zone of Typha latifolia growing on fly ash dumps.

    Science.gov (United States)

    Tiwari, Sadhna; Kumari, Babita; Singh, S N

    2008-03-01

    In this investigation, 11 bacterial strains were isolated from the rhizospheric zone of Typha latifolia. All the strains were aerobic, showed positive result with indole production and were able to grow in MacConkey agar. However, four strains were gram positive and others gram negative. These strains were inoculated separately in the fly ash with additional source of carbon to test their ability to increase the bioavailability or immobilization of toxic metals like Cu, Zn, Pb, Cd and Mn. It was observed that most of the bacterial strains either enhanced the mobility of Zn, Fe and Mn or immobilized Cu and Cd. However, there were a few exceptions. For example, in contrast to other bacterial strains, NBRFT6 enhanced immobility of Zn and Fe and NBRFT2 of Mn. On the other hand, in place of immobility induced by most of the bacterial strains, NBRFT8 and NBRFT9 enhanced bioavailability of Cu. However, in case of Cd, all the strains without any exception immobilized this metal. The results also indicated that the mobility/immobility of trace metals from the exchangeable fractions was the specific function of bacterial strains depending upon the several edaphic and environmental factors. Based on the extractability of metals from fly ash, a consortium of high performer bacterial strains will be further used to enhance the phytoextraction of metals from fly ash by metal accumulating plants. On the other hand, bacterial strains responsible for immobilization of metals may be used for arresting their leaching to water bodies.

  6. INVESTIGATION OF AMMONIA ADSORPTION ON FLY ASH DUE TO INSTALLATION OF SELECTIVE CATALYTIC REDUCTION SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    G.F. Brendel; J.E. Bonetti; R.F. Rathbone; R.N. Frey Jr.

    2000-11-01

    This report summarizes an investigation of the potential impacts associated with the utilization of selective catalytic reduction (SCR) systems at coal-fired power plants. The study was sponsored by the U.S. Department of Energy Emission Control By-Products Consortium, Dominion Generation, the University of Kentucky Center for Applied Energy Research and GAI Consultants, Inc. SCR systems are effective in reducing nitrogen oxides (NOx) emissions as required by the Clean Air Act (CAA) Amendments. However, there may be potential consequences associated with ammonia contamination of stack emissions and combustion by-products from these systems. Costs for air quality, landfill and pond environmental compliance may increase significantly and the marketability of ash may be seriously reduced, which, in turn, may also lead to increased disposal costs. The potential impacts to air, surface water, groundwater, ash disposal, ash utilization, health and safety, and environmental compliance can not be easily quantified based on the information presently available. The investigation included: (1) a review of information and data available from published and unpublished sources; (2) baseline ash characterization testing of ash samples produced from several central Appalachian high-volatile bituminous coals from plants that do not currently employ SCR systems in order to characterize the ash prior to ammonia exposure; (3) an investigation of ammonia release from fly ash, including leaching and thermal studies; and (4) an evaluation of the potential impacts on plant equipment, air quality, water quality, ash disposal operations, and ash marketing.

  7. Applied investigation on the interaction of hazardous elements binding on ultrafine and nanoparticles in Chinese anthracite-derived fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luis F.O., E-mail: lfsoliveira@univates.br [Centro Universitario Univates, Programa de Pos Graduacao Ambiente e Desenvolvimento, Rua Avelino Tallini, 171, Universitario, 95900-000 Lajeado, RS (Brazil); Environmental Science and Nanotechnology Department, Catarinense Institute of Environmental Research and Human Development - IPADHC, Capivari de Baixo, Santa Catarina (Brazil); Jasper, Andre [Centro Universitario Univates, Programa de Pos Graduacao Ambiente e Desenvolvimento, Rua Avelino Tallini, 171, Universitario, 95900-000 Lajeado, RS (Brazil); Andrade, Maria L. [Department of Plant Biology and Soil Science, University of Vigo, 36310 Vigo (Spain); Sampaio, Carlos H. [Universidade Federal do Rio Grande do Sul, Escola de Engenharia, Departamento de Metalurgia, Centro de Tecnologia, Av. Bento Goncalves, 9500, Bairro Agronomia, CEP: 91501-970, Porto Alegre, RS (Brazil); Dai, Shifeng; Li, Xiao; Li, Tian; Chen, Weimei; Wang, Xibo; Liu, Huidong; Zhao, Lixin [China University of Mining and Technology, Beijing (China); Hopps, Shelley G.; Jewell, Robert F. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States); Hower, James C., E-mail: james.hower@uky.edu [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States)

    2012-03-01

    A multifaceted instrumental approach was employed to determine the chemistry and mineralogy of pulverized-coal-combustion fly ashes from two Chinese power plants. Techniques included traditional optical microscopy, X-ray diffraction, and chemical analysis along with a variety of electron beam methods. The aim is to demonstrate and bring together the wide variety of procedures dealing with F as the key element of concern, and determining its location in the mineral nanoparticles. The Hg content of the Anwen (Songzao coalfield) fly ashes is higher than that of the Diandong (East Yunnan) fly ashes, possibly owing to the greater C and Cl in the Anwen fly ashes. Both fly ash sources contain a variety of amorphous and nano-crystalline trace-element-bearing particles, both associated with multi-walled carbon nanotubes and as particles independent of carbons.

  8. Evaluation of leachates from coal refuse blended with fly ash at different rates.

    Science.gov (United States)

    Stewart, B R; Daniels, W L; Zelazny, L W; Jackson, M L

    2001-01-01

    There is great interest in returning coal combustion products to mining sites for beneficial reuse as liming agents. A column study examined the effects of blending two coal fly ashes with an acid-forming coal refuse (4% pyritic S). Both fly ashes were net alkaline, but had relatively low neutralizing capacities. One ash with moderate alkalinity (CRF) was bulk blended with coal refuse at 0, 20, and 33% (w/w), while another lower alkalinity ash (WVF) was blended at 0, 5, 10, 20, and 33% (w/w). The columns were leached (unsaturated) weekly with 2.5 cm of simulated precipitation for >150 wk. Where high amounts of ash alkalinity (>20% w/w) were mixed with the coal refuse, pyrite oxidation was controlled and leachate pH was >7.0 with low metal levels throughout the study. At lower rates of alkalinity loading, trace metals were sequentially released from the WVF ash as the 5, 10, and 20% treatments acidified due to pyrite oxidation. Lechate metals increased in proportion to the total amounts applied in the ash. In this strongly acidic environment, metals such as Mn, Fe, and Cu were dissolved and leached from the ash matrix in large quantities. If ash is to be beneficially reused in the reclamation of acid-producing coal refuse, the alkalinity and potential acidity of the materials must be balanced through the appropriate addition of lime or other alkaline materials to the blend. Highly potentially acidic refuse material, such as that used here, may not be suitable for ash/refuse codisposal scenarios.

  9. Solid and fly ash materials ofbrown coal power plants, their characteristics and utilisation

    Directory of Open Access Journals (Sweden)

    Kovács Ferenc

    2002-09-01

    Full Text Available coal-fired power plants, a significant amount of residues is produced, depending on the technical parameters of coal separation and firing equipment. A large quantity of solid and fly ash and, in the case of flue gas desulphurisation, REA gypsum and wash-water is produced. The quantity of residues depends primarily on the ash and sulphur content of the fuel.Coal has a significant role in energy production and represents a considerable quantity in electric energy generation. At the turn of the millenary, about 4 billion tones of black coal and 800 million tones of brown coal and lignite are produced in the world annually. Depending on the ash content of the coals – it varies between 5-8% and 30-35% –, the quantity of solid and fly ash produced by firing is 1.0-1.5 billion tones per year. The quantity of residues of this kind accumulated in the past amounts to 100 billion tones.As far as the residues of coal-fired power plants are concerned, the annual fuel demand of the power plants of the Rhenish brown coal basin, where the average ash content of lignite is 7% and the average sulphur content is 0.2-0.8%, is 1 Mt referred to a power plant capacity of 100 MW. 60-70 kt solid + fly ash and, in the case of flue gas desulphurisation, 12-15 kt of gypsum is produced annually, referred to a capacity of 100 MW. In the East German areas, after the reconstruction of power plants, 30-50 kt of fly ash and, because of the higher sulphur content, 25-30 kt of gypsum and 4-5000 m3 of wash-water is produced annually, referred to a capacity of 100 MW.The composition of Hungarian lignite is significantly different to that of Rhenish brown coal. The ash content and combustible sulphur content of domestic lignite is considerably higher. The ash content of lignite varies between 15 and 25%, the average is 20%. In Visonta, 160-200 tones of solid + fly ash is produced annually, referred to a power plant capacity of 100 MW. With the flue gas desulphuriser installed

  10. Effects of coal fly ash on tree swallow reproduction in Watts Bar Reservoir, Tennessee.

    Science.gov (United States)

    Walls, Suzanne J; Meyer, Carolyn B; Iannuzzi, Jacqueline; Schlekat, Tamar H

    2015-01-01

    Coal-fly ash was released in unprecedented amounts (4.1 × 10(6) m(3) ) into the Emory River from the Tennessee Valley Authority Kingston Fossil Plant on Watts Bar Reservoir in Tennessee. Tree swallows were exposed to ash-related constituents at the ash release via their diet of emergent aquatic insects, whose larval forms can accumulate constituents from submerged river sediments. Reproduction of tree swallow colonies was assessed over a 2-year period by evaluating whether 1) ash constituent concentrations were elevated in egg, eggshell, and nestling tissues at colonies near ash-impacted river reaches compared to reference colonies, 2) production of fledglings per nesting female was significantly lower in ash-impacted colonies versus reference colonies, and 3) ash constituent concentrations or diet concentrations were correlated with nest productivity measures (clutch size, hatching success, and nestling survival, and fledglings produced per nest). Of the 26 ash constituents evaluated, 4 (Se, Sr, Cu, and Hg) were significantly elevated in tissues potentially from the ash, and 3 (Se, Sr, and Cu) in tissues or in swallow diet items were weakly correlated to at least one nest-productivity measure or egg weight. Tree swallow hatching success was significantly reduced by 12%, but fledgling production per nest was unaffected due to larger clutch sizes in the impacted than reference colonies. Bioconcentration from the ash to insects in the diet to tree swallow eggs appears to be low. Overall, adverse impacts of the ash on tree swallow reproduction were not observed, but monitoring is continuing to further ensure Se from the residual ash does not adversely affect tree swallow reproduction over time. Integr Environ Assess Manag 2015;11:56-66. © 2014 SETAC. © 2014 SETAC.

  11. Comparative study on elemental composition and DNA damage in leaves of a weedy plant species, Cassia occidentalis, growing wild on weathered fly ash and soil.

    Science.gov (United States)

    Love, Amit; Tandon, Rajesh; Banerjee, B D; Babu, C R

    2009-10-01

    Open dumping of fly ash in fly ash basins has significant adverse environmental impacts due to its elevated trace element content. In situ biomonitoring of genotoxicity is of practical value in realistic hazard identification of fly ash. Genotoxicity of openly disposed fly ash to natural plant populations inhabiting fly ash basins has not been investigated. DNA damage, and concentrations of As, Co, Cr, Cu and Ni in the leaves of natural populations of Cassia occidentalis growing at two contrasting sites-one having weathered fly ash (fly ash basin) and the other having soil (reference site) as plant growth substrates-were assessed. The foliar concentrations of As, Ni and Cr were two to eight fold higher in plants growing on fly ash as compared to the plants growing on soil, whereas foliar concentrations of Cu and Co were similar. We report, for the first time, based upon comet assay results, higher levels of DNA damage in leaf tissues of Cassia occidentalis growing wild on fly ash basin compared to C. occidentalis growing on soil. Correlation analysis between foliar DNA damage and foliar concentrations of trace elements suggests that DNA damage may perhaps be associated with foliar concentrations of As and Ni. Our observations suggest that (1) fly ash triggers genotoxic responses in plants growing naturally on fly ash basins; and (2) plant comet assay is useful for in situ biomonitoring of genotoxicity of fly ash.

  12. Numerical Analysis of Convective Transport of Fly Ash-Water Slurry through a Horizontal Pipe

    Directory of Open Access Journals (Sweden)

    Bibhuti Bhusan Nayak

    2015-06-01

    Full Text Available The thermal transport of solid-liquid suspension under turbulent flow condition is not well understood because of the complex interaction between the solid particles and the turbulent carrier fluid. The solid particles may enhance or suppress the rate of heat transfer and turbulence depending on their size and concentration. In the present paper, a three-dimensional numerical simulation is carried out in order to study the pressure drop and heat transfer characteristics of a liquid-solid slurry flow in a horizontal pipe. The simulation is performed by using the algebraic slip mixture (ASM model which is a part of the finite-volume based CFD software Ansys Fluent. The turbulence is handled by the RNG k – ε model. A hexagonal shape and cooper type non-uniform three-dimensional grid is created to discretize the computational domain. Spherical fly ash particles, with mass median diameter of 13mm for an average flow velocity ranging from 1–5 m/s and particle concentrations within 0–40% by volume for each velocity, are considered as the dispersed phase. The results illustrate that higher particle concentration in the flow causes an increase in the heat transfer and pressure drop. Moreover, both heat transfer and pressure drop are seen to show a positive dependence on the mean velocity of the flow.

  13. Cellular lightweight concrete containing high-calcium fly ash and natural zeolite

    Science.gov (United States)

    Jitchaiyaphum, Khamphee; Sinsiri, Theerawat; Jaturapitakkul, Chai; Chindaprasirt, Prinya

    2013-05-01

    Cellular lightweight concrete (CLC) with the controlled density of approximately 800 kg/m3 was made from a preformed foam, Type-I Portland cement (OPC), fly ash (FA), or natural zeolite (NZ), and its compressive strength, setting time, water absorption, and microstructure of were tested. High-calcium FA and NZ with the median particle sizes of 14.52 and 7.72 μm, respectively, were used to partially replace OPC at 0, 10wt%, 20wt%, and 30wt% of the binder (OPC and pozzolan admixture). A water-to-binder mass ratio (W/B) of 0.5 was used for all mixes. The testing results indicated that CLC containing 10wt% NZ had the highest compressive strength. The replacement of OPC with NZ decreased the total porosity and air void size but increased the capillary porosity of the CLC. The incorporation of a suitable amount of NZ decreased the setting time, total porosity, and pore size of the paste compared with the findings with the same amount of FA. The total porosity and cumulative pore volume decreased, whereas the gel and capillary pores increased as a result of adding both pozzolans at all replacement levels. The water absorption increased as the capillary porosity increased; this effect depended on the volume of air entrained and the type or amount of pozzolan.

  14. Ultrasound and shacking-assisted water-leaching of anions and cations from fly ash

    Directory of Open Access Journals (Sweden)

    Savić-Biserčić Marjetka

    2016-01-01

    Full Text Available Two mechanical extraction techniques were used for the extraction of environmentaly interesting elements from coal fly ash: shaking, in which the extraction process lasted from 6 to 24 hours, and ultrasonic sonication during 15 to 60 minutes, with water as extractant. The concentration of anions in fly ash extracts were determined by ion chromatography, while atomic absorption spectrometry was used for determination of: As, Pb, Cd, Ni, Cr, Zn, Cu, Fe, Mn and Al. The ultrasonic sonication yielded slightly higher amounts of extracted anions and Pb, Al, Mn and Fe, while shaking-assisted extraction was more efficient for the Cr, As, Zn and Ni ions. The changes in pH value, particle size distribution in colloid, zeta potential and conductivity during ultrasound-assisted extraction were measured in order to explain changes on the surface of fly ash particles in contact with water and different processes (adsorption, ion exchange, flocculation that occur in environmental conditions. Principal Component Analysis were used for assessing the effect of observed process parameters. Essential from a practical point of view is a quantitative evaluation of these elements leachable from coal fly ash to surface waters in environmental conditions and contamination of the environment. [Projekat Ministarstva nauke Republike Srbije, br. 172030, br. III45012 i br. III43009

  15. Fly ash: An alternative to powdered activated carbon for the removal ...

    African Journals Online (AJOL)

    This paper reports the use of powdered activated carbon (PAC) and raw coal fly ash (RFA) in the removal of eosin dye from aqueous solution in batch processes. Operational parameters such as contact time, initial dye concentration, pH and temperature were investigated. Adsorption equilibrium was established in 120 min ...

  16. Effect of Fly Ash and Carbon Reinforcement on Dry Sliding Wear Behaviour of Red Mud

    Directory of Open Access Journals (Sweden)

    Harekrushna Sutar

    2015-01-01

    Full Text Available This paper explains the sliding wear performance of red mud, fly ash, and carbon composite coating on mild steel. The complex mixture of red mud, fly ash, and carbon is plasma sprayed at 9 kW operating power level. The coatings are examined to study the coating morphology, XRD phase transformation, wear rate, and wear morphology. Wear rate (in terms of cumulative mass loss with sliding time has been demonstrated in the study. At first pure red mud is plasma coated to observe the coating characteristics and then compounded with 20% carbon, 30% carbon, and 20% carbon + 30% fly ash, separately by weight and sliding wear test conducted using pin on disc wear tester. The trial was performed at fixed track diameter of 100 mm and at sliding speed of 100 rpm (0.523 m/s at a load of 30 N. The results are compared. Declined cumulative mass loss by inclusion of fly ash and carbon is seen. This might be due to augmented interfacial tension and dense film build-up at boundary layer.

  17. Fly ash reactivity: extension and application of a shrinking core model and thermodynamic approach

    NARCIS (Netherlands)

    Brouwers, Jos; van Eijk, R.J.

    2002-01-01

    In the present paper a theoretical study is presented on the dissolution (reaction) of pulverised powder coal fly ash. A shrinking core model is derived for hollow spheres that contain two regions (outer hull and inner region). The resulting analytical equations are applied to the dissolution

  18. Sustainable asphalt pavement: Application of slaughterhouse waste oil and fly ash in asphalt binder

    Science.gov (United States)

    Sanchez Ramos, Jorge Luis

    Increasing energy costs, lack of sufficient natural resources and the overwhelming demand for petroleum has stimulated the development of alternative binders to modify or replace petroleum-based asphalt binders. In the United States, the petroleum-based asphalt binder is mainly used to produce the Hot Mix Asphalt (HMA). There are approximately 4000 asphalt plants that make 500 million tons of asphalt binder valued at roughly 3 billion/year. The instability of the world's oil market has pushed oil prices to more than 80 per barrel in 2012, which increased the cost of asphalt binder up to $570 per ton. Therefore, there is a timely need to find alternative sustainable resources to the asphalt binder. This paper investigates the possibility of the partial replacement of the asphalt binder with slaughterhouse waste and/or fly ash. In order to achieve this objective, the asphalt binder is mixed with different percentages of waste oil and/or fly ash. In order to investigate the effect of these additives to the performance of the asphalt binder, a complete performance grade test performed on multiple samples. The results of the performance grade tests are compared with a control sample to observe how the addition of the waste oil and/or fly ash affects the sample. Considering the increasing cost and demand of asphalt, the use of slaughterhouse waste oil and/or fly ash as a partial replacement may result in environmental and monetary improvements in the transportation sector.

  19. The effect of wash cleaning and demagnetization process on the fly ash physico-chemical properties

    Directory of Open Access Journals (Sweden)

    A. Baliński

    2007-04-01

    Full Text Available Problems related in this study concern the possibility of improving the physico-chemical properties of fly ash used as a base granular material in moulding mixtures. The investigations were carried out mainly to evaluate the process of the fly ash modification performed in order to stabilize its mineralogical and chemical composition. Changes in chemical composition, specific surface and helium density of fly ash after the process of its wash cleaning and demagnetization were examined. The analysis of the data has proved that the process of wash cleaning considerably reduces the content of sodium and potassium. Calcium and magnesium are washed out, too. The wash cleaning process of fly ash reduces also its true density. This fact can be due to the washing out of illite as well as some fractions of haematite (the grains weakly bonded to the glassy phase. The process of demagnetization allows removing about 25.7% of the magnetic phase calculated in terms of Fe2O3. The process of demagnetization is accompanied by a decrease in the content of aluminium, sodium, potassium and calcium, and a reduction in the size of the specific surface by over one half. The possible processes of transformation have also been discussed.

  20. Study on the compressive strength of fly ash based geo polymer concrete

    Science.gov (United States)

    Anand Khanna, Pawan; Kelkar, Durga; Papal, Mahesh; Sekar, S. K.

    2017-11-01

    Introduction of the alternative materials for complete replacement of cement in ordinary concrete will play an important role to control greenhouse gas and its effect. The 100% replacement of binder with fly ash (in integration with potassium hydroxide (koh) and potassium silicate (k2sio3) solutions) in concrete gives a significant alternative to conventional cement concrete. This paper focuses on the effect of alkaline solutions koh and k2sio3 on strength properties of fly ash based geo polymer concrete (fgpc); compared the strength at different molarities of alkaline activator koh at different curing temperature. Fly ash based geo polymer concrete was produced from low calcium fly ash, triggered by addition of koh and k2sio3 solution and by assimilation of superplasticizer for suitable workability. The molarities of potassium hydroxide as 8m, 10m and 12m molarities were used at various curing temperatures such as 60°c, 70 °c and 80°c. Results showed that for given proportion to get maximum compressive strength the optimum molarity of alkaline solution is 12m and optimum curing temperature is 70 °c.

  1. Mercury capture by native fly ash carbons in coal-fired power plants

    Science.gov (United States)

    Hower, James C.; Senior, Constance L.; Suuberg, Eric M.; Hurt, Robert H.; Wilcox, Jennifer L.; Olson, Edwin S.

    2013-01-01

    The control of mercury in the air emissions from coal-fired power plants is an on-going challenge. The native unburned carbons in fly ash can capture varying amounts of Hg depending upon the temperature and composition of the flue gas at the air pollution control device, with Hg capture increasing with a decrease in temperature; the amount of carbon in the fly ash, with Hg capture increasing with an increase in carbon; and the form of the carbon and the consequent surface area of the carbon, with Hg capture increasing with an increase in surface area. The latter is influenced by the rank of the feed coal, with carbons derived from the combustion of low-rank coals having a greater surface area than carbons from bituminous- and anthracite-rank coals. The chemistry of the feed coal and the resulting composition of the flue gas enhances Hg capture by fly ash carbons. This is particularly evident in the correlation of feed coal Cl content to Hg oxidation to HgCl2, enhancing Hg capture. Acid gases, including HCl and H2SO4 and the combination of HCl and NO2, in the flue gas can enhance the oxidation of Hg. In this presentation, we discuss the transport of Hg through the boiler and pollution control systems, the mechanisms of Hg oxidation, and the parameters controlling Hg capture by coal-derived fly ash carbons. PMID:24223466

  2. Analytical model for erosion behaviour of impacted fly-ash particles ...

    Indian Academy of Sciences (India)

    Fly ash particles entrained in the flue gas from boiler furnaces in coal-fired power stations can cause serious erosive wear on steel surfaces along the flow path. Such erosion can significantly reduce the operational life of the boiler components. A mathematical model embodying the mechanisms of erosion on behaviour, ...

  3. Efficacy of fly-ash based bio-fertilizers vs perfected chemical ...

    African Journals Online (AJOL)

    Fly-ash based Azotobacter and Azospirillum formulation alone and in combination with chemical fertilizer was evaluated for bio-efficacy on wheat. Population of Azotobacter and Azospirillum was also evaluated in treated soil. The results of the studies showed that, seed treatment with Azotobacter and Azospirillum and soil ...

  4. The Use of Fly Ash and Lime Sludge as Partial Replacement of Cement in Mortar

    Directory of Open Access Journals (Sweden)

    Vaishali Sahu

    2014-01-01

    Full Text Available The increased demand of drinking water and power has led huge generation of water treatment plant residue i.e. sludge and the thermal power plant by-product such as fly ash. Large quantities of sludge and fly ash are produced in India and disposed off by landfilling or dumping in and around sites. In this study fly ash and water softening sludge (lime sludge has been utilized in mortar. Two types of mortar (type I and II with four binder combinations have been tried. Binder I consists of 70% fly ash (FA and 30% lime sludge (LS , 0 % gypsum (G, binder II is 70% FA, 30% LS and 1% G, binder III is 50% FA, 30% LS and 20% cement and the binder IV is 40% FA, 40% LS with 20% cement. The effect of various combinations on strength has been discussed here. This paper outlines the composition of the composite material, method of preparation of mortar specimen, testing procedure and salient results thereof.

  5. Effect of size of fly ash particle on enhancement of mullite content ...

    Indian Academy of Sciences (India)

    Administrator

    (DTA), field effect scanning electron microscopy (FESEM), XRD and Fourier transform infrared (FTIR) spectroscopy. The results show ... cement in concrete. Because of the presence of SiO2 and. Al2O3 in high proportions in fly ash, it is used to synthe- size mullite. Mullite is an important and widely studied ceramic material.

  6. Analytical model for erosion behaviour of impacted fly-ash particles ...

    Indian Academy of Sciences (India)

    generated from a high temperature air-jet erosion-testing facility. It is hoped that the calibrated model will be useful for erosion analysis of boiler components. Keywords. Mathematical model; erosion rate; boiler components; fly ash impingement; tensile properties; steel grades. 1. Introduction. In coal-fired power stations, ...

  7. Evidence of Coal-Fly-Ash Toxic Chemical Geoengineering in the Troposphere: Consequences for Public Health

    Science.gov (United States)

    Herndon, J. Marvin

    2015-01-01

    The widespread, intentional and increasingly frequent chemical emplacement in the troposphere has gone unidentified and unremarked in the scientific literature for years. The author presents evidence that toxic coal combustion fly ash is the most likely aerosolized particulate sprayed by tanker-jets for geoengineering, weather-modification and climate-modification purposes and describes some of the multifold consequences on public health. Two methods are employed: (1) Comparison of 8 elements analyzed in rainwater, leached from aerosolized particulates, with corresponding elements leached into water from coal fly ash in published laboratory experiments, and (2) Comparison of 14 elements analyzed in dust collected outdoors on a high-efficiency particulate air (HEPA) filter with corresponding elements analyzed in un-leached coal fly ash material. The results show: (1) the assemblage of elements in rainwater and in the corresponding experimental leachate are essentially identical. At a 99% confidence interval, they have identical means (T-test) and identical variances (F-test); and (2) the assemblage of elements in the HEPA dust and in the corresponding average un-leached coal fly ash are likewise essentially identical. The consequences on public health are profound, including exposure to a variety of toxic heavy metals, radioactive elements, and neurologically-implicated chemically mobile aluminum released by body moisture in situ after inhalation or through transdermal induction. PMID:26270671

  8. Heavy metals extraction from municipal solid waste incineration fly ash using adapted metal tolerant Aspergillus niger.

    Science.gov (United States)

    Yang, Jie; Wang, Qunhui; Wang, Qi; Wu, Tingji

    2009-01-01

    This study focused on the adaptation of Aspergillus niger tolerating high concentration of heavy metals for bioleaching of fly ash. The Plackett-Burman design indicated that Al and Fe inhibited the growth of A. niger (AS 3.879 and AS 3.40) significantly. The single metal (Al and Fe) and multi-metals adapted AS 3.879 strain tolerated up to 3500 mg/L Al, 700 mg/L Fe, and 3208.1mg/L multi-metals, respectively. The order of metal extraction yield in two-step bioleaching of 60 and 70 g/L fly ash using Al adapted, multi-metals adapted and un-adapted AS 3.879 strains was as follows: multi-metals adapted>Al adapted>un-adapted. The multi-metals adapted strain grew with up to 70 g/L fly ash and secreted 256 mmol/L organic acids after 288 h, where 87.4% Cd, 64.8% Mn, 49.4% Zn and 45.9% Pb were dissolved. The extracted metals in TCLP test of the bioleached fly ash by multi-metals adapted strain were under the regulated levels in China.

  9. Cobalt(II removal from synthetic wastewater by adsorption on South African coal fly ash

    Directory of Open Access Journals (Sweden)

    Ochieng Aoyi

    2010-09-01

    Full Text Available Advanced wastewater-treatment techniques such as adsorption are essential in the removal of non- biodegradable toxic wastes from water. In this study, the use of South African coal fly ash, an industrial byproduct, has been investigated as a potential replacement for the current costly adsorbents used for removing heavy metals from wastewater. We utilised coal fly ash for the adsorption of cobalt(II ions from synthetic petrochemical wastewater and characterised its performance. A two-level three-factor full-factorial design was successfully employed for experimental design and analysis of the results. The combined effects of pH, initial concentration and adsorbent dose on cobalt(II removal were assessed using response surface methodology. Although the focus was on removal of cobalt(II, the adsorption was carried out in the presence of phenol and other heavy metal ions using the batch technique. The applicability of the Freundlich and Langmuir models to the equilibrium data was tested. Consequently, the equilibrium data was found to conform more favourably to the Freundlich isotherm than to the Langmuir isotherm; in this case, the coal fly ash had a maximum adsorption capacity of 0.401 mg/g for cobalt(II. We conclude that South African coal fly ash, as a natural, abundant and low-cost adsorbent, might be a suitable local alternative for elimination of cobalt(II from aqueous solutions.

  10. A comparative study on the use of fly ash and phosphogypsum in ...

    Indian Academy of Sciences (India)

    mechanical strength values while lowering the water absorption values. Utilization of these wastes additives is not only for conservation of clay resources, but also an alternative solution to a difficult and expensive waste disposal problems. Keywords. Fly ash; phosphogypsum; clay; brick; physical and mechanical properties.

  11. Mechanism and Chemical Reaction of Fly Ash Geopolymer Cement- A Review

    OpenAIRE

    A.M. Mustafa Al Bakri; Kamarudin, H.; M. Bnhussain; I. Khairul Nizar; W.I.W. Mastura

    2011-01-01

    This paper presents the work carried out on the chemical reaction, mechanism, role of materials, applications and microstructure of fly ash geopolymer cement. Geopolymeris a type of amorphous alumino-silicate cementitious material. Geopolymer can besynthesized by polycondensation reaction of geopolymeric precursor, and alkalipolysilicates. Literature demonstrates that the exact geopolymerization mechanism is not well understood because the geopolymerization process involves a substantially fa...

  12. Improving lithium-ion battery performances by adding fly ash from coal combustion on cathode film

    Energy Technology Data Exchange (ETDEWEB)

    Dyartanti, Endah Retno; Jumari, Arif, E-mail: arifjumari@yahoo.com; Nur, Adrian; Purwanto, Agus [Research Group of Battery & Advanced Material, Department of Chemical Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A Kentingan, Surakarta Indonesia 57126 (Indonesia)

    2016-02-08

    A lithium battery is composed of anode, cathode and a separator. The performance of lithium battery is also influenced by the conductive material of cathode film. In this research, the use of fly ash from coal combustion as conductive enhancer for increasing the performances of lithium battery was investigated. Lithium iron phosphate (LiFePO{sub 4}) was used as the active material of cathode. The dry fly ash passed through 200 mesh screen, LiFePO{sub 4} and acethylene black (AB), polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to form slurry. The slurry was then coated, dried and hot pressed to obtain the cathode film. The ratio of fly ash and AB were varied at the values of 1%, 2%, 3%, 4% and 5% while the other components were at constant. The anode film was casted with certain thickness and composition. The performance of battery lithium was examined by Eight Channel Battery Analyzer, the composition of the cathode film was examined by XRD (X-Ray Diffraction), and the structure and morphology of the anode film was analyzed by SEM (Scanning Electron Microscope). The composition, structure and morphology of cathode film was only different when fly ash added was 4% of AB or more. The addition of 2% of AB on cathode film gave the best performance of 81.712 mAh/g on charging and 79.412 mAh/g on discharging.

  13. Synthesis of cracked Calophyllum inophyllum oil using fly ash catalyst for diesel engine application

    KAUST Repository

    Muthukumaran, N.

    2015-04-16

    In this study, production of hydrocarbon fuel from Calophyllum inophyllum oil has been characterized for diesel engine application, by appraising essential fuel processing parameters. As opposed to traditional trans-esterification process, the reported oil was cracked using a catalyst, as the latter improves the fuel properties better than the former. In a bid to make the production process economically viable, a waste and cheap catalyst, RFA (raw fly ash), has been capitalized for the cracking process as against the conventional zeolite catalyst. The fuel production process, which is performed in a fixed bed catalytic reactor, was done methodologically after comprehensively studying the characteristics of fly ash catalyst. Significantly, fly ash characterization was realized using SEM and EDS, which demarcated the surface and internal structures of fly ash particles before and after cracking. After the production of hydrocarbon fuel from C. inophyllum oil, the performed compositional analysis in GC-MS revealed the presence of esters, parfins and olefins. Followed by the characterization of catalytically cracked C. inophyllum oil, suitable blends of it with diesel were tested in a single cylinder diesel engine. From the engine experimental results, BTE (brake thermal efficiency) of the engine for B25 (25% cracked C. inophyllum oil and 75% diesel) was observed to be closer to diesel, while it decreased for higher blends. On the other hand, emissions such as HC (hydrocarbon), CO (carbon monoxide) and smoke were found to be comparable for B25 with diesel. © 2015 Elsevier Ltd. All rights reserved.

  14. Arsenic and copper stabilisation in a contaminated soil by coal fly ash and green waste compost.

    Science.gov (United States)

    Tsang, Daniel C W; Yip, Alex C K; Olds, William E; Weber, Paul A

    2014-09-01

    In situ metal stabilisation by amendments has been demonstrated as an appealing low-cost remediation strategy for contaminated soil. This study investigated the short-term leaching behaviour and long-term stability of As and Cu in soil amended with coal fly ash and/or green waste compost. Locally abundant inorganic (limestone and bentonite) and carbonaceous (lignite) resources were also studied for comparison. Column leaching experiments revealed that coal fly ash outperformed limestone and bentonite amendments for As stabilisation. It also maintained the As stability under continuous leaching of acidic solution, which was potentially attributed to high-affinity adsorption, co-precipitation, and pozzolanic reaction of coal fly ash. However, Cu leaching in the column experiments could not be mitigated by any of these inorganic amendments, suggesting the need for co-addition of carbonaceous materials that provides strong chelation with oxygen-containing functional groups for Cu stabilisation. Green waste compost suppressed the Cu leaching more effectively than lignite due to the difference in chemical composition and dissolved organic matter. After 9-month soil incubation, coal fly ash was able to minimise the concentrations of As and Cu in the soil solution without the addition of carbonaceous materials. Nevertheless, leachability tests suggested that the provision of green waste compost and lignite augmented the simultaneous reduction of As and Cu leachability in a fairly aggressive leaching environment. These results highlight the importance of assessing stability and remobilisation of sequestered metals under varying environmental conditions for ensuring a plausible and enduring soil stabilisation.

  15. Secondary Industrial Minerals from Coal Fly Ash and Aluminium Anodising Waste Solutions

    NARCIS (Netherlands)

    Nugteren, H.W.

    2010-01-01

    Minerals that are extracted from the earth’s crust to be directly used for their properties are called industrial minerals. This research shows that such minerals can also be produced from industrial residues, hence the name secondary industrial minerals. In this thesis coal fly ash is chosen as one

  16. The Effect of Silane Addition on Chitosan-Fly Ash/CTAB as Electrolyte Membrane

    Science.gov (United States)

    Kusumastuti, E.; Isnaeni, D.; Sulistyaningsih, T.; Mahatmanti, F. W.; Jumaeri; Atmaja, L.; Widiastuti, N.

    2017-02-01

    Electrolyte membrane is an important component in fuel cell system, because it may influence fuel cell performance. Many efforts have been done to produce electrolyte membrane to replace comercial membrane. In this research, electrolyte membrane is composed of chitosan as an organic matrix and fly ash modified with CTAB and silane as inorganic filler. Fly ash is modified using silane as coupling agent to improve interfacial morphology between organic matrix and inorganic filler. This research aims to determine the best membrane performance based on its characteristics such as water uptake, mechanical properties, proton conductivity, and methanol permeability. The steps that have been done include silica preparation from fly ash, modification of silica surface with CTAB, silica coupling process with silane, synthesis of membranes with inversion phase method, and membrane characterization. The result shows that membrane C-FA/CTAB-Silane 10% (w/w) has the best performance with proton conductivity 8.00 x 10-4 S.cm-1, methanol permeability 3.37 x 10-7 cm.s-1, and selectivity 2.12 x 103 S.s.cm-3. The result of FTIR analysis on membrane C-FA/CTAB-Silane 10% shows that there is only physical interaction occured between chitosan, fly ash and silane, because there is no peak differences significantly at wave number 1000-1250 cm-1, while morphology analysis on membrane with Scanning Electron Microscopy (SEM) shows good dispersion and there is no agglomeration on chitosan matrix.

  17. Geochemistry of fly ash from desulphurisation process performed by sodium bicarbonate

    Energy Technology Data Exchange (ETDEWEB)

    Raclavska, Helena; Matysek, Dalibor; Raclavsky, Konstantin; Juchelkova, Dagmar [VSB - Technical University Ostrava, 17. listopadu 15, 708 33 Ostrava, Poruba (Czech Republic)

    2010-02-15

    The application of NEUTREC {sup registered} technology - desulphurisation by means of sodium bicarbonate - has been tested at the Trebovice coal-fired power plant (Ostrava, Czech Republic). This technology significantly influences the chemical composition of fly ash and the leachability of total dissolved substances (TDS), e.g., sulphates, fluorides and oxyanions (Se, Sb, Cr, As), which are monitored according to the Council of the European Union Decision 2003/33/EC. An increase of TDS in the water leachate from the fly ash obtained at 60% desulphurisation was influenced by sodium content, which is present in the form of Na{sup +} ions (85-90%). The percentages of sodium sulphate and sodium carbonate were between 5 and 10% of the total sodium content. In order to decrease the leachability of TDS, sodium, sulphates and oxyanion mixtures were prepared containing a sorbent (60% bentonite) and mixed with desulphurised and non-desulphurised fly ash in various ratios. The addition of CaO resulted in the formation of a new mineral phase, burkeite. None of the applied technologies tested for the processed fly ash resulted in the preparation of a water leachate which complied in all monitored parameters to the requirements of Council Decision 2003/33 EC for nonhazardous wastes. (author)

  18. [An FTIR and XPS study of immobilization of chromium with fly ash based geopolymers].

    Science.gov (United States)

    Liu, Si-Feng; Wang, Pei-Ming; Li, Zong-Jin; Lo, Irene M C

    2008-01-01

    Immobilization of Cr3+ with fly ash geopolymers was investigated by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopic (XPS) techniques. The chromium sludge, as Cr(OH)3, was prepared with chemical precipitation method. The amounts of aluminum and silicon leached before and after the chromium sludge addition were measured using ICP-AES. The results suggested that the amounts of silicon and aluminum leached were reduced for the fly ash geopolymers after chromium sludge was incorporated. The decrease of silicon leaching was more pronounced than aluminum. FTIR results showed that the intensity of the main peak shifted into lower and the wave number of Si--O--Si and Al--O--Si became higher. The XPS results indicated that the O(1s) bind energy decreased, Si(2p) and Cr(2p) bind energy increased, while Al(2p) bind energy remained unchanged due to Cr3+ addition. It was also confirmed that the chromium is easily incorporated into the fly ash geopolymers paste, and polymerized with silicate units. The immobilization of Cr3+ using fly ash geopolymers is attributed not only to physical encapsulation, but also to chemical reaction.

  19. NaOH-activated ground fly ash geopolymer cured at ambient temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kiatsuda Somna; Chai Jaturapitakkul; Puangrat Kajitvichyanukul; Prinya Chindaprasirt [King Mongkut' s University of Technology Thonburi, Bangkok (Thailand). Department of Environmental Engineering

    2011-06-15

    NaOH-activated ground fly ash geopolymers, cured at room temperature, were studied in this paper. Ground fly ash (GFA), with a median particle size of 10.5 {mu}m, was used as source material. NaOH concentrations of 4.5-16.5 M (M) were used as an alkali activator. Compressive strength tests and microstructure observations using SEM, EDX, XRD and FTIR were performed. Results indicated that GFA gave higher strength geopolymer paste compared to original fly ash. Ground fly ash could be used as a source material for making geopolymers cured at room temperature. An increase in NaOH concentration from 4.5 to 14.0 M increased the strength of GFA geopolymer pastes. Microstructure studies indicated that NaOH concentrations of 12.0-14.0 M created new crystalline products of sodium aluminosilicate. The compressive strengths at 28 days of 20.0-23.0 MPa were obtained with the NaOH concentrations of 9.5-14.0 M. Increasing the NaOH concentration beyond this point resulted in a decrease in the strength of the paste due to early precipitation of aluminosilicate products. 26 refs., 7 figs., 4 tabs.

  20. Synthesis of inorganic polymers using fly ash and primary lead slag.

    Science.gov (United States)

    Onisei, S; Pontikes, Y; Van Gerven, T; Angelopoulos, G N; Velea, T; Predica, V; Moldovan, P

    2012-02-29

    The present work reports on the synthesis and properties of inorganic polymers ("geopolymers") made of 100% fly ash from lignite's combustion, 100% primary lead slag and mixtures of the two. In the inorganic polymers with both fly ash and lead slag the main crystalline phases detected are wüstite, magnetite, sodium zinc silicate, quartz, anorthite, and gehlenite; litharge partially dissolves. FTIR analysis in these samples revealed that the main peaks and bands of end members also exist, along with a new amorphous reaction product. In terms of microstructure, both fly ash and lead slag dissolve and contribute in the binding phase whereas the larger particles act as aggregates. For an increasing lead slag in the composition, the binding phase is changing in chemistry and reaches PbO values higher than 50 wt.% for the 100% lead slag inorganic polymer. Regarding the properties of fly ash and lead slag inorganic polymers, compressive strength is higher than 35 MPa in all cases and water absorption diminishes as the lead slag content increases. A comparison of leaching results before and after polymerisation reveals that pH is an important factor as Pb is immobilised in the binding phase, unlike Zn and As. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Fresh properties and compressive strength of high calcium alkali activated fly ash mortar

    Directory of Open Access Journals (Sweden)

    Eslam Gomaa

    2017-10-01

    Full Text Available This paper reports the fresh properties and compressive strength of high calcium alkali-activated fly ash (AAFA mortar. Two different sources of class C fly ash, with different chemical compositions were used to prepare alkali-activated mortar mixtures. Four different sodium silicate to sodium hydroxide (SS/SH ratios of 0.5, 1.0, 1.5, and 2.5 were used as alkaline activators with a constant sodium hydroxide concentration of 10 M. Two curing regimes were also applied, oven curing at 70 °C for 24 h, and ambient curing at 23 ± 2 °C. The rest time, i.e., the time between casting the mortar cubes and starting the oven curing was 2 h. The results revealed that the setting time, and workability of mortar decreased with increasing the alkali to fly ash ratio, and decreasing the water to fly ash ratio. The optimum sodium silicate to sodium hydroxide ratio was 1.0, which showed the highest compressive strength and setting time. An increase of sodium silicate to sodium hydroxide ratio to 2.5 led to a significant reduction in the setting time, and workability of mortar. The 7-day compressive strength of the mortar approached 20.80 MPa for ambient cured regime and 41.10 for oven cured regime.

  2. Evaluation of leaching and ecotoxicological properties of sewage sludge-fly ash mixtures

    Energy Technology Data Exchange (ETDEWEB)

    C.A. Papadimitriou; I. Haritou; P. Samaras; A.I. Zouboulis [Technological Educational Institute of West Macedonia, Kozani (Greece)

    2008-03-15

    The objectives of this work were the evaluation of sewage sludge stabilization by mixing with fly ash, the examination of the physicochemical properties of the produced materials and their leachates and the assessment of their environmental impact by the evaluation of the ecotoxic characteristics. Different ratios of fly ash and sewage sludge (1:1, 1:2, 1:3, 1:6, and 1:9) were mixed for 48 and 72 h. After mixing, the liquid phase of the produced materials was analyzed for total coliforms and Escherichia coli, while the solid residue was dried and tested for the leaching characteristics by the application of TCLP and EN 12457-2 standard leaching methods. Furthermore, the produced leachates were analyzed for their content of specific metals, while their ecotoxicological characteristics were determined by the use of toxicity bioassays, using the marine photobacterium Vibrio fischeri and the crustacean Daphnia magna. The phytotoxicity of sewage sludge-fly ash mixtures was also determined by utilizing seeds of three higher plants (one monocotyl and two dicotyls). The mixtures exhibited low metal leaching in all cases, while the ecotoxic properties increased with the increase of fly ash/sewage sludge ratio. The phytotoxicity testing showed increased root length growth inhibition.

  3. Characterization of boron tolerant bacteria isolated from a fly ash dumping site for bacterial boron remediation.

    Science.gov (United States)

    Edward Raja, Chellaiah; Omine, Kiyoshi

    2013-08-01

    Boron is an essential micronutrient for plants, but can above certain concentrations be toxic to living organisms. A major environmental concern is the removal of boron from contaminated water and fly ash. For this purpose, the samples were collected from a fly ash dumping site, Nagasaki prefecture, Japan. The chemical characteristics and heavy metal concentration of the samples were performed by X-ray fluorescent analysis and leaching test. For bacterial analysis, samples were collected in sterile plastic sheets and isolation was carried out by serial dilution method. The boron tolerant isolates that showed values of maximum inhibitory concentration toward boron ranging from 100 to 260 mM level were screened. Based on 16S rRNA sequencing and phylogenetic analysis, the isolates were most closely related to the genera Bacillus, Lysinibacillus, Microbacterium and Ralstonia. The boron tolerance of these strains was also associated with resistant to several heavy metals, such as As (III), Cr (VI), Cd, Cu, Pb, Ni, Se (III) and Zn. Indeed, these strains were arsenic oxidizing bacteria confirmed by silver nitrate test. These strains exhibited their salt resistances ranging from 4 to 15 % were determined in Trypticase soy agar medium. The boron tolerant strains were capable of removing 0.1-2.0 and 2.7-3.7 mg l(-1) boron from the medium and fly ash at 168 h. Thus, we have successfully identified the boron tolerant and removal bacteria from a fly ash dumping site for boron remediation.

  4. Effect of Trona on the leaching of trace elements from coal fly ash.

    Science.gov (United States)

    2013-07-01

    Fly ashes were sampled from the ESPs by on-site contractors during air emission control tests. The injection tests were short-term, : lasting approximately three hours per test condition. EPRI received three batches of samples since November 2011, re...

  5. Hydrothermal conversion of South African coal fly ash into pure phase Zeolite Na-P1

    CSIR Research Space (South Africa)

    Gitari, MW

    2016-08-01

    Full Text Available South African coal combustion power utilities generate huge amounts of coal fly ash that can be beneficiated into zeolitic products. This chapter reports on the optimization of the presynthesis and synthesis conditions for a pure-phase zeolite Na-P1...

  6. Extraction and recovery of polycyclic aromatic hydrocarbons from highly sorptive matrices such as fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Griest, W. H.; Caton, J. E.; Guerin, M. R.; Yeatts, Jr., L. B.; Higgins, C. E.

    1979-01-01

    The highly sorptive nature of some potentially environmentally significant materials such as fly ash may seriously hinder quantitative extraction of their sorbed organic content. Radiolabeled tracers offer a convenient means of probing the sorptive nature of such matrices and of obtaining the corrections for extraction and handling recoveries which are necessary to quantitative analysis.

  7. The effect of low solid/liquid ratio on hydrothermal synthesis of zeolites from fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Tomasz T. Walek; Fumio Saito; Qiwu Zhang [Tohoku University, Sendai (Japan). Institute of Multidisciplinary Research for Advanced Materials

    2008-11-15

    Hydrothermal synthesis of zeolites from class F fly ash was carried out at solid/liquid (S/L) ratio of 4 g/dm{sup 3} to investigate the initial dissolution stage of the process. The low S/L ratio caused a significant increase in fly ash dissolution (up to 85 wt%) during first 4 h of reaction. It was shown that for S/L ratios typically used (50-150 g/dm{sup 3}) fly ash dissolution is largely limited. In these conditions zeolite crystals are formed on the surface of partially dissolved fly ash particles. This precludes further dissolution and results in formation of a low-crystallinity zeolite-like material. At low S/L ratio, a degree of crystallization of 80 wt% was observed, and NaP1, analcime and/or hydroxy-sodalite phases were obtained depending on the applied NaOH concentration and temperature. Single phase NaP1 zeolite was obtained in 2 M NaOH solution at temperature maintained at 104{sup o}C during the stage of dissolution and reduced to 80{sup o}C in the stage of crystallization. Application of low S/L ratio allows a clearer description of the relationships between the synthesis conditions and the products obtained. 40 refs., 9 figs., 2 tabs.

  8. Uses of -Fe 2 O 3 and fly ash as solid adsorbents

    Indian Academy of Sciences (India)

    particulate matter and as gas sensing devices in recent times. In the present study, adsorption of environmental toxic pollutant such as lead ions on solid adsorbents viz. -Fe2O3 and fly ash, are reported. Considerable adsorption was observed ...

  9. Designing of Multiphase Fly Ash/MWCNT/PU Composite Sheet Against Electromagnetic Environmental Pollution

    Science.gov (United States)

    Gujral, Parth; Varshney, Swati; Dhawan, S. K.

    2016-06-01

    Fly ash and multiwalled carbon nanotubes (MWCNT) reinforced multiphase polyurethane (PU) composite sheets have been fabricated by using a solution casting technique. Utilization of fly ash was the prime objective in order to reduce environmental pollution and to enhance the shielding properties of PU polymer. Our study proves that fly ash particles with MWCNTs in a PU matrix leads to novel hybrid high performance electromagnetic shielding interference material. Scanning electron microscopy confirms the existence of fly ash particles along with MWCNTs in a PU matrix. This multiphase composite shows total shielding effectiveness of 35.8 dB (>99.99% attenuation) in the Ku-band (12.4-18 GHz) frequency range. This is attributed to high dielectric losses of reinforcement present in the polymers matrix. The Nicolson-Ross-Weir algorithm has been applied to calculate the electromagnetic attributes and dielectric parameters of the PU samples by using scattering parameters ( S 11, S 22, S 12, S 21). The synthesized multiphase composites were further characterized by using x-ray diffraction, Fourier transform infrared spectroscopy, and thermo gravimetric analysis.

  10. PREPARATION AND PROPERTIES OF ALKALI-ACTIVATED CEMENT CONTAINING PHOSPHOROUS SLAG AND FLY ASH

    Directory of Open Access Journals (Sweden)

    Duo You

    2016-03-01

    Full Text Available Phosphorous slag is an industrial waste which potentially pollutes environments. The aim of the present work is to use phosphorous slag as a raw material to produce alkali-activated cement. The influence of mix proportion of phosphorous slag and fly ash, alkali content and modulus of water glass on the properties of alkali-activated phosphorous slag and fly ash cement (AA-PS-FA-C was studied. The results show that AA-PS-FA-C with normal setting performance and desirable mechanical properties can be prepared using water glass as the activator. Changing the fly ash content in the range of 0-40 wt% has only a small influence on the setting time of AA-PS-FA-C. The strengths significantly decrease when the fly ash content exceeds 30 wt%. The carbonation resistance of AA-PS-FA-C is similar to that of ordinary Portland cement (OPC, while the frost resistance is much better. The hardened paste of AA-PS-FA-C is much more compact than OPC paste.

  11. Reactivity of fly ash: extension and application of a shrinking core model

    NARCIS (Netherlands)

    Brouwers, Jos; van Eijk, R.J.

    2002-01-01

    In the present paper a theoretical study is presented on the dissolution (reaction) of pulverised powder coal fly ash. A shrinking core model is derived for hollow spheres that contain two regions (outer hull and inner region). The resulting analytical equations are applied to the dissolution

  12. Abu Terbang (Fly Ash Sebagai Bahan Tambah Untuk Meningkatkan Kuat Tekan Bata Beton (Paving Block

    Directory of Open Access Journals (Sweden)

    Gathot Heri Sudibyo

    2008-08-01

    Full Text Available This research was aimed to know the influence of fly ash addition at paving block stress strength. Variation of fly ash was 0%, 20%, 40%, 60%, and 80% from weight of cement with water cement ratio 0,25. The speciment was hexagonal and cube with the comparison 1 cement : 6 sand. The result showed that the stress strength of hexagonal paving block at 56 days with fly ash 20%, 40%, 60% and 80% was increase to 37,166% (7,057 MPa, 18,248% (3,465 MPa, 8.110% (1,54 MPa, and 14,193% (2,695 MPa. The cubic paving block at 56 days with fly ash 20%, 40%, 60% and 80% was increase to 35,932% (5,969 MPa,15,135% (2,514 MPa, 9,534% (1,584 MPa, and 8,318% (1,382 MPa.

  13. Effects of slag and fly ash in concrete in chloride environment

    NARCIS (Netherlands)

    Polder, R.B.

    2012-01-01

    This paper addresses experience from The Netherlands with blast furnace slag and fly ash in concrete in chloride contaminated environments, both from the field and the laboratory. Use of slag produced in The Netherlands started in the 1930s and CEM III/B LH HS, with typically 70% slag, became the

  14. Evidence of Coal-Fly-Ash Toxic Chemical Geoengineering in the Troposphere: Consequences for Public Health

    Directory of Open Access Journals (Sweden)

    J. Marvin Herndon

    2015-08-01

    Full Text Available The widespread, intentional and increasingly frequent chemical emplacement in the troposphere has gone unidentified and unremarked in the scientific literature for years. The author presents evidence that toxic coal combustion fly ash is the most likely aerosolized particulate sprayed by tanker-jets for geoengineering, weather-modification and climate-modification purposes and describes some of the multifold consequences on public health. Two methods are employed: (1 Comparison of 8 elements analyzed in rainwater, leached from aerosolized particulates, with corresponding elements leached into water from coal fly ash in published laboratory experiments, and (2 Comparison of 14 elements analyzed in dust collected outdoors on a high-efficiency particulate air (HEPA filter with corresponding elements analyzed in un-leached coal fly ash material. The results show: (1 the assemblage of elements in rainwater and in the corresponding experimental leachate are essentially identical. At a 99% confidence interval, they have identical means (T-test and identical variances (F-test; and (2 the assemblage of elements in the HEPA dust and in the corresponding average un-leached coal fly ash are likewise essentially identical. The consequences on public health are profound, including exposure to a variety of toxic heavy metals, radioactive elements, and neurologically-implicated chemically mobile aluminum released by body moisture in situ after inhalation or through transdermal induction.

  15. Fly ash-amended compost as a manure for agricultural crops

    Energy Technology Data Exchange (ETDEWEB)

    Menon, M.P.; Sajwan, K.S.; Ghuman, G.S.; James, J.; Chandra, K. (Savannah State College, GA (United States))

    1993-11-01

    Homemade organic compost prepared from lawn grass clippings was amended with fine fly ash collected from a coal-fired power plant (SRS 484.D. Savannah River Site, Aiken, SC) to investigate its usefulness as a manure in enhancing nutrient uptake and increasing dry matter yield in selected agricultural crops. Three treatments were compared: five crops (mustard, collard, string beans, bell pepper, and eggplant) were each grown on three kinds of soil: soil alone, soil amended with composted grass clippings, and soil amended with the mixed compost of grass clippings and 20% fly ash. The fly ash-amended compost was found to be effective in enhancing the dry matter yield of collard greens and mustard greens by 378% and 348%, respectively, but string beans, bell pepper, and eggplant did not show any significant increase in dry matter yield. Analysis of the above-ground biomass of these last three plants showed they assimilated high levels of boron, which is phytotoxic; and this may be the reason for their poor growth. Soils treated with fly ash-amended compost often gave higher concentrations than the control for K, Ca, Mg, S, Zn, and B in the Brassica crops. 18 refs., 2 figs., 5 tabs.

  16. Removal of Mn from aqueous solution using fly ash and its hydrothermal synthetic zeolite.

    Science.gov (United States)

    Belviso, Claudia; Cavalcante, Francesco; Di Gennaro, Spartaco; Lettino, Antonio; Palma, Achille; Ragone, Pietro; Fiore, Saverio

    2014-05-01

    A number of water purification processes have been developed in recent years based on the utilisation of low-cost materials with high pollutant removal efficiency. Among these materials, fly ash and zeolite synthesised from fly ash are two examples of high-efficiency adsorbents. Column absorption tests were performed in order to compare the manganese sorption behaviour of an Italian coal fly ash and zeolite synthesised from it. Different masses of both materials (10-60 g) were exposed to solutions containing a total metal concentration of 10 mg/L. Batch adsorption studies were also conducted to determine the effect of time on the removal on Mn sequestration. The results indicate that both materials are effective for the removal of Mn from aqueous solution by precipitation due to the high pH of the solid/liquid mixtures. However, the leaching tests reveal that the amount of Mn removed from the fly ash was greater than that leached from the zeolite, thereby indicating that the metal is partially sequestrated by zeolite. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Hydrophobic high surface area zeolites derived from fly ash for oil spill remediation.

    Science.gov (United States)

    Sakthivel, Tamilselvan; Reid, David L; Goldstein, Ian; Hench, Larry; Seal, Sudipta

    2013-06-04

    Fly ash, a coal combustion byproduct with a predominantly aluminosilicate composition, is modified to develop an inexpensive sorbent for oil spill remediation. The as-produced fly ash is a hydrophilic material with poor sorption capacity. A simple two-step chemical modification process is designed to improve the oil sorption capacity. First, the fly ash was transformed to a zeolitic material via an alkali treatment, which increased the specific surface area up to 404 m(2) g(-1). Then, the material was surface functionalized to form a hydrophobic material with high contact angle up to 147° that floats on the surface of an oil-water mixture. The reported oil sorption capacities of X-type zeolite sorbent with different surface functionalization (propyl-, octyl-, octadecyl-trimethoxysilane and esterification) were estimated to 1.10, 1.02, 0.86, and 1.15 g g(-1), respectively. Oil sorption was about five times higher than the as-received fly ash (0.19 g g(-1)) and also had high buoyancy critical for economic cleanup of oil over water.

  18. Mechanically activated fly ash as a high performance binder for civil engineering

    Science.gov (United States)

    Rieger, D.; Kullová, L.; Čekalová, M.; Novotný, P.; Pola, M.

    2017-01-01

    This study is aimed for investigation of fly ash binder with suitable properties for civil engineering needs. The fly ash from Czech brown coal power plant Prunerov II was used and mechanically activated to achieve suitable particle size for alkaline activation of hardening process. This process is driven by dissolution of aluminosilicate content of fly ash and by subsequent development of inorganic polymeric network called geopolymer. Hardening kinetics at 25 and 30 °C were measured by strain controlled small amplitude oscillatory rheometry with strain of 0.01 % and microstructure of hardened binder was evaluated by scanning electron microscopy. Strength development of hardened binder was investigated according to compressional and flexural strength for a period of 180 days. Our investigation finds out, that mechanically activated fly ash can be comparable to metakaolin geopolymers, according to setting time and mechanical parameters even at room temperature curing. Moreover, on the bases of long time strength development, achieved compressional strength of 134.5 after 180 days is comparable to performance of high grade Portland cement concretes.

  19. Effects of sodium hydroxide (NaOH) solution concentration on fly ash-based lightweight geopolymer

    Science.gov (United States)

    Ibrahim, W. M. W.; Hussin, K.; Abdullah, M. M. A.; Kadir, A. A.; Deraman, L. M.

    2017-09-01

    In this study, the effects of NaOH concentration on properties of fly ash-based lightweight geopolymer were investigated. Lightweight geopolymer was produced using fly ash as source materials and synthetic foaming agents as air entraining agent. The alkaline solutions used in this study are combination of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) solution. Different molarities of NaOH solution (6M, 8M, 10M, 12M, and 14M) are taken for preparation of 50 x 50 x 50 mm cubes of lightweight geopolymer. The ratio of fly ash/alkaline solution, Na2SiO3/NaOH solution, foaming agent/water and foam/geopolymer paste were kept constant at 2.0, 2.5, 1:10 and 1:1 respectively. The samples were cured at 80°C for 24 hours and left at room temperature for tested at 7 days of ageing. Physical and mechanical properties such as density, water absorption, compressive strength and microstructure property were determined from the cube dried samples. The results show that the NaOH molarity had effects on the properties of lightweight geopolymer with the optimum NaOH molarity found is 12M due to the high strength of 15.6 MPa, lower water absorption (7.3%) and low density (1440 kg/m3). Microstructure analysis shows that the lightweight geopolymer contain some porous structure and unreacted fly ash particles remains.

  20. Optimization of activator solution and heat treatment of ground lignite type fly ash geopolymers

    Science.gov (United States)

    Molnár, Z.; Szabó, R.; Rácz, Á.; Lakatos, J.; Debreczeni, Á.; Mucsi, G.

    2017-02-01

    Geopolymers are inorganic polymers which can be produced by the reaction between silico aluminate oxides and alkali silicates in alkaline medium. Materialscontaining silica and alumina compounds are suitable for geopolymer production. These can beprimary materials or industrial wastes, i. e. fly ash, metallurgical slag and red mud. In this paper, the results of the systematic experimental series are presented which were carried out in order to optimize the geopolymer preparation process. Fly ash was ground for different residence time (0, 5, 10, 30, 60 min) in order to investigate the optimal specific surface area. NaOH activator solution concentration also varied (6, 8, 10, 12, 14 M). Furthermore, sodium silicate was added to NaOH as a network builder solution. In this last serie different heat curing temperatures (30, 60, 90°C) were also applied. After seven days of ageing the physical properties of the geopolymer(compressive strength and specimen density)were measured. Chemical leaching tests on the rawmaterial and the geopolymers were carried out to determine the elements which can be mobilized by different leaching solutions. It was found that the above mentioned parameters (fly ash fineness, molar concentration and composition of activator solution, heat curing) has great effect on the physical and chemical properties of geopolymer specimens. Optimal conditions were as follows: specific surface area of the fly ash above 2000 cm2/g, 10 M NaOH, 30°C heat curing temperature which resulted in 21 MPa compressive strength geopolymer.

  1. Microstructural and Mineralogical Analysis of Alkali Activated Fly Ash-Slag Pastes

    NARCIS (Netherlands)

    Nedeljkovic, M.; Arbi Ghanmi, K.; Zuo, Y.; Ye, G.; Miao, Changwen; Sun, Wei; Liu, Jiaping; Chen, Huisu; Ye, Guang; van Breugel, Klaas

    2016-01-01

    The performances of alkali activated materials (AAM) are strongly related to their microstructures. The microstructure development is mainly affected by chemistry of the primary raw materials. In the present study the influence of different proportions of fly ash and slag (100:0, 70:30, 50:50,

  2. Mössbauer, XRD, and Complex Thermal Analysis of the Hydration of Cement with Fly Ash

    Directory of Open Access Journals (Sweden)

    Vili Lilkov

    2013-01-01

    Full Text Available Hydration of cement with and without fly ash is studied with Mössbauer spectroscopy, XRD, and thermal analysis. Iron in cement is present as Fe3+-ions and occupies two octahedral positions, with close isomer shifts and quadrupole splittings. Iron in fly ash is present as Fe2+ and Fe3+, and the Mössbauer spectra display three doublets—two for Fe3+ in octahedral coordination and one for Fe2+. A third doublet was registered in the hydrating plain cement pastes after the 5th day, due to Fe3+ in tetrahedral coordination in the structure of the newly formed monosulphate aluminate. In cement pastes with fly ash, the doublet of tetrahedral iron is formed earlier because the quantity of ettringite and portlandite is low and more monosulphate crystallizes. No Fe(OH3 phase forms during hydration of C4AF. The fly ash displays pozzolanic properties, which lead to lowering of the portlandite quantity in the cement mixtures and increasing of the high temperature products.

  3. Alkali-activated fly ash. Relationship between mechanical strength gains and initial ash chemistry

    Directory of Open Access Journals (Sweden)

    Palomo, A.

    2008-09-01

    Full Text Available Alkali-activated fly ash is the primary component of a new generation of high-strength, durable binders with excellent mechanical properties and durability (on occasion bettering traditional Portland cement performance. Moreover, development of these cements may contribute to mitigating CO2 emissions, since the base material is an industrial by-product. The present study was conducted to determine the effect of the composition of the initial materials (SiO2/Al2O3 and Na2O/Al2O3 ratios on the mechanical properties, nature and composition of the reaction products. The results obtained indicate that there is no linear relationship between these ratios and mechanical strength, but rather a series of optimal values above and below which strength declines. In the specific case of the ratios studied in the present paper, these values were: SiO2/Al2O3= 4.0 and Na2O/Al2O3= 1.0 (molar ratios.Las cenizas volantes activadas alcalinamente constituyen la base de una nueva generación de cementos con muy interesantes propiedades mecánicas, adherentes y durables (a veces incluso mejores que las de los cementos Portland tradicionales. Adicionalmente el desarrollo de estos cementos podría contribuir a mitigar las emisiones de CO2 a la atmósfera, ya que el material base de los mismos puede estar formado por subproductos industriales. En la presente investigación se realizó un estudio para determinar la influencia de la composición de los materiales iniciales (ratios SiO2/Al2O3 y Na2O/Al2O3 en las propiedades mecánicas y en la naturaleza y composición de los productos de reacción. Los resultados obtenidos indican que no existe una relación lineal de dichas ratios con las resistencias mecánicas, sino que existen unos valores óptimos, por encima y debajo de los cuales las resistencias mecánicas disminuyen. En el caso concreto de las ratios estudiadas en el presente trabajo estos valores serian: SiO2/Al2O3= 4,0 y Na2O/Al2O3= 1,0 (relaciones molares

  4. Sorption and chemical transformation of PAHs on coal fly ash. Technical progress report No. 1, [October--December 1991

    Energy Technology Data Exchange (ETDEWEB)

    Mamantov, G.; Wehry, E.L.

    1991-12-31

    The objective of this research is to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. Studies to be carried out in this project include: (1) Fractionation of heterogeneous coal fly ash samples into different particle types varying in size and chemical composition (carbonaceous, mineral-magnetic, and mineral nonmagnetic); (2) Measurement of the rates of chemical transformation of PAHs and PAH derivatives (especially nitro-PAHs) and the manner in which the rates of such processes are influenced by the chemical and physical properties of coal fly ash particles; (3) Chromatographic and spectroscopic studies of the nature of the interactions of coal fly ash particles with PAHs and PAH derivatives; (4) Characterization of the fractal nature of fly ash particles (via surface area measurements) and the relationships of ``surface roughness`` of fly ash particles to the chemical behavior of PAHs sorbed on coal ash particles; (5) Identification of the major products of chemical transformation of PAHs on coal ash particles, and examination of any effects that may exist of the nature of the coal ash surface on the identities of PAH transformation products; and (6) Studies of the influence of other sorbed species on the chemical behavior of PAHs and PAH derivatives on fly ash surfaces. PAHs are deposited, under controlled laboratory conditions, onto coal ash surfaces from the vapor phase, in order to mimic the processes by which PAHs are deposited onto particulate matter in the atmosphere.

  5. Radiological significance of coal, slag and fly ash samples from the Eastern Black Sea region

    Energy Technology Data Exchange (ETDEWEB)

    Damla, Nevzat [Batman Univ. (Turkey). Dept. of Physics; Cevik, Ugur [Karadeniz Technical Univ., Trabzon (Turkey). Dept. of Physics; Kara, Ayhan [Osmaniye Korkut Ata Univ. (Turkey). Dept. of Physics

    2012-11-15

    This work presents a study of natural radioactivity levels in coal and its combustion residues (fly ash and slag) used in the houses in Black Sea Region, Turkey. Coal, fly ash and slag samples were provided from different locations of the region and analyzed by gamma spectroscopy using a high-purity germanium detector (HPGe). Also, chemical analyses of these samples were carried out using energy dispersive X-ray fluorescence spectrometer. The mean {sup 226}Ra activity concentrations in coal, slag and fly ash were measured as 83, 99 and 38 Bq kg{sup -1}, respectively. The mean {sup 232}Th activity concentrations in coal, slag and fly ash were measured as 108, 113 and 50 Bq kg{sup -1}, respectively. The mean {sup 40}K activity concentrations in coal, slag and fly ash were found to be 366, 381 and 204 Bq kg{sup -1}, respectively. The potential radiological hazards associated to these materials were evaluated by calculating the radium equivalent activity (Ra{sub eq}), the air absorbed gamma dose rate (D), the annual effective dose rate (AED), the external hazard index (H{sub ex}) and internal hazard index (H{sub in}) and compared with the internationally accepted or reference values. The mean Ra{sub eq} values of the coal, fly ash and slag samples were lower than the recommended maximum values 370 Bq kg{sup -1} by the Organization for Economic Cooperation and Development (OECD). The overall mean outdoor terrestrial gamma air absorbed dose rate in coal, fly ash and slag samples are 119, 129 and 62 nGy h{sup -1} and the corresponding outdoor annual effective doses are 0.60, 0.32 and 0.64 mSv y{sup -1}, which is higher than the worldwide average (0.07 mSv y{sup -1}), respectively. Moreover, the enrichment factors relative to the input coal are calculated for the radionuclide contents observed. Calculated enrichment factor values for {sup 226}Ra and {sup 232}Th were found 1.14 and 1.01, respectively. (orig.)

  6. Fly ash leachate generation and qualitative trends at Ohio test sites

    Energy Technology Data Exchange (ETDEWEB)

    Solc, J.; Foster, H.J.; Butler, R.D. [Energy & Environmental Research Center, Grand Forks, ND (United States)

    1995-12-01

    Under the sponsorship of the U.S. Department of Energy, the environmental impact and potential contamination from landfilled fly ash (coal conversion solid residues - CCSRs) have been studied at field sites in Ohio. The progressive increase of moisture content within pilot cells over depth and time facilitated intensive chemical processes and generation of highly alkaline (pH of 10 to 12) leachate. Chemistry of pore water from lys