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Abstract

Geopolymers are a new class of materials that can be synthesized using natural minerals, and waste materials. Among these substrates, the use of fly ash is desirable as it involves the conversion of a copious waste material into a useful product. The aim of the research was geopolymers synthesis from coal fly ash and biomass ash. Concentrated sodium hydroxide and sodium silicate solutions were used as activators in geopolymerisation reaction. The results show that both coal fly ash and biomass ash can be utilized as source materials for the production of geopolymers. The surface morphology and chemical composition analysis were examined for the obtained geopolymers and ashes from coal and biomass combustion by SEM-EDS methods. It was found almost total disappearance of spherical forms of grains and reduction the porosity of structure for geopolymer based on fly ash from coal combustion. While the structure of the geopolymer based ash from biomass combustion is more porous. The UV-VIS-NIR spectra were performed on the coal fly ash, biomass ash and geopolymers. They showed that the obtained geopolymers possess optical and photocatalytic properties. The similarity of the geopolymer network and the zeolite framework in relation to ion exchange and accommodation of metal ions open questions on possibilities for the application of geopolymer materials as amorphous analogues of zeolite. The FT-IR spectra analyses were used on the geopolymers before and after metals sorption. It was found that geopolymer based on ash from biomass combustion has better sorption properties compared to geopolymer based on ash from coal combustion.

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Authors and Affiliations

Elżbieta Sitarz-Palczak
Jan Kalembkiewicz
Dagmara Galas
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Abstract

Strength and permeability properties along with microstructural evolution of hardened slurries composed of fly ash from fluidal bed combustion of brown coal and an addition of OPC/BFSC is assessed in this paper. An increase in the amount of fly ash in slurries influences the development of mechanical strength and a decrease of hydraulic conductivity. SEM, XRD, and porosity analyses confirmed formation of watertight microstructures. The structure of slurries is composed of ettringite, C-S-H phase, AFt, and AFm phases. Ettringite crystallises as relatively short needles forming compact clusters or intermixed with the C-S-H phase. The occurring C-S-H phases are mainly of type I – fibrous and type II – honeycomb

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Authors and Affiliations

Z. Kledyński
P. Falaciński
A. Machowska
J. Dyczek
Ł. Kotwica
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Abstract

The article concerns fly ashes generated from the combustion of hard coal and deposited on landfills. Investigation results describing fly ash taken from a combustion waste landfill are presented in the article. The investigation results indicate a possibility for combusting the coal reclaimed by separation from the fly ash and utilizing the remaining fly ash fractions.

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Authors and Affiliations

Aleksandra Sambor
Arkadiusz Szymanek
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Abstract

Due to the fact that the landfill deposition of municipal waste with the higher heating value (HHV) than 6 MJ/kg in Poland is prohibited, the application of waste derived fuels for energy production seems to be good option. There is a new combined-heat-and-power (CHP) plant in Zabrze, where varied solid fuels can be combusted. The formation of ashes originating from the combustion of alternative fuels causes a need to find ways for their practical application and demands the knowledge about their properties. Therefore, the present work is devoted to studying the co-combustion of solid recovered fuel (SRF) and coal, its impact on fly ash quality and the potential application of ashes to synthesis zeolites. The major objectives of this paper is to present the detail characteristics of ash generated during this process by using the advanced instrumental techniques (XRF, XRD, SEM, B ET, TGA). The co-combustion were carried out at 0.1 MWth fluidized bed combustor. The amount of SRF in fuel mixture was 1, 5, 10 and 20%, respectively. The focus is on the comparison the ashes depending on the fuel mixture composition. Generally, the ashes characterise high amounts of SiO2, Al2O3 and Fe2O3. It is well observed, that the chemical composition of ashes from co-combustion of blends reflects the amount of SRF addition. Considering the chemical composition of studied ashes, they can be utilize as a zeolites A. The main conclusions is that SRF can be successfully combusted with coal in CFB technology and the fly ashes obtained from coal + SRF fuel mixtures can be used to synthesis zeolites.
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Authors and Affiliations

Aleksandra Ściubidło
Wojciech Nowak
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Abstract

One of the elements of the Polish Energy Policy program is the development of renewable energy, including energy from biomass combustion. In Poland, the Green Block was built at the Połaniec Power Station fired with 100% biomass fuel. This solution is conducive not only to obtaining energy but also to improving environmental protection. During the combustion of biomass in a fluidized bed boiler, about 50 thousand tons of fly ash per year being a source of nutrients for plants, for example potassium salts, phosphorus, calcium, boron compounds, etc. was derived. The subject of the research were three types of ashes from biomass combustion containing 80% dendromass and 20% agromass. Agromas was made of straw, dried material or sliced palm nuts. The physical characteristics and chemical composition of three basic fly ash samples are presented. Due to the high fineness and thus dusting during spreading, it was found that there is no possibility of the direct use of fly ash from biomass combustion as an alkalizing agent for acidic soils. The lowest bulk density was demonstrated by samples of fly ash originating from the combustion of biomass containing 20% straw as agromass, while the poorest in potassium and phosphorus were ash samples obtained from the combustion of biomass containing 20% agromass in the form of palm kernel slate. As additional components, mineral acids as well as inorganic compounds, including industrial waste, were used to correct the chemical composition and to mineral fertilizer granulation. The number of introduced components was related to the postulated composition of the produced fertilizer. Examples of mineral fertilizers obtained, both simple and multicomponent fertilizers, are presented.

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Authors and Affiliations

Sylwester Eugeniusz Żelazny
Andrzej Jarosiński
Keywords fly ash REE leaching
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Abstract

The aim of the work was to draw attention to the usefulness of the alkaline thermal activation process with sodium hydroxide in the process of rare earth metal leaching (REE), from fly ash with hydrochloric acid and nitric acid(V). The work is a part of the authors’ own research aimed at optimizing the REE recovery process coming from fly ash from hard coal combustion.

The article contains an assessment of the possibility of leaching rare earth metals (REE) from fly ash originating from the combustion of hard coal in one of the Polish power plants. The process was carried out for various samples consisting of fly ash and sodium hydroxide and for different temperatures and reaction times. The process was carried out for samples consisting of fly ash and sodium hydroxide containing respectively 10, 20 and 30% on NaOH by weight in relation to the weight of fly ash. Homogenization of these mixtures was carried out wet, and then they were baked at 408K, 433K and 473K, for a period of three hours. The mixture thus obtained was ground to a particle size of less than 0.1 mm and washed with hot water to remove excessive NaOH. The solid post-reaction residue was digested in concentrated HCl at 373K for 1 hour at a weight ratio fs/fc of 1:10. The results of chemical analysis and scanning microscopic analysis along with EDS analysis and X-ray analysis were used to characterize the physicochemical properties of the tested material.

The results indicated that REE recovery from fly ash strictly depends on heat treatment temperature with NaOH, and an increase in REE recovery from alkaline-activated fly ash along with increasing the amount of NaOH in relation to fly ash mass.

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Authors and Affiliations

Sylwester Żelazny
Henryk Świnder
ORCID: ORCID
Andrzej Jarosiński
Barbara Białecka
ORCID: ORCID
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Abstract

The galvanic sludges contain a number of toxic heavy metals, potentially mobilized as chemically active ions under environmental conditions as. This study explores the application of fly ash-based geopolymers for the removal of Zn ions from galvanizing sludge. In this study, geopolymers, synthesized via the geopolymerization method, were used to remove Zn from post-galvanized sewage sludge. Two types of geopolymers were used, derived from ash from coal combustion and biomass combustion. Structural, morphological, and surface properties were characterized using FTIR and SEM, respectively. In addition, BET and Langmuir isotherms, along with analyses such as t-Plot and BJH method for porous solids were conducted. The results indicate that the geopolymer derived from coal combustion ash is a more effective sorbent for Zn(II) ions, exhibiting a removal efficiency of 99.9%, compared to 40.7% for the geopolymer derived from biomass combustion ash. The FTIR spectra analysis reveals the presence of bonds between the -OH and/or Si-OH groups on the geopolymers’ surface and the Zn(II) ions. The environmentally and economically advantageous process maximizes the recovery of a valuable component at minimal cost, yielding relatively clean monometallic waste suitable for reuse.
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Bibliography

[1]. Adewuyi, YG. (2021). Recent Advances in Fly-Ash-Based Geopolymers: Potential on the Utilization for Sustainable Environmental Remediation, ACS Omega, 24, pp. 15532-15542. DOI:10.1021/acsomega.1c00662
[2]. Akono, A.T., Koric, S. & Kriven, W.M. (2019). Influence of pore structure on the strength behavior of particle- and fiber reinforced metakaolin-based geopolymer composites, Cement and Concrete Composites, 104, pp. 103361. DOI:10.1016/j.cemconcomp.2019.103361
[3]. Alehyen, S., Zerzouri, M., el Alouani, M., el Achouri, M. & Taibi M. (2017). Porosity and fire resistance of fly ash based geopolymer. Journal of Materials and Environmental Sciences, 8, pp. 3676-3689
[4]. Ayilara, M.S., Olanrewaju, O.S., Babalola, O.O. & Odeyemi, O. (2020). Waste management through composition: Challenges and Potentials, Sustainability, 12, pp. 4456-4479. DOI:10.3390/su12114456
[5]. Barakat, M.A. (2003). The pyrometallurgical processing of galvanizing zinc ash and flue dust, Journal of Minerals, Metals & Materials Society, 55, pp. 26–29. DOI:10.1007/s11837-003-0100-4
[6]. Bednarik, M., Vondruska, M.& Koutny, M. (2005). Stabilization/solidification of galvanic sludges by asphalt emulsions, Journal of Hazardous Materials, 122, pp. 139-145. DOI:10.1016/j.jhazmat.2005.03.021
[7]. Brylewska, K., Rożek, P., Król, M. & Mozgawa, W. (2018). The influence of dealumination/desilication on structural properties of metakaolin-based geopolymers, Ceramics International, 44, pp. 12853-12861. DOI:10.1016/J.CERAMINT.2018.04.095
[8]. Butenegro, J.A., Bahrami, M., Abenojar, J. & Martínez, M.A. (2021). Recent Progress in Carbon Fiber Reinforced Polymers Recycling: A Review of Recycling Methods and Reuse of Carbon Fibers, Materials, 14, pp. 6401. DOI:10.3390/ma14216401
[9]. Donohue, M.D. & Aranovich, G.L. (1998). Adsorption hysteresis in porous solids, Journal of Colloid and Interface Science, 205, pp. 121-130. DOI:10.1006/jcis.1998.5639
[10]. Dvořák, P. & Jandova, J. (2005). Hydrometallurgical recovery of zinc from hot dip galvanizing ash, Hydrometallurgy, 77, pp. 29-33. DOI:10.1016/j.hydromet.2004.10.007
[11]. Galas, D., Kalembkiewicz, J. & Sitarz-Palczak, E. (2016). Physicochemistry, morphology and leachability of selected metals from post-galvanized sewage sludge from screw factory in Łańcut, SE Poland, Contemporary Trends in Geoscience, 5, pp. 83-91. DOI:10.1515/ctg-2016-0006
[12]. Jha, M.K., Kumar, V.& Singh R.J. (2001). Review of hydrometallurgical recovery of zinc from industrial wastes, Resources, Conservation and Recycling, 33, pp. 1-22. DOI:10.1016/S0921-3449(00)00095-1
[13]. Imtiaz, L., Rehman, S.K.U., Memon, S.A., Khan, M.K. & Javed, M.F. (2020). A review of recent developments and advances in eco-friendly geopolymer concrete, Applied Sciences, 10, pp. 7838-7894. DOI:10.3390/app10217838
[14]. Irisawa, T., Iwamura, R., Kozawa, Y., Kobayashi, S. & Tanabe, Y. (2021). Recycling methods for thermoplastic-matrix composites having high thermal stability in focusing on reuse of the carbon fibers, Carbon, 175, pp. 605. DOI:10.1016/j.carbon.2021.01.042
[15]. Jeyasundar, P.G.S.A., Ali, A. & Zhang, Z. (2020). Waste treatment approaches for environmental sustainability, Microorganisms for Sustainable Environmental and Health, 6, pp. 119-135. DOI:10.1016/B978-0-12-819001-2.00006-1
[16]. Khan, M.N.N., Kuri, J.C. & Sarker, P.K. (2021). Effect of waste glass powder as a partial precursor in ambient cured alkali activated fly ash and fly ash-GGBFS mortars, Journal of Building. Engineering, 34, pp. 101934-101945. DOI:10.1016/j.conbuildmat.2020.120177
[17]. Kriven W.M., Bell J.L. & Gordon M. (2006). Microstructure and Microchemistry of Fully-Reacted Geopolymers and Geopolymer Matrix Composites. In: Bansal, N.P., Singh, J.P., Kriven, W.M., Schneider, H., Advances in Ceramic Matrix Composites IX (pp. 227-250). The American Ceramic Society, Wiley, New York 2006.
[18]. Krishnan, S., Zulkapli, N.S., Kamyab, H., Taib, S.M., Bin Md Din, M.F., Majid, Z.A., Chaiprapat, S., Kenzo, I., Ichikawa, Y., Nasrullah, M., Chelliapan, S. & Othman, N. (2021). Current technologies for recovery of metals from industrial wastes: An overview, Environmental Technology & Innovation, 22, pp.101525. DOI:10.1016/j.eti.2021.101525
[19]. Król, M., Rożek, P., Chlebda ,D. & Mozgawa, W. (2018). Influence of alkali metal cations/type of activator on the structure of alkali-activated fly ash - ATR-FTIR studies, Spectrochim. Acta Part A: Molecular and Biomolecular Spectroscopy, 198, pp. 33-37. DOI:https://doi.org/10.1016/j.saa.2018.02.067
[20]. Krstić, I., Zec, S., Lazarević, V., Stanisavljević, M. & Golubović, T (2018). Use of sintering to immobilize toxic metals present in galvanic sludge into a stabile glass-ceramic structure, Science of Sintering, 50, pp. 139-147. DOI:10.2298/SOS1802139K
[21]. Kwon, O-S. & Sohn, I.L. (2020). Fundamental thermokinetic study of a sustainable lithium-ion battery pyrometallurgical recycling process, Resources, Conservation and Recycling, 158, pp. 104809. DOI:10.1016/j.resconrec.2020.104809.
[22]. Letcher, R.M.b& Vallero, D.A. (2019). Waste. A Handbook for Management, 2, pp. 585-630. DOI:10.1016/B978-0-12-381475-3.10034-8
[23]. Li, M., Xu, J. & Li, B. (2018). Analysis of development of hazardous waste disposal technology in China, IOP Conf. Series: Earth and Environmental Science, 178, pp. 1-7. DOI:10.1088/1755-1315/178/1/012027
[24]. Luo, X., Liu, G., Xia, Y., Chen, L., Jiang, Z., Zheng, H. & Wang, Z. (2017). Use of biochar-compost to improve properties and productivity of the degraded coastal soil in the Yellow River Delta China, Journal of Soil and Sediments, 17, pp. 780-789. DOI:10.1007/s11368-016-1361-1
[25]. Luukkonen, T., Runtti, H., Niskanen, M., Tolonen, E., Sarkkinen, M., Kemppainen, K.,Rämö, J. & Lassi, U. (2016). Simultaneous removal of Ni(II), As(III), and Sb(III) from spiked mine effluent with metakaolin and blast-furnace-slag geopolymers, Journal of.Environmental Management, 166, pp. 579-588. DOI:10.1016/j.jenvman.2015.11.007
[26]. Luz, C.A., Rocha, J.C., Cheriaf, M. & Pera, ,J. (2009). Valorization of galvanic sludge in sulfoaluminate cement, Construction and Building Materials, 23, pp. 595-601. DOI:10.1016/j.conbuildmat.2008.04.004
[27]. Makisha, N. & Yunchina, M. (2017). Methods and solutions for galvanic waste water treatment, MATEC Web of Conferences, 106, pp. 1-6. DOI:10.1051/matecconf/201710607016
[28]. Nanda, S. & Berruti, F. (2021). Municipal solid waste management and landfilling technologies: a review, Environmental Chemical Letter, 19, pp. 1433-1456. DOI:10.1007/s10311-020-01100-y
[29]. Pu, S., Duan, P., Yan, C. & Ren, D. (2016). Influence of sepiolite addition on mechanical strength and microstructure of fly ash-metakaolin geopolymer paste. Advanced Powder Technology,27, pp. 2470-2477. DOI:10.1016/j.apt.2016.09.002
[30]. Riaz, M., Bing Chen, A., Aminul Haque, M. & Shah, S.F.A. (2020). Utilization of industrial and hazardous waste materials to formulate energy-efficient hygrothermal biocomposites, Journal of Cleaner Production, 250, pp. 119469. DOI:10.1016/j.jclepro.2019.119469
[31]. Rossini, G. & Bernardes, A.M. (2006). Galvanic sludge metals recovery by pyrometallurgical and hydrometallurgical treatment, Journal of Hazardous Materials, 131, pp. 210-216. DOI:10.1016/j.jhazmat.2005.09.035.
[32]. Rudnik, E. (2019). Investigation of industrial waste materials for hydrometallurgical recovery of zinc, Minerals Engineering,139, pp. 105871. DOI:10.1016/j.mineng.2019.105871
[33]. Rybak, J., Gorbatyuk, S.M., Bujanovna-Syuryun, K.C., Khairutdinov, A., Tyulyaeva, Y. & Makarov, P.S. (2021). Utilization of Mineral Waste: A Method for Expanding the Mineral Resource Base of a Mining and Smelting Company, Metallurgist, 64, pp. 851-861. DOI:10.1007/s11015-021-01065-5
[34]. Sanito, R.C., Bernuy-Zumaeta, M., You, S-J. & Wang Y-F. (2022). A review on vitrification technologies of hazardous waste, Journal of Environmental Management, 316, pp. 115243. DOI:10.1016/j.jenvnman.2022.115243
[35]. Sinha, S., R. Choudhari, R., Mishra, D., Shekhar, S., Agrawal, A. & Sahu, K.K. (2020). Valorisation of waste galvanizing dross: Emphasis on recovery of zinc with zero effluent strategy, Journal of Environmental Management, 256, pp. 109985. DOI:10.1016/j.jenvman.2019.109985
[36]. Sitarz–Palczak, E.; Kalembkiewicz, J. & Galas, D. (2019). Comparative study on the characteristics of coal fly ash and biomass ash geopolymers, Archives of Environmental Protection 45, pp. 126-135. DOI:10.24425/aep.2019.126427
[37]. Stepanov, S., Morozov, N., Morozova, N., Ayupov, D., Makarov, D. & Baishev, D. (2016). Efficiency of Use of Galvanic Sludge in Cement Systems, Procedia Engineering, 165, pp.1112-1117. DOI:10.1016/j.proeng.2016.11.827
[38]. Świerk, K., Bielicka, A., Bojanowska, I. & Maćkiewicz, Z. (2007). Investigation of Heavy Metals Leaching from industrial wastewater sludge, Polish Journal of Environmental Studies, 16, pp. 447-451.
[39]. Šćiban, M., Radetić, B., Kevrešan, Z. & Klašnja, M. (2007). Adsorption of heavy metals from electroplating wastewater by wood sawdust, Bioresource Technology, 98, pp. 402-409. DOI:10.1016/j.biortech.2005.12.014
[40]. Toledo, M., Siles, J.A., Gutierrez, M.C. & Martin, M.A. (2018). Monitoring of the composting process of different agroindustrial waste: influence of the operational variables on the odorous impact, Waste Management, 76, pp. 266-274. DOI:10.1016/j.wasman.2018.03.042
[41]. Ugwu, E.I. & Agunwamba, J.C. (2020). A review on the applicability of activated carbon derived from plant biomass in adsorption of chromium, copper, and zinc from industrial wastewater, Environmental Monitoring and Assessment, 192, pp. 240-252. DOI:10.1007/s10661-020-8162-0
[42]. Yang, J., Firsbach, F. & Sohn, I.L. (2022). Pyrometallurgical processing of ferrous slag “co-product” zero waste full utilization: A critical review, Resources, Conservation and Recycling, 178, pp. 106021. DOI:10.1016/j.resconrec.2021.106021
[43]. Zehua, J., Liya, S. & Yuansheng, P. (2020). Synthesis and toxic metals (Cd, Pb, and Zn) immobilization properties of drinking water treatment residuals and metakaolin-based geopolymers, Materials Chemistry and Physics, 242, pp. 1-9. DOI:10.1016/j.matchemphys.2019.122535
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Authors and Affiliations

Elżbieta Sitarz-Palczak
1
ORCID: ORCID

  1. Rzeszow University of Technology, Poland
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Abstract

The durability characteristics of Engineered Cementitious Composites (ECC) with various fibers such as polypropylene and glass were investigated in view of developing composites with high resistance to cracking. ECC offer large potential for durable civil infrastructure due to their high tensile strain capacity and controlled micro-crack width. In this study, fibre volume fractions (0.5%, 1%, 1.5%, and 2%) of both polypropylene and glass fibers varied and durability measures such as a rapid chloride penetration test, sorptivity, water absorption, acid attack, and sulphate attack were measured. Increasing the fiber content up to 1.5% improved the durability properties of ECC. The test results indicate that the glass fiber-reinforced Engineered Cementitious Composites have better durability characteristics than polypropylene fiber-reinforced ECC.

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Authors and Affiliations

S. Ranjith
R. Venkatasubramani
V. Sreevidya
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Abstract

This article presents the results of the study of changes in mineral and chemical composition of artificial aggregates consisting of coal shale (a hard coal mining waste) and fluidized ashes. Such an aggregate was used for road construction. After completion of the construction works but before making the road available for public use, significant deformation of the surface in the form of irregular buckling of the asphalt layer occurred. It was excluded that this resulted from mining damage, design errors or performance mistakes, among others. A study of the materials that had been incorporated in the construction layers was undertaken in order to find the component and the mechanism responsible for the buckling of the road surface. A comparison of the mineral and chemical composition of aggregate samples collected from the embankment where the road buckled with the reference sample and samples from places without deformations showed that the bumps in the road embankment consisted of minerals that were not initially present in the aggregate. Wastes produced as a result of high temperatures (slag and power plants ashes, metallurgical wastes) are not as stable in terms of chemical and phase composition in the hypergenic environment. As a result of the processes occurring in the road embankment, anhydrite, which is the primary component of fluidized ashes, was transformed into gypsum and ettringite. As a result of contact with water CaO (present in fluidized ashes) easily changed into calcium hydroxide. As the crystallization of these minerals is expansive, it resulted in the filling of pores and, in extreme cases, in a substantial increase in the volume of the aggregate and, consequently, in the deformation of the road surface.
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Authors and Affiliations

Zdzisław Adamczyk
Marcin Grygierek
Marian Łupieżowiec
Jacek Nowak
Ewa Strzałkowska
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Abstract

The problem of of the use of fly ash still constitutes a research and exploration area for scientists. This is due to the fact that, 6,000,000 Mg of coal combustion by-products (CCB) are storage on landfills yearly in Poland alone. One of the potential directions of using fly ash is to use it as a substrate in hydrothermal syntheses of mesoporous materials (synthetic zeolites). Zeolites are aluminosilicates with a spatial structure. Due to their specific structure they are characterized by a number of specific properties among others molecular-sieve, ion-exchange and catalytic that can be used in engineering and environmental protection. So far, the synthesis has been carried out using coal combustion by-products such as fly ash or microsphere. The article analyzes whether separation from the fly ash of the appropriate fraction (below 63 μm) will affect the formation of zeolite grains. The syntheses were carried out using class F fly ash and the fraction separated from it, which was obtained by sieving the ash through a 63 μm sieve. Chemical (XRF) and mineralogical (XRD, SEM-EDS) analyzes were carried out for substrates as well as the obtained reaction products. In the case of substrates, the analysis did not show any significant differences between the ash and the separated fraction. However, in products after synthesis (Na-X zeolite with a small amount of Na-P1 zeolite, and small amounts of quartz and unreacted aluminosilicate glass - mullite) higher aluminum and sodium contents were observed from the separated fraction, with a lower calcium and potassium content. A small proportion of illite was observed on the diffraction curve of the zeolite from the fraction. Observations of grain morphology showed no differences in formation. Based on the conducted analyzes, it can be stated that, considering the economics of the synthesis process, the separation of fine fractions from the fly ash does not affect the quality of the synthesis process.

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Authors and Affiliations

Dorota Czarna-Juszkiewicz
Piotr Kunecki
Rafał Panek
Magdalena Wdowin
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Abstract

The reduction of mercury emissions in currently existing coal-based power plant solutions by each method i.e. preliminary, primary and secondary (consisting of introducing coal into the combustion chamber and then removing mercury from the combustion gases arising from the combustion process) does not solve the problem of achieving the required limits by power plants. Therefore, the need has arisen to look for new, effective solutions.

The results presented in the work concern the analysis of environmental benefits for the use of zeolites obtained from by-products of coal combustion such as fly ash (from hard coal and lignite) in technologies for removing gaseous forms of mercury. The tested zeolites were silver-modified X-type structures. The reference material in the considerations was active carbon impregnated with bromine – a commercially available sorbent on the market.

The article considers environmental benefits resulting from the use of tested zeolites taking the product life cycle, sorbent efficiency and the possibility of its regeneration compared to activated carbon (AC/Br) into account. The LCA analysis was performed taking the estimated material and energy balances of the manufacturing processes into account. When comparing the production process of type X zeolite materials on the processing line and activated carbons in the amount necessary to capture 375 g Hg from exhaust gases, the LCA analysis showed that zeolites contribute to a lower potential impact on the environment. The advantage is that 5 times less zeolite sorbent than activated carbons is needed to capture the same amount of mercury. In addition, zeolite materials can be regenerated, which extends their life time

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Authors and Affiliations

Łukasz Lelek
Magdalena Wdowin
ORCID: ORCID
Rafał Panek
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Abstract

Fly ash which has been separated from the flue gas stream as a result of fossil fuels combustion constitutes a huge amount of waste generated worldwide. Due to environmental problems, many directions of their rational use have been developed. Various attempts to convert fly ash into sorption materials, mainly synthetic zeolites, are conducted successfully. In this paper, an attempt was made to convert fly ash from lignite combustion from one of the Polish power plants, using alkaline hydrothermal synthesis. The primary phases in the fly ash were: quartz, gehlenite, mullite, hematite, feldspar, lime, anhydrite, occasionally grains of ZnO phase and pyrrhotite, glass and unburned fuel grains. As a result of hydrothermal synthesis a material containing new phases – pitiglianoite and tobermorite was obtained. Among the primary ash constituents, only gehlenite with an unburned organic substance, on which tobermorite with crystallized pitiglianoite was present. As a result of detailed testing of products after synthesis, it was found that among the tested grains:

• two populations can be distinguished – grains containing MgO and Fe2O3 as well as grains

containing Fe2O3 or MgO or containing none of these components,

• the main quantitative component was pitiglianoite,

• pitiglianoite was present in larger amounts in grains containing Fe2O3 or MgO or in the absence of both components than in grains in which Fe2O3 and MgO were found.

The results of the study indicate that in post-synthesis products, the contribution of components were as follows: pitiglianoite – 39.5% mas., tobermorite – 54% mas., gehlenite – 3% mas. and organic substance – 3.5% mas.

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Authors and Affiliations

Barbara Białecka
ORCID: ORCID
Zdzisław Adamczyk
ORCID: ORCID
Magdalena Cempa
ORCID: ORCID
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Abstract

Increasing environmental pressure against waste disposal, particularly fine waste surface storage and concern about mining damages have resulted in an increase in the popularity of a fly ash, tailing and binding agent mixture used as compaction grout of roof fall rocks in a gob area of longwalls. Backfilling of voids forming as a result of exploitation with the fall of roof with mixtures containing fine-grained industrial wastes is a common practice in coal mines. It is aimed at achieving numerous technological and ecological advantages as well as at controlling mining hazards. Research on hydraulic transport of fine-grained slurry conducted to date focused mainly on issues related to the analysis of the conditions related to pipeline transportation. The processes concerning the propagation of mixtures within the gob, on the other hand, remain largely unknown. The process of flow of fine-grained slurry through the caving is subject to a series of factors related, among other things, with the properties of the applied wastes and mixtures, the characteristics of the gob as well as the variability of these properties during the flow through the gob and in time. Due to the lack of sufficient knowledge pertaining to the changes taking place in the gob and in the slurry while it penetrates the gobs, no methods allowing for the design and optimization of the gob grouting process have been established so far. The paper presents the selected results of laboratory tests regarding the flow of ash and water mixtures in a model of a gob, pertaining to two selected types of fly ash produced in hard coal combustion, particularly concerning the impact of the type of the ash and the density of the slurry on the effectiveness of the gob grouting process.

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Authors and Affiliations

Marcin Krzysztof Popczyk
Rafał Jendruś
ORCID: ORCID
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Abstract

The cenospheres are formed during the mineral transformation stage in coal combustion. Their content in fly ashes from the combustion of different types of coals varies over a rather wide range from 0.01 to 35.6 wt.%. The cenospheres has three main elements, silicon, aluminium and iron, the oxides of which account for about 89% of the material. Mineralogical analysis using XRD shows that as-received cenospheres mainly contain mullite and quartz as main mineralogical phases. The size of cenospheres varies between 5 and 500 [...], as the most common dimension is 20-300 [...]. The cenospheres are characterized by a low bulk density (0.2-0.8 g/cm3) and can be easily separated by gravitational methods in the form of a concentrate in aqueous media or collected from a water surface of lagoons intended for storage of ash and slag waste. The unique properties of these hollow microspheres make them amenable for wide applications. For example the cenospheres can be used to produce various lightweight construction products, including lightweight cements and aggregates in lightweight concrete.

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Authors and Affiliations

Elżbieta Haustein
Bernard Quant
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Abstract

The use of biomass in the energy industry is the consequence of ongoing efforts to replace Energy from fossil fuels with energy from renewable sources. However, due to the diversity of the biomass, its use as a solid fuel generates waste with diverse and unstable chemical composition. Waste from biomass combustion is a raw material with a very diverse composition, even in the case of using only one type of biomass. The content of individual elements in fly ash from the combustion of biomass ranges from zero to tens of percent. This makes it difficult to determine the optimal recovery methods. The ashes from the combustion of biomass are most commonly used in the production of building materials and agriculture. This article presents the elemental composition of the most commonly used biomass fuels. The results of the analysis of elemental composition of fly ashes from the combustion of forest and agricultural biomass in fluidized bed boilers used in the commercial power industry were presented. These ashes are characterized by a high content of calcium (12.3–19.4%), silicon (1.2–8.3%), potassium (0.05–1.46%), chlorine (1.1–6.1%), and iron (0.8–6.5%). The discussed ashes contained no sodium. Aluminum was found only in one of the five ashes. Manganese, chromium, copper, nickel, lead, zinc, sulfur, bismuth, titanium and zirconium were found in all of the examined ashes. The analysis of elemental composition may allow for a preliminary assessment of the recovery potential of a given ash.

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Authors and Affiliations

Alicja Uliasz-Bocheńczyk
ORCID: ORCID
Eugeniusz Mokrzycki
ORCID: ORCID
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Abstract

Deposits used as fertilizer bring to soil both biogens necessary for plant growth and other ingredients such as metals. including heavy metals. Knowledge of quantities and rate in which heavy metals are to be released to soil from granulates is important because of their toxic influence on plants (in the case of high metals concentration). This paper presents results of investigation of elution of Cu. Zn, Ni, Cd, Pb. and Cr from granulates prepared from municipal sewage sludge, hard coal ash and brown coal ash. Elution to water solution was carried out in static conditions with single-stage and tree-stage extraction. Heavy metal a component of sludge-ash granulates eluted in various quantities, i.e. from trace for cadmium to 9.26-9.53 mg/kg of d.m. for zinc. Among the soluble forms of metals the most mobile are (in decreasing sequence): Cu > Pb> Zn> Ni in granulates containing brown coal ash and Cu> Pb> Ni> Zn in granulates contain hard coal ash.
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Authors and Affiliations

Czesława Rosik-Dulewska
ORCID: ORCID
Katarzyna Głowala
Urszula Karwaczyńska
Jolanta Robak
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Abstract

For ages, concrete has been used to construct underwater structures. Concrete laying underwater is a very complex procedure important to the success or failure of underwater projects. This paper elucidates the influence of alkali activator ratios on geopolymers for underwater concreting; focusing on the geopolymer concrete synthesized from fly ash and kaolin activated using sodium hydroxide and sodium silicate solutions. The geopolymer mixtures were designed to incorporate multiple alkali activator ratios to evaluate their effects on the resulting geopolymers’ properties. The fresh concrete was molded into 50 mm cubes in seawater using the tremie method and tested for its engineering properties at 7 and 28 days (curing). The control geopolymer and underwater geopolymers’ mechanical properties, such as compressive strength, water absorption density, and setting time were also determined. The differences between the control geopolymer and underwater geopolymer were determined using phase analysis and functional group analysis. The results show that the geopolymer samples were optimally strengthened at a 2.5 alkali activator ratio, and the mechanical properties of the control geopolymer exceeded that of the underwater geopolymer. However, the underwater geopolymer was determined to be suitable for use as underwater concreting material as it retains 70% strength of the control geopolymer.
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Authors and Affiliations

Fakhryna Hannanee Ahmad Zaidi
1
ORCID: ORCID
Romisuhani Ahmad
1 2
ORCID: ORCID
Mohd Mustafa Al Bakri Abdullah
3 2
ORCID: ORCID
Wan Mastura Wan Ibrahim
1 2
ORCID: ORCID
Ikmal Hakem Aziz
3 2
ORCID: ORCID
Subaer Junaidi
4
ORCID: ORCID
Salmabanu Luhar
5 2
ORCID: ORCID

  1. Universiti Malaysia Perlis, Faculty of Engineering Technology, Sungai Chuchuh, 02100 Padang Besar, Perlis, Malaysia
  2. Universiti Malaysia Perlis (UniMAP), Geopolymer & Green Technology, Centre of Excellence (CEGeoGTech), Perlis, Malaysia
  3. Universiti Malaysia Perlis, Faculty of Chemical Engineering Technology, Taman Muhibbah, 02600 Jejawi, Arau, Perlis, Malaysia
  4. Universitas Negeri Makassar, Geopolymer & Green Material Group, Physics Department, FMIPA, Indonesia
  5. Frederick Research Center, P.O Box 24729, 1303 Nicosia, Cyprus
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Abstract

The density, compressive strength, and thermal insulation properties of fly ash geopolymer paste are reported. Novel insulation material of glass bubble was used as a replacement of fly ash binder to significantly enhance the mechanical and thermal properties compared to the geopolymer paste. The results showed that the density and compressive strength of 50% glass bubble was 1.45 g/cm3 and 42.5 MPa, respectively, meeting the standard requirement for structural concrete. Meanwhile, the compatibility of 50% glass bubbles tested showed that the thermal conductivity (0.898 W/mK), specific heat (2.141 MJ/m3K), and thermal diffusivity (0.572 mm2/s) in meeting the same requirement. The improvement of thermal insulation properties revealed the potential use of glass bubbles as an insulation material in construction material.
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Authors and Affiliations

Noor Fifinatasha Shahedan
1
ORCID: ORCID
Mohd Mustafa Al Bakri Abdullah
1 2
ORCID: ORCID
Norsuria Mahmed
1 2
ORCID: ORCID
Liew Yun Ming
1 2
ORCID: ORCID
Shayfull Zamree Abd Rahim
1
ORCID: ORCID
Ikmal Hakem A Aziz
1
ORCID: ORCID
Aeslina Abdul Kadir
3
ORCID: ORCID
Andrei Victor Sandu
4
ORCID: ORCID
Mohd Fathullah Ghazali
1
ORCID: ORCID

  1. Universiti Malaysia Perlis (UniMAP), Center of Excellence Geopolyme & Green Technology (CEGeoGTech), Perlis, Malaysia
  2. Universiti Malaysia Perlis (UniMAP), Faculty of Chemical Engineering Technology, Perlis, Malaysia
  3. Universiti Tun Hussein Onn Malaysia, Faculty of Civil and Environmental Engineering, Johor, Malaysia
  4. Faculty of Materials Science and Engineering, Gheorghe Asachi Technical University of Iasi, Iasi, Romania
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Abstract

This paper reports on the flexural properties of thin fly ash geopolymers exposed to elevated temperature. The thin fly ash geopolymers (dimension = 160 mm × 40 mm × 10 mm) were synthesised using12M NaOH solution mixed with designed solids-to-liquids ratio of 1:2.5 and Na2SiO3/NaOH ratio of 1:4 and underwent heat treatment at different elevated temperature (300°C, 600°C, 900°C and 1150°C) after 28 days of curing. Flexural strength test was accessed to compare the flexural properties while X-Ray Diffraction (XRD) analysis was performed to determine the phase transformation of thin geopolymers at elevated temperature. Results showed that application of heat treatment boosted the flexural properties of thin fly ash geopolymers as the flexural strength increased from 6.5 MPa (room temperature) to 16.2 MPa (1150°C). XRD results showed that the presence of crystalline phases of albite and nepheline contributed to the increment in flexural strength.
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Authors and Affiliations

Yong-Sing Ng
1 2
Yun-Ming Liew
1 2
ORCID: ORCID
Cheng-Yong Heah
1 3
Mohd Mustafa Al Bakri Abdullah
1 2
ORCID: ORCID
Hui-Teng Ng
1 2
Lynette Wei Ling Chan
4

  1. Universiti Malaysia Perlis (UniMAP), Center of Excellence Geopolymer and Green Technology (CeGeoGTech), Kangar, 01000 Perlis, Malaysia
  2. Universiti Malaysia Perlis (UniMAP), Faculty of Chemical Engineering Technology, Kangar, 01000 Perlis, Malaysia
  3. Universiti Malaysia Faculty of Mechanical Engineering Technology, Perlis (UniMAP), Kangar, 01000 Perlis, Malaysia
  4. Ceramic Research Company Sdn Bhd (Guocera-Hong Leong Group), Lot 7110, 5½ Miles, Jalan Kapar, 42100 Klang, Selangor, Malaysia
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Abstract

The paper presents the results of hydrothermal zeolitization of fly ash from hard coal combustion in one of the Polish power plants. The synthesis was carried out using various NaOH fly ash mass ratio (3.0, 4.0 and 6.0) and the effect of NaOH concentration in the activating solution on composition of synthesized sample was tested. The process was carried out under the following permanent conditions temperature: 90°C, time – 16 hours, water solution of NaOH (L)/fly ash (g) ratio – 0.025. In the studied fly ash the dominant chemical components were SiO2 and Al2O3, while the main phase components were mullite, quartz and hematite, and a significant share of amorphous substance (glass and unburnt organic substance). After hydrothermal synthesis, the presence of unreacted fly ash phases was found in the products, as well as new phases, the quality and quantity of which depend on the NaOH to fly ash mass ratio used for synthesis:

 for ratio 3.0 – Na-LSX type zeolite and hielscherite,

 for ratio 4.0 – Na-LSX type zeolite, hielscherite and hydrosodalite,

 for ratio 6.0 – hydrosodalite and hielscherite.

The grains in all products of synthesis are poly-mineral. However, it was found that the new phases, overgrowing the unreacted phase components of fly ash, crystallize in a certain order. Hielscherite is the first crystallizing phase, on which the Na-LSX type zeolite crystallizes then, and the whole is covered by hydrosodalite. In the products of synthesis, the share of sodium-containing phases (the Na-LSX type zeolite and hydrosodalite) increases with the increasing concentration of NaOH in the solution used for the process.

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Authors and Affiliations

Zdzisław Adamczyk
ORCID: ORCID
Magdalena Cempa
ORCID: ORCID
Barbara Białecka
ORCID: ORCID
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Abstract

The aim of this research was to assess the content and composition of the pollutants emitted by domestic central heating boilers equipped with an automatic underfeed fuel delivery system for the combustion chamber. The comparative research was conducted. It concerned fuel properties, flue gas parameters, contents of dust (fl y ash) and gaseous substances polluting the air in the flue gases emitted from a domestic CH boiler burning bituminous coal, pellets from coniferous wood, cereal straw, miscanthus, and sunflower husks, coniferous tree bark, and oats and barley grain. The emission factors for dust and gaseous air pollutants were established as they are helpful to assess the contribution of such boilers in the atmospheric air pollution. When assessing the researched boiler, it was found out that despite the development in design and construction, flue gases contained fly ash with a significant EC content, which affected the air quality.

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Authors and Affiliations

Jan Konieczyński
Ewelina Cieślik
Bogusław Komosiński
Tomasz Konieczny
Barbara Mathews
Tomasz Rachwał
Grzegorz Rzońca
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Abstract

The paper presents investigation results of the migration of a chemical compound contained in fly ash deposited on a dry furnace waste landfill site exposed to weather conditions. Climate conditions are able to significantly affect chemical component distribution in a block of deposited, moving chemical compounds to different depths. The main aim of the investigations was to determine the chemical component distribution of deposited fly ash in the landfill. Identification of chemical components based on XRF analysis indicated the existence of differences in both tested storage layer and the fraction of fly ash.

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Authors and Affiliations

Aleksandra Sambo
Arkadiusz Szymanek
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Abstract

The paper describes the results of various actions and industrial tests conducted in order to decrease the content of unburned carbon in the fly ash of a circulating fluidised bed combustor (CFBC). Several attempts to improve the situation were made and the effects of several parameters on the unburned carbon content in the fly ash were investigated (e.g. bed temperature, cyclone separation efficiency, fuel particle size distribution, boiler hydrodynamics, grid design, and fuel data). Unfortunately, no satisfactory solution to these problems was found. Probably, apart from attrition and char fragmentation, additional factors also contributed to the formation of unburned carbon in the CFBC fly ash.

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Authors and Affiliations

Rafał Kobyłecki

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