scholarly journals Preparation of Synthetic Zeolites from Coal Fly Ash by Hydrothermal Synthesis

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1267
Author(s):  
David Längauer ◽  
Vladimír Čablík ◽  
Slavomír Hredzák ◽  
Anton Zubrik ◽  
Marek Matik ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Combustion ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Product Analysis ◽  
Coal Combustion Products ◽  
X Ray ◽  
Wide Range ◽  
Silica Alumina

Large amounts of coal combustion products (as solid products of thermal power plants) with different chemical and physical properties cause serious environmental problems. Even though coal fly ash is a coal combustion product, it has a wide range of applications (e.g., in construction, metallurgy, chemical production, reclamation etc.). One of its potential uses is in zeolitization to obtain a higher added value of the product. The aim of this paper is to produce a material with sufficient textural properties used, for example, for environmental purposes (an adsorbent) and/or storage material. In practice, the coal fly ash (No. 1 and No. 2) from Czech power plants was firstly characterized in detail (X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), particle size measurement, and textural analysis), and then it was hydrothermally treated to synthetize zeolites. Different concentrations of NaOH, LiCl, Al2O3, and aqueous glass; different temperature effects (90–120 °C); and different process lengths (6–48 h) were studied. Furthermore, most of the experiments were supplemented with a crystallization phase that was run for 16 h at 50 °C. After qualitative product analysis (SEM-EDX, XRD, and textural analytics), quantitative XRD evaluation with an internal standard was used for zeolitization process evaluation. Sodalite (SOD), phillipsite (PHI), chabazite (CHA), faujasite-Na (FAU-Na), and faujasite-Ca (FAU-Ca) were obtained as the zeolite phases. The content of these zeolite phases ranged from 2.09 to 43.79%. The best conditions for the zeolite phase formation were as follows: 4 M NaOH, 4 mL 10% LiCl, liquid/solid ratio of 30:1, silica/alumina ratio change from 2:1 to 1:1, temperature of 120 °C, process time of 24 h, and a crystallization phase for 16 h at 50 °C.

scholarly journals Mineralogical and Environmental Geochemistry of Coal Combustion Products from Shenhuo and Yihua Power Plants in Xinjiang Autonomous Region, Northwest China

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 496 ◽  
Author(s):  
Wu ◽  
Li ◽  
Zhuang ◽  
Querol ◽  
Moreno ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Combustion ◽  
Inductively Coupled Plasma ◽  
Power Plants ◽  
Environmental Geochemistry ◽  
Combustion Products ◽  
Coal Combustion Products ◽  
X Ray ◽  
Inductively Coupled ◽  
Xinjiang Autonomous Region

The mineralogical and geochemical characteristics of feed coals and coal combustion products (CCPs) from the Shenhuo and Yihua Power Plants in Xinjiang Autonomous Region, were studied by means of proximate analysis, Power X-ray diffraction (XRD), scanning electron microscopy with Energy Dispersive X-ray analyzer (SEM-EDX), inductively coupled plasma atomic emission spectrometry (ICP-MS) and inductively coupled plasma mass spectrometry (ICP-AES). The environmental geochemistry of CCPs was evaluated by Al-normalized enrichment factor as well as European Standard EN-12457 leaching test. Two feed coals have the characteristics of low sulfur content, medium to high volatiles matter yields, medium moisture content, super low to medium ash yield, medium to high calorific value and low mineral content. The main crystalline facies in fly ash and slag are quartz and mullite, with a small amount of calcite, and some unburned carbon. Hematite, SrSO4 and barite also can be observed in fly ashes by SEM. Typical plerophere occurs in fine fly ash rather than the coarse fly ash. The concentration of most trace elements in CCPs falls within the lower concentration range of European fly ashes. With respect to the partitioning behavior of trace elements during coal combustion, S is highly volatile, and Mg, Na, Zn, B, Co, As, Nb, Zr, Cu and K also show certain volatility, which may to some extent emit to the atmosphere. Furthermore, leaching experiments show that leachable concentrations of most of the potentially toxic elements in CCPs are low, and the CCPs fall in the range between inert and nonhazardous landfill material regulated by the 2003/33/EC Decision.

The Latest Research in Mongolia on the Utilization of Coal Combustion By-Products

2021 ◽  
Vol 323 ◽  
pp. 8-13
Author(s):  
Jadambaa Temuujin ◽  
Damdinsuren Munkhtuvshin ◽  
Claus H. Ruescher
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Coal Combustion ◽  
Power Plants ◽  
Thermal Power ◽  
Thermal Power Plants ◽  
Power Stations ◽  
Thermal Power Stations ◽  
Coal Ashes ◽  
By Products

With a geological reserve of over 170 billion tons, coal is the most abundant energy source in Mongolia with six operating thermal power stations. Moreover, in Ulaanbaatar city over 210000 families live in the Ger district and use over 800000 tons of coal as a fuel. The three thermal power plants in Ulaanbaatar burn about 5 million tons of coal, resulting in more than 500000 tons of coal combustion by-products per year. Globally, the ashes produced by thermal power plants, boilers, and single ovens pose serious environmental problems. The utilization of various types of waste is one of the factors determining the sustainability of cities. Therefore, the processing of wastes for re-use or disposal is a critical topic in waste management and materials research. According to research, the Mongolian capital city's air and soil quality has reached a disastrous level. The main reasons for air pollution in Ulaanbaatar are reported as being coal-fired stoves of the Ger residential district, thermal power stations, small and medium-sized low-pressure furnaces, and motor vehicles. Previously, coal ashes have been used to prepare advanced materials such as glass-ceramics with the hardness of 6.35 GPa, geopolymer concrete with compressive strength of over 30 MPa and zeolite A with a Cr (III) removal capacity of 35.8 mg/g. Here we discuss our latest results on the utilization of fly ash for preparation of a cement stabilized base layer for paved roads, mechanically activated fly ash for use in concrete production, and coal ash from the Ger district for preparation of an adsorbent. An addition of 20% fly ash to 5-8% cement made from a mixture of road base gave a compressive strength of ~ 4MPa, which exceeds the standard. Using coal ashes from Ger district prepared a new type of adsorbent material capable of removing various organic pollutants from tannery water was developed. This ash also showed weak leaching characteristics in water and acidic environment, which opens up an excellent opportunity to utilize.

Total reflection X-ray fluorescence analysis of fly ash from Bulgarian coal-fired power plants

2015 ◽  
Vol 69 (5) ◽  
Author(s):  
Albena K. Detcheva ◽  
Svilen E. Mitsiev ◽  
Paunka S. Vassileva ◽  
Juri H. Jordanov ◽  
Metody G. Karadjov ◽  
...  
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Internal Standard ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
X Ray

AbstractThe contents of Cl, Ca, K, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Ba and Pb in raw coal fly ash from five Bulgarian power plants were determined by total reflection X-ray fluorescence (TXRF), using gallium as the internal standard. The samples were analysed as in slurry form in Triton

scholarly journals Composition and Morphology Characteristics of Magnetic Fractions of Coal Fly Ash Wastes Processed in High-Temperature Exposure in Thermal Power Plants

2019 ◽  
Vol 9 (9) ◽  
pp. 1964 ◽  
Author(s):  
Dinh-Hieu Vu ◽  
Hoang-Bac Bui ◽  
Bahareh Kalantar ◽  
Xuan-Nam Bui ◽  
Dinh-An Nguyen ◽  
...  
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Combustion Process ◽  
Mineralogical Composition ◽  
Striking Difference ◽  
Thermal Power Plants ◽  
Power Stations ◽  
Magnetic Components

Coal-fired power stations are one of the primary sources of power generation in the world. This will produce considerable amounts of fly ash from these power stations each year. To highlight the potential environmental hazards of these materials, this study is carried out to evaluate the characterization of fly ashes produced in thermal power plants in northern Vietnam. Fly ash was firstly fractionated according to size, and the fractions were characterized. Then, each of these fractions was analyzed with regard to their mineralogical features, morphological and physicochemical properties. The analytical results indicate a striking difference in terms of the characteristics of particles. It was found that magnetic fractions are composed of magnetite hematite and, to a lower rate, mullite, and quartz. Chemical analyses indicate that the non-magnetic components mainly consist of quartz and mullite as their primary mineral phases. As the main conclusion of this research, it is found that the magnetic and non-magnetic components differ in terms of shape, carbon content and mineralogical composition. In addition, it was found that magnetic components can be characterized as more spheroidal components compared to non-magnetic ones. This comprehensive characterization not only offers a certain guideline regarding the uses of different ash fractions but it will also provide valuable information on this common combustion process.

scholarly journals Analysis of Content of Selected Critical Elements in Fly Ash

2016 ◽  
Vol 62 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Dorota Makowska ◽  
Faustyna Wierońska
Keyword(s):  
Fly Ash ◽  
Coal Combustion ◽  
Power Plants ◽  
Raw Materials ◽  
Coal Fly Ash ◽  
New Mineral ◽  
The European Union ◽  
Cobalt Chromium ◽  
Critical Elements ◽  
Potential Source

AbstractPursuant 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.

POSSIBLE USE OF FLY ASH IN CERAMIC INDUSTRIES: AN INNOVATIVE METHOD TO REDUCE ENVIRONMENTAL POLLUTION

2013 ◽  
Vol 22 ◽  
pp. 99-102 ◽  
Author(s):  
GAYATRI SHARMA ◽  
S. K. MEHLA ◽  
TARUN BHATNAGAR ◽  
ANNU BAJAJ
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Fine Particles ◽  
Thermal Power ◽  
Coal Ash ◽  
Natural Soil ◽  
Thermal Power Plants ◽  
Silica Alumina ◽  
Near Future ◽  
Land Water

The process of coal combustion results in coal ash, 80% of which is very fine in nature & is thus known as fly ash. Presently, in India, about 120 coal based thermal power plants are producing about 90-120 million tons of fly ash every year. With increase in demand of power energy, more and more thermal power plants are expected to commission in near future and it is expected that fly ash generation will be 225 million tons by 2017. Disposal of fly ash requires large quantity of land, water and energy and its fine particles, if not disposed properly, by virtue of their weightless, can become air born and adversely affect the entire Environment. These earth elements primarily consist of silica, alumina & iron etc. and its physicochemical parameters are closely resembles with volcanic ash, natural soil etc. These properties, therefore, makes it suitable for use in ceramic industries and helps in saving the environment and resources.

scholarly journals Coal Fly Ash Ceramics: Preparation, Characterization, and Use in the Hydrolysis of Sucrose

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Ricardo Pires dos Santos ◽  
Jorge Martins ◽  
Carlos Gadelha ◽  
Benildo Cavada ◽  
Alessandro Victor Albertini ◽  
...  
Keyword(s):  
Fly Ash ◽  
Surface Area ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Coal Ash ◽  
Mineralogical Composition ◽  
Degree Of Hydrolysis ◽  
High Degree ◽  
Hydrolysis Of

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 compaction pressures (63.66–318.30 MPa) and sintered at 1200°C for 4 h. Mineralogical composition (by X-ray diffraction) and surface area were studied. The ceramic prepared with 318.30 MPa presented the highest surface area (35 m2/g) and amount of immobilized enzyme per g of support (76.6 mg/g). In assays involving sucrose inversion, it showed a high degree of hydrolysis (around 81%) even after nine reuses and 30 days’ storage. Therefore, coal fly ash ceramics were demonstrated to be a promising biotechnological alternative as an immobilization support for the hydrolysis of sucrose.

scholarly journals CONVERSION OF COAL FLY ASH TO ZEOLITE-BASED IRON OXIDE MAGNETIC NANOCOPOSITES BY MODIFIED FUSION-HYDROTHERMAL SYNTHESIS

2020 ◽  
pp. 30-35
Author(s):  
Silviya Boycheva ◽  
Denitza Zgureva
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Fly Ash ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Coal Ash ◽  
Low Temperature Processing ◽  
Oxide Phases ◽  
Stage Synthesis

Coal fly ash generated in Thermal Power Plants is utilized for synthesis of zeolites due to its aluminosilicate composition. The highest degree of zeolitization of coal ash in a particular zeolite phase is achieved by double-stage synthesis involving successive alkaline melting and hydrothermal activation of the reaction mixtures, while the uniform distribution of the iron oxides transferred from the raw coal ash is ensured by ultrasonic treatment. However, the applied melting step results in the oxidation of the magnetic iron oxide phases to non-magnetic ones, which results in the loss of magnetic properties of the resulting materials. The present investigation focuses on an improved double- stage synthesis procedure by the addition of raw coal ash containing magnetite between high temperature and low temperature processing. In this way, the magnetic phase is retained in the final product and the magnetic properties of the zeolites are preserved, which is important for their application in the adsorption of pollutants from wastewater.

Application of Coal Bottom Ash Zeolite on Lignin and Methylene Blue Adsorption

2019 ◽  
Vol 948 ◽  
pp. 26-32
Author(s):  
Galuh Yuliani ◽  
Siska Mutiara ◽  
Agus Setiabudi
Keyword(s):  
Methylene Blue ◽  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Bottom Ash ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Methylene Blue Adsorption ◽  
X Ray ◽  
Coal Bottom Ash

The amount of coal combustion byproducts, such as fly ash and bottom ash, generated by coal-based thermal power plants has been increasing at an alarming rate, hence creating huge problems on their treatments and disposals. One of the promising approaches for proper utilization of these byproducts is the conversion of fly ash and bottom ash to zeolites. In this research, zeolites wereprepared from coal bottom ash (RBA) by relatively simple and cheap conversion process using NaOH at 90°C for 24h. Prior to this, the RBA was pretreated using H2SO4 for 4h. The resulted zeolite was characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). XRD results confirmed the formation of sodium aluminosilicate hydrate predominated upon the bottom ash and NaOH 5M ratio of 1:8. XRF results also indicated the domination of Al2O3 and SiO2 in the zeolite composition. FTIR spectra showed characteristic zeolite peaks at 900-1100, 400-500 and 550-660 cm–1forSi-O, Al-O, and Si-O-Al absorptions, respectively. The synthetic zeolite was then applied as an adsorbent for lignin and methylene blue in aqueous solutions. It was found that the Qmax for lignin and methylene blue was16.13 mg/g and 34.13 mg/g, respectively. When fitted using Langmuir and Freundlich isotherm models, the methylene blue adsorption data fitted Langmuir isotherm while those of lignin fitted Freundlich isotherm. It was concluded that the chemical interaction between zeolite and methylene blue may lead to the chemisorption mechanism to prevail.

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