Fly Ash-Based Geopolymer: Green Material in Carbon-Constrained Society

2021 ◽  
Vol 321 ◽  
pp. 65-71
Author(s):  
Hoc Thang Nguyen ◽  
Phong Thanh Dang
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Bottom Ash ◽  
Coal Ash ◽  
Raw Material ◽  
Engineering Properties ◽  
Gravimetric Analysis ◽  
Green Materials ◽  
Alumino Silicate

Climate change is recognized as a global problem and even the industrial and construction sectors are trying to reduce the green-house gas emissions, especially on CO2 emissions. In Vietnam, the coal-fired thermal power plants are discharging millions of tons of CO2 and coal ash annually. This coal ash is comprised of about 80% of fly ash and the rest is bottom ash. This study would like to introduce one of the potential solutions in a carbon-constrained society that would not only manage the fly ash but also utilized this as raw material for green materials through geopolymerization. The geopolymer-based material has lower energy consumption, minimal CO2 emissions and lower production cost as it valorizes industrial waste. The fly ash containing high alumino-silicate resources from a coal-fired power plant in Vietnam was mixed with sodium silicate and sodium hydroxide solutions to obtain the geopolymeric pastes. The pastes were molded in 10x10x20cm molds and then cured at room temperature for 28 days. The 28-day geopolymer specimens were carried out to test for engineering properties such as compressive strength (MPa), volumetric weight (kg/m3), and water absorption (kg/m3). The microstructure analysis was also conducted for this eco-friendly materials using X ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Differential Thermal Analysis - Thermal Gravimetric Analysis (DTA-TGA).

Compressive Strength and Density of Cementless Unfired Lightweight Brick Utilizing Coal Ash from Coal-Fired Thermal Power Plant

2013 ◽  
Vol 594-595 ◽  
pp. 527-531
Author(s):  
Mohamad Ezad Hafez Mohd Pahroraji ◽  
Hamidah Mohd Saman ◽  
Mohamad Nidzam Rahmat ◽  
Kartini Kamaruddin ◽  
Ahmad Faiz Abdul Rashid
Keyword(s):  
Compressive Strength ◽  
Power Plant ◽  
Thermal Power Plant ◽  
Thermal Power ◽  
Bottom Ash ◽  
Coal Ash ◽  
Hydrated Lime ◽  
Raw Material ◽  
The World ◽  
Blastfurnace Slag

Millions tons of coal ash which constitute of fly ash and bottom ash were produced annually throughout the world. They were significant to be developed as masonry brick to substitute the existing widely used traditional material such as clay and sand brick which were produced from depleting and dwindling natural resources. In the present study, the coal ash from coal-fired thermal power plant was used as the main raw material for the fabrication of cementless unfired lightweight brick. The binder comprising of Hydrated Lime (HL)-activated Ground Granulated Blastfurnace Slag (GGBS) system at binding ratio 30:70, 50:50 and 70:30 were used to stabilize the coal ash in the fabrication process of the brick. Foam was used to lightweight the brick. The compressive strength and ambient density were evaluated on the brick. The results indicated that the brick incorporating HL-GGBS system achieved higher strength of 20.84N/mm2 at 28 days compare to the HL system with strength of 13.98N/mm2 at 28 days. However, as the quantity of foam increase at 0%, 25%, 50%, 75% and 100%, the strength and density for the brick decreased.

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

2016 ◽  
Vol 56 (4) ◽  
pp. 265-282 ◽  
Author(s):  
Usman Haider ◽  
Zdenek Bittnar ◽  
Lubomír Kopecky ◽  
Vít Šmilauer ◽  
Jaroslav Pokorny ◽  
...  
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Chemical Properties ◽  
Cementitious Materials ◽  
Individual Particle ◽  
Particle Analysis ◽  
Fly Ashes ◽  
Alumino Silicate ◽  
Individual Particles

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.

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 Leachability of Self-Compacting Concrete (SCC) Incorporated With Fly Ash and Bottom Ash by Using Static Leaching Procedure (SLT)

2015 ◽  
Vol 773-774 ◽  
pp. 1261-1265 ◽  
Author(s):  
Aeslina Abdul Kadir ◽  
Mohd Ikhmal Haqeem Hassan ◽  
Syed Khairul Hafizi bin Syed Mohamad
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Power Plants ◽  
Bottom Ash ◽  
Coal Ash ◽  
Negative Effects ◽  
Self Compacting Concrete ◽  
Aas Method ◽  
Set Up ◽  
Synthetic Acid

The growing demand for electricity resulted in the construction of many coal fired power plants. The increment of the consumption of coal by power plants lead up to production of coal ash. Coal ash contains a range of toxic elements that may have negative effects to human and environmental health. Fly ash (FA) and bottom ash (BA) are the solid residues and mostly arise from coal combustion that being disposed in large quantities every year. The focus of the study is to determine the leachability of Self-Compacting Concrete (SCC) incorporated with FA and BA by using Static Leachate Test (SLT) method. In this study, FA and BA were collected from Kapar Energy Ventures Coal Power Plant in Selangor. The characteristics of Ordinary Portland cement (OPC), FA and BA were determined by using X-Ray Fluorescent (XRF) technique. The different percentages of FA (replace cement) and BA (replace sand) which is 0%, 10%, 20% and 30% were incorporated respectively into SCC. Ten reactors were set up for the leachability test for each solid specimen by using SLT method. The concentrations of leachate samples were analyzed for selected heavy metals content by using Atomic Absorption Spectroscopy (AAS) method. After 40 days conducting the test, the concentrations of selected heavy metals (As, Mn, Cu, Cr, Zn, Ni, Fe and Pb) in the synthetic acid rain leachates from the SCC specimens were significantly lower than the limit specified by the USEPA and EPAV. Therefore, incorporating of FA and BA up to 30% into SCC is potentially feasible.

scholarly journals Fly ash and slag utilization for the Serbian railway substructure

Transport ◽  
2016 ◽  
Vol 33 (2) ◽  
pp. 389-398 ◽  
Author(s):  
Mirjana Vukićević ◽  
Zdenka Popović ◽  
Jovan Despotović ◽  
Luka Lazarević
Keyword(s):  
Fly Ash ◽  
Power Plant ◽  
Thermal Power Plant ◽  
Power Plants ◽  
Thermal Power ◽  
Cement Industry ◽  
Engineering Properties ◽  
Thermal Power Plants ◽  
Nikola Tesla ◽  
Railway Substructure

Approximately 7 million tons of fly ash and slag are produced in thermal power plants in Serbia every year, only 3% of which is used in the cement industry. About 300 million tons of the ash-slag mixture are disposed in landfills, occupying an area of approximately 1600 hectares and generating environmental issues. Fly ash from Serbian power plants has pozzolanic properties and due to low concentration of calcium compounds (less than 10% CaO), they do not have self-cementing properties. According to the ASTM C618-15, this ash is from class F. According to the European Standard EN 197-1:2011, this ash is siliceous (type V) ash. From April 2014 to May 2015, an investigation of engineering properties of fly ash and mixtures of fly ash and slag from landfill (without or with binders of cement/lime) was conducted at the Laboratory of Soil Mechanics at the Faculty of Civil Engineering of the University of Belgrade (Serbia) and at the Institute for Testing of Materials – IMS Institute in Belgrade. The laboratory test results were showed in the study ‘Utilization of fly ash and slag produced in the TPP JP EPS thermal power plants for construction of railways’. Four kinds of waste materials from Serbian power plants were laboratory tested: (a) an ash-slag mixture from landfills at the ‘Nikola Tesla A’ thermal power plant; (b) fly ash from silos in the ‘Nikola Tesla B’ thermal power plant; (c) an ash-slag mixture from landfills at the ‘Kostolac A’ and ‘Kostolac B’ thermal power plants and ‘Srednje kostolačko ostrvo’ landfill; (d) fly ash from the ‘Kostolac’ thermal power plant. The following physical and mechanical properties of ash and mixtures were investigated: grain size distribution, Atterberg limits, specific gravity, moisture-density relationship, shear strength parameters in terms of effective stresses, California Bearing Ratio (CBR), and deformation parameters. The paper presents the results of laboratory tests of the materials with and without binders, and based on the laboratory results and previous research, the paper presents possibilities of using fly ash and slag for the construction of railway substructure in the planned construction and reconstruction of railway network in Serbia. The obtained results indicate that tested fly ash and ash-slag mixture have met the technical requirements and that they have the potential to be used in railway substructure.

scholarly journals Characteristics of high carbon ash as a raw material for spontaneous combustion inhibitor and its field demonstration

2020 ◽  
Author(s):  
Seok Un Park ◽  
Jae Kwan Kim ◽  
Dong Ik Shin
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Bituminous Coal ◽  
Spontaneous Combustion ◽  
Bottom Ash ◽  
Frequency Factor ◽  
Raw Material ◽  
Unburned Carbon ◽  
Mixing Ratio ◽  
High Carbon

Abstract In this study, we examined the physical chemistry, fuel characteristics and combustion reactivity of high carbon ash as a raw material for spontaneous combustion inhibitor in order to solve the problem of spontaneous combustion which has been often occurring in coal yard of coal-fired power plants in Korea. The high carbon ash has higher activation energy and lower frequency factor than bituminous coal, so combustion began at a relatively higher temperature than bituminous coal. In case of fly ash, the heat transfer characteristics were better than those of bottom ash and pond ash, and in case of coarse particles of fly ash, they were found to be highly applicable as a raw material for spontaneous combustion inhibitor due to their relatively high unburned carbon content. As a result of manufacturing spontaneous combustion inhibitors along with asphalt and PFAD (palm fatty acid distillate), the contact angle to water was more than 90° regardless of the mixing ratio, showing hydrophobic surface characteristics, and it was found that the hardness and viscosity of spontaneous combustion inhibitors increased as the mixing ratio of high carbon ash increased. In addition, when spontaneous combustion inhibitors manufactured were applied to coal stockpiles in coal yard at coal-fired power plants, there was little change in the internal temperature of coal stockpiles and the highest value of instantaneous increasing rate per minute was found to be lowered from 1.60°C/min to 0.061°C/min, indicating that spontaneous combustion inhibitors using high carbon coal ash had a great effect of preventing spontaneous combustion.

scholarly journals Technical and radiological characterisation of fly ash and bottom ash from thermal power plant

2021 ◽  
Author(s):  
Emilija Fidanchevski ◽  
Biljana Angjusheva ◽  
Vojo Jovanov ◽  
Pece Murtanovski ◽  
Ljubica Vladiceska ◽  
...  
Keyword(s):  
Fly Ash ◽  
Effective Dose ◽  
Dose Rate ◽  
Power Plants ◽  
Annual Effective Dose ◽  
Health Effect ◽  
Thermal Power ◽  
Bottom Ash ◽  
Effective Dose Rate ◽  
Annual Effective Dose Rate

AbstractHuge quantities of fly ash and bottom ash are generated from thermal power plants and it presents great concern for country, mainly due to the environmental effects. In this study, fly ashes and bottom ash were characterized from technical and radiological aspects. Health effect due to the activity of radionuclides 226Ra, 232Th and 40K was estimated via radium equivalent activity (Raeq), external hazards index (Hex), the external absorbed dose rate (D) and annual effective dose rate (EDR). The specific surface area (40.25 m2 g−1), particle density (1.88 g cm−3) and LOI (23.49%) were typical for bottom ash. Siliceous fly ash contained 32% reactive silica. The annual effective dose rate for all ashes is ≤ 0.2 mSv y−1. Both, fly ash and bottom ash present potential secondary raw materials to be used for building purposes as result of their technological and radiological assessment.

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.

Coal ash as structural fill, with special reference to Ontario experience

1988 ◽  
Vol 25 (4) ◽  
pp. 694-704 ◽  
Author(s):  
P. S. Toth ◽  
H. T. Chan ◽  
C. B. Cragg
Keyword(s):  
Fly Ash ◽  
Groundwater Monitoring ◽  
Bottom Ash ◽  
Coal Ash ◽  
Engineering Properties ◽  
Physical Behavior ◽  
Corrosion Studies ◽  
Groundwater Regime ◽  
The Impact

Fly ash and bottom ash obtained from coal-fired electric power generating stations can be used as alternatives to natural materials for the construction of structural fills. The engineering properties of coal ash pertinent to its use in structural fills are discussed. Four case studies of coal ash structural fills are presented. The performance of these fills was monitored during and after construction. These cases demonstrate that the physical behavior of fly ash is similar to that of silt and that it can be handled with similar methods. Groundwater monitoring data from existing fly ash fills are presented to show the impact that ash leachate migrating into the groundwater regime has on water quality. Results of long-term corrosion studies are presented to show that metals buried in ash, used in such structures as culverts, cable ducts, guard rails and streetlights, are not adversely affected. Ash leachate was found not to be detrimental to good-quality concrete structures. Key words: fly ash, fill, compaction, leachate, corrosion, concrete.

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