scholarly journals The Solidification/Stabilization of Wastewater (From a Landfill Leachate) in Specially Designed Binders Based on Coal Ash

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5610
Author(s):  
Carmen-Lidia Oproiu ◽  
Georgeta Voicu ◽  
Alina Bădănoiu ◽  
Adrian-Ionuţ Nicoară
Keyword(s):  
Fly Ash ◽  
Complex Analysis ◽  
Waste Treatment ◽  
Bottom Ash ◽  
Liquid Waste ◽  
Coal Ash ◽  
X Ray Diffraction ◽  
Pozzolanic Reactivity ◽  
Calcium Silicate Hydrates ◽  
Cementitious Systems

The aim of this study is to assess the possibility to solidify/stabilize a liquid waste from a municipal waste landfill using binders based on coal ash (fly ash and bottom ash) and specially designed cements for waste treatment (INERCEM). The leaching test proved that all cementitious systems are efficient for the solidification/stabilization of the studied wastes and can reduce the leaching potential of heavy metals present in both liquid waste and coal ash. Therefore, these wastes cease to be a source of environmental pollution. X-ray diffraction (XRD) and thermal complex analysis (DTA-TG) were used to assess the nature and amount of compounds formed in these cementitious systems during the hydration and hardening processes; ettringite, calcium silicate hydrates and CaCO3 were the main compounds formed in these systems assessed by these methods. The microstructure of hardened specimens was assessed by scanning electronic microscopy (SEM); the presence of hydrate phases, at the surface of cenospheres present in fly ash, proved the high pozzolanic reactivity of this phase.

scholarly journals Reactivity of Ground Coal Bottom Ash to Be Used in Portland Cement

J ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 223-232
Author(s):  
Esperanza Menéndez ◽  
Cristina Argiz ◽  
Miguel Ángel Sanjuán
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Bottom Ash ◽  
Blended Cement ◽  
Coal Ash ◽  
Pozzolanic Reaction ◽  
Natural Sand ◽  
Coal Bottom Ash ◽  
Novel Material ◽  
Pozzolanic Properties

Ground coal bottom ash is considered a novel material when used in common cement production as a blended cement. This new application must be evaluated by means of the study of its pozzolanic properties. Coal bottom ash, in some countries, is being used as a replacement for natural sand, but in some others, it is disposed of in a landfill, leading thus to environmental problems. The pozzolanic properties of ground coal bottom ash and coal fly ash cements were investigated in order to assess their pozzolanic performance. Proportions of coal fly ash and ground coal bottom ash in the mixes were 100:0, 90:10, 80:20, 50:50, 0:100. Next, multicomponent cements were formulated using 10%, 25% or 35% of ashes. In general, the pozzolanic performance of the ground coal bottom ash is quite similar to that of the coal fly ash. As expected, the pozzolanic reaction of both of them proceeds slowly at early ages, but the reaction rate increases over time. Ground coal bottom ash is a promising novel material with pozzolanic properties which are comparable to that of coal fly ashes. Then, coal bottom ash subjected to an adequate mechanical grinding is suitable to be used to produce common coal-ash cements.

Microstructure and Mechanical Properties of Ambiently-Cured Blended Coal Ash-Based Geopolymer Concrete

2016 ◽  
Vol 857 ◽  
pp. 400-404
Author(s):  
Tian Yu Xie ◽  
Togay Ozbakkaloglu
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Compressive Strength ◽  
Fly Ash ◽  
Bottom Ash ◽  
Coal Ash ◽  
Geopolymer Concrete ◽  
Mass Ratio ◽  
Blended Coal ◽  
Microstructure And Mechanical Properties

This paper presents the results of an experimental study on the behavior of fly ash-, bottom ash-, and blended fly and bottom ash-based geopolymer concrete (GPC) cured at ambient temperature. Four bathes of GPC were manufactured to investigate the influence of the fly ash-to-bottom ash mass ratio on the microstructure, compressive strength and elastic modulus of GPC. All the results indicate that the mass ratio of fly ash-to-bottom ash significantly affects the microstructure and mechanical properties of GPCs

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.

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.

An Overview of Fly Ash and Bottom Ash Replacement in Self-Compaction Concrete

2013 ◽  
Vol 594-595 ◽  
pp. 465-470 ◽  
Author(s):  
Aeslina binti Abdul Kadir ◽  
Mohd Ikhmal Haqeem Hassan
Keyword(s):  
Fly Ash ◽  
Coal Combustion ◽  
Building Materials ◽  
Bottom Ash ◽  
Coal Ash ◽  
Limestone Powder ◽  
Conventional Concrete ◽  
Hydraulic Lime ◽  
Pollution Problem ◽  
Labor Requirements

Over the centuries, concrete is commonly been used in construction world due to its properties. From the conventional concrete until the concrete that has been diversify with innovations, the usefulness is still the same, which is as building materials. One of the innovations called Self-Compaction Concrete (SCC). SCC is a type of concrete that does not require any mechanical compaction at all. This type of concrete will leveled and compacted under its self-weight. Such concrete will accelerate the placement, reduce the labor requirements needed for consolidation, finishing and eliminate environmental pollution. In terms of sustainability, previous researchers have recycled so many waste in SCC for example coal ash, silica fume, hydraulic lime, rice husk ash and fine limestone powder. Recently, recycling fly ash and bottom ash in SCC has grasped the attention of researchers as it demonstrated promising results. Furthermore, previous investigations already confirmed the potential of fly ash and bottom ash in replacing aggregates in SCC represents a better option than landfill and at the same time will decrease pollution problem especially in coal combustion area. This paper reviews the fly ash and bottom ash replacement in SCC.

A review on fly ash from coal-fired power plants: chemical composition, regulations, and health evidence

2020 ◽  
Vol 35 (4) ◽  
pp. 401-418 ◽  
Author(s):  
Kristina M. Zierold ◽  
Chisom Odoh
Keyword(s):  
Fly Ash ◽  
Chemical Composition ◽  
Power Plants ◽  
Waste Product ◽  
Bottom Ash ◽  
Coal Ash ◽  
Epidemiological Studies ◽  
The World ◽  
Main Component ◽  
Surface Impoundments

AbstractThroughout the world, coal is responsible for generating approximately 38% of power. Coal ash, a waste product, generated from the combustion of coal, consists of fly ash, bottom ash, boiler slag, and flue gas desulfurization material. Fly ash, which is the main component of coal ash, is composed of spherical particulate matter with diameters that range from 0.1 μm to >100 μm. Fly ash is predominately composed of silica, aluminum, iron, calcium, and oxygen, but the particles may also contain heavy metals such as arsenic and lead at trace levels. Most nations throughout the world do not consider fly ash a hazardous waste and therefore regulations on its disposal and storage are lacking. Fly ash that is not beneficially reused in products such as concrete is stored in landfills and surface impoundments. Fugitive dust emissions and leaching of metals into groundwater from landfills and surface impoundments may put people at risk for exposure. There are limited epidemiological studies regarding the health effects of fly ash exposure. In this article, the authors provide an overview of fly ash, its chemical composition, the regulations from nations generating the greatest amount of fly ash, and epidemiological evidence regarding the health impacts associated with exposure to fly ash.

scholarly journals Leaching characteristics of wastes from Kemerkoy (Mugla-Turkey) power plant

2013 ◽  
Vol 2 (1) ◽  
pp. 51-57
Keyword(s):  
Fly Ash ◽  
Power Plant ◽  
Thermal Power Plant ◽  
Thermal Power ◽  
Extraction Procedure ◽  
Bottom Ash ◽  
Coal Ash ◽  
Toxicity Tests ◽  
Western Coast ◽  
Ash Disposal

A main problem related to coal ash disposal is the heavy metal content of the residue. In this regard, experimental results of numerous studies have indicated that toxic trace metals may leach when fly ash and bottom ash contacts with water. In this study, fly ash and bottom ash samples obtained from Kemerköy thermal power plant, located on the south-western coast of Turkey, were subjected to toxicity tests such as the extraction procedures (EP) and toxicity characteristic leaching procedures (TCLP) of the U.S. Environmental Protection Agency (U.S. EPA), the so-called Method A extraction procedure of the American Society of Testing and Material (ASTM). When Pb and Cd concentrations, analysed according to EP and TCLP, were considered, Kemerköy fly and bottom ash can be classified as a hazardous waste under the principles of the Federal Resource Conservation and Recovery Act (RCRA). Based on the geochemical analyses carried out, it was also determined that several toxic trace elements, such as Pb, Zn, Cd, Cu and Co were enriched at the fly and bottom ash of Kemerköy thermal power plant.

scholarly journals Coal ash Portland Cement Mortars Sulphate Resistance

2021 ◽  
Vol 7 (1) ◽  
pp. 98-106
Author(s):  
Esperanza Menéndez ◽  
Cristina Argiz ◽  
Miguel Ángel Sanjuán
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Coal Fly Ash ◽  
Electrical Power ◽  
Bottom Ash ◽  
Coal Ash ◽  
Sodium Sulphate ◽  
Sulphate Attack ◽  
Coal Bottom Ash ◽  
Cement Mortars

Coal fly ash (CFA), coal bottom ash (CBA) are residues produced in thermo-electrical power stations as result of the coal combustion in the same boiler. Therefore, some characteristics of the coal fly ash (CFA) are comparable with those of the coal bottom ash (CBA). Nevertheless, coal bottom ash size is larger than coal fly ash one. Consequently, it was found that it is necessary to grind the coal bottom ash (CBA) to reach a similar size to that one of the CFA. The objective of this paper is to evaluate the performance of Portland cement mortars made with coal fly ash (CFA), coal bottom ash (CBA) or mixes (CFA+CBA), against sulphate attack. The methodology is based on the expansion of slender bars submerged in a sodium sulphate solution (5%) according to the ASTM C-1012/C1012-13 standard. It has been found that mortars elaborated with CEM I 42.5 N (without ashes) presented the largest expansion (0.09%) after a testing period of 330 days. Mortars made with CEM II/A-V exhibited lower expansion (0.03%). Summing up, it can be established that mortar expansion decreases when the coal ash amount increases, independently of the type of coal ash employed. The novelty of this paper relies on the comparison between the performances of Portland cement mortars made with coal fly ash (CFA) or coal bottom ash (CBA) exposed to external sulphate attack. Doi: 10.28991/cej-2021-03091640 Full Text: PDF

Characterization of Coal Fly Ash for Use in Synthesis of Zeolites

2018 ◽  
Vol 930 ◽  
pp. 578-583
Author(s):  
Augusto César Cavalcanti Gomes ◽  
Andrea de Vasconcelos Ferraz ◽  
Lucimar Pacheco Gomes da Rocha
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Coal Ash ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inorganic Oxides ◽  
Chemical Treatments ◽  
Xrf Scanning ◽  
The Matrix ◽  
Physical And Chemical

Due to the large quantity of fly ash produced during the combustion of coal, it has become necessary to give greater applicability to this residue of low commercial value. The residue contains inorganic oxides which can act on the crystalline structure of zeolites, namely silicon and aluminum oxide. The coal ash was submitted to physical and chemical treatments with the aim of potentiating the silicon and aluminum extraction from the residue. The pure ash and the treated ashes were characterized by: X-ray fluorescence (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transformation infrared spectroscopy (FTIR). By means of the carried out characterizations it was observed that the treatments were effective for the extraction of aluminosilicates from the matrix. The treatments did not affect the morphology, the crystalline phases and neither the chemical composition of the ashes. Seeing this, the coal ash and its treatments showed to be a precursor for the synthesis of zeolites.

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