Studies on the Leaching and Weathering Processes of Coal Ashes

1983 ◽  
Vol 15 (11) ◽  
pp. 163-191 ◽  
Author(s):  
Hay Leim ◽  
Magnusöm Sandstr ◽  
Tom Wallin ◽  
Anders Carne ◽  
Ulla Rydevik ◽  
...  
Keyword(s):  
Power Plants ◽  
Coal Ash ◽  
Mass Action ◽  
Equilibrium Analysis ◽  
Metal Leaching ◽  
Magnetic Fraction ◽  
Fly Ashes ◽  
X Ray ◽  
Weathering Processes ◽  
Coal Ashes

Within the Swedish project Coal-Health-Environment (Kol-Hälsa-Mi1jö) leaching studies were made on several types of coal ashes, fly ashes, bottom ashes and scrubber sludges. Studies were made on the effects of pH, pCl, pCO3. pEDTA and pSO4, in the leaching solution on the leaching of metals from coal ashes. As a model for the leaching system, we studied the leaching of Cr, Co, Ni, tu, Zn, Mo, Se, As, Cd and Pb. The leaching of the metals was found to increase with pH for pH less than 2 and pH greater than 9, and to decrease for 2 > pH > 6. The metal leaching behaviour may in part be explained by the mass-action law. We have also made long-term leaching tests of several coal ashes from Danish and Finnish Power Plants using leaching water of different pH. The dominating crystalline phases in the different coal ashes have been identified by X-ray diffraction technique. The major species in the different coal ashes were found to be mullite (3A12.2SiO2), α-quartz (Sio2) and the iron oxides magnetite and hematite. Leaching and X-ray studies were also made on the magnetic fraction of the fly ashes. Equilibrium analysis were made on the system Me-OH-Cl-CO32− - SO42−, where Me = Cr, Co, Ni, Cu, Zn, Mo, Se, As, Cd and Pb, partly using the computer program HALTAFALL. A model for the metal leaching from a coal ash deposit will be discussed.

Transmitted and Reflected Visible Light Microscopy of Two Bituminous Fly Ashes

1984 ◽  
Vol 43 ◽  
Author(s):  
Donald L. Biggs ◽  
Joseph J. Bruns
Keyword(s):  
Fly Ash ◽  
Light Microscopy ◽  
Silicate Glass ◽  
Power Plants ◽  
Magnetic Fraction ◽  
Fly Ashes ◽  
Complete Replacement ◽  
Replacement Product ◽  
Nonmagnetic Particles ◽  
Ferrite Spinel

AbstractFly ashes of high magnetic content taken from two midwestern power plants were examined to determine the mineralogy of the magnetic and nonmagnetic fractions. Fly ash spheres from the magnetic fraction are predominantly composed of ferrite spinel, hematite and silicate glass. The hematite appears to be a replacement product of the original ferrite spinel. Nonmagnetic phases include mullite, lime, small amounts of hematite and silicate glass. Quartz morphology indicates that it did not fuse in the furnace. Mullite and lime have morphologies indicative of crystallization in the furnace. Hematite is bonded to the nonmagnetic particles or as a complete replacement of ferrite spinel spheres.

Mineralogy and Physical and Chemical Characteristics of Coal Ash from Yang Zonghai Power Plant

2010 ◽  
Vol 177 ◽  
pp. 497-501
Author(s):  
Feng Rui Zhai ◽  
Zhong Zhou Yi ◽  
Qun Cai ◽  
Huan Bin Song ◽  
Li Li Zhang ◽  
...  
Keyword(s):  
Power Plant ◽  
Particle Diameter ◽  
Coal Ash ◽  
Chemical Characteristics ◽  
Test Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Physical And Chemical Characteristics ◽  
Coal Ashes ◽  
Physical And Chemical

The modality, physical and chemical characteristics, mineralogy and distribution of particle size of coal ash were studied by modern analytic technology SEM, spectral analysis, X - ray Diffraction (XRD) and laser granularity analyzer. The test results show that the mineralogy of coal ashes is dominated mainly by mullite, quartz and hematite.The coal ash of Yang Zonghai power plant has lower content of calcium oxide and is low calcium ash.At the same time, the losing amount is low to burn.The particle diameter is small and mainly concentrates on the range of 1-40 m.

scholarly journals PEMANFAATAN LIMBAH PEMBAKARAN BATUBARA (BOTTOM ASH) PADA PLTU SURALAYA SEBAGAI MEDIA TANAM DALAM UPAYA MENGURANGI PENCEMARAN LINGKUNGAN

Kilat ◽  
2018 ◽  
Vol 6 (2) ◽  
pp. 129-138
Author(s):  
Redaksi Tim Jurnal
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Bottom Ash ◽  
Coal Ash ◽  
Direct Consequence ◽  
Growing Medium ◽  
Plant Remains ◽  
Mixed Medium ◽  
Research Procedure ◽  
Coal Ashes

This research on the utilization of coal-ash that is wasted at the coal-fired power plant is conducted with the intention to become an effort to alleviate environmental impact of the power plant. The by-production of such waste in coal-fired power plants is a direct consequence of the rising demand on electricity as one of human basic needs in modern lifestyle. Endeavor to save the environment is a manifestation of the good culture of environmental awareness; indeed, human being shall act responsibly for the soundness of the environment. Some sufficient amounts in different composition of coal bottom-ash from a coal-fired power plant mixed with another medium were implemented toward a variety of plants, i.e. a certain type of Orchid (“Moon” Orchid or Phalaenopsis amabilis), Tomato (Solanum lycopersicum) , and Sansevieria. A series of mixed medium with different composition (each particular composition is in triplicate), is prepared consisting of 0%, 25%, 50%. 75%, and 100% of Bottom Ash, consecutively. The observed result shows that Bottom Ash is not suitable for the orchid plant as its medium. This more probably results from the fact that the pH of Bottom Ash tends to be more alkaline, while the Orchid plant would only be growing optimally in acidic - normal condition. In the case of Tomato plant, Bottom Ash is usable to be the plant growing medium; in fact an increase of Bottom Ash percentage expedites the plant growth from its seed to become small plants. Another plant under observation is Sansivieria. Bottom Ash turns out to be suitable as a medium for this plant. In fact, this type of plant remains growing steadily and normally in media with variable percentage of Bottom Ash, all along the research procedure. Bottom Ash contains some nutrient that are beneficial to plants, such as Boron (B), Phosphorus (P) and among other elements are Cu, Zn, Mn, Mo dan Se. Most of coal-ashes tend to be alkaline with pH ranging from 8 to12.

scholarly journals Mineralogical and Chemical Characteristics of Coal Ashes from Two High-Sulfur Coal-Fired Power Plants in Wuhai, Inner Mongolia, China

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 323 ◽  
Author(s):  
Qiang Wei ◽  
Weijiao Song
Keyword(s):  
Trace Elements ◽  
Inner Mongolia ◽  
Power Plants ◽  
Bottom Ash ◽  
Distribution Patterns ◽  
Combustion Products ◽  
Chemical Characteristics ◽  
Fly Ashes ◽  
Coal Combustion Products ◽  
Coal Ashes

The mineralogical and chemical characteristics of the feed coals and coal combustion products (CCPs) from two power plants (Xilaifeng and Damo) that consume coals from the Wuda Coalfield, Inner Mongolia, were investigated, using XRD, SEM–EDS, XRF, and ICP-MS. The feed coals from Xilaifeng and Damo are both of high ash yield (52.93% and 48.36%, respectively), and medium and high total sulfur content (2.22% and 3.32%, respectively). The minerals in the feed coals are primarily composed of kaolinite, quartz, illite, pyrite, and, to a lesser extent, gypsum and anatase. In addition to the elevated incompatible elements (Nb, Ta, Zr, Hf and Th), Li and Hg are enriched in the feed coals from the Xilaifeng and Damo power plants, respectively. Rare earth elements and yttrium (REY) are more enriched in the feed coals from Xilaifeng (194 μg/g) than those of Damo (93.9 μg/g). The inorganic phases of CCPs from both power plants are mainly composed of amorphous phase, quartz, hematite, illite, and anhydrite. Compared with the feed coals, concentrations of most trace elements in the CCPs are elevated, and they are preferentially enriched in the fly ashes relative to the bottom ashes (*f/b > 1), especially F, As, Sr, Mo, Se, and Hg (*f/b > 2.5). Furthermore, most trace elements (Xilaifeng: excluding Li, Cr, Co, Ni, Rb, Nb and Cs; Damo: excluding Li, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Cs and Ba) are more enriched in the (fine) fly ashes relative to the laboratory high-temperature coal ashes (HTAs). The REY barely differentiate in either the fly ash or bottom ash from Xilaifeng. In contrast, the REY in the fine and coarse fly ashes from Damo have very similar H-type distribution patterns with negative Ce and slightly positive Y anomalies. Attention should be paid to the enriched toxic elements (including F, As and Hg) in the fly ashes from both power plants due to possible adverse environmental effect.

scholarly journals Mössbauer and X-ray Studies of Phase Composition of Fly Ashes Formed after Combustion of Ekibastuz Coal (Kazakhstan)

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 929
Author(s):  
Adilkhan Shokanov ◽  
Mikhail Vereshchak ◽  
Irina Manakova
Keyword(s):  
Phase Composition ◽  
Power Plants ◽  
Thermal Power ◽  
Hyperfine Interactions ◽  
Mixed Valence ◽  
X Ray Diffraction ◽  
Fly Ashes ◽  
Environment Effect ◽  
X Ray ◽  
Magnetite Fe3o4

Mössbauer spectroscopy and X-ray diffraction have been used to study samples of fly ashes formed after combustion of coal from the Ekibastuz basin at the thermal power plants TPP-2 and TPP-3 in Almaty (Kazakhstan). It has been established that the fractions of fly ashes contain iron in the form of magnetite Fe3O4 and hematite α-Fe2O3. The mixed valence of iron Fe3+ ↔ Fe2+ in the octahedral sublattice of magnetite is destroyed by isostructural substitution impurities. Maghemite γ-Fe2O3 is additionally present in the fly ash of TPP-3 as a product of magnetite slow oxidation. It was shown that at T ≥ 1400 °C the proportion of magnetite in fly ashes increases due to decomposition of hematite, maghemite, hercynite and the drop of iron content in mullite. It was concluded that the amount of iron in magnetite is a temperature indicator of fly ashes formation. The parameters of hyperfine interactions have been determined in the iron-containing minerals of fly ashes. It was identified that formation of the fly ashes structure occurs in oxidizing atmosphere, since no traces were revealed of reducing environment effect on the phase composition.

ANALYSIS OF CROPS GROWN ON COAL-ASH TREATED SOILS

2005 ◽  
Vol 15 (03n04) ◽  
pp. 301-308
Author(s):  
VENKATATHRI VIJAYAN
Keyword(s):  
Trace Elements ◽  
Power Plants ◽  
Thermal Power ◽  
Coal Ash ◽  
Thermal Power Plants ◽  
Solid Residue ◽  
Pond Ash ◽  
X Ray ◽  
Maize Grain ◽  
Increasing Trends

Coal ash is a major component of solid residue resulting by coal-fired thermal power plants. Trace elements like Mn , Cu , Zn , As , Se , Mo and Pb in fly ash and pond ash samples collected from ten coal-fired thermal power plants in India, and crops (rice, wheat, maize grain and straw and onion bulbs) grown on coal ash treated soils at Angul, Bakreswar and Farakka sites of India have been analysed at Institute of Physics by Particle Induced X-ray Emission and Energy Dispersive X-Ray Fluorescence techniques. Our analysis shows that the concentrations of trace elements of grains are higher than in straws. Increasing trends in the uptake of micro-nutrients by the crops due to application of coal ash, were recorded, but within permissible limits.

scholarly journals Quasi Natural Approach for Crystallization of Zeolites from Different Fly Ashes and Their Application as Adsorbent Media for Malachite Green Removal from Polluted Waters

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1064
Author(s):  
Denitza Zgureva ◽  
Valeria Stoyanova ◽  
Annie Shoumkova ◽  
Silviya Boycheva ◽  
Georgi Avdeev
Keyword(s):  
Chemical Composition ◽  
Malachite Green ◽  
Power Plants ◽  
Thermal Power ◽  
Alkaline Treatment ◽  
Heterogeneous Structure ◽  
Fly Ashes ◽  
X Ray ◽  
Natural Approach ◽  
Wide Range

Worldwide disposal of multi-tonnage solid waste from coal-burning thermal power plants (TPPs) creates serious environmental and economic problems, which necessitate the recovery of industrial waste in large quantities and at commercial prices. Fly ashes (FAs) and slag from seven Bulgarian TPPs have been successfully converted into valuable zeolite-like composites with various applications, including as adsorbents for capturing CO2 from gases and for removal of contaminants from water. The starting materials generated from different types of coal are characterized by a wide range of SiO2/Al2O3 ratio, heterogeneous structure and a complex chemical composition. The applied synthesis procedure resembles the formation of natural zeolites, as the raw FAs undergo long-term self-crystallization in an alkaline aqueous solution at ambient temperature. The phase and chemical composition, morphology and N2 adsorption of the final zeolite products were studied by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-Ray Diffraction (XRD) and Brunauer–Emmett–Teller (BET) analyses. The growth of faujasite (FAU) crystals as the main zeolite phase was established in all samples after 7 and 14 months of alkaline treatment. Phillipsite (PHI) crystals were also observed in several samples as an accompanying phase. The final products possess specific surface area over 400 m2/g. The relationships between the surface properties of the investigated samples and the characteristics of the raw FAs were discussed. All of the obtained zeolite-like composites were able to remove the highly toxic dye (malachite green, MG) from water solutions with efficiency over 96%. The experimental data were fitted with high correlation to the second-order kinetics.

scholarly journals Distribution of Some Ecotoxic Elements in Fuel and Solid Combustion Residues in Poland

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1131 ◽  
Author(s):  
Henryk R. Parzentny ◽  
Leokadia Róg
Keyword(s):  
Fly Ash ◽  
Inductively Coupled Plasma ◽  
Power Plants ◽  
Dendritic Structure ◽  
Atomic Emission ◽  
Magnetic Fraction ◽  
Petrographic Composition ◽  
X Ray ◽  
Distribution Of Elements ◽  
Combustion Residues

The purpose of this paper is to assess the content and distribution of some elements in coal from two bituminous coal basins and in fly ash and slag derived from combustion of the coals in six power plants in Poland. The petrographic composition and distribution of elements were characterized in the tested samples, using reflected light microscope, X-ray powder diffractometer, inductively coupled plasma atomic emission spectroscopy, and scanning electron microscope with energy dispersive X-ray. The highest content of elements in coal occurs in siderite. In Al-Si particles, as well as in magnetite with skeletal and dendritic structure crystallized on the surface of Al-Si microspheres or cenospheres included in fly ash size < 0.05 mm and in the magnetic fraction of slag, the highest content of elements was noted. Due to the content of elements, fly ash and slag were considered to be neutral for the soil environment. Correlations, which have not been described before, have been observed between the likely mode of binding of some elements in coal and their distribution in fly ash and slag. These correlations could be of particular value when predicting the content and distribution of elements in combustion residues and in the assessment of their environmental toxicity.

The comparison of regulations on fly ash as a hazardous waste in Indonesia and several countries

2021 ◽  
Vol 26 (2) ◽  
pp. 150-162
Author(s):  
Januarti Jaya Ekaputri ◽  
M. Shahib Al Bari
Keyword(s):  
Fly Ash ◽  
Hazardous Waste ◽  
Power Plants ◽  
Government Regulation ◽  
Bottom Ash ◽  
Coal Ash ◽  
Oral Toxicity ◽  
Fly Ashes ◽  
Indonesian Government ◽  
The Status

This paper aims to encourage the Indonesian government to review the 2014 Government Regulation (PP) number 101 related to coal-ash. Fly ashes at power plants overload the landfills and requires complete handling solution. The utilization of fly ash in Indonesia are facing the issues, one of these is the categorization of fly ash as a hazardous waste. As a result, its utilization requires permissions from the ministry of environment and forestry. In this paper, a comparative study of fly ash classification as hazardous waste in India, United States of America, China and Vietnam was conducted. India and China are the coal importer from Indonesia. US regulation was once referred when drafting PP number 101. Vietnam is chosen as comparison in Southeast Asia. The Toxicity Characteristic Leaching Procedure (TCLP) results of fly ashes from 16 Indonesian power plants proved that their toxic content was lower than the TCLP parameters in the regulation. Acute Oral Toxicity Test (LD50) results showed that fly ash and bottom ash with dosage up to 7000 mg/kg did not cause fatalities. This study is a reference for the Indonesian government to verify the status of fly ash to be utilized as much as possible in various fields.

scholarly journals Leaching of the potentially toxic pollutants from composites based on waste raw material

2012 ◽  
Vol 18 (3) ◽  
pp. 373-383 ◽  
Author(s):  
Anja Terzic ◽  
Zagorka Radojevic ◽  
Ljiljana Milicic ◽  
Ljubica Pavlovic ◽  
Zagorka Acimovic
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Microstructural Analysis ◽  
Construction Materials ◽  
Significant Risk ◽  
Raw Material ◽  
Fly Ashes ◽  
X Ray ◽  
Toxic Pollutants ◽  
Physico Chemical

The disposal of the fly ash generated in coal based power-plants may pose a significant risk to the environment due to the possible leaching of hazardous pollutants, such as toxic metals. Also, there is a risk of leaching even when fly ash is built-in the construction composites. Fly ashes from various landfills were applied in several composite samples (mortar, concrete and brick) without any physical or thermal pre-treatment. The leachability of the potentially toxic pollutants from the fly ash based products was investigated. The leaching behavior and potential environmental impact of the 11 potentially hazardous elements was tracked: Pb, Cd, Zn, Cu, Ni, Cr, Hg, As, Ba, Sb and Se. A detailed study of physico-chemical characteristics of the fly ash, with accent on trace elements and the chemical composition investigation is included. Physico/chemical properties of fly ash were investigated by means of X-ray fluorescence, differential thermal analysis and X-ray diffraction methods. Scanning electron microscope was used in microstructural analysis. The results show that most of the elements are more easily leachable from the fly ash in comparison with the fly ash based composites. The leaching of investigated pollutants is within allowed range thus investigated fly ashes can be reused in construction materials production.

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