Characterization of North American Lignite Fly Ashes I. Chemical Variation

1987 ◽  
Vol 113 ◽  
Author(s):  
Robert J. Stevenson ◽  
James C. Collier ◽  
John J. Crashell ◽  
Larry R. Quandt
Keyword(s):  
Fly Ash ◽  
North American ◽  
Direct Relationship ◽  
Bulk Sample ◽  
Geographic Region ◽  
Chemical Variation ◽  
Fly Ashes ◽  
Lignite Fly Ash ◽  
Chemical Variability ◽  
The Individual

ABSTRACTThe chemical variation of central North American lignite fly ash can be compared using the major and minor oxide analyses and the distribution pattern of the inter-grain chemistries of the individual fly ash particles. AAS and electron microprobe chemical analysis of nineteen fly ashes have been used to illustrate the variations in bulk sample and individual grain chemistry. This information documents the chemical variability of the lignite fly ashes by geographic region. There is a direct relationship between grains rich in SiO2 and Al2O3 and in the Na2O content of the grains in lignite derived fly ashes. There is also a direct relationship between grains rich in CaP and the MgO and SO3 content of the grains in lignite derived fly ashes.

Semi-Quantitative XRD Analysis of Fly Ash Using Rutile as an Internal Standard

1988 ◽  
Vol 32 ◽  
pp. 569-576 ◽  
Author(s):  
A. Thedchanamoorthy ◽  
G.J. McCarthy
Keyword(s):  
Fly Ash ◽  
Error Analysis ◽  
North American ◽  
Intensity Ratio ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Xrd Analysis ◽  
X Rays ◽  
Fly Ashes ◽  
Crystalline Phases

AbstractXRD analysis of fly ash was quantitated using the Reference Intensity Ratio (RIR) method and rutile (TiO2) as an internal standard. Rutile RIR's for 15 of the crystalline phases commonly observed in North American fly ash were determined. Error analysis on the various steps in quantitation indicated that precision ranged from ±10% of the amount present for phases that diffract x-rays strongly to ±21% for weakly diffracting phases. Limit of detection in the mostly glassy fly ashes ranged from 0.2% for lime, the most strongly diffracting phase, to 3.5% for weakly diffracting mullite. Accuracy evaluated with a simulated fly ash was within the limits established by precision, but in actual fly ash samples, accuracy will be a function of the match between the crystallinity and composition of the analyte and the analyte standard. Overlaps among peaks of some of the important phases require intensity proportioning; for this reason, the method is best described as semi-quantitative.

Characterization of North American Lignite Fly Ashes II. XRD Mineralogy

1987 ◽  
Vol 113 ◽  
Author(s):  
G. J. McCarthy ◽  
D. M. Johansen ◽  
A. Thedchanamoorthy ◽  
S. J. Steinwand ◽  
K. D. Swanson
Keyword(s):  
Fly Ash ◽  
Bituminous Coal ◽  
Coal Fly Ash ◽  
Fly Ashes ◽  
X Ray ◽  
Mining Areas ◽  
Lignite Fly Ash ◽  
Coal Fly Ashes ◽  
Ferrite Spinel

ABSTRACTX-ray powder diffraction has been used to determine the crystalline phase mineralogy in samples of fly ash from each of the lignite mining areas of North America. The characteristic phases of North Dakota lignite fly ashes were periclase, lime, merwinite and the sulfate phases anhydrite, thenardite and a sodalite-structure phase. Mullite was absent in these low-Al2O3 ashes. Montana lignite ash mineralogy had characteristics of ND lignite and MT subbituminous coal fly ashes; mullite and C3A were present and the alkali sulfates were absent. Texas and Louisiana lignite fly ashes had the characteristic mineralogy of bituminous coal fly ash: quartz, mullite, ferrite-spinel (magnetite) and minor hematite. Even though their analytical CaO contents were 7–14%, all but one lacked crystalline CaO-containing phases. Lignite fly ashes from Saskatchewan were generally the least crystalline of those studied and had a mineralogy consisting of quartz, mullite, ferrite spinel and periclase. Quantitative XRD data were obtained. The position of the diffuse scattering maximum in the x-ray diffractograms was indicative of the glass composition of the lignite fly ash.

scholarly journals Distribution of Lanthanides, Yttrium, and Scandium in the Pilot-Scale Beneficiation of Fly Ashes Derived from Eastern Kentucky Coals

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 105 ◽  
Author(s):  
James C. Hower ◽  
John G. Groppo ◽  
Prakash Joshi ◽  
Dorin V. Preda ◽  
David P. Gamliel ◽  
...  
Keyword(s):  
Rare Earth ◽  
Fly Ash ◽  
Power Plants ◽  
Pilot Scale ◽  
Fly Ashes ◽  
Eastern Kentucky ◽  
Minor Elements ◽  
High Concentrations ◽  
The Individual ◽  
Plant Basis

In this study, Central Appalachian coal-derived fly ashes from two power plants were beneficiated in a pilot-scale facility in order to produce a product with a relatively consistent concentration of rare earth elements (REE). The <200-mesh final fly ash product was produced by removing the carbon- and Fe-rich particles prior to screening at 200 mesh (75 µm). The Plant D fly ash had high concentrations of CaO and SO3, which were diminished through the two months when the ash was being beneficiated, representing a consequence of the heat, humidity, and excessive rainfall in the Kentucky summer. The high CaO and SO3 concentrations through the early runs likely contributed to the lower REE in the <200-mesh products of those runs. Of the non-REE minor elements, Ba, V, Mn, Zn, and As showed the greatest between-run variations within the runs for each plant. The overall REE concentrations proved to be similar, both on a between-run basis for the individual fly ash sources and on a between-plant basis. Variations in fly ash quality will occur in larger-scale operations, so on-going attention to the fly ash quality and the response of the fly ash to beneficiation is necessary. Changes in the Plant D fly ash with time imply that both the freshness of the original ash and the length and conditions of its storage at the site of beneficiation could be factors in the quality and consistency of the processed fly ash.

Use of a Database of Chemical, Mineralogical and Physical Properties of North American Fly Ash to Study the Nature of Fly Ashand Its Utilization as a Mineral Admixture in Concrete

1989 ◽  
Vol 178 ◽  
Author(s):  
G. J. Mccarthy ◽  
J. K. SOLEM ◽  
O. E. Manz ◽  
D. J. Hassett
Keyword(s):  
Fly Ash ◽  
North American ◽  
Chemical Constituents ◽  
Mineral Admixture ◽  
Test Results ◽  
Fly Ashes ◽  
Physical Test ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Bulk Chemical

AbstractA database of chemical, mineralogical and physical characteristics of North American fly ashes has been assembled by the Western Fly Ash Research, Development and Data Center. One-hundred and seventy-eight representative ashes were divided into three groups according to their analytical CaO content: low-calcium, <10%; intermediate-calcium, 10–20%; high-calcium, 20+%. Statistical analyses were performed within each of the three groups. Thirty-two plots relating chemical composition, mineralogy and physical test results are presented. Extensive discussions relating the chemistry and mineralogy of the ash to the source coal, the distribution of the chemical constituents among crystalline and glassy phases, and the reactions of these phases in concrete are given. The consistency of high-calcium fly ash generated at a Midwestern U.S. power station fired with Wyoming bituminous coal was studied using ninety-three ashes collected over a two year period. The availability of mineralogy for each ash leads to a more thorough understanding of the bulk chemical and physical test results used in evaluating fly ashes for utilization, and in modeling their behavior after disposal

scholarly journals Effect of Lignite Fly Ash on the Growth and Reproduction of Earthworm Eisenia fetida

2009 ◽  
Vol 6 (2) ◽  
pp. 511-517 ◽  
Author(s):  
S. Sarojini ◽  
S. Ananthakrishnasamy ◽  
G. Manimegala ◽  
M. Prakash ◽  
G. Gunasekaran
Keyword(s):  
Fly Ash ◽  
Eisenia Fetida ◽  
Power Plants ◽  
Thermal Power ◽  
Biological Properties ◽  
Cow Dung ◽  
Physical Chemical ◽  
Lignite Fly Ash ◽  
Agricultural Use ◽  
Growth And Reproduction

Fly ash is an amorphous ferroalumino silicate, an important solid waste around thermal power plants. It creates problems leading to environmental degradation due to improper utilization or disposal. However, fly ash is a useful ameliorant that may improve the physical, chemical and biological properties of soils and is a source of readily available plant macro and micronutrients when it is used with biosolids. Supply of nutrients from fly ash with biosolids may enhance their agricultural use. The growth and reproduction ofEisenia fetidawas studied during vermicomposting of fly ash with cowdung and pressmud in four different proportions (T1,T2,T3& T4) and one controli.e.,cow dung and pressmud alone. The growth, cocoon and hatchlings production were observed at the interval of 15 days over a period of 60 days. The maximum worm growth and reproduction was observed in bedding material alone. Next to that the T1was observed as the best mixture for vermiculture.

Influence of Different Mineral Precursors on the Properties of Fly Ash Based Alkali-Activated Mortars

2018 ◽  
Vol 761 ◽  
pp. 73-78 ◽  
Author(s):  
Matej Špak ◽  
Pavel Raschman
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Chemical Composition ◽  
Coal Combustion ◽  
Pure Aluminum ◽  
Partial Replacement ◽  
Black Coal ◽  
Fly Ashes ◽  
Final Composition ◽  
Alkali Activated

Alkali-activated materials based on fly ash are widely developed and also produced on the present. Some of fly ashes are not suitable for production of alkali-activated materials because of their inconvenient chemical composition. Alumina-silicates are the most important components that are needed to accomplish the successful reaction. The proper content of amorphous phase of alumina-silicates and its proportion as well should be provided for the final composition of alkali-activated materials. The influence of pure aluminum oxide powder as well as raw milled natural perlite on mechanical properties and durability of alkali-activated mortars was investigated. These minerals were used as partial replacement of fly ash coming from black coal combustion. In addition, the mortars were prepared by using different alkali activators.

Evaluation of Synthetic Aggregate from Lignite Fly Ash

1974 ◽  
Vol 100 (1) ◽  
pp. 27-40
Author(s):  
Roger L. Engelke ◽  
William B. Ledbetter ◽  
Bob M. Gallaway
Keyword(s):  
Fly Ash ◽  
Lignite Fly Ash

Electrokinetic Phenomena and Surface Characteristics of Fly Ash Particles

1984 ◽  
Vol 43 ◽  
Author(s):  
R. I. A. Malek ◽  
D. M. Roy
Keyword(s):  
Fly Ash ◽  
Surface Characteristics ◽  
Ionic Species ◽  
Point Of Zero Charge ◽  
Fly Ashes ◽  
Electrokinetic Phenomena ◽  
Zeta Potentials ◽  
Low Calcium ◽  
High Calcium

AbstractThe zeta-potentials of two fly ashes were studied (high-calcium and low-calcium). It was found that they possess a point of charge reversal at pH = 10.5 to 12. The point of zero charge (low-calcium fly ash) was found to be at pH = 5. Furthermore, it shifted to more acidic values after the fly ash is aged in several calcium-containing solutions. The surficial changes that could happen when mixing fly ashes with cement and concrete were further evaluated by aging fly ashes in different solutions: Ca(OH)2, CaSO4·2H2O, NaOH and water solutions. Information from analyses for different ionic species in the solutions and characterization of the solid residues (XRD and SEM) was used in tentative explanations for the different behavior of the two types of fly ash in cementitious mixtures and concrete.

Low Cement/High Fly Ash Concretes: Their Properties and Response to Chemical Admixtures

1987 ◽  
Vol 113 ◽  
Author(s):  
V. H. Dodson
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Calcium Hydroxide ◽  
Pozzolanic Reaction ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Fly Ashes ◽  
Chemical Admixtures ◽  
Reaction With Water

ABSTRACTIn practice, the amount of fly ash added to portland cement concrete varies depending upon the desired end properties of the concrete. Generally, when a given portland cement concrete is redesigned to include fly ash, between 10 and 50% of the cement is replaced by a volume of fly ash equal to that of the cement. Sometimes as much as twice the volume of the cement replaced, although 45.4 kg (100 lbs) of cement will only produce enough calcium hydroxide during its reaction with water to react with about 9 kg (20 lbs) of a typical fly ash. The combination of large amounts of certain fly ashes with small amounts of portland cement in concrete has been found to produce surprisingly high compressive strengths, which cannot be accounted for by the conventional “pozzolanic reaction”. Ratios of cement to fly ash as high as 1:15 by weight can produce compressive strengths of 20.7 MPa (3,000 psi) at I day and over 41.4 MPa (6,000 psi) at 28 days. Methods of identifying these “hyperactive” fly ashes along with some of the startling results, with and without chemical admixtures are described.

scholarly journals Fly Ash Modified Coalmine Solid Wastes for Stabilization of Trace Metals in Mining Damaged Land Reclamation: A Case Study in Xuzhou Coalmine Area

2018 ◽  
Vol 15 (10) ◽  
pp. 2317 ◽  
Author(s):  
Jiu Huang ◽  
Peng Wang ◽  
Chaorong Xu ◽  
Zhuangzhuang Zhu
Keyword(s):  
Fly Ash ◽  
Trace Metal ◽  
Soil Layer ◽  
Fly Ashes ◽  
Migration Ability ◽  
Metal Elements ◽  
Trace Metal Elements ◽  
Simulated Precipitation ◽  
Backfill Materials

In China, coalmine wastes, such as gangues, are used for reclamation of mining subsided land. However, as waste rocks, gangues contain several trace metal elements, which could be released under natural weathering and hydrodynamic leaching effects and then migrate into the reclamed soil layer. However, it is very difficult to find adequate other backfill materials for substitution of gangues. In this paper, we present a novel method and case study to restrict the migration ability of trace metal elements in gangues by using another kind of coalmine solid waste—fly ashes from coal combustion. In this study, fly ashes were mixed with gangues in different mass proportions 1:0.2, 1:0.4, 1:0.6 and 1:0.8 as new designed backfill materials. Due to the help of fly ash, the occurrence states of studied trace metal elements were greatly changed, and their releasing and migration ability under hydrodynamic leaching effect were also significantly restricted. In this research seven trace metal elements in gangues Cu, Zn, Pb, Cd, Cr, Mn and Ni were studied by using soil column hydrodynamical leaching method and simulated precipitation for one year. The results show that under the driving of natural precipitation trace metal elements were generally transported deep inside the reconstructed land base, i.e., far away from soil layer and most of the trace metal elements were transformed into a bonded state, or combined in inert occurrence states, especially the residual state. With this method, the migration activities of tested trace metal elements were greatly restricted and the environmental potential risk could be significantly reduced.

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