Variability and Trends in Iowa Fly Ashes

1986 ◽  
Vol 86 ◽  
Author(s):  
Scott Schlorholtz ◽  
Ken Bergeson ◽  
Turgut Demirel
Keyword(s):  
Fly Ash ◽  
Chemical Composition ◽  
Power Plant ◽  
Coefficient Of Variation ◽  
Power Plants ◽  
Chemical Properties ◽  
Physical Analysis ◽  
Fly Ashes ◽  
High Calcium ◽  
Physical And Chemical

ABSTRACTAn investigation has been made of the variability of physical and chemical properties of high-calcium (Class C) fly ashes from four Iowa power plants. The investigation summarizes results obtained from three years (1983 through 1985) of monitoring of the various power plants. All four of the power plants burn low-sulfur, sub-bituminous coal from Wyoming. Fly ash samples were obtained from the power plants in accordance to the procedures described in ASTM C 311. Laboratory testing methods were similar to those specified by ASTM C 311. During the three year period, 102 samples were subjected to chemical and physical analysis while an additional 349 samples were subjected to physical analysis only. In general, the four power plants produce fly ashes of similar mineralogy and chemical composition. The observed time variation of the chemical composition of fly ash from a single power plant was quite small. The sulfur content consistently showed the largest coefficient of variation of the 10 elements studied. Physical characteristics of the fly ashes (as measured by ASTM tests) were also fairly uniform over long periods of time, when considered on an individual power plant basis. Fineness, when measured by wet washing using a 325 mesh sieve, consistently exhibited the largest coefficient of variation of any of the physical properties studied.

Monitoring of Fluctuations in the Physical and Chemical Properties of a High-Calcium Fly Ash

1987 ◽  
Vol 113 ◽  
Author(s):  
Scott Schlorholtz ◽  
Ken Bergeson ◽  
Turgut Demirel
Keyword(s):  
Fly Ash ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Physical And Chemical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Morphological Studies ◽  
High Calcium ◽  
Physical And Chemical ◽  
And Chemical Properties

ABSTRACTThe physical and chemical properties of fly ash produced at Ottumwa Generating Station have been monitored since April, 1985. The fly ash is produced from burning a low sulfur, sub-bituminous coal obtained from the Powder River Basin near Gillette, Wyoming. One-hundred and sixty samples of fly ash were obtained during the two year period. All of the samples were subjected to physical testing as specified by ASTM C 311. About one-hundred of the samples were also subjected to a series of tests designed to monitor the self-cementing properties of the fly ash. Many of the fly ash samples were subjected to x-ray diffraction and fluorescence analysis to define the mineralogical and chemical composition of the bulk fly ash as a function of sampling date. Hydration products in selected hardened fly ash pastes, were studied by x-ray diffraction and scanning electron microscopy. The studies indicated that power plant operating conditions influenced the compressive strength of the fly ash paste specimens. Mineralogical and morphological studies of the fly ash pastes indicated that stratlingite formation occurred in the highstrength specimens, while ettringite was the major hydration product evident in the low-strength specimens.

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.

scholarly journals Reactivity of fly ashes milled in different milling devices

2019 ◽  
Vol 58 (1) ◽  
pp. 179-188 ◽  
Author(s):  
Yong-Sik Chu ◽  
Batmunkh Davaabal ◽  
Dae-Sung Kim ◽  
Sung-Kwan Seo ◽  
Yoo Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Surface Area ◽  
Thermal Power ◽  
Chemical Properties ◽  
Particle Size Reduction ◽  
Attrition Mill ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Physical And Chemical

Abstract The effect of two different milling devices, namely attrition mill versus vibration mill, on the reactivity of fly ash was studied. High calcium fly ash from 4th Thermal power station of Ulaanbaatar (Mongolia) was used for the experiments. The raw and processed samples were characterized by XRD, SEM, Particle size distribution, BET, Blaine surface area and density measurements. The efficiency of 1 hour milling was evaluated with the Blaine surface area set to be more than 5000 cm2/g. The physical and chemical properties of the attrition milled fly ash changed not much compared to the vibration milled samples. For example the d50 particle size became reduced from 29 µm to 6 µm by attrition milling and in vibration milled fly ash it was reduced to 7 µm. The density increased from 2.44 g/cm3 of raw fly ash to 2.84 g/cm3 and 2.79 g/cm3 in attrition and vibration milled samples, respectively. Mechanical milling revealed not only a particle size reduction but also the formation of a denser microstructure. As a result the vibration milled fly ash showed a weaker interaction with the alkaline solution (8 M NaOH used here) compared to the attrition milled fly ash. Consequently, compressive strength of the binder prepared using the attrition milled fly ash was higher, 61 MPa, while for vibration milled fly ash it was 49 MPa. For comparison unmilled fly ash, it was 21 MPa.

Influence of Physical and Chemical Properties on the Activity of Fly Ashes

1987 ◽  
Vol 113 ◽  
Author(s):  
F. Sybertz
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Hydrochloric Acid ◽  
Potassium Hydroxide ◽  
Chemical Properties ◽  
Experimental Program ◽  
Physical And Chemical Properties ◽  
Fly Ashes ◽  
Physical And Chemical ◽  
And Chemical Properties

ABSTRACTIn an experimental program, the suitability of various methods for testing the pozzolanic activity of fly ash was investigated. The research was conducted on virtually all fly ashes approved as concrete additives in Germany. This paper discusses differences in the particle size distribution and the solubility on dissolution with hydrochloric acid and potassium hydroxide of the fly ashes. It also reports on interrelationships between the physical and chemical properties of the fly ashes and the workability and strength of mortars containing fly ash.

Mineralogy and Chemical Composition of High-Calcium Fly Ashes and Density Fractions from a Coal-Fired Power Plant in China

2010 ◽  
Vol 24 (2) ◽  
pp. 834-843 ◽  
Author(s):  
Yongchun Zhao ◽  
Junying Zhang ◽  
Chong Tian ◽  
Hailong Li ◽  
Xinyu Shao ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Power Plant ◽  
Fly Ashes ◽  
Density Fractions ◽  
High Calcium

Stabilization Characteristics of Clays Using Class C Fly Ash

1998 ◽  
Vol 1611 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Anil Misra
Keyword(s):  
Fly Ash ◽  
Chemical Properties ◽  
Clay Soils ◽  
Statistical Characteristics ◽  
Oxide Content ◽  
Physical And Chemical Properties ◽  
High Calcium ◽  
Class C ◽  
Physical And Chemical ◽  
And Chemical Properties

Coal-burning utilities using subbituminous coal from Wyoming typically produce fly ash, which, because of its high calcium oxide content, may be classified as Class C fly ash. These ashes are characterized by their self-cementing property and therefore can be used for soil improvement. Stabilization characteristics of clay soils blended with Class C fly ash were evaluated. Because fly ash is a by-product, uniformity of its physical and chemical properties is significant for quality control. The statistical characteristics of fly ash physical and chemical properties are obtained and compared with the data in literature. Fly ash is blended with several different clay soils of varying plasticity to study moisture-density relationships and strength behavior of stabilized soils. It is observed that the fly ash used in these experiments has a rapid hydration characteristic. Consequently, higher densities and strengths are achieved when the compaction is performed with little or no delay after the addition of moisture to clay-fly ash blends. Conversely, delayed compaction produces low densities and strength. In addition, it is observed that the stabilization characteristics are closely related to the soil mineral type and plasticity. Results also are presented for strength gain behavior with curing period for the various soil-fly ash blends.

scholarly journals The Use of Borax in Deterring Flash Setting of High Calcium Fly Ash Based Geopolymer

2016 ◽  
Vol 857 ◽  
pp. 416-420 ◽  
Author(s):  
Antoni ◽  
Stephen Wibiatma Wijaya ◽  
Juan Satria ◽  
Agung Sugiarto ◽  
Djwantoro Hardjito
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Fly Ash ◽  
Chemical Composition ◽  
Setting Time ◽  
Chemical Properties ◽  
Physico Chemical ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Positive Effect

Geopolymer that was made with high CaO content fly ash was found to have higher compressive strength than the low CaO fly ash, using the same mixture composition. This effect could be due to the physico-chemical properties of the fly ash, in respect to its particle size or the chemical composition. Although it was not widely published, the occurrence of flash setting of geopolymer was known to occur when using high CaO content fly ash as the precursor. Geopolymer paste may solidify within minutes after the addition of alkali activators, making it very difficult to cast in big volume. This paper investigate the effect of borax addition to the high calcium fly ash-based geopolymer mixture to reduce the occurrence of flash setting. It was found that the setting time can be extended significantly, with the addition of 5% borax, by mass, of fly ash. The addition of borax also have positive effect on increasing the compressive strength of geopolymer.

scholarly journals Separation Process and Microstructure-Chemical Composition Relationship of Cenospheres from Lignite Fly Ash Produced from Coal-Fired Power Plant in Thailand

2020 ◽  
Vol 10 (16) ◽  
pp. 5512
Author(s):  
Sorachon Yoriya ◽  
Phattarathicha Tepsri
Keyword(s):  
Fly Ash ◽  
Chemical Composition ◽  
Power Plant ◽  
Particle Diameter ◽  
Calcium Content ◽  
Aluminosilicate Glass ◽  
Structure Property ◽  
Lignite Fly Ash ◽  
High Calcium ◽  
Mae Moh

The cenosphere is one becoming a focus of the power plant in terms of value addition and ash management. This study presents a systematic investigation and characterization of physical properties, morphological structures, and chemical composition of cenospheres separated from fly ash produced from the Mae Moh coal-fired power plant, Thailand. To our knowledge, this is the first report on cenospheres separation from Mae Moh class C fly ash, with high calcium content ~24 wt.%, by adopting the traditional wet separation method (using water as the medium) to separate the lightweight cenospheres. Various effects of process parameters (fly ash-to-water ratio, stirring method, ultrasonication, and size classification) were designed to examine the cenosphere recovery yield in comparison. The result has revealed the limit of physical stirring-settling effect associated with the cenospheres content by nature governing the percent recovery. The bulk cenospheres were subject to size sieving into different sized fractions, with the structure-chemical composition relationship established for more insight. The particle diameter/shell thickness ratio revealed its significant correlation with the aluminosilicate glass composition, with the relating cenosphere shell structures (single-ring and porous) mapped to compare for a better elucidation of their structure-property relationship. The phase composition was also studied.

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