Relationship of coal ash viscosity to chemical composition
Laboratory analyses of coal slags were used to predict the behavior of slag in power boilers. An attempt to relate slag composition (amount SiO/sub 2/, Al/sub 2/O/sub 3/, Fe/sub 2/O/sub 3/, TiO/sub 2/, CaO, MgO, Na/sub 2/O, and K/sub 2/O) to the slag viscosity was made. A previous method cited was developed by the Bureau of Mines and describes the relationship of SiO/sub 2/ content of the slag and the slag viscosity over a given temperature range. Designated as the Equivalent Silica Percentage, the relationship is described by the following equation: (SiO/sub 2/ x 100)/(SiO/sub 2/ + Fe/sub 2/O/sub 3/ + CaO + MgO) = Equivalent Silica Percentage. This correlation holds reasonably well for slags with SiO/sub 2/ to Al/sub 2/O/sub 3/ ratios not in excess of 1 to 4. The authors found that the point at which the slag viscosity increases at a significantly higher rate per unit decrease in temperature was described by the relationship: (Fe/sub 2/O/sub 3/)/(Fe/sub 2/O/sub 3/ + 1.11 FeO + 1.43 Fe) x 100. This relationship was termed the Ferric Percentage. At or above a Ferric Percentage of 20, the temperature at which the viscosity increases more rapidly becomes largely dependent on the content of Fe in the slag. A final method of estimating slag viscosity, the base to acid ratio, was also determined. As this ratio increases to 1, the viscosity of the slag decreases.
- OSTI ID:
- 6557764
- Journal Information:
- Combustion; (United States), Journal Name: Combustion; (United States) Vol. 31:5; ISSN COMBA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010600* -- Coal
Lignite
& Peat-- Properties & Composition
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ASHES
BASES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL COMPOSITION
COAL
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
IRON
IRON COMPOUNDS
IRON OXIDES
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MATERIALS
METALS
OXIDES
OXYGEN COMPOUNDS
POTASSIUM COMPOUNDS
POTASSIUM OXIDES
RESIDUES
SILICON COMPOUNDS
SILICON OXIDES
SLAGS
SODIUM COMPOUNDS
SODIUM OXIDES
TEMPERATURE DEPENDENCE
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VISCOSITY