Transformation of pyrite to pyrrhotite and its implications in coal conversion processes
Thesis/Dissertation
·
OSTI ID:6294169
The thermodynamics and kinetics of the transformation of pyrite to pyrrhotite are investigated. The thermodynamics of the iron-sulfur system are discussed and equations describing its equilibrium in inert and reductive atmospheres are presented. The equations are verified by experimentation. The kinetics of pyrite decomposition are investigated in liquid and gaseous environments. From thermogravimetric analysis, the activation energies for the reduction in various atmospheres and at pressures from 10/sup -7/ to 10/sup 1/ MPa are measured. A detailed chemical mechanism for the transformation is given, including assignment of activation energies to the mechanistic steps. The changes in surface morphology which occur during the transformation are described from results of examination with scanning electron microscopy, mercury porosimetry, and surface area measurement by krypton adsorption. Differences in reactivity of various pyrites are attributed to differences in impurity concentration and changes in the area of particular crystallographic faces. Implications of this study for the utilization of coal are discussed and suggestions for future work are described.
- OSTI ID:
- 6294169
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
01 COAL, LIGNITE, AND PEAT
010400* -- Coal
Lignite
& Peat-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ACTIVATION ENERGY
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
DECOMPOSITION
ELECTRON MICROSCOPY
ENERGY
FLUIDS
GASES
GRAVIMETRIC ANALYSIS
HIGH VACUUM
IMPURITIES
IRON COMPOUNDS
IRON SULFIDES
KINETICS
LIQUIDS
LOW PRESSURE
MEASURING INSTRUMENTS
MEDIUM PRESSURE
MEDIUM VACUUM
MICROSCOPY
MINERALS
MORPHOLOGY
POROSIMETERS
PRESSURE DEPENDENCE
PYRITE
PYRRHOTITE
QUANTITATIVE CHEMICAL ANALYSIS
REACTION KINETICS
SCANNING ELECTRON MICROSCOPY
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
SURFACE AREA
SURFACE PROPERTIES
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
TRANSITION ELEMENT COMPOUNDS
YIELDS
010400* -- Coal
Lignite
& Peat-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ACTIVATION ENERGY
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
DECOMPOSITION
ELECTRON MICROSCOPY
ENERGY
FLUIDS
GASES
GRAVIMETRIC ANALYSIS
HIGH VACUUM
IMPURITIES
IRON COMPOUNDS
IRON SULFIDES
KINETICS
LIQUIDS
LOW PRESSURE
MEASURING INSTRUMENTS
MEDIUM PRESSURE
MEDIUM VACUUM
MICROSCOPY
MINERALS
MORPHOLOGY
POROSIMETERS
PRESSURE DEPENDENCE
PYRITE
PYRRHOTITE
QUANTITATIVE CHEMICAL ANALYSIS
REACTION KINETICS
SCANNING ELECTRON MICROSCOPY
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
SURFACE AREA
SURFACE PROPERTIES
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
TRANSITION ELEMENT COMPOUNDS
YIELDS