Mechanism of fine-coal dewatering by silicone additives. Final report
The objectives of this study were to explore the utility of silicones in the enhancement of coal dewatering and in particular to elucidate the mechanism of the effect. Both basic surface studies and practical dewatering assessments were used to address the problem. Several techniques were employed including surface tension, contact angle, and zeta potential measurements, ESCA (Electron Spectroscopy for Chemical Analysis), flow microcalorimetry and the EIMCO leaf filter laboratory dewatering test. A wide variety of silicone materials and bituminous coals were examined and comparisons were made with the behavior of organic flocculants and surfactants. Three mechanisms are commonly encountered in dewatering discussions: surface tension lowering; contact angle increase; and flocculation effects. All three elements were found to be important in coal dewatering by silicones. The most effective and widely applicable silicones were found to be aminofunctional polymer emulsions. It is postulated that these function by a combined hydrophobing/flocculation effect. Highly surface active silicone surfactants were also found to be useful when used in combination with organic flocculants. Silicone materials were identified that were more effective than organic flocculants and surfactants on two of the three key coals examined in this study. The project culminated in a successful plant trial of the aminofunctional silicone emulsions at the Bradford Coal Co., Bigler, PA. 31 references, 31 figures, 21 tables.
- Research Organization:
- Dow Corning Corp., Auburn, MI (USA)
- OSTI ID:
- 6737900
- Report Number(s):
- EPRI-CS-3548; ON: TI84920436
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COAL FINES
WATER REMOVAL
SILICONES
USES
BENCH-SCALE EXPERIMENTS
BITUMINOUS COAL
CALORIMETRY
CLEANING
COAL PREPARATION
ELECTRON SPECTROSCOPY
EMULSIONS
EXPERIMENTAL DATA
FILTERS
FLOCCULATION
FUEL SLURRIES
MIXTURES
SURFACE TENSION
WATER
BLACK COAL
CARBONACEOUS MATERIALS
COAL
COLLOIDS
DATA
DISPERSIONS
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROGEN COMPOUNDS
INFORMATION
MATERIALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
OXYGEN COMPOUNDS
POLYMERS
PRECIPITATION
REMOVAL
SEPARATION PROCESSES
SILOXANES
SLURRIES
SPECTROSCOPY
SURFACE PROPERTIES
SUSPENSIONS
013000* - Coal
Lignite
& Peat- Transport
Handling
& Storage