Use of surfactants in fine coal dewatering
Removal of moisture from fine coal (less than 500 microns in size) by filtration and thermal drying contributes heavily to the cost of the clean coal. As an alternative to the thermal drying, the use of surfactants in vacuum filtration was investigated. The effect of cationic (dodecyl pyridinium chloride, Arosurf MG 83A), anionic (Aerosol-OT) and non-ionic (Triton X-114, Triton X-100) surfactants on the filtration and dewatering characteristics of -32 mesh Pittsburgh seam-Bruceton mine coal was investigated by conducting adsorption, dynamic and equilibrium experiments at various surfactant concentrations. The surfactant concentration was monitored by measuring the surface tension of aqueous solution. The adsorption isotherm of the surfactants exhibited three different regions, characteristic of a bilayer formation. A model for the adsorption isotherm, incorporating the orientation of the surfactant molecules at the surface of the coal particles was proposed. The observed complex behavior of the moisture content versus the surfactant concentration curve was explained on a consistent basis with the proposed model. An improvement in the dewatering characteristic was observed, whenever the surfactant adsorption made the coal surface hydrophobic.
- OSTI ID:
- 5927098
- Country of Publication:
- United States
- Language:
- English
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