Demineralization Of Coal Research Articles

Surfactants in coal technology

AbstractThe principal uses of surfactants and related compounds in coal technology are the control of coal dust, the purification of coal from admixtures by flotation, the dispersion of coal in water for transportation through pipelines and as a fuel system, the dispersion of coal in fuel with subsequent burning of the coal/oil mixture, demineralization of coal, freeze‐conditioning agents and side‐car release agents for railroad transport of coal. These applications have been reviewed in this order. This overview demonstrates that the use of surfactants in coal technology is rapidly growing with the increasing interest in utilizing coal as a source of energy and that basic studies are in progress to explain the underlying surface chemical phenomenon.

Magnetic desulphurization of coal

The rationale for magnetic demineralization of coal depends on the paramagnetism of a portion of the coal minerals, their liberation, and their capture by magnetic forces. Pyrite is especially important, being the major form of sulphur in many commercial coals. An experimental separator consisting of a column, packed with either steel wool or screens, inserted in the bore of a solenoid magnet was employed in the present systematic study of high-gradient magnetic separation techniques in cool-water slurries. Particle size fractions in the range 0–600 μm and slurry velocities up to 4.0 cm/s were studied. Practically all liberated pyritic sulphur was removed magnetically at a field of 20 kOe. Up to 90% of the solid material fed to the separator was recovered. The data confirmed the effects of particle size and slurry velocity that were predicted by a theoretical model, based on the force balance on a mineral particle in the vicinity of a magnetized strand. An economic analysis based on a conceptual continuous magnetic cleaning plant indicates that the process is commercially attractive.