| 摘要 |
A process is disclosed for removing sulfur and ash, particularly clay and pyrite from coal particles having a mesh size of 30 or less. A slurry of coal particles is agitated in an ultrasonic mixer to separate the contaminants from the coal and weaken chemically-bonded contaminants on the coal surface. The clay and pyrite particles are dispersed as a colloid in the aqueous medium of the slurry. Treatment of the slurry with sonic energy also subdivides the particles along ash or clay seams. The slurry is then separated in a centrifuge and in froth-flotation cells so that coal particles greater than 2 microns are recovered and a slurry is again formed. The repulped slurry is then treated with sonic energy and ozone to release further quantities of surface components from the coal particles. The slurry is again treated in a centrifuge and coal particles 2 microns and greater are recovered. The slurry is normalized before each treatment with sonic energy and ozone to a pH of 6-9 to maintain the released contaminants as colloids suspended in the aqueous medium of the slurry. |
