METHOD OF AND APPARATUS FOR PRETREATING SEDIMENT SLUDGES IN PARTICULARY VERY FINELY GRAINED FLOTATION WASTE MATERIAL FROM HARD COAL CLEANING PROCESSES

摘要

Slurry with fine coal grain particles, from the sedimentation stage of coal washery plant, is further treated to extract useful products. The slurry is mixed with water in rotary drum (8) and then classified to remove particles above 3 mms (17) in trommel screen (13). Particles below 3 mms are passed from screen 13 to separator (20) which separates particles into two fractions, 0.5mm to 3mm and below 0.5mm. The fine grains below 0.5mm are processed in a flotation apparatus (44, 48) and the particles from 0.5 to 3mm are processed in helical gravity separators (25, 35). Similar fractions thereby obtained are brought together for de-watering and the plant provides fine grain washed coal with 10.12% ash content and fine grain dirt with an ash content of about 80%. The fine grain coal can be burned while the fine grain dirt can be used for making building blocks. The water used in the plant is largely recycled. IMAGE