Abstract
Dry dense medium separation using a gas-solid fluidized bed was applied to separate lump coal for dry coal cleaning. A mixture of zircon sand and silica sand was used as the fluidized medium. Float-sink experiments using a cylindrical column indicated that fluidizing air velocity affects the separation efficiency ; the cause was discussed considering density-segregation of the medium and fluidization intensity near the bed surface. Continuous separation experiments were conducted on lump coal in the size range of +11.1～31.5 mm in the fluidized bed with medium density of 1650 kg / m3 and feed rate of 50 kg / h. Comparison of the feed rate and the recovery rate indicated that the feed and the recovery were in equilibrium after 10 minutes of operation. The experiments resulted in nearly perfect separation; the mass percentage 69.4% of floaters was almost same with the value 68.7% of lump coal with density less than 1650 kg / m3. Measurements of calorific value and ash content indicated that the separator produced an upgrade in calorific value of +2441 kcal / kg and reduced the ash content by 59.2%.
