Triboelectric Separation of Fine Coal By Using an Electric Field Fluidized Bed

The occurrence of tribocharge is a universal phenomenon in gas-solid fluidization. After particle-particle or particle-wall contacts, coal particles obtain negative or and most mineral particles receive opposite polarity charge in fluidized bed. A novel electric field fluidized bed was set up to clean fine coal. The results show that the enrichment effect of fine coal in the fluidized bed is enhanced with the decease of bed height, and the separation performance increase with the increasing fluidization gas velocity and electric field. The sorting voltage is the most significant factor affecting the enrichment effect among the three. Under conditions of 60 kV voltage, 16.53 cm/s fluidization gas velocity and 2.5 mm static bed height, the clean coal with 9.84% ash content can be obtained after 30 minutes of operation, and the combustible recovery was 21.76%. It is confirmed that fine coal cleaning by the electric field fluidized bed is prospective, meanwhile further research work is needed to improve the recovery.