Development of Air Dense Medium Fluidized Bed Technology For Dry Beneficiation of Coal – A Review

Wet processing of coal requires a large quantity of water. Waste generated from wet process ties up a significant amount of water and land. The slurry ponds also pose serious problems in case of dam breakage. Dry beneficiation of coal offers a better alternative approach for cleaning coal. An overview on the development of separation technology for beneficiation of coal using dense medium fluidized bed system is described. A theory of the dry separation relevant to coal beneficiation by density difference has been highlighted. This paper summarizes past and present development of different designs and operational features of a counter-current cascade fluidization (CCFC) system and air dense medium fluidized bed separator (ADMFBS) based on their separation efficiency for different sizes of coal at different scales of operation. For fine coal beneficiation, magnetically stabilized bed improves the separation efficiency by preventing the back mixing of the separated solids.