Dry processing of high ash Indian coal by air fluidized vibrating deck

Processing of noncoking coals in India is limited due to the high cost involved in wet processing. In the present study, dry beneficiation of two high ash Indian non coking coal samples from two different coalfields, namely, Talcher (coal-A) and Ib Valley (coal-B) having diverse characteristics are studied using an air fluidized vibrating deck separator. Washing characteristics of two coal samples indicate that coal-A was easy-to-wash and coal-B was difficult to wash. The near-gravity materials (NGM) present in coal-B were higher than coal-A due to different geographical origin. The responses of dry separation of two coal samples studied under varied process variables were found to be dependent on the washability characteristics and the operating parameters used for achieving the desired product. The performance of dry beneficiation is described by the recovery of combustibles, ash rejection, ash recovery in clean coal (R-A/cc), Ecart probable error (Ep), and organic efficiency. It is found that Ep of the dry process was 0.17 for easy-to-wash coal (coal-A) and 0.23 for difficult-to-wash coal (coal-B). The organic efficiency of coal-A was 91% and 80% for coal-B at optimum condition. The prospective of dry separation of high ash Indian coal using air fluidized vibration technology was found to be effective for achieving product with 34% ash content.