Coal Washing Process Plant. 1. Coal Washing Plant (1). The excavator or loader feeds raw materials to the hopper of trommel scrubber; here trommel scrubber with 2-layer screen at the end. After washing off the clay, screen three outputs: above 50mm,20-50mm, and below 20mm. Above 50mm and 20-50mm, outputs are transported to another place by belt ...