Pressure drop changes during dissolution of pyrite cinder in a fixed bed

The percolation leaching of heavy metals from pyrite cinder in a packed bed is considered in this work. Flow rate and physicochemical parameters have been analysed in a gravity percolation leaching system with a simultaneous dissolution reaction. The structure of the unconsolidated bed of porous cin der changes during operation as a consequence of the leaching phenomenon. T he variables that influence the flow rate are: bed length, particle size di stribution and leaching liquor characteristics. Head loss changes during op eration are mainly explained in terms of the fine particle redistribution, migration along the bed and thickening at the bottom. Experimental values o f effective void fraction are compared with values from Ergun's equation mo dified to be applied to a layered bed. (C) 2001 Elsevier Science B.V. All r ights reserved.