Process for neutralising harmful powders and plant that carries out this method

摘要

A process for neutralising harmful powders that uses a furnace (1) comprising a floor slab (2a) under a basin (3) laterally to which a tapping channel (4) is provided and closed at the top by a cover (5) with the central hole (5a) through which a system of automatic feeding (5b) causes the fall of the powders (10) to dispose of. Through the floor slab (2a) electrodes (12) are inserted into the basin (3) immersed in a molten bath (9) that is formed in the lower part of the basin (3) up to the height of the tapping channel (4), whereby the level of the molten bath (9) in the basin (3) of the furnace (1) exceeds of several centimetres the tapping channel (4). Above the bath (9) three layers are found: a first layer (20) at the viscous state near the melting point contacting the bath (9); a second layer (21) porous and fragile for effect of the heating of the harmful powders freeing CO2; a third layer (22) of powders that are fed from the above. The third layer (22), for its high characteristics of heat insulating, is at a temperature close to the room temperature, whereby possible sublimated molecules of elements at low vapour tension, for example cadmium and mercury, which may escape from the melting basin, condense in the third layer and are not released further up.