Electrostatic separation of brass from industrial wastes

Previous studies have demonstrated that electrostatic separation can be successfully employed for the recycling of nonferrous metals from chopped electric wire and cable scrap. The aim of this work was to investigate the possibility of using electric field forces for the selective sorting of other granular mixtures, such as brass dross. Laboratory tests of electrostatic separation were carried out on three samples: (0.08-1) mm, (0.08-0.2) mm and (0.2-1) mm, containing more than 66% of brass. Sample 1 was separated in a corona-electrostatic field, generated by a standard electrode arrangement: grounded rotating roll electrode (diameter 150 mm) and two high-voltage electrodes (wire-type dual corona electrode+tubular electrode). Processing of the other two samples was carried out in an extended corona field, generated between a matrix-type multi-needle corona electrode and a roll electrode of large diameter (250 mm). Chemical analysis of the products showed that more than 90% of the brass can be recovered at a grade higher than 95%. The extended corona field electrode arrangement proposed in this work seems to be a promising solution for the effective recycling of other granular wastes containing copper, aluminium, and their alloys.