Roll-type electrostatic separators are mostly employed for the selective sorting of conductive and non-conductive constituents of granular mixtures. In case of waste electric and electronic equipment, several conductive materials may be simultaneously present in the composition of the granular mixture to be separated. The aim of this paper is to prove the feasibility of processing an Aluminum/Copper/PVC mixture using a roll-type electrostatic separator. Three high-voltage electrode configurations were studied. Experiments prove that the association of a high-voltage S-shaped plate electrode with a corona wire electrode gives the best separation results. The electric forces pin the corona-charged PVC particles to the roll electrode, while the lighter aluminum and heavier copper particles are diverted to the high-voltage electrode. The aluminum contained in the copper product can be removed by a second pass in a separator that makes use only of the S-shaped electrode. In this way, 75% of the aluminum particles and 99.97% of the PVC particles can be removed, to obtain a 98% pure copper product. |
