REVIEW ANALYSIS WITH SOME EXPERIMENTAL RESULTS IN THE CHARACTERIZATION OF WASTE PRINTED CIRCUIT BOARDS (WPCBs) BY PHYSICAL PROCESS FOR METALS CLASSIFICATION AND PRECIOUS METALS RECOVERY

Physical process represents an important step for treatment of waste printed circuit boards (WPCBs), this being necessary for metals classification and their recovery. This work reports a review analysis coupled with lab-scale tests in WPCB treatment. The operations consisted in comminuting (shredding by a hand cutter and crushing with a mill having multi-use rotational knives equipped with a bottom sieve) and size separation (sieve shaker with a set of four sieves). Four various PCBs samples were used, differenced by provenience, on which chemical characterization was performed in order to observe metals distribution at different particle size after physical process. Due high content in all samples, copper was noticed as main element, followed by iron, tin, lead and zinc, their concentrations ranged from a sample to another one. Presence of precious metals in a large amount represents an important factor by economic point of view for waste PCBs treatment. By size distribution was noticed that more than 45% of metallic part was concentrated in the coarse fraction (2>1nun), which mean that the metals are not completely liberated by plastic materials. This will be a determinant factor for a further hydrometallurgical process.