ABSTRACT
Waste electrical and electronic equipment (WEEE) is an important secondary source of metals.
Particularly discarded printed circuit boards (PCB), despite their relative small weight fraction,
are a valuable secondary source of copper (Cu), iron (Fe), aluminum (Al), nickel (Ni), zinc
(Zn), gold (Au), silver (Ag) and palladium (Pd). The concentration of these metals in the
discarded PCB varies greatly, depending on the source of the material, manufacture year, type
of the board and the manufacture technology. There is not yet a standard method to characterize
and assay the metals in discarded PCB. In this chapter, a new characterization and total metal
method is presented, and its application on a number of PCB from desktop computers, laptop
computers, computer parts, mobile phones and telecom devices is carried out. Furthermore,
multi-criteria analysis (MCA) using analytic hierarchy process (AHP) is used to rank and select
the most appropriate technology for metal recovery from discarded PCB. The analysis is based
on a number of criteria, viz. economic, environmental, social and technical criteria, along with
a number of sub-criteria. The metal concentration assayed resulted in a varied concentration of
Cu (9.3% – 38.4% by weight) across particle sizes (<500 µm, 500 – 1600 µm and 1600 – 2500
µm) and board types, along with considerable concentrations (by weight) of Fe (1.4% – 7.5%),
Al (0.1% – 3.0%), Ni (0.1% – 2.4%), Zn (0.03% – 1.0%), Pb (0.04% – 0.9%) and Au (21-320
ppm). The MCA study revealed that biohydrometallurgical route is slightly preferred over a
hydrometallurgical routes in technology selection for sustainable metals recovery from WEEE.
In the global environmental agenda, waste in no longer regarded as an unwanted material with
