ABSTRACT
Waste electrical and electronic equipment (WEEE) is an important secondary source of
valuable metals. Particularly discarded printed circuit boards (PCB) contain high concentrations
of valuable metals, varying greatly among the type of boards, the manufacture year, source
device, and the production technology. Hydrometallurgical processing is an efficient way to
selectively extract and subsequently recover metals from discarded high grade PCB. In this
work, we propose a two-step process to extract copper (Cu) and gold (Au) from a high grade
telecom server PCB. The boards contained 262.4 and 0.320 mg/g Cu and Au, respectively,
which constituted the 98.1% of the total value. The metal extraction process was optimized
using response surface methodology (RSM) by central composite design (CCD). The optimized
process parameters showed that 3.92 M H2SO4, 3.93 M H2O2, 6.98% (w/v) pulp density and
3.7 hours contact time, and 0.038 M CuSO4, 0.3 M S2O32−, 0.38 M NH4OH, 10.76% pulp
density (w/v) 6.73 hours were optimal for the maximal extraction of Cu and Au, respectively.
