| Summary: | Extraction of gold(III) from printed circuit board (PCB) waste using two phase
system of aqueous polyethylene glycol/(NH4)2SO4 was performed. The research
was carried out through three steps. The first step was selective dissolution of
PCB waste. The second step was dissolution of PCB waste in aqua regia. The
final step was extraction of gold(III) from printed circuit board (PCB) waste using
two phase system of aqueous polyethylene glycol/(NH4)2SO4.
Selective dissolution processes of copper metals have been performed by
using mixture of H2O2 30% (v/v) and H2SO4 4 M with the volume ratio 3 : 1 and
immersion for 3 days. The dissolution of PCB waste was performed by using aqua
regia microwave assisted for 90 seconds. Metal composition of PCB waste sample
was determined by X-ray fluorescence spectrometry analysis (XRF). Total
amount of copper in selective dissolution solution was determined by AAS. Total
amount of gold which soluble in aqua regia and extracted in PEG phase were
analyzed by UV-Vis spectrofotometer, whereas the non-target metals composition
which soluble in aqua regia were analyzed by Inductively Coupled Plasma Optical
Emission Spectrometry (ICP-OES).
The result showed that selective solution of PCB waste yield 25,415
mg/kg of copper. The dissolution of gold from PCB waste using aqua regia, both
with and without selective dissolution yield Au(III) 2,308 mg/kg and 1,244 mg/kg
respectively. Gold(III) is quantitatively extracted (95.7%) into PEG-rich phase in
pH = 2. Presence of Zn2+ and Cu2+ ions in solution could decrease efficiency
extracted of Au(III). Presence of additional chloride did not influence significant
toward extraction efficiency of the Au(III) from solution that dissolution of PCB
waste. The Au(III) had extracted succesfully from PCB waste yield 42%.
Keywords: extraction, gold, polyethylene glycol, Printed Circuit Board
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