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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472 EISSN: 1735-1472
Vol. 12, No. 8, 2015, pp. 2603-2612
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Bioline Code: st15245
Full paper language: English
Document type: Research Article
Document available free of charge
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International Journal of Environment Science and Technology, Vol. 12, No. 8, 2015, pp. 2603-2612
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Recovery of valuable metal concentrate from waste printed circuit boards by a physical beneficiation technology
He, J. F.; Duan, C. L.; He, Y. Q. & Zhang, H. J.
Abstract
It is greatly significant to separate precious
metals from the waste printed circuit boards (PCBs) with
appropriate methods for the resource recycling and environment
protection. A combined physical beneficiation
technology for the recovery of waste PCBs was investigated.
Waste PCBs were disassembled into substrates and
slots firstly. Waste PCB substrates were crushed to the size
below 1 mm by a wet impact crushing approach. The
double Rosin–Rammler functions were proposed to
describe the particle size distribution characteristic of the
substrates. The crushing products of the substrates were
separated by a self-designed water-medium tapered column
separation bed. The results indicate that the separation
efficiency of 93.9 % and metal recovery rate of 93.7 % are
obtained with a water discharge of 5.5 m3/h, feeding
capacity of 250 g/min and inclination angle of 35°. Waste
PCB slots were crushed to the size range of 0.5–5 mm by a
dry impact crushing approach and separated by an active
pulsing air classifier. The separation results show that a
separation efficiency of 92.4 % and metal recovery rate of
96.2 % are obtained with the airflow velocity of 2.90 m/s
and pulsing frequency of 2.33 Hz. The mismatching
components in the metal concentrate are relatively less
with suitable operating conditions. Precious metals could
be obtained by the further separation and purification of
metal concentrates. The technology has great potential to
be applied in the field of waste PCB recycling.
Keywords
Waste printed circuit boards (PCBs); Wet impact crushing; Water-medium tapered column
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