Recovery of materials from waste printed circuit boards by vacuum pyrolysis and vacuum centrifugal separation.
In this research, a two-step process consisting of vacuum pyrolysis and vacuum centrifugal separation was employed to treat waste printed circuit boards (WPCBs). Firstly, WPCBs were pyrolysed under vacuum condition at 600 °C for 30 min in a lab-scale reactor. Then, the obtained pyrolysis residue was heated under vacuum until the solder was melted, and then the molten solder was separated from the pyrolysis residue by the centrifugal force. The results of vacuum pyrolysis showed that the type-A of WPCBs (the base plates of which was made from cellulose paper reinforced phenolic resin) pyrolysed to form an average of 67.97 wt.% residue, 27.73 wt.% oil, and 4.30 wt.% gas; and pyrolysis of the type-B of WPCBs (the base plates of which was made from glass fiber reinforced epoxy resin) led to an average mass balance of 72.20 wt.% residue, 21.45 wt.% oil, and 6.35 wt.% gas. The results of vacuum centrifugal separation showed that the separation of solder was complete when the pyrolysis residue was heated at 400 °C, and the rotating drum was rotated at 1200 rpm for 10 min. The pyrolysis oil and gas can be used as fuel or chemical feedstock after treatment. The pyrolysis residue after solder separation contained various metals, glass fibers and other inorganic materials, which could be recycled for further processing. The recovered solder can be reused directly and it can also be a good resource of lead and tin for refining.
Zhou
Yihui
Y
School of Chemistry and Chemical Engineering, Central South University, Changsha Hunan 410083, People's Republic of China.
Wu
Wenbiao
W
Qiu
Keqiang
K
D002498:Centrifugation / Q000379:methods*; D003201:Computers; D004581:Electronics; D004867:Equipment Design; D008420:Manufactured Materials; D008422:Materials Testing; D010636:Phenols / Q000737:chemistry; D059027:Recycling / Q000379:methods; D012037:Refuse Disposal / Q000379:methods*; D013696:Temperature; D013997:Time Factors; D014618:Vacuum; D018505:Waste Management / Q000379:methods
D010636:Phenols