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Separation Process for Metallic Elements in Electric and Electronic Equipment Waste
Ryuichi Agawa*, Minoru Nishida*, Yasuhiro Tsugita**, Takao Araki* and Shin-ichi Kurozu***
* Faculty of Engineering, Ehime University
** Sumitomo Metal Mining Co, Ltd.
*** Environment Facility Center, Engineering and Environment Group, Sumitomo Heavy Industries, Ltd.
õ Correspondence should be addressed to Minoru Nishida:
Faculty of Engineering, Ehime University
i3 Bunkyo-cho, Matsuyama, Ehime, 790-8577 Japanj
Abstract
Used printed circuit boardsiUPCBjcontain Cu, Au, Ag, Pd and other valuable metals, as well as elements such as Cu, Cr, Pb and Br that are harmful to the environment. Metal recovery from UPCBs is therefore important to protect the environment and to utilize secondary resources. In this research, the materials from the UPCB of a discarded personal computer were examined. After the UPCB was cut into 20 mm square pieces, it was heated at 873 K to remove resins such as C, H and N. After heating, the UPCB was crushed by a ball mill and the milled powder was separated by sieving. The crushed UPCBiover 250 Źmjwere sorted into magnetic and nonmagnetic particles by magnetic force. Since the fine powderiunder 250Źmjcontained 39 mass of C, it was heated to 1273 K in an atmosphere of 95 Ar { 5 O2, The powder was heated again to 1773 K in an atmosphere of 97 Ar { 3 H2. As a result, the slag and metal were separated, and 80 of the valuable metals in the UPCB were recovered.
Key words: print circuit board, heat treatment, slag adjustment, separation process