Abstract
Used printed circuit boards (UPCB) contain 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 UPCB (over 250μm) were sorted into magnetic and nonmagnetic particles by magnetic force. Since the fine powder (under 250μm) contained 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.
