EARTH

[31001-12-11] Recovery of tin from waste printed circuit board using physical and chemical separation

○Shigekazu Harada¹, Megumi Takeuchi¹, Kazutoshi Haga¹, Shigeru Kawamura¹, Yasushi Takasaki¹, Atsushi Shibayama¹ (1. Akita University)

JI Whan Ahn（KIGAM）, Richard Alorro (Curtin University)

Keywords:Recycling, Printed circuit board, Tin, Color sorting, Leaching

In case of Japan, waste printed circuit board (WPCB) is mainly treated by smelting process with copper concentrate to recover copper and precious metals. However, tin is distributed to the slag phase because it is easily oxidized than copper in this process. The recovery ratio of tin as metal is small. Therefore, the authors aim to develop new recycling technology which combines physical and chemical separation to selectively recover and refine tin from WPCB before it is charged into a copper smelting process. In previous study, when the mixture of metal (hereinafter called mixed metal) which is obtained from the WPCB by crushing, comminuting, and gravity separation was separated by color sorting, it's possible to recover tin concentrate which tin grade is 36% and tin recovery is 76% (Recovery is calculated assuming tin amount in product after gravity separation is 100%) . After tin is concentrated, it's refined by chemical separation which uses leaching and electrowinning. In his paper, we report the possibility of tin concentration by color sorting of mixed metal and the result of leaching which uses granular solder and tin powder as raw materials for preliminary test of tin leaching.