Enrichment of the metallic components from waste printed circuit boards by a mechanical separation process using a stamp mill
Printed circuit boards incorporated in most electrical and electronic equipment contain valuable metals such as Cu, Ni, Au, Ag, Pd, Fe, Sn, and Pb. In order to employ a hydrometallurgical route for the recycling of valuable metals from printed circuit boards, a mechanical pre-treatment step is neede...
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Published in | Waste management (Elmsford) Vol. 29; no. 3; pp. 1132 - 1137 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Kidlington
Elsevier Ltd
01.03.2009
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | Printed circuit boards incorporated in most electrical and electronic equipment contain valuable metals such as Cu, Ni, Au, Ag, Pd, Fe, Sn, and Pb. In order to employ a hydrometallurgical route for the recycling of valuable metals from printed circuit boards, a mechanical pre-treatment step is needed. In this study, the metallic components from waste printed circuit boards have been enriched using a mechanical separation process. Waste printed circuit boards shredded to <10
mm were milled using a stamp mill to liberate the various metallic components, and then the milled printed circuit boards were classified into fractions of <0.6, 0.6–1.2, 1.2–2.5, 2.5–5.0, and >5.0
mm. The fractions of milled printed circuit boards of size <5.0
mm were separated into a light fraction of mostly non-metallic components and a heavy fraction of the metallic components by gravity separation using a zig-zag classifier. The >5.0
mm fraction and the heavy fraction were subjected to two-step magnetic separation. Through the first magnetic separation at 700
Gauss, 83% of the nickel and iron, based on the whole printed circuit boards, was recovered in the magnetic fraction, and 92% of the copper was recovered in the non-magnetic fraction. The cumulative recovery of nickel–iron concentrate was increased by a second magnetic separation at 3000
Gauss, but the grade of the concentrate decreased remarkably from 76% to 56%. The cumulative recovery of copper concentrate decreased, but the grade increased slightly from 71.6% to 75.4%. This study has demonstrated the feasibility of the mechanical separation process consisting of milling/size classification/gravity separation/two-step magnetic separation for enriching metallic components such as Cu, Ni, Al, and Fe from waste printed circuit boards. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0956-053X 1879-2456 |
DOI: | 10.1016/j.wasman.2008.06.035 |