Journal of Korea Society of Waste Management (한국폐기물자원순환학회지)

Korea Society of Waste Management (한국폐기물자원순환학회)
권호 표지

Recovery of Metal Concentrates from Waste Printed Circuit Boards by Mechanical Separation Processes

기계적 분리공정에 의한 폐인쇄회로기판으로부터 금속 농축물의 회수

Yoo, Jae-Min;Jeong, Jin-Ki;Kim, Sang-Bae;Yoo, Kyoung-Keun;Kim, Min-Seuk;Lee, Jae-Chun
유재민;정진기;김상배;유경근;김민석;이재천

  • Published : 2007.10.31
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Abstract

Printed Circuit Boards (PCBs) are used in most electrical and electronic equipment (EEE), which contain valuablemetals such as Cu, Ni, Au, Ag, Pd, Fe, Sn, Pb etc. In this study, the mechanical separation has been investigated withan objective to recover valuable metals from PCBs ofobsolete printers, the amount of generation of which increasingconsistently particularly with wasted EEEs. The PCBs crushed to sizes less than 10 mm were milled to liberate metalliccomponents by a stamp mill. The milled products were then classified by vibration screen into +5 mm, -5.0/+2.5 mm,~2.5/+1.2mm, -1.2/+0.6mm and -0.6 mm. The magnetic metallic components were separated by a two-step magneticseparation procedure consisting of hand magnet with magnetic intensity of 700 Gauss and drum-type magnetic separatorwith magnetic intensity of 3,000 Gauss. More than 99% of ferromagnetic Fe and Ni were recovered as magnetic fractionand, the metallic grade of which was about 72%. As a whole, about 80% of metallic components were recovered asmagnetic fraction and their grade exceeded 90%. PCBs particles ofsize -5 mm were then separated into underflow fractionand overflow fraction by gravity separation using a zigzag gravity separator. The major component of the underflowfraction and overflow fraction was metallic and non-metallic respectively. Afterwards, two-step magnetic separation wasconducted for the underflow fraction. About 45% of the metallic components in the underflow fraction was recoveredby the two-step magnetic separation and the grade of metallic components was about 76%. Meanwhile, about 70% ofcopper was recovered from the non-magnetic fraction. During the first step of magnetic separation with 700 Gauss, 98%of Cu was recovered from the non-magnetic fraction. The grade of Cu reaches to 75%. The study demonstrated thatvaluable metals such as Fe, Ni, Cu in waste PCBs could be recovered by a mechanical separation process consisting ofcrushing, milling, gravity separation, magnetic separation steps.

Keywords

References

  1. Widmer, R., Oswald-Krapf, H., Sinha-Khetriwal, D., Schnellmann, M. and Bni, H. : Global perspectives on e-waste, Environmental impact assessment Review, Vol. 25, Issue 5, pp. 436-458 (2005) https://doi.org/10.1016/j.eiar.2005.04.001
  2. Sum, E. Y. L. : The recovery of metals from electronic scrap, Journal of Metal, Vol. 43, No. 4, pp. 53-61 (1991)
  3. Brodersen, K., Tartler, D., Bergmann, H. W., Werner, G. D. and Eder, S. : Scrap of electronics; Hazardous waste or raw material resource, Proceedings of the 1992 International Conference on the Recycling of Metals, The ASM European Office (Eds.), ASM, Brussels, Belgium, pp. 45-51 (1992)
  4. Hoffmann, J. E. : Recovering precious metals from electronic scrap, Journal of Metal, Vol. 44, No. 7, pp. 43-48 (1992)
  5. Matusewicz, R. W. and Baldock, B. R. : Ausmelt technology for recycling of computer boards and other high value materials, Proceedings of the Fourth International Symposium on Recycling of Metals and Engineered Materials, Stewart, D.L., Daley, J.C. and Stephens, R.L. (Eds.), TMS, Warrendale, PA, USA, pp. 701-710 (2000)
  6. Hageluken, C. : Recycling of electronic scrap at Umicore's integrated metals smelter and refinery, ERZMETALL, Vol. 59, No. 3, pp. 152-161 (2006)
  7. Dunning, Jr. B. W. : Precious metals recovery from electronic scrap and solder used in electronics manufacture, IC 9059, U.S. Bureau of Mines, Washington, D.C., USA, pp. 44-56 (1986)
  8. Mecucci, A. and Scott, K. : Leaching and electrochemical recovery of copper, lead and tin from scrap printed circuit boards, Journal of Chemical Technology & Biotechnology, 77, pp. 449-457 (2002) https://doi.org/10.1002/jctb.575
  9. Koyama, K., Tanaka, M. and Lee, J-c. : Copper leaching behavior from waste printed circuit board in ammoniacal alkaline solution, Materials Transactions, Vol. 47, No. 7, pp. 1788-1792 (2006) https://doi.org/10.2320/matertrans.47.1788
  10. 김민석, 이재천, 정진기, 김병수, 김은영 : 전해생성된 염소에 의한 폐인쇄회로기판으로부터 동의 침출, 자원리싸이클링학회지, Vol. 14, No. 5, pp. 45-53 (2005)
  11. 이재천, 이민용, 신희영 : 형상분리법에 의한 폐PCBs로부터 유가금속의 회수연구, 자원리싸이클링학회지, Vol. 5, No. 3, pp. 37-43 (1996)
  12. Zhang, S. and Forssberg, E. : Mechanical separation-oriented characterization of electronic scrap, Resources, Conservation and Recycling, Vol. 21, Issue 4, pp. 247-269 (1997) https://doi.org/10.1016/S0921-3449(97)00039-6
  13. Lee, J.-c., Koyanaka, S., Lee, M. Y., Ohya, H. and Endoh, S. : Recovery of copper, tin and lead from the spent printed circuit boards (PCBs) by the shape separation method, Shigen-to-Sozai : Journal of the Mining and Materials Processing Institute of Japan, 113, pp. 357-362 (1998)
  14. Veit, H. M., Pereira, C. de C. and Bernardes, A. M. : Using mechanical processing in recycling printed wiring boards, Jorunal of Metal, Vol. 54, No. 6, pp. 45-47 (2002)
  15. Cui, J. and Forssberg, E. : Mechanical recycling of waste electric and electronic equipment: a review, Journal of Hazardous Materials, Vol. 99, Issue 3, pp. 243-263 (2003) https://doi.org/10.1016/S0304-3894(03)00061-X
  16. 이재천, 한정환, 안재우 : 폐전기.전자기기의 토탈 리싸이클링 기술개발, 자원재활용기술개발사업 보고서, 2C-A-1-1, 한국지질자원연구원 (2006)
  17. 이재천, 이강인, 이철경, 양동효 : 기계적 전처리에 의한 반도체 IC칩 스크랩으로부터 유가금속의 분리에 관한 연구, 자원리싸이클링학회지, Vol. 3, No. 1, pp. 38-43 (1994)