Disentanglement of random access memory cards to regenerate copper foil: A novel thermo-electrical approach

Khushalini Ulman; Anirban Ghose; Samane Maroufi; Irshad Mansuri; Veena Sahajwalla

doi:10.1016/j.wasman.2018.10.002

Disentanglement of random access memory cards to regenerate copper foil: A novel thermo-electrical approach

Waste Manag. 2018 Nov:81:138-147. doi: 10.1016/j.wasman.2018.10.002. Epub 2018 Oct 9.

Authors

Khushalini Ulman¹, Anirban Ghose², Samane Maroufi³, Irshad Mansuri⁴, Veena Sahajwalla⁵

Affiliations

¹ Sustainable Materials Research and Technology Centre (SMaRT Centre), School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney 2052, Australia. Electronic address: k.ulman@student.unsw.edu.au.
² Sustainable Materials Research and Technology Centre (SMaRT Centre), School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney 2052, Australia. Electronic address: a.ghose@unsw.edu.au.
³ Sustainable Materials Research and Technology Centre (SMaRT Centre), School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney 2052, Australia. Electronic address: s.maroufi@unsw.edu.au.
⁴ Sustainable Materials Research and Technology Centre (SMaRT Centre), School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney 2052, Australia. Electronic address: i.mansuri@unsw.edu.au.
⁵ Sustainable Materials Research and Technology Centre (SMaRT Centre), School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney 2052, Australia. Electronic address: veena@unsw.edu.au.

PMID: 30527030
DOI: 10.1016/j.wasman.2018.10.002

Abstract

This paper reports the development of a novel process combining thermal and electrical treatments, which are optimised to provide efficient recovery of copper foil from Random Access Memory cards (RAMs). A primary thermal transformation at 900 °C facilitates a highly efficient recovery of copper foils from RAMs during the secondary processing in the electrical fragmenter, using only 10 pulses at 150 kV. The process yield was 98% and inductively coupled plasma (ICP) analysis showed that the copper foils had 98% purity. X-ray diffraction (XRD) confirmed the presence of copper in a crystalline face-centred cubic (FCC) form. Scanning electron microscopy (SEM) - energy dispersive spectroscopy (EDS) analysis of the foils assisted in understanding the underlying mechanism of electrical separation. Transmission electron microscopy (TEM) gave a new perspective on the regeneration of copper foils wherein new copper grains depicted a ribbon like growth pattern. The copper foils had an electrical conductivity similar to that of commercially available pure copper sheets. Thus, the mechanism of thermo-electrical transformation was studied in detail and regenerated copper foils of high electrical conductivity were afforded from end-of-life RAMs.

Keywords: Copper recovery; Random access memory (RAM) cards; Recycling; Thermo-electrical treatment.

MeSH terms

Copper / chemistry*
Electric Conductivity
Electricity*
Spectrum Analysis, Raman
Temperature

Substances

Copper