Disentanglement of random access memory cards to regenerate copper foil: A novel thermo-electrical approach. (November 2018)

• Record Type: Journal Article
• Authors: Ulman, Khushalini; Ghose, Anirban; Maroufi, Samane; Mansuri, Irshad; Sahajwalla, Veena
• Is Part Of: Waste management. Volume 81(2018)
• Page Start: 138
• Page End: 147
• Publication Date: 2018-11
• Subjects: Random access memory (RAM) cards -- Recycling -- Thermo-electrical treatment -- Copper recovery; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2018.10.002
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: Copper foil recovery by thermo-electrical approach. Initial thermal treatment at 900 °C improves separation in fragmentation step. Process yield: 98%; Copper purity: 98%. SEM-EDS explain mechanism of electrical separation. TEM depicts regeneration of copper grains in ribbon-like pattern. 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.