title: High temperature transformations of waste printed circuit boards from computer monitor and CPU: Characterisation of residues and kinetic studies.
abstract: This paper investigates the high temperature transformation, specifically the kinetic behaviour of the waste printed circuit board (WPCB) derived from computer monitor (single-sided/SSWPCB) and computer processing boards - CPU (multi-layered/MLWPCB) using Thermo-Gravimetric Analyser (TGA) and Vertical Thermo-Gravimetric Analyser (VTGA) techniques under nitrogen atmosphere. Furthermore, the resulting WPCB residues were subjected to characterisation using X-ray Fluorescence spectrometry (XRF), Carbon Analyser, X-ray Photoelectron Spectrometer (XPS) and Scanning Electron Microscopy (SEM). In order to analyse the material degradation of WPCB, TGA from 40°C to 700°C at the rates of 10°C, 20°C and 30°C and VTGA at 700°C, 900°C and 1100°C were performed respectively. The data obtained was analysed on the basis of first order reaction kinetics. Through experiments it is observed that there exists a substantial difference between SSWPCB and MLWPCB in their decomposition levels, kinetic behaviour and structural properties. The calculated activation energy (EA) of SSWPCB is found to be lower than that of MLWPCB. Elemental analysis of SSWPCB determines to have high carbon content in contrast to MLWPCB and differences in materials properties have significant influence on kinetics, which is ceramic rich, proving to have differences in the physicochemical properties. These high temperature transformation studies and associated analytical investigations provide fundamental understanding of different WPCB and its major variations.
authors.affiliation: Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, UNSW Australia, Sydney, NSW 2052, Australia.
authors.forename: Raghu Raman
authors.initials: RR
authors.lastname: Rajagopal
authors.affiliation: Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, UNSW Australia, Sydney, NSW 2052, Australia. Electronic address: r.rajarao@unsw.edu.au.
authors.forename: Ravindra
authors.initials: R
authors.lastname: Rajarao
authors.affiliation: Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, UNSW Australia, Sydney, NSW 2052, Australia.
authors.forename: Veena
authors.initials: V
authors.lastname: Sahajwalla
mesh_terms: D002244:Carbon; D003201:Computers; D059029:Electronic Waste; D006358:Hot Temperature; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D009584:Nitrogen; D056951:Photoelectron Spectroscopy; D059027:Recycling / Q000379:methods*; D013818:Thermogravimetry
chemical_list: D002244:Carbon; D009584:Nitrogen
keywords: Activation energy; Kinetics; Residual characterisation; Waste PCB