An innovative route for valorising iron and aluminium oxide rich industrial wastes: Recovery of multiple metals.

Several industrial wastes including biomass, fly ashes, red mud, mill scales, water treatment residues, have significant concentrations of metal oxides: FeO, AlO, TiO, SiO etc. Several efforts have been made towards recovering metals within these wastes. Rather than recovering one metal at a time, we report a novel approach for simultaneously extracting multiple metals from mixed oxides in a single process step.

Concentration of rare earth elements during high temperature pyrolysis of waste printed circuit boards.

An in-depth investigation was carried out on the recovery of rare earth elements (REEs) from a variety of waste printed circuit boards (PCBs). High temperature pyrolysis was carried out at 850 °C for 15 min using horizontal resistance and thermal plasma furnaces with different levels of turbulence. The concentration of REEs in key pyrolysis residues, namely, copper rich red metallic fraction, lead/tin rich white metallic fraction and slag rich carbonaceous residues, were determined using ICP analysis.

Formation of carbyne-like materials during low temperature pyrolysis of lignocellulosic biomass: A natural resource of linear sp carbons.

The exploration, understanding and potential applications of 'Carbyne', the one-dimensional sp allotrope of carbon, have been severely limited due to its extreme reactivity and a tendency for highly exothermic cross-linking. Due to ill-defined materials, limited characterization and a lack of compelling definitive evidence, even the existence of linear carbons has been questioned. We report a first-ever investigation on the formation of carbyne-like materials during low temperature pyrolysis of biobased lignin, a natural bioresource.

A novel approach for reducing toxic emissions during high temperature processing of electronic waste.

A novel approach is presented to capture some of the potentially toxic elements (PTEs), other particulates and emissions during the heat treatment of e-waste using alumina adsorbents. Waste PCBs from mobile phones were mechanically crushed to sizes less than 1mm; their thermal degradation was investigated using thermo-gravimetric analysis. Observed weight loss was attributed to the degradation of polymers and the vaporization of organic constituents and volatile metals.

High temperature investigations on optimising the recovery of copper from waste printed circuit boards.

High temperature pyrolysis investigations were carried out on waste printed circuit boards (PCBs) in the temperature range 800-1000°C under inert conditions, with an aim to determine optimal operating conditions for the recovery of copper. Pyrolysis residues were characterized using ICP-OES analysis, SEM/EDS and XRD investigations. Copper foils were successfully recovered after pyrolysis at 800°C for 10-20 min; the levels of Pb and Sn present were found to be quite low and these were generally present near the foil edges.