Date: 11-27-2018 - Tuesday - 08:00 PM - 10:00 PM
Rasoul Nekouei1 Farshid Pahlevani1 V. Sahajwalla1

1, University of New South Wales, Sydney, New South Wales, Australia

Every year a huge volume of electronic wastes (e-waste) are being discarded with an increasing trend due to the technological and scientific advancements. To many countries, these kind of waste is to be a major concern since various kind of materials including metals (basic and pernicious metals), polymers and ceramics are combined elaborately and too hard to be separated readily. Printed circuit boards (PCBs) are considered as one of the main splits of e-wastes containing around 35% metals. Disregarding ceramics and polymers, metallic portion includes Cu, Zn, Ni, Sn and Fe, making the waste valuable as a secondary source of row materials after the initial processing of sepration and purification. In this research, we focused on the metallic portion of waste PCBs to turn them into a value-added alloy usable in a practical application. The main goal was transforming squeezed metallic particles with different composition to homogenous nano-structured particles. To achieve the aim, we used mechanical alloying in room temperature and liquid N2 (cryomilling) in different milling time. After the initial mechanical sepration, the metallic portion was subjected to ball milling. The parameters such as powder to ball ratio, rotation speed, time and temperature were optimized followed by characterisation. The heat input energy was calculated to indicate the formation of nano-structured alloy. The powder characterized by TEM, STEM and SAED patterns which revealed a homogenous nano-crystalline (<100nm) alloy of (Cu79-Zn13-Fe3-Sn3-Ni1). Lattice parameters, grain size (40nm) and lattice strain (0.73%) were measured by XRD analysis. High resolution XPS analyses approved the presence of an insignificant oxide on the surface. A broad peak between 350-650 nm in UV-Vis spectrum confirmed the chemical homogeneity of the particles. Finally, the particles were applied in nanofluid application by dispersion into deionized water followed by monitoring pH and conductivity variations. The conductivity of optimized particles was 10 times more than deionized water. To conclude, using this method, waste PCBs were transformed to an applicable alloy without using any solution or heat.

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