Selective Disintegration–Milling to Obtain Metal-Rich Particle Fractions from E-Waste
Date
2022
Authors
Blumbergs, Ervins
Serga, Vera
Shishkin, Andrei
Goljandin, Dmitri
Shishko, Andrej
Zemcenkovs, Vjaceslavs
Markus, Karlis
Baronins, Janis
Pankratov, Vladimir
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Abstract
Various metals and semiconductors containing printed circuit boards (PCBs) are abundant in any electronic device equipped with controlling and computing features. These devices inevitably constitute e-waste after the end of service life. The typical construction of PCBs includes mechanically and chemically resistive materials, which significantly reduce the reaction rate or even avoid accessing chemical reagents (dissolvents) to target metals. Additionally, the presence of relatively reactive polymers and compounds from PCBs requires high energy consumption and reactive supply due to the formation of undesirable and sometimes environmentally hazardous reaction products. Preliminarily milling PCBs into powder is a promising method for increasing the reaction rate and avoiding liquid and gaseous emissions. Unfortunately, current state-of-the-art milling methods also lead to the presence of significantly more reactive polymers still adhered to milled target metal particles. This paper aims to find a novel and double-step disintegration–milling approach that can provide the formation of metal-rich particle size fractions. The morphology, particle fraction sizes, bulk density, and metal content in produced particles were measured and compared. Research results show the highest bulk density (up to 6.8 g·cm−3) and total metal content (up to 95.2 wt.%) in finest sieved fractions after the one-step milling of PCBs. Therefore, about half of the tested metallic element concentrations are higher in the one-step milled specimen and with lower adhered plastics concentrations than in double-step milled samples. © 2022 by the authors.--//-- This is an open access article Blumbergs E., Serga V., Shishkin A., Goljandin D., Shishko A., Zemcenkovs V., Markus K., Baronins J., Pankratov V. "Selective Disintegration–Milling to Obtain Metal-Rich Particle Fractions from E-Waste"
(2022) Metals, 12 (9), art. no. 1468, DOI: 10.3390/met12091468 published under the CC BY 4.0 licence.
Description
This research was supported by ERDF project no. 1.1.1.1/20/A/139 “Development of sustainable recycling technology of electronic scrap for precious and non-ferrous metals extraction”. The project was co-financed by REACT-EU funding to mitigate the effects of the pandemic crisis. The article was published with the financial support from the Riga Technical University Research Support Fund. This research was also supported by the Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2. The authors would also like to mention the support from the “Innovation Grants for Maritime Students” performed at Latvian Maritime Academy (project no: 1.1.1.3/18/A/006, funded by the European Regional Development Fund—ERDF, Republic of Latvia).
Keywords
Research Subject Categories::NATURAL SCIENCES::Physics , disintegration , e-waste , e-waste mechanical pretreatment , e-waste milling , precious metals , printed circuit boards