Real-time monitoring system for improving corona electrostatic separation in the process of recovering waste printed circuit boards

Li, Jia; Zhou, Quan; Xu, Zhenming

doi:10.1177/0734242x14554647

Cited by 8 publications

(7 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With the inappropriate selection of parameters, electrostatic separation will not be effective and may even damage the electrode through spark discharge [40]. Large grains are often combinations of metals with plastic and ceramic materials, and thus the efficiency of metal recovery from PCBs may be low [36,45]. Depending on the conditions of the separation process, the type of feed fed to the separator, the following product ranges can be obtained: 9%-27% conductive grains (metals), 2%-6% mixed grains, and 67%-85% nonconductive grains [38,43].…”

Section: Introductionmentioning

confidence: 99%

Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation

et al. 2021

View full text Add to dashboard Cite

This paper analyses the impact of the method of grinding printed circuit boards (PCBs) in a knife mill on the efficiency and purity of products obtained during electrostatic separation. The separated metals and plastics and ceramics can be used as secondary raw materials. This is in line with the principle of circular economy. Three different screen perforations were used in the mill to obtain different sizes of ground grains. Moreover, the effect of cooling the feed to cryogenic temperature on the final products of separation was investigated. The level of contamination of the concentrate, intermediate, and waste obtained as a result of the application of fixed, determined electrostatic separation parameters was assessed using ICP-AES, SEM–EDS, XRD, and microscopic analysis as well as specific density. The yields of grain classes obtained from grinding in a knife mill were tested through sieve analysis and by using a particle size analyser. The test results indicate that using a knife mill with a 1 mm screen perforation along with cooling the feed to cryogenic temperature significantly improves the efficiency of the process. The grinding products were characterised by the highest release level of the useful substance—metals in the free state. The purity of the concentrate and waste obtained from electrostatic separation was satisfactory, and the content of the intermediate, in which conglomerates of solid metal–plastic connections were present, was very low. The yield of concentrate and waste amounted to 26.2% and 71.0%, respectively. Their purity, reflected in the content of the identified metals (valuable metals), was at the level of 93.3% and 0.5%, respectively. In order to achieve effective recovery of metals from PCBs by means of electrostatic separation, one should strive to obtain a feed composed of grains <1000 μm and, optimally, <800 μm.

show abstract

Section: Introductionmentioning

confidence: 99%

Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation

et al. 2021

View full text Add to dashboard Cite

show abstract

“…So far, remaining grain classes have not been tested for the following reasons: in the grain class of 2.00-0.56 mm there were significant connections of metals with non-metals parts that reduce the purity of the concentrate, while for grains lower than 0.1 mm, the damage of electrode triggered by high risk of spark discharge [16] can occurred. In addition, the aggregation effect may appear for this class, which may also affect the efficiency of separation [13,14]. However, despite this, it is planned that the efficiency of electrostatic separation will be tested for grain size < 0.1 mm.…”

Section: Methods Preparation For Electrostatic Separationmentioning

confidence: 99%

Recovery of Metals from Printed Circuit Boards By Means of Electrostatic Separation

Franke

Suponik

Nuckowski

et al. 2020

Management Systems in Production Engineering

View full text Add to dashboard Cite

Without the use of appropriate recycling technologies, the growing amount of electronic waste in the world can be a threat to the development of new technologies, and in the case of improper waste management, may have a negative impact on the environment. This is due to the fact that this waste contains large amounts of valuable metals and toxic polymers. Therefore, it should be recycled in accordance with the assumptions of the circular economy. The methods of mechanical recovery of metals from electronic waste, including printed circuits, may be widely used in the future by waste management companies as well as metal production and processing companies. That is why, a well-known and easily applicable electrostatic separation (ES) method was used to recover metals from printed circuit boards. The grain class of 0.32 - 0.10 mm, obtained after grinding the boards, was fed to a separator. Feed and separation products were analyzed by means of ICP-AES, SEM/EDS and XRD. The concentrate yield obtained after electrostatic separation amounted to 32.3% of the feed. Its density was 11.1 g/cc. Out of the 91.44% elements identified in the concentrate, over 90% were metals. XRD, SEM observations and EDS analysis confirmed the presence of non-metallic materials in the concentrate. This relatively high content of impurities indicates the need to grind printed circuit board into grain classes smaller than 0.32-0.10 mm.

show abstract

“…Combined with this approach, other physical separation methods could be of interest, such as Corona discharge or gravity shaking, which are not yet reported to have been used with disassembled components, except for plastic parts [90,91].…”

Section: Sorting By Physical Separationmentioning

confidence: 99%

Dismantling of Printed Circuit Boards Enabling Electronic Components Sorting and Their Subsequent Treatment Open Improved Elemental Sustainability Opportunities

et al. 2021

View full text Add to dashboard Cite

This critical review focuses on advanced recycling strategies to enable or increase recovery of chemical elements present in waste printed circuit boards (WPCBs). Conventional recycling involves manual removal of high value electronic components (ECs), followed by raw crushing of WPCBs, to recover main elements (by weight or value). All other elements remain unrecovered and end up highly diluted in post-processing wastes or ashes. To retrieve these elements, it is necessary to enrich the waste streams, which requires a change of paradigm in WPCB treatment: the disassembly of WPCBs combined with the sorting of ECs. This allows ECs to be separated by composition and to drastically increase chemical element concentration, thus making their recovery economically viable. In this report, we critically review state-of-the-art processes that dismantle and sort ECs, including some unpublished foresight from our laboratory work, which could be implemented in a recycling plant. We then identify research, business opportunities and associated advanced retrieval methods for those elements that can therefore be recovered, such as refractory metals (Ta, Nb, W, Mo), gallium, or lanthanides, or those, such as the platinum group elements, that can be recovered in a more environmentally friendly way than pyrometallurgy. The recovery methods can be directly tuned and adapted to the corresponding stream.

show abstract

Real-time monitoring system for improving corona electrostatic separation in the process of recovering waste printed circuit boards

Cited by 8 publications

References 32 publications

Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation

Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation

Recovery of Metals from Printed Circuit Boards By Means of Electrostatic Separation

Dismantling of Printed Circuit Boards Enabling Electronic Components Sorting and Their Subsequent Treatment Open Improved Elemental Sustainability Opportunities

Contact Info

Product

Resources

About