scholarly journals Dismantling of Waste Printed Circuit Boards with the Simultaneous Recovery of Copper: Experimental Study and Process Modeling

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5186
Author(s):  
Szabolcs Fogarasi ◽  
Árpád Imre-Lucaci ◽  
Florica Imre-Lucaci
Keyword(s):  
Environmental Performance ◽  
Printed Circuit Boards ◽  
Electrochemical Process ◽  
Circuit Boards ◽  
Electronic Components ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Different Types ◽  
Leaching Solution ◽  
The Impact

The study was carried out with the aim to demonstrate the applicability of a combined chemical–electrochemical process for the dismantling of waste printed circuit boards (WPCBs) created from different types of electronic equipment. The concept implies a simple and less polluting process that allows the chemical dismantling of WPCBs with the simultaneous recovery of copper from the leaching solution and the regeneration of the leaching agent. In order to assess the performance of the dismantling process, various tests were performed on different types of WPCBs using the 0.3 M FeCl3 in 0.5 M HCl leaching system. The experimental results show that, through the leaching process, the electronic components (EC) together with other fractions can be efficiently dismounted from the surface of WPCBs, with the parallel electrowinning of copper from the copper rich leaching solution. In addition, the process was scaled up for the dismantling of 100 kg/h WPCBs and modeled and simulated using process flow modelling software ChemCAD in order to assess the impact of all steps and equipment on the technical and environmental performance of the overall process. According to the results, the dismantling of 1 kg of WPCBs requires a total energy of 0.48 kWh, and the process can be performed with an overall low environmental impact based on the obtained general environmental indexes (GEIs) values.

Nanovoid Formation at Cu/Cu/Cu Interconnections of Blind Microvias: A Field Study

2019 ◽  
Vol 2019 (1) ◽  
pp. 000492-000502 ◽  
Author(s):  
T. Bernhard ◽  
L. Gregoriades ◽  
S. Branagan ◽  
L. Stamp ◽  
E. Steinhäuser ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Structural Integrity ◽  
Weak Link ◽  
Critical Factor ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Different Types ◽  
Key Factor ◽  
Electrical Reliability ◽  
The Impact

Abstract A key factor for a high electrical reliability of multilayer High Density Interconnection Printed Circuit Boards (HDI PCBs) is the thermomechanical stability of stacked microvia interconnections. With decreasing via sizes and higher numbers of interconnected layers, the structural integrity of these interconnections becomes a critical factor and is a topic of high interest in current research. The formation of nanovoids and inhibited Cu recrystallization across the interfaces are the two main indications of a weak link from the target pad to the filled via. Based on TEM/EDX measurements on a statistically relevant number of stacked and blind microvias produced in the industrial field, different types of nanovoid phenomena are revealed at the Cu/Cu/Cu junction. The types of nanovoids were categorized relating to the time of appearance (before or after thermal treatment), the affected interfaces or layers and the impact on the Cu recrystallization. The main root causes for each void type are identified and the expected impact on the thermomechanical stability of the via junction is discussed.

scholarly journals Effect of Graphite on Copper Bioleaching from Waste Printed Circuit Boards

Minerals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 79 ◽  
Author(s):  
Linlin Tong ◽  
Qianfei Zhao ◽  
Ali Kamali ◽  
Wolfgang Sand ◽  
Hongying Yang
Keyword(s):  
Printed Circuit Boards ◽  
Acid Leaching ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Copper Leaching ◽  
Initial Ph ◽  
Efficient Extraction ◽  
Bacteria Culture ◽  
The Impact

The efficient extraction of copper as a valuable metal from waste printed circuit boards (WPCBs) is currently attracting growing interest. Here, we systematically investigated the impact of bacteria on the efficiency of copper leaching from WPCBs, and evaluated the effect of graphite on bioleaching performance. The HQ0211 bacteria culture containing Acidithiobacillus ferrooxidans, Ferroplasma acidiphilum, and Leptospirillum ferriphilum enhanced Cu-leaching performance in either ferric sulfate and sulfuric acid leaching, so a final leaching of up to 76.2% was recorded after 5 days. With the addition of graphite, the percentage of copper leaching could be increased to 80.5%. Single-factor experiments confirmed the compatibility of graphite with the HQ0211 culture, and identified the optimal pulp density of WPCBs, the initial pH, and the graphite content to be 2% (w/v), 1.6, and 2.5 g/L, respectively.

Experimental Study on Impact Mechanical Properties of Waste Printed Circuit Boards

2010 ◽  
Vol 113-116 ◽  
pp. 1123-1127
Author(s):  
Nian Xin Zhou ◽  
Ya Qun He ◽  
Chen Long Duan ◽  
Shu Ai Wang
Keyword(s):  
Mechanical Properties ◽  
Printed Circuit Boards ◽  
Impact Load ◽  
Circuit Board ◽  
Circuit Boards ◽  
X Ray ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
The Impact ◽  
Scanning Electron

Comminution is a key part of the reutilization of discarded circuit board. In order to find out the most appropriate method of crushing, the characteristics of the materials and the mechanical properties of resistance impact of discarded circuit boards were studied. The substrate of circuit boards, slots of ISA and PCI were adopted as the specimen. The scanning electron microscope (SEM) and energy disperse X-ray spectroscopy (EDX) were used to characterize and analyze the combined state of the fracturing materials on the specimen surfaces after comminution. Results showed that the metals and nonmetals in the slots were crushed and dissociated easily.At the same time, the metal and nonmetal combined interfaces in the substrate have a trend to be broken and separated under the impact effect, which means the crushing circuit board has a favorable break effect under impact load.

scholarly journals Disassembly of waste printed circuit boards using air heating and centrifugal force

2019 ◽  
Vol 23 ◽  
pp. 28
Author(s):  
Ricardo Soares Rubin ◽  
Marco Aurélio Soares de Castro ◽  
Dennis Brandão
Keyword(s):  
Centrifugal Force ◽  
Printed Circuit Boards ◽  
Power Supplies ◽  
Circuit Boards ◽  
Electronic Components ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Hot Air ◽  
Air Heating ◽  
Plastic Parts

Waste electrical and electronic equipment is a significant source of material that can contribute to reduce environmental impacts associated to extraction and discard stages; therefore, it is necessary to develop efficient recycling processes for components such as Printed Circuit Boards (PCBs). Current methods for PCB recycling may be optimized by previous disassembly of such components. In the work reported here, an especially designed and manufactured centrifuge was employed to disassemble PCBs from power supplies (PS-PCBs) and memory chips (ME-PCBs) of personal computers (PCs), through combination of hot air flow and centrifugal force. The results showed that the device was capable of separating tin solder, electronic components (EC) and PCB substrate, as long as hazardous components and plastic parts are previously removed. A scanning electron microscope (SEM) with combined energy dispersive X-ray (EDX) analyzer showed that the recovered solder had under 3%wt of contamination; therefore, it can be employed in the production of new soldering material, replacing the more commonly used solder dross. EC recovery rates were up to 94%wt for PS-PCBs and 32%wt for ME-PCBs, and once components such as inductors were not visibly damaged in the process, possibilities of reusing recovered components may be further investigated.

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

2021 ◽  
Vol 13 (18) ◽  
pp. 10357
Author(s):  
Ange A. Maurice ◽  
Khang Ngoc Dinh ◽  
Nicolas M. Charpentier ◽  
Andrea Brambilla ◽  
Jean-Christophe P. Gabriel
Keyword(s):  
Printed Circuit Boards ◽  
Chemical Elements ◽  
Subsequent Treatment ◽  
Circuit Boards ◽  
Electronic Components ◽  
Waste Streams ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Processing Wastes ◽  
Review State

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.

scholarly journals Recovery of gold and base metals from waste printed circuits boards

2021 ◽  
Vol 9 (Especial2) ◽  
pp. 62-71
Author(s):  
Eleazar Salinas-Rodríguez ◽  
Juan Hernández-Ávila ◽  
María Isabel Reyes-Valderrama ◽  
Ventura Rodríguez-Lugo ◽  
Justo Fabián Montiel-Hernández ◽  
...  
Keyword(s):  
Experimental Study ◽  
Printed Circuit Boards ◽  
Precious Metals ◽  
Electrochemical Process ◽  
Base Metals ◽  
Circuit Boards ◽  
Gold Extraction ◽  
Printed Circuit ◽  
Printed Circuits ◽  
Waste Printed Circuit Boards

This lab-scale experimental study presents a novel combined hydrometallurgical and electrochemical process for gold and non-precious metals (Cu, Ni, Pb and Zn) recovery, from waste printed circuit boards (PCB´s). First, a leaching of pins from PCB´s has been carried out and complete gold extraction was obtained using H2SO4 0.5 M (pH ≈ 1.5)/O2 (1 atm) in the temperature range from 288 to 343 K. The activation energies found showed values of 97.2 kJ∙mol-1, 86 kJ∙mol-1 and 93.6 kJ∙mol-1 for Cu, Ni and Zn respectively. Afterwards, leaching liquor was treated electrochemically in several conditions: selective Cu and Pb removal was performed at pH 1.5 and Ni and Zn removal was also obtained when pH increased to 5. All processes involved here are friendly, and even, final liquor could be reutilized.

Sign in / Sign up

Export Citation Format

Share Document