scholarly journals Optimal Thermal Treatment for Effective Copper Recovery in Waste Printed Circuit Boards by Physical Separation: Influence of Temperature and Gas

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1213
Author(s):  
Boram Kim ◽  
Seongsoo Han ◽  
Seungsoo Park ◽  
Seongmin Kim ◽  
Minuk Jung ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Treatment ◽  
Mechanical Strength ◽  
Physical Properties ◽  
Printed Circuit Boards ◽  
Separation Efficiency ◽  
Size Fraction ◽  
Copper Recovery ◽  
Circuit Boards ◽  
Printed Circuit

Printed circuit boards (PCBs) are difficult to recycle because of the layered structure of non-metal (i.e., epoxy resin, glass fiber) and copper. In this work, we conducted a systematic investigation to effectively recover copper from PCB. A thermal treatment was employed for improving the crushing performance of PCB and conducted by varying the temperature and the gas. Then, the mechanical strength, degree of liberation (DL), and copper separation efficiency of the heat-treated and untreated PCBs were investigated. After heat treatment under a 300 °C air atmosphere, the mechanical strength of PCB decreased from 386.36 to 24.26 MPa, and copper liberation improved from 9.3% to 100% in the size range of a coarser size fraction (>1400 μm). Accordingly, when electrostatic separations were performed under these conditions, a high-Cu-grade concentrate and high recovery could be obtained. The results show that the change in the physical properties of the PCBs leads to an improvement in the DL following thermal decomposition at 300 °C in air. Our study elucidates the physical properties of PCBs and the DL under various heat treatment conditions. Furthermore, it shows that the heat treatment condition of 300 °C in air is ideal for recovering copper from the PCB.

scholarly journals Effective Recovery Process of Copper from Waste Printed Circuit Boards Utilizing Recycling of Leachate

JOM ◽  
2020 ◽  
Author(s):  
Joona Rajahalme ◽  
Siiri Perämäki ◽  
Roshan Budhathoki ◽  
Ari Väisänen
Keyword(s):  
Hydrogen Peroxide ◽  
Sulfuric Acid ◽  
Printed Circuit Boards ◽  
Sulfuric Acid Concentration ◽  
Recovery Process ◽  
Copper Recovery ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Acid Consumption

AbstractThis study presents an optimized leaching and electrowinning process for the recovery of copper from waste printed circuit boards including studies of chemical consumption and recirculation of leachate. Optimization of leaching was performed using response surface methodology in diluted sulfuric acid and hydrogen peroxide media. Optimum leaching conditions for copper were found by using 3.6 mol L−1 sulfuric acid, 6 vol.% hydrogen peroxide, pulp density of 75 g L−1 with 186 min leaching time at 20°C resulting in complete leaching of copper followed by over 92% recovery and purity of 99.9% in the electrowinning. Study of chemical consumption showed total decomposition of hydrogen peroxide during leaching, while changes in sulfuric acid concentration were minor. During recirculation of the leachate with up to 5 cycles, copper recovery and product purity remained at high levels while acid consumption was reduced by 60%.

Copper Recovery from Printed Circuit Boards from Smartphones Through Bioleaching

2019 ◽  
pp. 837-844 ◽  
Author(s):  
Lidiane Maria de Andrade ◽  
Carlos Gonzalo Alvarez Rosario ◽  
Mariana Alves de Carvalho ◽  
Denise Crocce Romano Espinosa ◽  
Jorge Alberto Soares Tenório
Keyword(s):  
Printed Circuit Boards ◽  
Copper Recovery ◽  
Circuit Boards ◽  
Printed Circuit

scholarly journals Selective leaching of copper from waste printed circuit boards (PCBs) using glycine as a complexing agent

2021 ◽  
Keyword(s):  
Printed Circuit Boards ◽  
Size Fraction ◽  
Complexing Agent ◽  
Copper Extraction ◽  
Circuit Boards ◽  
Selective Leaching ◽  
Ambient Conditions ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Copper Leaching

<p>In this research, the selective leaching of copper from waste printed circuit boards (PCBs) using glycine as a complexing agent was investigated. PCBs were pulverized and sieved, which allowed obtaining a PCBs powder of particle size fraction ≤ 1mm. The PCBs powder has been characterized by several techniques before and after leaching. In order to understand the copper extraction process, the reaction mechanisms, and to determine the optimal leaching parameters, the effects of a range of parameters during copper leaching were investigated, including leaching time, solid-to-liquid ratio, mechanical stirring rate, leaching temperature and glycine concentration. Copper leaching from PCBs waste powder was identified as a complex four-stage gas-liquid-solid process that is carried out slowly under ambient conditions. Glycine shows a very significant selectivity for copper during leaching process allowing dissolving copper from PCBs waste with a percentage of 92.8% under ambient conditions.</p>

A New Technology for Recovery of Metals from Waste Printed Circuit Boards

2014 ◽  
Vol 675-677 ◽  
pp. 698-703 ◽  
Author(s):  
Wei Liu ◽  
Chao Liang ◽  
Wen Qing Qin ◽  
Fen Jiao
Keyword(s):  
Printed Circuit Boards ◽  
Size Range ◽  
New Technology ◽  
Shaking Table ◽  
Copper Recovery ◽  
Copper Extraction ◽  
Circuit Boards ◽  
Pressure Oxidation ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards

Recycling of metallic fractions from waste printed circuit boards (PCBs) using gravity separation and hydrometallurgy was investigated. The obtained research fruits were listed as follows: (1) When being pulverized to finer than 0.4mm, waste PCBs could be generally dissociated from plastics. (2) Shaking table was shown to be suitable for processing pulverized PCBs. Pulverized PCBs containing 6.97% copper was enriched to 33.55% in a single operation and the copper recovery was 90.3% in the best size range of separation. (3) Pressure oxidation leaching was shown to be effective for separating copper from aluminum and tin. The leaching extraction of aluminum and tin were 86.6% and 96.3%, copper extraction was 1% or less under the optimal conditions.

Hydrometallurgical Process for Copper Recovery from Waste Printed Circuit Boards (PCBs)

2011 ◽  
Vol 32 (2) ◽  
pp. 90-104 ◽  
Author(s):  
Hoang Long Le ◽  
Jinki Jeong ◽  
Jae-Chun Lee ◽  
Banshi D. Pandey ◽  
Jae-Min Yoo ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Copper Recovery ◽  
Hydrometallurgical Process ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards

scholarly journals Assessment of sampling and chemical analysis of waste printed circuit boards from WEEE: gold content determination

10.30544/427 ◽  
2019 ◽  
Vol 25 (2) ◽  
pp. 171-182
Author(s):  
Martina Laubertova ◽  
Marcela Malindzakova ◽  
Jarmila Trpcevska ◽  
Natasa Gajic
Keyword(s):  
Chemical Analysis ◽  
Mobile Phones ◽  
Printed Circuit Boards ◽  
Size Fraction ◽  
Heterogeneous Materials ◽  
Sampling Procedure ◽  
Gold Content ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards

Waste printed circuit boards (WPCBs) from discarded mobile phones and smartphones are considerably heterogeneous materials with a high gold content (approx. 490 grams per ton). The aim of our chemical analysis of samples of WPCBs was to determine the amounts of gold using open acid digestion and atomic absorption spectrometry (HR CS AAS). The test samples designated for chemical analysis must genuinely represent the bulk WPCBs from which they are taken. This study aimed to develop a correct sampling procedure to analyze the heterogeneous materials from printed circuit boards; explicitly concerning the influence of particle size on the precision of chemical analysis of WPCBs from discarded mobile phones. Chemical analysis of the representative sample of WPCBs with a grain size fraction of d ≤ 200 μm determined that the gold content was 475 g∙t-1 with a low variation coefficient and low dispersion which indicates very high accuracy of the designed sampling procedure.

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