scholarly journals Determination of Liberation Degree of Mechanically Processed Waste Printed Circuit Boards by Using the Digital Microscope and SEM-EDS Analysis

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1202 ◽  
Author(s):  
Pedro Pereira Gonçalves ◽  
Akira Otsuki
Keyword(s):  
Printed Circuit Boards ◽  
Image Acquisition ◽  
Target Component ◽  
Circuit Boards ◽  
Characterization Methods ◽  
Printed Circuit ◽  
Advantages And Disadvantages ◽  
Waste Printed Circuit Boards ◽  
Digital Microscope ◽  
Processed Waste

Characterization of heterogeneous materials, such as particles from mechanically processed waste printed circuit boards, is a challenging task. The majority of characterization methods either give average information or information that is very limited and in a tiny area of specific interest. That said, capturing such heterogeneity is significantly important for any kind of processes. Degree of liberation, indicating how much the target component is liberated from the non-valuable components, is a key property to determine the success of subsequent process for valuable material recovery. This work analyzed the degree of liberation of metals within the products of hammer milling process via the combination of image acquisition and analysis. The digital microscope and a scanning electron microscope (SEM) coupled with the energy dispersive spectroscopy (EDS) were used for image acquisition and elemental mapping, in order to evaluate the selective liberation under different milling conditions (i.e., feed mass, milling time) for different metals (mainly Cu and Al) and particle size fractions. The obtained liberation degree was also modelled and determined the liberation parameters that were compared. The results showed that the degree of liberation significantly depend on the milling conditions and metals we analyzed, and well correlated with the selective metal enrichment behavior. Results between the two methods showed some similarities and discrepancies. The advantages and disadvantages of the above two methods were identified and discussed in the paper, in addition to their methodological developments.

Non-Metallic Materials from Waste Printed Circuit Boards (PCBs): Characteristics, Environmental Risk and Recycling

2015 ◽  
Vol 768 ◽  
pp. 576-587
Author(s):  
Zhi Tong Yao ◽  
Wen Yi Yuan ◽  
Zheng Miao Xie ◽  
Jun Hong Tang
Keyword(s):  
Environmental Risk ◽  
Building Materials ◽  
Printed Circuit Boards ◽  
Chemical Components ◽  
Metallic Materials ◽  
Circuit Boards ◽  
Physical Treatment ◽  
Printed Circuit ◽  
Advantages And Disadvantages ◽  
Waste Printed Circuit Boards

Printed circuit boards (PCBs) are the typical and fundamental components of almost all electric and electronic equipments. The mechanical and physical treatment of PCBs generates a large amount of non-metallic materials and thus there is an urgent need to develop alternative treatment methods for them. In this study, the characteristics and environmental risk of non-metallic materials were analyzed. The current recycling methods were investigated as well. The results showed that their chemical components were distinct for the glass fiber/epoxy laminated boards and paper/phenolic laminated boards. The presence of bromine, chlorine, copper, chromium and lead would pose a threat to the environment during its recycling. The current recycling methods included landfill, preparing composites and building materials, pyrolysis and combustion. These methods had their own distinct advantages and disadvantages. The comparative analysis indicated that preparing composites may be an alternative recycling method. Molten salt oxidation (MSO) technology is prospective and need be further studied.

scholarly journals Non-Destructive Characterization of Mechanically Processed Waste Printed Circuit Boards: X-ray Fluorescence Spectroscopy and Prompt Gamma Activation Analysis

2019 ◽  
Vol 3 (2) ◽  
pp. 54 ◽  
Author(s):  
Akira Otsuki ◽  
Pedro Pereira Gonçalves ◽  
Christian Stieghorst ◽  
Zsolt Révay
Keyword(s):  
Activation Analysis ◽  
Printed Circuit Boards ◽  
Prompt Gamma Activation Analysis ◽  
Prompt Gamma ◽  
Circuit Boards ◽  
Gamma Activation ◽  
X Ray ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Processed Waste

This work aimed to characterize the deportment/concentration and liberation/association of the metals and light elements within mechanically processed waste printed circuit boards (PCBs) that hold the complex and heterogeneous structure and distribution of different material components. Waste PCBs passed through a series of mechanical processing (i.e., comminution and sieving) for metal recovery and were then characterized without further destroying the particles in order to capture their heterogeneity. The characterizations were performed in a laboratory and large-scale neutron facility. The results obtained with a portable X-ray fluorescence spectroscopy and prompt gamma activation analysis were compared and confirmed the good agreement and complementarities in general. The advantages and disadvantages of the two different methods were identified and discussed in this paper, in relation to their application to the analysis of mechanically processed PCB particles.

LEACHING OF METALS FROM WASTE PRINTED CIRCUIT BOARDS (WPCBs) USING SULFURIC AND NITRIC ACIDS

2014 ◽  
Vol 13 (10) ◽  
pp. 2601-2607 ◽  
Author(s):  
Jae-chun Lee ◽  
Manoj Kumar ◽  
Min-Seuk Kim ◽  
Jinki Jeong ◽  
Kyoungkeun Yoo
Keyword(s):  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards

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%.

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