scholarly journals Chemical and microbial leaching of base metals from obsolete cell-phone printed circuit boards

2018 ◽  
Vol 28 (6) ◽  
pp. 333-339 ◽  
Author(s):  
Bhumika R. Khatri ◽  
Asha B. Sodha ◽  
Monal B. Shah ◽  
Devayani R. Tipre ◽  
Shailesh R. Dave
Keyword(s):  
Cell Phone ◽  
Printed Circuit Boards ◽  
Base Metals ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Microbial Leaching

Metal Leaching Efficiency from Waste Printed Circuit Boards by Inorganic Acid

2019 ◽  
Vol 45 (3) ◽  
pp. 355-362
Author(s):  
Zhenfeng Xiong ◽  
Ying Huang ◽  
Kemei Zhou ◽  
Dong Zhang ◽  
Juan Bao ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Printed Circuit Boards ◽  
Base Metals ◽  
Circuit Boards ◽  
Aqua Regia ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Inorganic Acids ◽  
Mass Fractions ◽  
Leaching Efficiency

Waste printed circuit boards (WPCBs) from personal computers were ground and subjected to a two-step leaching process using two inorganic acids (nitric acid and aqua regia) to leach metals. Three kinds of samples were used: the whole WPCB, the golden finger part, and the WPCB excluding the golden finger. Leaching efficiencies of metals from these samples for different nitric acid concentrations (followed by aqua regia) were evaluated to identify the best concentration of nitric acid. The extracted Au concentration from the golden finger was 5.5 times of that from the whole WPCB board. Metals that compete with Au, such as Ni and Fe, have lower mass fractions in the whole WPCB board compared to those in the golden finger. However, Cu comprises a higher proportion in the golden finger. Au can be effectively separated from most other metals by initially leaching the ground WPCB with 5M nitric acid, followed by leaching with aqua regia. Considering the high leaching proportion of Au, it is advantageous to leach Au and base metals separately from the golden finger and from WPCB excluding the golden finger.

scholarly journals Development of a Physical Separation Route for the Concentration of Base Metals from Old Wasted Printed Circuit Boards

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1014
Author(s):  
Pedro Jorge Walburga Keglevich de Buzin ◽  
Weslei Monteiro Ambrós ◽  
Irineu Antônio Schadach de Brum ◽  
Rejane Maria Candiota Tubino ◽  
Carlos Hoffmann Sampaio ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Electronic Devices ◽  
Preliminary Evidence ◽  
Composition Analysis ◽  
Base Metals ◽  
Circuit Boards ◽  
Physical Separation ◽  
Printed Circuit ◽  
Processing Circuit

Wastes from old electronic devices represent a significant part of the electronic scrap generated in developing countries, being commonly sold by collectors as low-value material to recycling hubs abroad. Upgrading the quality of this waste type could drive the revenue of recyclers, and thus, boost the recycling market. On this basis, this study investigated the possibility of concentrating metals from old wasted printed circuit boards through a physical separation-based route. Preparation of samples comprised fragmentation, size classification, density, and magnetic separation steps, followed by chemical and macro composition analysis. Cu, Al, Fe, and Sn constituted the major metals encountered in the scraps, including some peak concentrations of Zn, Sb, Pb, Ba, and Mn. Four distinct concentrate products could be obtained after suitable processing: (a) a light fraction composed of plastics and resins; (b) an aluminum concentrate; (c) a magnetic material concentrate, containing mainly iron; (d) a final concentrate containing more than 50% in mass of copper and enriched with nonferrous metals. Preliminary evidence showed that further processes, like the separation of copper wires through drumming, can potentially improve the effectiveness of the proposed processing circuit and should guide future works.

Microbial Leaching of Metals from Printed Circuit Boards

2007 ◽  
pp. 99-102 ◽  
Author(s):  
Sabine Willscher ◽  
M. Katzschner ◽  
K. Jentzsch ◽  
S. Matys ◽  
Herbert Pöllmann
Keyword(s):  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Microbial Leaching

Recovery of base metals, silicon and fluoride ions from mobile phone printed circuit boards after leaching with hydrogen fluoride and hydrogen peroxide mixtures

2018 ◽  
Vol 78 ◽  
pp. 781-788 ◽  
Author(s):  
Walner Costa Silva ◽  
Roger de Souza Corrêa ◽  
Calvin Sampaio Moreira da Silva ◽  
Júlio Carlos Afonso ◽  
Rubens Souza da Silva ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Mobile Phone ◽  
Hydrogen Fluoride ◽  
Printed Circuit Boards ◽  
Base Metals ◽  
Circuit Boards ◽  
Fluoride Ions ◽  
Printed Circuit

Microbial Leaching of Metals from Printed Circuit Boards

2007 ◽  
Vol 20-21 ◽  
pp. 99-102 ◽  
Author(s):  
Sabine Willscher ◽  
M. Katzschner ◽  
K. Jentzsch ◽  
S. Matys ◽  
Herbert Pöllmann
Keyword(s):  
Printed Circuit Boards ◽  
Complete Separation ◽  
Circuit Boards ◽  
Secondary Mineral ◽  
Polymer Carrier ◽  
Printed Circuit ◽  
Mineral Particles ◽  
Processing Facility ◽  
Microbial Leaching ◽  
Leaching Experiments

Electrical and electronic equipment (EEE), e.g. printed circuit boards, contain substantial amounts of metals, e.g. Cu, Pb and Sn. The objective of this work was to investigate the bioleaching of a material, originating from a technical waste processing facility, as one possible way of a complete separation of the metals from the polymer carrier. During the leaching experiments the mechanism of the leaching process was investigated, and biofilms and precipitates were analyzed by microscopical (SEM) and spectroscopical methods (EDX, XRF, XRD). The enhanced formation of exopolymer layers seems to promote the precipitation of secondary mineral particles beneath and the sorption of particles from the suspension on the layer surface.

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