scholarly journals Hydrometallurgical Treatment of Waste Printed Circuit Boards: Bromine Leaching

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 462 ◽  
Author(s):  
Hao Cui ◽  
Corby Anderson
Keyword(s):  
Printed Circuit Boards ◽  
Sodium Concentration ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Inorganic Acids ◽  
Valuable Metals ◽  
Bromine Concentration ◽  
Hydrometallurgical Treatment ◽  
Solid Liquid

This paper demonstrates the recovery of valuable metals from shredded Waste Printed Circuit Boards (WPCBs) by bromine leaching. Effects of sodium bromide concentration, bromine concentration, leaching time and inorganic acids were investigated. The most critical factors are sodium concentration and bromine concentration. It was found that more than 95% of copper, silver, lead, gold and nickel could be dissolved simultaneously under the optimal conditions: 50 g/L solid/liquid ratio, 1.17 M NaBr, 0.77 M Br2, 2 M HCl, 400 RPM agitation speed and 23.5 °C for 10 hours. The study shows that the dissolution of gold from waste printed circuit boards in a Br2-NaBr system is controlled by film diffusion and chemical reaction.

Supercritical CO2-induced alteration of a polymer–metal matrix and selective extraction of valuable metals from waste printed circuit boards

2020 ◽  
Vol 22 (20) ◽  
pp. 7080-7092
Author(s):  
Peng Peng ◽  
Ah-Hyung Alissa Park
Keyword(s):  
Metal Matrix ◽  
Supercritical Co2 ◽  
Printed Circuit Boards ◽  
Selective Extraction ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Valuable Metals ◽  
Polymer Metal

Supercritical CO2-induced treatment of heterogeneous waste printed circuit boards resulted in selective recoveries of Au, Ni and Cu.

scholarly journals Extraction of Copper and Zinc from Waste Printed Circuit Boards

Recycling ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 36 ◽  
Author(s):  
Ayorinde Emmanuel Ajiboye ◽  
Folorunsho Emmanuel Olasehinde ◽  
Ojo Albert Adebayo ◽  
Olubode John Ajayi ◽  
Malay Kumar Ghosh ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Selective Extraction ◽  
Leach Solution ◽  
Economic Resources ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Valuable Metals ◽  
Extraction Selectivity ◽  
Cu And Zn

The recovery of valuable metals from waste printed circuit boards (WPCBs) is crucial in order to harness their economic resources, and prevents potential environmental contamination. However, selective extraction of Cu and Zn, and the co-extraction of other metals as impurities at ambient temperature using selected lixiviants such as HCl, H2SO4, HNO3, trifluoromethanesulfonic acid (TFMS), NaOH, and mixtures of NaCl and CuCl2 was studied. It is shown that the extraction efficiencies of all the metals increased with increases in lixiviant concentrations. High selectivity of Cu and Zn toward Fe were achieved in dilute H2SO4, HNO3, TFMS, and 0.5 M NaCl + 0.1 M CuCl2, and low dissolution of Pb (<5%) was observed in all H2SO4 lixiviants. Almost 100% Zn extraction using NaOH lixiviants without trace of other metals was achieved. Therefore, 0.5 M NaCl + 0.5 M CuCl2, 1.0 M HNO3, 0.5 M H2SO4, and 1.0 M TFMS showed high extraction selectivity toward Cu and Zn with low chemical consumption, and produced pregnant leach solution rich in Cu and Zn, as well as residue containing Fe, Ni, and other metals.

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 Characteristics of Metals Leached from Waste Printed Circuit Boards Using Acidithiobacillus ferrooxidans

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 224
Author(s):  
Jinsung An
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Printed Circuit Boards ◽  
Cost Effective ◽  
Low Grade ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Iron Oxidizing Bacteria ◽  
Valuable Metals ◽  
Leaching Characteristics

The aim of this study was to compare leaching characteristics of metals from printed circuit boards (PCBs), taken from waste electrical and electronic equipment in the presence and in the absence of the iron-oxidizing bacteria, Acidithiobacillus ferrooxidans. A. ferrooxidans not only increases the leached concentration of Cu from the PCBs, but also inhibits the components of the 0K medium and leached Cu from forming precipitates such as libethenite (Cu2(PO4)(OH)), thereby assisting Cu recovery from the PCBs. In addition, the leached concentration of Pb from PCBs decreased in the presence of A. ferrooxidans, due to Pb forming amorphous precipitates. It is expected that Pb is not highly toxic to A. ferrooxidans. Consequently, A. ferrooxidans can be used as a cost-effective and environmentally friendly way to leach out valuable metals from PCBs as low-grade urban ore.

Investigation on Dissolution of Brominated Epoxy Resin Using Ionic Liquid [Bmim]Cl from Waste Printed Circuit Boards

2015 ◽  
Vol 768 ◽  
pp. 588-594 ◽  
Author(s):  
Min Xu ◽  
Jing Wei Wang ◽  
Yu Xing Mao ◽  
Hong Yong Xie
Keyword(s):  
Ionic Liquid ◽  
Epoxy Resin ◽  
Printed Circuit Boards ◽  
Dissolution Mechanism ◽  
Circuit Boards ◽  
Liquid Ratio ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Brominated Epoxy Resin ◽  
Solid Liquid

Treatment technology of brominated epoxy resin (BER) is still a big challenge to waste printed circuit boards (PCBs) recycling. In order to make full use of the materials, ionic liquid 1-butyl-3-methyl imidazole chloride ([Bmim]Cl) was used to dissolve BER to separate glass fibers from PCB nonmetallic powders. The effects of dissolving parameters including temperature, time and solid/ liquid ratio on the dissolution rate of BER were investigated. The dissolved BER were regenerated and were characterized by FTIR and thermal analysis. Results showed that [Bmim]Cl was a good direct solvent for BER dissolution and at a suitable condition of 170°Cfor 6 hours with solid/liquid ratio of 1: 20 (g/g), nearly 90% of BER in original powders were dissolved. The possible dissolution mechanism was also discussed.

Evaluating waste printed circuit boards recycling: Opportunities and challenges, a mini review

2017 ◽  
Vol 35 (4) ◽  
pp. 346-356 ◽  
Author(s):  
Abhishek Kumar Awasthi ◽  
Gabriel Ionut Zlamparet ◽  
Xianlai Zeng ◽  
Jinhui Li
Keyword(s):  
Large Scale ◽  
Printed Circuit Boards ◽  
Review Article ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Valuable Metals ◽  
Rapid Generation

Rapid generation of waste printed circuit boards has become a very serious issue worldwide. Numerous techniques have been developed in the last decade to resolve the pollution from waste printed circuit boards, and also recover valuable metals from the waste printed circuit boards stream on a large-scale. However, these techniques have their own certain specific drawbacks that need to be rectified properly. In this review article, these recycling technologies are evaluated based on a strength, weaknesses, opportunities and threats analysis. Furthermore, it is warranted that, the substantial research is required to improve the current technologies for waste printed circuit boards recycling in the outlook of large-scale applications.

Selective Leaching of Valuable Metals from Waste Printed Circuit Boards

2003 ◽  
Vol 53 (7) ◽  
pp. 897-902 ◽  
Author(s):  
Chi Jung Oh ◽  
Sung Oh Lee ◽  
Hyung Sik Yang ◽  
Tae Jun Ha ◽  
Myong Jun Kim
Keyword(s):  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Selective Leaching ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Valuable Metals
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