Decouple and compare the role of abiotic factors and developed iron and sulphur oxidizers for enhanced extraction of metals from television printed circuit boards

2018 ◽  
Vol 54 (4) ◽  
pp. 591-601 ◽  
Author(s):  
Asha B. Sodha ◽  
Monal B. Shah ◽  
Sufiya A. Qureshi ◽  
Devayani R. Tipre ◽  
Shailesh R. Dave
Keyword(s):  
Printed Circuit Boards ◽  
Abiotic Factors ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Extraction Of Metals

scholarly journals The Role of Focus Position in Single Pulse Laser Drilling of Highly Reflecting Materials

2019 ◽  
Vol 2 (1) ◽  
pp. 61-68
Author(s):  
György Meszlényi ◽  
Enikő Bitay
Keyword(s):  
Pulse Laser ◽  
Laser Processing ◽  
Printed Circuit Boards ◽  
Focal Spot ◽  
Single Pulse ◽  
Laser Drilling ◽  
Focus Position ◽  
Circuit Boards ◽  
Printed Circuit

Abstract The laser processing of materials which are highly reflective at laser wavelengths is problematic. We have to take into account that only a small part of the energy is absorbed, the main part being reflected. In this article we examine the laser processing of highly reflective copper and silver at 1070 nm wavelength. In laser drilling of printed circuit boards it is necessary to drill copper layer as well. In highly reflecting materials we can drill smaller holes because of the low energy efficiency. Naturally in single pulse laser drilling the focus position plays a key role: at the focal spot of the laser beam smaller diameter holes are produced, further from the focal spot, higher diameter holes are produced.

scholarly journals Green Zero-Waste Metal Extraction and Recycling from Printed Circuit Boards

2021 ◽  
Vol 5 (1) ◽  
pp. 39
Author(s):  
Halimeh Askari Sabzkoohi ◽  
Georgios Kolliopoulos
Keyword(s):  
Circular Economy ◽  
Printed Circuit Boards ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
Metal Extraction ◽  
Circuit Boards ◽  
Acid Base ◽  
Zero Waste ◽  
Printed Circuit ◽  
Extraction Of Metals

The development of a truly circular economy necessitates the recovery and recycling of resources from secondary streams. In this work, we studied the extraction of metals from printed circuit boards (PCBs) using choline chloride: ethylene glycol deep eutectic solvents: Cu, Ni, Zn, and Sn were selectively extracted from the PCBs, with >75% extraction after 72 h for Cu, Ni, and Sn, and circa. 45% extraction for Zn. This solvometallurgical approach promises to minimize the use of water and acid/base reagents in processing. The results show a considerable ability to compete with current methods of metal extraction and therefore generate a strong potential to attain the goal of a sustainable circular economy via zero-waste green urban mining.

scholarly journals Role of Actinomycete sp. in Bio-extraction of Copper from Electronic Waste

2021 ◽  
Vol 12 (5) ◽  
pp. 6723-6740
Keyword(s):  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Nitrogen Sources ◽  
Dissolution Mechanism ◽  
Circuit Boards ◽  
Carbon And Nitrogen Sources ◽  
Nitrate Medium ◽  
Carbon And Nitrogen ◽  
Printed Circuit

Copper is bioleached from printed circuit boards (PCBs) using Actinomycete sp. It was identified by 16S rRNA, called Streptomyces graminofaciens. The tolerance of S. graminofaciens towards copper showed that it couldn’t live in the presence of copper sulfate. The process was carried out by culturing 3.09×103 CFU of S. graminofaciens in 50 ml of modified starch nitrate medium for three days at 200 rpm and 30C and then 0.5% e-waste was added for other 5 days. Glucose (0.01 g/ml) and ammonium sulfate (0.002g/ml) were the best carbon and nitrogen sources. At pH 5, the leached copper was 88.1%. The bio-dissolution mechanism was investigated via the production of enzymes of S. graminofaciens metabolites, which showed that the higher dissolution has occurred in an un-denatured sample (non-heating) than the denatured one (heating). FTIR spectra confirmed the action of S. graminofaciens through the disappearance and appearance of some peaks. SEM showed that the e-waste gained more pores as a result of bio-treatment, which refers to the liberation of metals in solution.

scholarly journals Influence of a Polycarboxylate Based Solution on Stability of Hydrogen Peroxide and Application to E-waste Leaching

2020 ◽  
Vol 26 (1) ◽  
pp. 17-23
Author(s):  
Ersin Y. Yazici
Keyword(s):  
Hydrogen Peroxide ◽  
Printed Circuit Boards ◽  
Catalytic Decomposition ◽  
Copper Extraction ◽  
Circuit Boards ◽  
H2o2 Decomposition ◽  
Printed Circuit ◽  
High Consumption ◽  
Alkaline Conditions ◽  
Extraction Of Metals

Hydrogen peroxide with its high oxidising potential is commonly used in hydrometallurgical extraction of metals from ores, anode slimes and waste materials (e.g. WEEE) and treatment of cyanidation effluents. Main detraction to H2O2 is its rapid catalytic decomposition leading to prohibitively high consumption. Effect of pH (0-4), Cu(II) (0-10 g.l-1) and temperature (20-80°C) on H2O2 stability was investigated using response surface methodology. Influence of neutral-alkaline conditions (pH 7.3-11.8) and presence of solids (1-20% w/v) was also tested. A polycarboxylate based solution (PBS) was utilised to improve H2O2 stabilisation. The significance order of parameters on H2O2 decomposition was temperature > pH > Cu(II). Elevating the level of these parameters increased H2O2 decomposition. The activation energy (60.7±2.5 kJ.mol-1) indicated a chemically controlled process. Alkaline conditions (up to pH 11.8) led to higher H2O2 decomposition. Presence of solids adversely affected H2O2 stability under certain conditions. The addition of PBS significantly improved (up to 54%) H2O2 stability in the presence of copper. The presence of PBS in H2SO4-H2O2 leaching of waste of printed circuit boards (WPCBs) enhanced copper extraction by up to 19%. PBS can be suitably utilised to stabilise and hence reduce H2O2 consumption in aqueous solutions particularly in the presence of copper.

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