scholarly journals Recovery of metals from waste printed circuit boards by supercritical water pre-treatment combined with acid leaching process

2013 ◽  
Vol 33 (5) ◽  
pp. 1251-1257 ◽  
Author(s):  
Fu-Rong Xiu ◽  
Yingying Qi ◽  
Fu-Shen Zhang
Keyword(s):  
Supercritical Water ◽  
Printed Circuit Boards ◽  
Acid Leaching ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Leaching Process ◽  
Waste Printed Circuit Boards ◽  
Pre Treatment

scholarly journals Effect of Acid Leaching Pre-Treatment on Gold Extraction from Printed Circuit Boards of Spent Mobile Phones

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 362
Author(s):  
Nicolò Maria Ippolito ◽  
Franco Medici ◽  
Loris Pietrelli ◽  
Luigi Piga
Keyword(s):  
Mobile Phones ◽  
Printed Circuit Boards ◽  
Acid Leaching ◽  
Economic Feasibility ◽  
Circuit Boards ◽  
Gold Extraction ◽  
Printed Circuit ◽  
Solid Ratio ◽  
Thiourea Complex ◽  
Pre Treatment

The effect of a preliminary acid leaching for the recovery of gold by thiourea from printed circuit boards (PCBs) of spent mobile phones, was investigated. Preliminary leaching is aimed to recover copper in the leachate that would compete with gold in the successive leaching of the residue with thiourea, thus preventing the formation of the gold-thiourea complex. Two hydrometallurgical routes were tested for the recovery of copper first, and gold after. The first one was based on a two-step leaching that utilizes sulfuric acid and hydrogen peroxide in the preliminary leaching and then thiourea for the recovery of gold in the successive leaching: A copper and gold recovery of 81% and 79% were obtained, respectively. In the second route, nitric acid was used: 100% of copper was recovered in the leachate and 85% of gold in the thiourea successive leaching. The main operative parameters, namely thiourea and ferric sulphate concentrations, leach time, liquid-solid ratio, and temperature were studied according to a factorial plan strategy. A flowsheet of the processes was proposed, and a mass balance of both routes was obtained. Finally, qualitative considerations on the technical and economic feasibility of the different routes were made.

scholarly journals Effect of Graphite on Copper Bioleaching from Waste Printed Circuit Boards

Minerals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 79 ◽  
Author(s):  
Linlin Tong ◽  
Qianfei Zhao ◽  
Ali Kamali ◽  
Wolfgang Sand ◽  
Hongying Yang
Keyword(s):  
Printed Circuit Boards ◽  
Acid Leaching ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Copper Leaching ◽  
Initial Ph ◽  
Efficient Extraction ◽  
Bacteria Culture ◽  
The Impact

The efficient extraction of copper as a valuable metal from waste printed circuit boards (WPCBs) is currently attracting growing interest. Here, we systematically investigated the impact of bacteria on the efficiency of copper leaching from WPCBs, and evaluated the effect of graphite on bioleaching performance. The HQ0211 bacteria culture containing Acidithiobacillus ferrooxidans, Ferroplasma acidiphilum, and Leptospirillum ferriphilum enhanced Cu-leaching performance in either ferric sulfate and sulfuric acid leaching, so a final leaching of up to 76.2% was recorded after 5 days. With the addition of graphite, the percentage of copper leaching could be increased to 80.5%. Single-factor experiments confirmed the compatibility of graphite with the HQ0211 culture, and identified the optimal pulp density of WPCBs, the initial pH, and the graphite content to be 2% (w/v), 1.6, and 2.5 g/L, respectively.

Isolation and characterization of copper leaching microbes from sanitary landfills for copper bioleaching of waste printed circuit boards

2021 ◽  
Author(s):  
Muhammad Syafiq Razali ◽  
Fatimah Azizah Riyadi ◽  
Fazrena Nadia Md Ak ◽  
Muhamad Ali Muhammad Yuzir ◽  
Nor’azizi Othman ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Acid Leaching ◽  
Metal Extraction ◽  
Soluble Form ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Isolation And Characterization

Abstract Electronic waste has been the fastest increasing waste generated globally and predicted to surpass 111 million tons per year by the end of 2050. The amount of e-waste is a concern not just due to its volume, but also due to its high composition of heavy metal elements, which has leads to increased development of urban mining in terms of heavy metal extraction. One common method of extraction, i.e., acid leaching, is known for its harmful residual leachate, in which can have a high impact on the environment. This focuses on the alternative leaching techniques known as bioleaching, which take advantages of microbial activity in mobilization of metal into a more soluble form. Strains from sanitary landfill soil were isolated in acidic media and identified as Bacillus sp. strain SE, Lysinibacillus sp. strain SE2, Bacillus sp. strain S1A, and Oryzobacter sp. strain SC. Among the isolated stains, the identified strain Oryzobacter sp. strain SC was able to extract up to 23.36 ppm copper from waste printed circuit boards using a two-step bioleaching process, confirming the ability of the strain to perform bioleaching of copper from e-waste.

Behaviour of zinc during the process of leaching copper from WPCBs by typical acidic ionic liquids

RSC Advances ◽  
2015 ◽  
Vol 5 (44) ◽  
pp. 34921-34926 ◽  
Author(s):  
Mengjun Chen ◽  
Jiqin Wang ◽  
Jinxiu Huang ◽  
Haiyan Chen
Keyword(s):  
Heavy Metals ◽  
Ionic Liquids ◽  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Leaching Behavior ◽  
Printed Circuit ◽  
Leaching Process ◽  
Waste Printed Circuit Boards ◽  
Copper And Zinc ◽  
Acidic Ionic Liquids

The leaching behavior of zinc, representing heavy metals, during the process of recycling copper in typical acidic ionic liquids from waste printed circuit boards was examined and the connection between copper and zinc during the leaching process was investigated in detail.

scholarly journals Simulation and economic analysis of a hydrometallurgical approach developed for the treatment of waste printed circuit boards (WPCB)

2018 ◽  
Vol 20 (4) ◽  
pp. 695-699
Keyword(s):  
Sulfuric Acid ◽  
Printed Circuit Boards ◽  
Material Balance ◽  
Precious Metals ◽  
Industrial Plant ◽  
Circuit Boards ◽  
Metal Powders ◽  
Printed Circuit ◽  
Leaching Process ◽  
Waste Printed Circuit Boards

<p>This paper presents the main achievements of a hydrometallurgical process to recover base and precious metals from waste printed circuit boards (WPCB). The technology comprises a first leaching process performed in a two-step counter current way with sulfuric acid and hydrogen peroxide for base metals solubilization and a consecutive cross leaching process with thiourea, ferric sulfate and sulfuric acid to extract precious metals. Furthermore, the reach solutions are subjected to cementation procedure with zinc powder to recover the elements of interests as metal powders. The spent solution achieved after cementation of precious metals is partially recycled within the process and the other part is treated by Fenton process and then neutralized with lime. Considering the achieved results at the laboratory level, the entire procedure was simulated using SuperPro Designer software to determine the process economy for an industrial plant. Besides this, the use of this software allows achieving the material balance of a process and the design of the plant. As a result, the process implementation at a larger scale is simulated and the main issues that can result in such a case can be determined and solved.</p>

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