Bacterial leaching of copper, zinc, nickel and aluminum from discarded printed circuit boards using acidophilic bacteria

Technological innovations and increased demand for electronic devices resulted in production of more and more waste with highmetal content. Worldwide, 50 million tons of WEEE (Waste from Electrical and Electronic Equipment) are generated each year. Giventhe metal content present in electrical waste (e-waste), it is considered to be an urban mine and, if properly treated, can serve as analternative secondary source of metals. Waste printed circuit boards (WPCBs) that constitute approx. 3-5% of WEEE by weight areof particular importance. They contain, on average, 30-40% of metals by weight, with higher purity than in minerals. With environmental and economic benefits in mind, increasing attention is being paid to the development of processes to recover metals and othervaluable materials from WPCBs. The research presented in the article aimed at assessing the usefulness of the biotechnological methodfor leaching of selected metals from e-waste. The results indicate that it is possible to mobilize metals from WPCBs using microorganisms such as Acidithiobacillus ferroxidans bacteria

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Total Recovery of Gold Contained in Computer Printed Circuit Boards. Leaching Kinetics of Cu, Zn and Ni

Journal of the Mexican Chemical Society ◽

10.29356/jmcs.v56i2.312 ◽

2017 ◽

Vol 56 (2) ◽

Author(s):

María Isabel Reyes ◽

Isauro Rivera ◽

Francisco Patiño ◽

Mizraim U. Flores ◽

Martín Reyes

Keyword(s):

Printed Circuit Boards ◽

Metal Layer ◽

Circuit Boards ◽

Gold Substrate ◽

Total Recovery ◽

Printed Circuit ◽

Reaction Orders ◽

Copper Zinc ◽

Kinetics Of

In this study a thorough characterization of certain printed circuit boards has been carried out; it was found that they are made up of a polymer layer, a metal layer of Cu, Zn and Ni, and a gold substrate. A kinetic study of the acid dynamic leaching of copper, zinc and nickel has been carried out, finding out that these elements’ dissolution allows the gold substrate to be physically separated; then, the gold particles are separated from the polymer by filtration. The reaction orders were calculated vs. H2SO4 concentration, and the activation energy was calculated as well; reaction orders of n = 0.265, n = 0.247 and n = 0.245 were found for Cu, Zn and Ni respectively, while Ea = 86.3, Ea = 95.3 and Ea = 11.2 kJ/mol were found for Cu, Zn and Ni respectively. When the attack time is over, a shiny, solid product has been obtained; it was characterized by SEM-EDS and AAS, confirming that it is metallic gold, with a purity of 100 and 99.9% according to the respective technique.

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The Effect of Specific Conditions on Cu, Ni, Zn and Al Recovery from PCBS Waste Using Acidophilic Bacterial Strains

Archives of Metallurgy and Materials ◽

10.1515/amm-2016-0049 ◽

2016 ◽

Vol 61 (1) ◽

pp. 261-264 ◽

Cited By ~ 12

Author(s):

A. Mrážiková ◽

J. Kaduková ◽

R. Marcinčáková ◽

O. Velgosová ◽

J. Willner ◽

...

Keyword(s):

Printed Circuit Boards ◽

Bacterial Culture ◽

Copper Recovery ◽

Acidithiobacillus Thiooxidans ◽

Circuit Boards ◽

Bacterial Strains ◽

Printed Circuit ◽

Copper Zinc ◽

Static Conditions ◽

Nickel Dissolution

The objective of this work was to evaluate the influence of static, stirring and shaking conditions on copper, zinc, nickel and aluminium dissolution from printed circuit boards (PCBs) using the mixed acidophilic bacterial culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The results revealed that static conditions were the most effective in zinc and aluminium dissolution. Zinc was removed almost completely under static conditions, whereas maximum of nickel dissolution was reached under the stirring conditions. The highest copper recovery (36%) was reached under stirring conditions. The shaking conditions appeared to be the least suitable. The relative importance of these systems for the bioleaching of copper and nickel decreased in the order: stirring, static conditions, shaking.

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