scholarly journals Recovery of gold and base metals from waste printed circuits boards

2021 ◽  
Vol 9 (Especial2) ◽  
pp. 62-71
Author(s):  
Eleazar Salinas-Rodríguez ◽  
Juan Hernández-Ávila ◽  
María Isabel Reyes-Valderrama ◽  
Ventura Rodríguez-Lugo ◽  
Justo Fabián Montiel-Hernández ◽  
...  
Keyword(s):  
Experimental Study ◽  
Printed Circuit Boards ◽  
Precious Metals ◽  
Electrochemical Process ◽  
Base Metals ◽  
Circuit Boards ◽  
Gold Extraction ◽  
Printed Circuit ◽  
Printed Circuits ◽  
Waste Printed Circuit Boards

This lab-scale experimental study presents a novel combined hydrometallurgical and electrochemical process for gold and non-precious metals (Cu, Ni, Pb and Zn) recovery, from waste printed circuit boards (PCB´s). First, a leaching of pins from PCB´s has been carried out and complete gold extraction was obtained using H2SO4 0.5 M (pH ≈ 1.5)/O2 (1 atm) in the temperature range from 288 to 343 K. The activation energies found showed values of 97.2 kJ∙mol-1, 86 kJ∙mol-1 and 93.6 kJ∙mol-1 for Cu, Ni and Zn respectively. Afterwards, leaching liquor was treated electrochemically in several conditions: selective Cu and Pb removal was performed at pH 1.5 and Ni and Zn removal was also obtained when pH increased to 5. All processes involved here are friendly, and even, final liquor could be reutilized.

scholarly journals Dismantling of Waste Printed Circuit Boards with the Simultaneous Recovery of Copper: Experimental Study and Process Modeling

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5186
Author(s):  
Szabolcs Fogarasi ◽  
Árpád Imre-Lucaci ◽  
Florica Imre-Lucaci
Keyword(s):  
Environmental Performance ◽  
Printed Circuit Boards ◽  
Electrochemical Process ◽  
Circuit Boards ◽  
Electronic Components ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Different Types ◽  
Leaching Solution ◽  
The Impact

The study was carried out with the aim to demonstrate the applicability of a combined chemical–electrochemical process for the dismantling of waste printed circuit boards (WPCBs) created from different types of electronic equipment. The concept implies a simple and less polluting process that allows the chemical dismantling of WPCBs with the simultaneous recovery of copper from the leaching solution and the regeneration of the leaching agent. In order to assess the performance of the dismantling process, various tests were performed on different types of WPCBs using the 0.3 M FeCl3 in 0.5 M HCl leaching system. The experimental results show that, through the leaching process, the electronic components (EC) together with other fractions can be efficiently dismounted from the surface of WPCBs, with the parallel electrowinning of copper from the copper rich leaching solution. In addition, the process was scaled up for the dismantling of 100 kg/h WPCBs and modeled and simulated using process flow modelling software ChemCAD in order to assess the impact of all steps and equipment on the technical and environmental performance of the overall process. According to the results, the dismantling of 1 kg of WPCBs requires a total energy of 0.48 kWh, and the process can be performed with an overall low environmental impact based on the obtained general environmental indexes (GEIs) values.

Mechanism of Gold Cyanidation in Bioleaching of Precious Metals from Waste Printed Circuit Boards

2020 ◽  
Vol 8 (51) ◽  
pp. 18975-18981
Author(s):  
Mi Lin ◽  
Zhe Huang ◽  
Zhihui Yuan ◽  
Yonggao Fu ◽  
Jiaqi Hu ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Precious Metals ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards

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.

Sign in / Sign up

Export Citation Format

Share Document