Selective recovery of Copper from waste mobile phone printed circuit boards using Sulphuric acid leaching

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.

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Impact of Pulverization, Pretreatment and pH Regulation on Microbial Extraction of Metals from Waste Mobile Phone Printed Circuit Boards

Applied Biochemistry and Microbiology ◽

10.1134/s0003683821050173 ◽

2021 ◽

Vol 57 (5) ◽

pp. 675-682

Author(s):

S. C. Thacker ◽

N. S. Nayak ◽

D. R. Tipre ◽

S. R. Dave

Keyword(s):

Mobile Phone ◽

Printed Circuit Boards ◽

Ph Regulation ◽

Circuit Boards ◽

Printed Circuit ◽

Extraction Of Metals

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Effect of Graphite on Copper Bioleaching from Waste Printed Circuit Boards

Minerals ◽

10.3390/min10010079 ◽

2020 ◽

Vol 10 (1) ◽

pp. 79 ◽

Cited By ~ 4

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.

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