Alkaline electrochemical leaching of Sn and Pb from the surface of waste printed circuit board and the stripping of gold by methanesulfonic acid. Issue 2 (26th July 2019)

• Record Type: Journal Article
• Authors: Zhang, Xiaojiao; Zhang, Chenglong; Zheng, Feilong; Ma, En; Wang, Ruixue; Bai, Jianfeng; Yuan, Wenyi; Wang, Jingwei
• Is Part Of: Environmental progress & sustainable energy. Volume 39:Issue 2(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-07-26
• Subjects: alkaline electrochemical leaching -- gold recovery -- methane sulfonic acid -- waste printed circuit board; Environmental engineering -- Periodicals; Sustainable engineering -- Periodicals; Environmental chemistry -- Periodicals; 333.7
• DOI: 10.1002/ep.13324
• Languages: English
• ISSNs: 1944-7442

Abstract

ABSTRACT: The variety of metals and organic in the waste printed circuit board (PCB) that makes them harmful to environment but also contain high economic value. The precious metals of gold on the surface of waste PCB has a high recovery value. In this article, a cleaner hydrometallurgical process for production of Sn, Pb, and Au from the surface of waste PCB was developed. With the alkaline electrochemical leaching, 100% of Sn and Pb in the solder can be extracted at NaOH concentration of 3 mol/L, current density of 300A/m 2, and temperature over 8°C after electrochemical leaching of 120 min, and the components can be removed simultaneously. With the technique of methane sulfonic acid etching, the copper and nickel undered the gold plate were leached and then the gold foil can be collected. The optimum conditions of methane sulfonic acid etching technique was explored: under the room temperature, with the solid‐liquid ratio of 1:5, the amount of the hydrogen peroxide is 20%, and the volume fraction of methane sulfonic acid is 15%, the soaking time of the phone board is 150 min (the coating flaking time varied slightly due to the type difference of plates), the recovering rate of gold may be up to 95%. In addition, the method has a good selectivity for element Au, the stripped gold can be melted directly, while the treated waste PCB can be used for other metal or nonmetal recovering, the solution can also be recycled after recovering copper and nickel.