ISSN: 1003-6326
CN: 43-1239/TG
CODEN: TNMCEW

Vol. 27    No. 3    March 2017

Recovery of noble metals in chlorination-leaching solution by potential-controlled reduction method
HU Yi-wen1, HE Qiang1, WANG Ri1, WANG Qiu-yu1, HUANG Shao-yong2
(1. Jiangxi Copper Technology Research Institute Co., Ltd., Jiangxi Copper Corporation, Nanchang 330096, China;
2. Guixi Smelt, Jiangxi Copper Corporation, Guixi 335424, China
)
Abstract: Using sodium sulfite as the reducing agent, the recovery of noble metals in chlorination-leaching solution by potential-controlled reduction was investigated. The results show that, when the reduction potential of Au is controlled at 530-550 mV, 98% Au in the chlorination-leaching solution is reduced and precipitated as raw-gold powder while Pt, Pd and Te are almost not reduced. The content of Au in the obtained raw-gold powder is above 98% and those of Se, Te, Cu and Pb are all lower than 0.10% (mass fraction). Also, the potential value of gold reduction has good adaptability to many different kinds of the chlorination-leaching solutions that have various concentrations of Au or H+. Then, when the reduction potential of Pt/Pd is controlled in 390-420 mV, the concentration of Au, Pt and Pd in the precipitated-gold solution can be reduced to below 1 mg/L while most of Te still remains. The content of noble metals in the collected Pt-Pd concentrate is remarkably high and that of impurities is comparatively low. In addition, the determined potential value of Pt/Pd reduction exhibits greatly adaptable to those precipitated-gold solutions with different Pt/Pd concentrations or acidity as well as reaction temperature. Accordingly, the noble metals in chlorination-leaching solutions will selectively precipitate and preliminarily separate from other elements by potential-controlled reduction method.
Key words: chlorination-leaching solution; noble metal; potential; reduction; sodium sulfite
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
Managed by Central South University (CSU)