Affiliation:
1. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China
2. State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China
3. Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming 650093, China
Abstract
The process of germanium–tannin complex is the oldest form of technology for extracting germanium from Ge-containing solutions. This reaction mechanism is relatively controversial as it imposes restrictions on ideas and methods for reducing the amount of tannin. In this paper, using SEM, TEM, FT-IR, XPS, NMR, TOF-SIMS and UV diffuse reflectance spectroscopy for a deep analysis of germanium–tannin complex, the mechanism of extracting germanium from Ge-containing solutions with tannins is investigated. The results show that the theoretical tannin complex mass is 30 times that of tannin mass, and the complex rate reaches 98.84%. The changes of -OH stretching band in FT-IR spectra, the emergence of C3H3GeO7, C2H3GeO6, and C8H7GeO7 in TOF-SIMS images, and the shift of Ge and O banding energy in XPS detail spectra provided definitive evidence for the germanium–tannin complex process, highlighting that the formed complexes of tannins with germanium involve six coordinate Ge-O bonds, which are obtained through orthophenol hydroxyl groups in tannins reacting with Ge4+. Furthermore, the complex mode of germanium–tannins is layer polymerization, which finally forms an agglomeration of complex flocs. The findings of this research is innovative, and can have a profound impact on the future introduction of various methods to reduce the mass of tannins.
Funder
National Natural Science Foundation of China
National Key Research and Development Program of China
Yunnan Applied Basic Research Projects
Major Science and Technology Project of Yunnan Province
Subject
General Materials Science,Metals and Alloys