Recovery of germanium from leach solutions of fly ash using solvent extraction with various extractants
Rights accessOpen Access
The solvent extraction of germanium and some heavy metals by commercial tri-octyl/decyl amine (Alamine 336), N-methyl-N, N-dioctyl chloride (Aliquat 336) and phosphine oxide (Cyanex 923) has been studied. In each extraction system, germanium was only extracted from a solution containing nickel, cadmium, cobalt, and zinc, which had a composition similar to gasification coal fly ash aqueous leach solutions. Under a comparable condition, the germanium extraction efficiency by the aforementioned extractants was in the order Aliquat 336 > Alamine 336 > Cyanex 923. The slope analysis method showed that 2 moles of Alamine 336 and Aliquat 336, as well as 4 moles of Cyanex 923, participated in the extraction of germanium. In amine extraction systems, tartaric acid was required as a complexant used to convert germanium to anionic species. As a result, the ratio of 2 (mole ration of tartaric acid to Ge) was required to complete anionic complexation. On the other hand, oxalic acid with a concentration of 0.1 M was chosen as a proper solvated complexant in the Cyanex 923 system. HCl solutions with concentrations of 1 and 2 M can properly strip germanium from the loaded Alamine 336 and Aliquat 336, respectively. In addition, 0.1 M NaOH was sufficient for germanium stripping from Cyanex 923. Consequently, it can be concluded that Aliquat 336 can be an economical and industry-friendly extractant for germanium solvent extraction from a mixed solution.
CitationKamran, H., Irannajad, M., Fortuny, A., Sastre, A. Recovery of germanium from leach solutions of fly ash using solvent extraction with various extractants. "Hydrometallurgy", Gener 2018, vol. 175, p. 164-169.