Zidong Tan,Yong Zhen,Chang Wei,Xin Jin,Xingbin Li,Gang Fan,XingGuo Luo
In this study, germanium was selectively extracted using an organic phase containing 3% C7-9 hydroxamic acid (YW100), 15% Di(2-ethylhexyl)phosphoric acid (D2EHPA), 35% Tri(octyl-decyl) amine (N235), and 47% kerosene from the Ge-slag sulfuric acid leaching solution. Then, the solution was stripped by the 1 mol/L NH4F solution to obtain a germanium extraction ratio of 99.4% and a stripping ratio of 96.2% after three extraction and stripping stages. The total organic carbon (TOC) was used to characterize the total organic matter amount in the raffinate. Compared to the “YW100 + D2EHPA” extraction system, the “YW100 + D2EHPA + N235” extraction system reduced 80% of the water solubility loss of YW100 and improved the phase separation performance. In addition, the mechanisms of germanium extraction and phase separation improvement were studied. The coordination number of YW100 and germanium is 3, while the coordination number of D2EHPA is 1.
The composite sulfate solution generated during zinc hydrometallurgy is rich in Ga and Ge, Zn, Al, and other elements. However, existing single extraction systems exhibit poor efficiency for simultaneous Ga and Ge extraction. In addition, the high co-extraction rate of Al hinders the subsequent separation of Al from Ga. In this study, an innovative process—based on synergistic extraction with P507–YW100 and stepwise stripping—was proposed to realize efficient separation and recovery of Ga and Ge. An extraction system, composed of 15 vol% P507 and 4 vol% YW100, yielded Ga and Ge extraction efficiencies of 97.38 % and 99.23 %, respectively. Subsequently, a two-stage extraction process was applied, which increased the extraction efficiencies of Ga and Ge to > 99.5 %. Consequently, the concentrations of these elements in the raffinate were reduced to < 5 mg/L, and the extraction efficiency of Al reached 12.06 %. To minimize the impact of Al on the purities of the subsequent Ga and Ge products, an innovative selective stripping method, involving the use of 6 mol/L of HCl, was applied. The resulting stripping efficiency of Al reached 92.97 %, whereas those of both Ga and Ge were < 1 %. Subsequently, 2 mol/L of H 2 SO 4 was used to preferentially strip Ga, and a 1.5 mol/L NH 4 F solution was used to strip Ge. Ultimately, Ga and Ge stripping efficiencies of 97.07 % and 96.16 %, respectively, were achieved. This process establishes an efficient and environmentally friendly method for recovering gallium and germanium from complex sulfate systems, significantly promoting the clean separation and value-added utilization of rare metals in the zinc hydrometallurgical process.
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