锌粉置换镓锗渣草酸浸出过程
从锌置换渣中分段浸出锌、铅、镓和锗
Trans. Nonferrous Met. Soc. China 31(2021) 555−564Hydrometallurgical process for recovery ofZn, Pb, Ga and Ge from Zn refinery residuesShuai RAO1,2,3, Zhi-qiang LIU1,2,3, Dong-xing WANG1,2,3,Hong-yang CAO1,2,3, Wei ZHU1,2,3, Kui-fang ZHANG1,2,3, Jin-zhang TAO1,2,31. Research Institute of Rare Metals, Guangdong Academy of Sciences, Guangzhou 510650, China;2. State Key Laboratory of Separation and Comprehensive Utilization of Rare Metals,Guangdong Academy of Sciences, Guangzhou 510650, China;3. Guangdong Province Key Laboratory of Rare Earth Development and Application,Guangdong Academy of Sciences, Guangzhou 510650, ChinaReceived 3 March 2020; accepted 28 October 2020Abstract: Zn, Pb, Ga and Ge were separated and recovered from zinc refinery residues by stepwise leaching. In the first stage, by leaching with H2SO4 media, more than 90% of Zn and 99% of Ga were dissolved, leaving 92% of Ge in the leaching residue. In the second stage, by leaching with HCl media, approximately 99% of Pb and less than 2% of Ge were selectively dissolved. Finally, the remaining 90% of Ge was extracted in 1 mol/L NaOH solution by destroying the correlation between SiO2 and Ge. XRD pattern of the leaching residue demonstrated that ZnSO4·H2O, PbSO4 and SiO2 were removed sequentially through the stepwise leaching. The proposed process achieved high recoveries of Zn, Pb, Ga and Ge, thus presenting a potential industrial application.Key words: zinc refinery residues; gallium; germanium; stepwise leaching1 IntroductionGermanium (Ge) and gallium (Ga) areconsidered as strategic metals in many countriesowing to their wide applications in high-tech fieldssuch as semiconductors, optical fibers and solarcells [1−4]. However, geological and mineralogicalstudies have shown that it is difficult to findindependent deposits enriched with Ga and Ge [5,6].Currently, Ga and Ge are mainly extracted fromnon-ferrous metal residues [7−10] or secondaryresources [11,12]. The ZnS ores located inGuangdong province contain relatively highcontents of Ga and Ge [13,14]. Based on theproperties of the raw material, pressure leaching isapplied to treating the minerals for recovering Zn,Ga and Ge. During pressure leaching, almost allZn, Ga and Ge are dissolved in the leachingsolution. Zinc powder is then used as thereducing agent to remove Pb and Fe during thesubsequent purification procedure. Ga and Ge(0.1−0.5 wt.%) are also enriched in Zn refineryresidues, which usually contain large amounts of Pband Fe [15,16].Currently, Ga and Ge are extracted from zincplant residues by hydrometallurgical methodsowing to high economic benefits and lowenvironment pollution [17−19]. However, since Gaand Ge are closely correlated with Fe and Si, therecoveries of Ga and Ge are relatively low. Duringsulfuric acid leaching, the formation of silica gelresults in a deteriorating filtration performanceand significant loss of Ga and Ge [20]. To avoid theCorresponding author:Zhi-qiangLIU;Tel:+86-20-61086372;E-mail:*****************DOI:10.1016/S1003-6326(21)65517-61003-6326/© 2021 The Nonferrous Metals Society of China. Published by Elsevier Ltd & Science PressShuai RAO, et al/Trans. Nonferrous Met. Soc. China 31(2021) 555−564 556problem, hydrofluoric acid has been supplemented to sulfuric acid solutions to enhance the leaching rates of Ga and Ge [21]. However, the subsequent defluorination procedure constrains its commercial applications. Alkaline leaching has also been proposed to recover Ga and Ge [22]. Although a relatively high recovery of Ga and Ge is obtained, a large amount of sodium hydroxide is consumed owing to the dissolution of Pb and Si [23]. Organic weak acids provide milder leaching conditions than mineral acids; therefore, they exhibit a high selectivity [24]. LIU et al [25] researched the recovery of Ga and Ge from Zn refinery residues using an oxalic acid solution after selectively removing Cu and Zn in a sulfuric acid solution. Although this method can achieve high leaching rates of Ga and Ge, it is difficult to regenerate the leaching agent, resulting in a high production cost. In general, considering environmental conservation and process efficiency, there is no appropriate technology for the comprehensive recovery of valuable metals, including Zn, Pb, Ga and Ge, from Zn refinery residues.In this study, based on the properties of Zn refinery residues, stepwise leaching is proposed for the comprehensive recovery of Zn, Pb, Ga and Ge from Zn refinery residues. Firstly, Zn and Ga are dissolved in a sulfuric acid solution through controlled suitable leaching conditions, leaving behind Ge and Pb in the leaching residue. The resulting leaching solution can be further processed by adjusting the pH of the leaching solution to a weak acid environment for an effective separation of Zn and Ga. Secondly, Pb is selectively removed in a hydrochloric acid solution based on the complexation between Pb2+and Cl−. Moreover, a PbCl2product can be obtained through cooling crystallization. Finally, Ge is effectively extracted in a sodium hydroxide solution by destroying the embedded correlation between Ge and silica. The stepwise leaching method is a novel technology for the effective recovery of valuable metals from Zn refinery residues, with the potential to be applied on an industrial scale.2 Experimental2.1 MaterialsThe Zn refinery residue was obtained from a Zn metallurgy enterprise located in Shaoguan city, Guangdong province, China. Before conducting leaching, the material was dried, grounded and sieved to a particle size below 100 μm. The main elemental content of the residue was determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Table 1 shows that the residue mainly contains Zn, Pb, Fe and Si. The contents of Ga and Ge are 0.15 wt.% and 0.47 wt.%, respectively.Table 1 Main elemental contents of Zn refinery residue (wt.%)Zn Pb Fe Si Ga Ge 5.93 4.18 6.30 12.6 0.15 0.47The main phases of the Zn refinery residue were determined by X-ray diffraction (XRD). As shown in Fig. 1, the main diffraction peaks were related to some obvious phases, including SiO2, ZnSO4·H2O, PbSO4and ZnFe2O4. No other characteristic peaks corresponding to Ga or Ge phases were detected, owing to their low contents.Fig. 1 XRD pattern of Zn refinery residueFigure 2 shows the SEM image and elemental surface scanning images of the Zn refinery residue. The residue was mainly composed of many tiny dark particles representing SiO2. Some large blocky-shaped particles suggesting various phases were also observed. The brightest particle can be viewed as PbSO4, owing to the enrichment of Pb. Similarly, Fe and Zn were concentrated in some gray particles, confirming the presence of ZnFe2O4. The distributions for Ga and Ge were very sparse due to their low contents.Shuai RAO, et al/Trans. Nonferrous Met. Soc. China 31(2021) 555−564 5572.2 Experimental procedureBased on the properties of Zn refinery residue, an environmentally friendly and economical process was proposed for the efficient recovery of Zn, Pb, Ga and Ge. The integrated process flow comprises three procedures, as shown in Fig. 3, namely, Zn and Ga leaching in a H 2SO 4 solution, Pb recovery in a HCl solution, and Ge extraction in a NaOH solution. After Zn and Ga leaching, the pH of the leaching solution was adjusted to weak acid for the separation of Zn and Ga by adding ZnO.During Pb recovery, soluble 24PbClcomplex was transformed into PbCl 2 precipitate through dilution and cooling crystallization. The crystalline mothersolution was regenerated by adding CaCl 2. The pHof the leaching solution obtained from Ge extraction was adjusted to a weak alkaline condition for the separation of Ge and Si by adding HCl. All leaching experiments were performed in a beaker immersed in a water bath with a thermostat, equipped with a magnetic stirrer. All chemical reagents used were analytical grade.Fig. 2 SEM image and main elemental surface scanning images of Zn refinery residueFig. 3 Principal flow sheet for recovering valuable metals from Zn refinery residueShuai RAO, et al/Trans. Nonferrous Met. Soc. China 31(2021) 555−564 5582.3 Analytical methodsThe phases of the material and leaching residue were determined using a Rigaku TTRAX-3 X-ray diffraction instrument (40 kV, 30 mA, 10 (°)/min). The contents of the main elements, including Zn, Pb, Fe, Ga, Ge and Si, were determined using an inductively coupled plasma- atomic emission spectrometer (Thermo Electron IRIS Intrepid II XSP). The morphology and chemical composition of the samples were analyzed through SEM−EDS (SEM, JEOL, Ltd., JSM−6360LV).3 Results and discussion3.1 Zn and Ga leaching in H2SO4 solutionOwing to the formation of Ge−silica gel and PbSO4 precipitate in a H2SO4 solution, sulfuric acid leaching mainly focuses on the leaching efficiency of Zn and Ga. Moreover, the separation of Zn and Ga should also be considered after the leaching is completed. The φ–pH diagram for a Zn−Ga−Fe−H2O system has been depicted using the HSC 6.0. As illustrated in Fig. 4, Zn2+, Ga3+and Fe3+ were predominant under the acidic conditions, suggesting that sulfuric acid was an effective leaching agent to extract Zn and Ga. However, Zn, Ga and Fe each presented a different pH of hydrolysis precipitation. The precipitation of Ga3+and Fe3+in the form of Fe(OH)3and Ga(OH)3could occur at a pH above 3.0, while soluble Zn2+ existed in the solution at a pH below 6.0. Therefore, an effective separation of Zn and Ga could be obtained by adjusting the pH of the leaching solution to be 3.0−6.0.Fig. 4φ–pH diagram for Zn−Ga−Fe−H2O system at 25 °C (α(Zn2+)=1, α(Fe3+)=1, α(Ga3+)=0.01)Based on the above analyses, the effect of sulfuric acid concentration on the leaching process was investigated in detail. The other leaching conditions included a liquid solid ratio of 10 mL/g, reaction temperature of 80 °C, and leaching time of 2 h. As shown in Fig. 5, increasing the sulfuric acid concentration to 2 mol/L improved the leaching rate of Ga significantly. The Ga leaching rate approached 100% in a 2 mol/L H2SO4solution. Moreover, large amounts of Zn and Fe dissolved in the leaching solution, whereas the Ge leaching rate was relatively low due to the formation of Ge−silica gel. Therefore, a suitable sulfuric acid concentration of 2 mol/L should be selected for optimal leaching of Zn and Ga.Fig. 5 Effect of H2SO4 concentration on leaching rates of Zn, Fe, Ga and GeTable 2 lists the main elemental content of the leaching residue obtained in a 2 mol/L H2SO4 solution. It can be seen that Zn, Fe and Ga decreased significantly, whereas Pb, Si and Ge increased in the H2SO4 leaching residue. The XRD pattern of the H2SO4 leaching residue is shown in Fig. 6. Compared with the results in Fig. 1, the characteristic peaks of ZnSO4·H2O disappeared and the remaining phases contained ZnFe2O4, SiO2 and PbSO4. Figure 7 presents the SEM image of the H2SO4 leaching residue. Based on the results of the EDS analyses from Table 3, the blocky-shaped particles given by Spots 1 and 2 were confirmed as PbSO4and ZnFe2O4, respectively. These tiny dark particles (Spots 3, 4, and 5) were viewed as an enriching Si phase. More importantly, these enriching Si particles exhibited a high Ge content.Shuai RAO, et al/Trans. Nonferrous Met. Soc. China 31(2021) 555−564 559Table 2Main elemental contents of leaching residue obtained in 2 mol/L H2SO4 solution (wt.%)Zn Pb Fe Si Ga Ge 1.49 9.64 1.52 26.1 0.01 1.03Fig. 6 XRD pattern of H2SO4 leaching residueFig. 7 SEM image of H2SO4 leaching residueTable 3 Chemical composition of selected particles shown in Fig. 7 (wt.%)Element Spot 1 Spot 2 Spot 3 Spot 4 Spot 5 O 20.17 27.54 50.98 45.47 45.01S 9.87 − 3.51 − 4.06Zn −27.01 0.6 0.84 2.29Pb 69.69 −−10.87 10.09Fe −41.44 1.82 0.9 2.11Si −0.84 37.15 36.51 30.08Ga −−−−−Ge −0.01 2.02 2.18 2Once the leaching was completed, Ga and Fe were deposited as Ga(OH)3and Fe(OH)3 by adjusting the pH of the leaching solution to 4.0. The resulting ZnSO4 solution could be returned to the Zn recovery procedure, while the precipitate was further treated to extract Ga. The precipitate obtained in this study exhibited an amorphous phase structure, as shown in Fig. 8. The contents of Fe and Ga in the precipitate were 30.08 and 1.00 wt.%, respectively, suggesting that Ga in the precipitate was over five times higher than that in the material.Fig. 8 XRD pattern of precipitate obtained from H2SO4 leaching solution3.2 Pb recovery in HCl solutionAfter selective dissolution of Zn, Ga and Fe, the leaching residue was mainly composed of Pb, Ge and Si. Due to the formation of soluble 24Pb(OH)-complex in an alkaline solution, it was necessary to remove Pb before extracting Ge. Based on the complexation between Pb2+and Cl−, HCl was selected as a suitable leaching agent. The distribution curves of the Pb species with different Cl−concentrations were constructed using the Medusa software. As shown in Fig. 9, PbCl2 precipitate predominated under a relatively low Cl−concentration condition, while an increased Cl−concentration was beneficial for the formation ofsoluble 24PbCl-complex. This suggests that Pb recovery should be conducted under larger leaching agent concentration and higher liquid-to-solid ratio conditions. Therefore, the leaching process was performed with a liquid-to-solid ratio of 20 mL/g at 90 °C for 2 h. Figure 10 shows the effect of HCl concentration on the leaching rates of Pb and Ge. The leaching rate of Pb enhanced with an increasing HCl concentration from 0.5 to 2 mol/L. Almost all of the PbSO4 dissolved in a 2 mol/L HCl solution, with the Ge leaching rate below 2%.Shuai RAO, et al/Trans. Nonferrous Met. Soc. China 31(2021) 555−564 560Fig. 9Distribution of Pb species at different pH for Pb2+−Cl−−H2O system at 25 °CTable 4 lists the main elemental contents of the leaching residue. It can be seen that Ge increased to above 1.37 wt.% in the leaching residue, whereas the content of Pb reduced to below 0.1 wt.%. The main phases of the leaching residue were SiO2 and ZnFe2O4, as shown in Fig. 11. Compared with Fig. 7, Fig. 12 shows that the brightest particles representing the PbSO4 phase were seldom observed. Moreover, there was a close correlation between Ge and Si based on the Ge−Si surface distribution diagram.Fig. 10 Effect of HCl concentration on leaching rates of Pb and GeFig. 11 XRD pattern of HCl leaching residueTable 4 Main elemental contents of leaching residue obtained in 2 mol/L HCl solution (wt.%)Zn Pb Fe Si Ga Ge 1.29 0.078 1.31 30 0.007 1.37Fig. 12 SEM image and Ge−Si surface distribution of leaching residue obtained in 2 mol/L HCl solutionShuai RAO, et al/Trans. Nonferrous Met. Soc. China 31(2021) 555−564 561After completion of the Pb leaching, it is necessary to recover Pb from the leaching solution.A 24PbCl -complex can be transformed into PbCl 2 precipitate by decreasing the reaction temperature and Cl − concentration [26]. Therefore, the leaching solution was processed by dilution and cooling. Then, the PbCl 2 product was obtained by liquid −solid separation. The Pb content in the solution lowered from 4.78 to 1.79 g/L, suggesting that approximately 37.4% of Pb remained in the leaching solution. More than 60% of Pb was recovered in the form of PbCl 2, as shown in Fig. 13. The PbCl 2 product containing 74.3 wt.% Pb exhibited a high purity without any additional characteristic peaks. As shown in Fig. 14, after cooling crystallization, the resultingsolution wasregenerated by adding CaCl 2to remove 24SO -byprecipitation reaction between 24SO - and Ca 2+, allowing for the regenerated solution to be used in the subsequent lead removing procedure.Fig. 13 XRD pattern of PbCl 2 product from HCl leaching solutionFig. 14 XRD pattern of precipitate obtained from regeneration of leaching agent3.3 Extraction of Ge in NaOH solutionTo remove silica −germanium gel, NaOH is used as the leaching agent to effectively extract Ge. Leaching experiments were conducted at 80 °C with a liquid solid ratio of 20 mL/g for 2 h. Figure 15 shows the effect of NaOH concentration on the leaching rates of Ge and Si. An increased NaOH concentration significantly improved the dissolution efficiency of Ge and Si. More than 99% of Ge and 90% of Si were dissolved in 1 mol/L NaOH solution. Table 5 lists the main elemental contents of the NaOH leaching residue. Fe and Zn increased inthe leaching residue, whereas Gedecreased to 0.06%. The XRD pattern, shown in Fig. 16, indicates the main phases of the leaching residue to be SiO 2, ZnS and ZnFe 2O 4. ComparedFig. 15 Effect of NaOH concentration on leaching rates of Si and GeFig. 16 XRD pattern of NaOH leaching residueTable 5 Main elemental contents of leaching residue obtained in 1 mol/L NaOH solution (wt.%) Zn Fe Pb Si Ga Ge 6.817.10.117.690.010.06Shuai RAO, et al/Trans. Nonferrous Met. Soc. China 31(2021) 555−564562 with Fig. 8, new characteristic peaks of ZnS were observed owing to an increased Zn content in the leaching residue. Figure 17 shows the SEM image and main elemental surface distribution of the alkaline leaching residue. The tiny silica − germanium gel particles dissolved entirely, and the remaining particles, including ZnS, ZnFe 2O 4 and SiO 2, were large, preventing adequate dissolution through atmospheric leaching.Fig. 17 SEM image and main elemental surface scanning maps of leaching residueAfter Ge leaching, it is necessary to separate Ge and Si from the leaching solution owing to the dissolution of SiO 2. According to the φ−pH diagram for the Ge −Si −H 2O system in Fig. 18, Ge −silica gel can be destroyed by promoting the formation ofsoluble 3HGeO - and 3SiO(OH)-in an alkaline solution. After the leaching is complete, the precipitation of Si in the form of amorphous silicon dioxide can occur by adjusting the pH to be 6.0−12.0, allowing for an effective separation of Geand Si. Therefore, in this study, the pH of the alkaline leaching solution was adjusted to be 9.0 by adding 2 mol/L HCl. The Si content in the leaching solution lowered to less than 0.3 g/L, as shown in Table 6, allowing for an excellent Ge −Si separation efficiency. Moreover, Zn, Pb and Fe were also adequately removed. The leaching solution could then be used to recover Ge through precipitation or solvent extraction. The white precipitate obtained from the Ge −Si separation procedure was amorphous silicon dioxide and, therefore, no obvious characteristic peaks were observed, as shown in Fig. 19.Fig. 18 φ−pH diagram for Ge −Si −H 2O system at 25 °C (α(Si 4+)=1, α(Ge 4+)=0.01)Table 6 Main elemental contents of leaching solution adjusted to pH 9.0 (mg/L) Zn Pb Fe Si Ga Ge <0.5 <0.5<0.5268.1<0.5254.1Fig. 19 XRD pattern of white precipitate obtained during Ge and Si separationShuai RAO, et al/Trans. Nonferrous Met. Soc. China 31(2021) 555−564 5634 Conclusions(1) More than 90% of Zn and 99% of Ga were leached in a 2 mol/L H2SO4 solution with a liquid–solid ratio of 10 mL/g at 80 °C after 2 h, leaving approximately 92% of Ge in the leaching residue. The content of Ga in the precipitate was over 5 times higher than in the raw material.(2) About 99% of Pb and less than 2% of Ge were dissolved in a 2 mol/L HCl solution with a liquid-to-solid ratio of 20 mL/g at 90 °C for 2 h. A PbCl2 byproduct with a high purity was obtained by cooling crystallization.(3) During alkaline leaching, the remaining 90% of the Ge was extracted in a 1 mol/L NaOH solution with a liquid-to-solid ratio of 20 mL/g at 80 °C for 2 h. An effective Ge−Si separation was conducted by adjusting the pH of the leaching solution to 9.0.AcknowledgmentsThe authors are grateful for the financial supports from the National Natural Science Foundation of China (51804083, 51704081), the National Key Research and Development Project (2018YFC1903104), the Natural Science Foundation of Guangdong Province, China (2019A1515011628), the Science and Technology Planning Project of Guangzhou (201904010106) of China, and Guangdong Academy of Science Doctor Special Program of China (2020GDASYL-0104027, 2019GDASYL-0105079, 2019GDASYL-0302011, 2019GDASYL-0402003).References[1]FTHENAKIS V, WANG Wen-ming, KIM H C. Life cycleinventory analysis of the production of metals used inphotovoltaics [J]. Renewable and Sustainable EnergyReviews, 2009, 13(3): 493−517.[2]CAROLAN D. Recent advances in germanium nanocrystals:Synthesis, optical properties and applications [J]. Progress inMaterials Science, 2017, 90: 128−158.[3]FRENZEL M, MIKOLAJCZAK C, REUTER M A,GUTZMER J. Quantifying the relative availability ofhigh-tech by-product metals−The cases of gallium,germanium and indium [J]. Resources Policy, 2017, 52:327−335.[4]SIONTAS S, LI D, WANG H, A. V. P. S A, ZASLAVSKYA, PACIFICI D. High-performance germanium quantum dotphotodetectors in the visible and near infrared [J]. MaterialsScience in Semiconductor Processing, 2019, 92: 19−27. [5]LU Fang-hai, XIAO Tang-fu, LIN Jian, NING Zeng-ping,LONG Qiong, XIAO Li-hua, HUANG Fang, WANG Wan-kun, XIAO Qing-xiang, LAN Xiao-long, CHEN Hai-yan. Resources and extraction of gallium: A review [J].Hydrometallurgy, 2017, 174: 105−115.[6]MOSKALYK R R. Review of germanium processingworldwide [J]. Minerals Engineering, 2004, 17(3): 393−402.[7]FRENZEL M, HIRSCH T, GUTZMER J. Gallium,germanium, indium, and other trace and minor elements in sphalerite as a function of deposit type: A meta-analysis [J].Ore Geology Reviews, 2016, 76: 52−78.[8]LU Fang-hai, XIAO Tang-fu, LIN Jian, LI An-jing, LONGQiong, HUANG Fang, XIAO Li-hua, LI Xiang, WANG Jia-wei, XIAO Qing-xiang, CHEN Hai-yan. Recovery of gallium from Bayer red mud through acidic leaching-ion exchange process under normal atmospheric pressure [J].Hydrometallurgy, 2018, 175: 124−132.[9]KUL M, TOPKAYA Y. Recovery of germanium and othervaluable metals from zinc plant residues [J].Hydrometallurgy, 2008, 92(3): 87−94.[10]MACÍAS-MACÍAS K Y, CENICEROS-GÓMEZ A E,GUTIÉRREZ-RUIZ M E, GONZÁLEZ-CHÁVEZ J L, MARTÍNEZ-JARDINES L G. Extraction and recovery of the strategic element gallium from an iron mine tailing [J].Journal of Environmental Chemical Engineering, 2019, 7(2): 102964.[11]ZHOU Jia-zhi, ZHU Neng-wu, LIU Huang-rui, WUPing-xiao, ZHANG Xiao-ping, ZHONG Zu-qi. Recovery of gallium from waste light emitting diodes by oxalic acidic leaching [J]. Resources, Conservation and Recycling, 2019, 146: 366−372.[12]CHEN Wei-Sheng, CHANG Bi-Cheng, CHIU Kai-Lun.Recovery of germanium from waste optical fibers by hydrometallurgical method [J]. Journal of Environmental Chemical Engineering, 2017, 5(5): 5215−5221.[13]LIU Fu-peng, LIU Zhi-hong, LI Yu-hu, LIU Zhi-yong, LIQi-hou, WEN Da-min. Sulfuric leaching process of zinc powder replacement residue containing gallium and germanium [J]. The Chinese Journal of Nonferrous Metals, 2016, 26(4): 908−918. (in Chinese)[14]LIU Fu-peng, LIU Zhi-hong, LI Yu-hu, LIU Zhi-yong, LIQi-hou. Leaching mechanism of zinc powder replacement residue containing gallium and germanium by high pressure acid leaching [J]. The Chinese Journal of Nonferrous Metals, 2014, 24(4): 1091−1098. (in Chinese)[15]LIU Fu-peng, LIU Zhi-hong, LI Yu-hu, LIU Zhi-yong, LIQi-hou, ZENG Li. Extraction of gallium and germanium from zinc refinery residues by pressure acid leaching [J].Hydrometallurgy, 2016, 164: 313−320.[16]LIU Fu-peng, LIU Zhi-hong, LI Yu-hu, WILSON B P,LUNDSTRÖM M. Recovery and separation of gallium (III) and germanium (IV) from zinc refinery residues: Part I: Leaching and iron (III) removal [J]. Hydrometallurgy, 2017, 169: 564−570.[17]WU Xue-lan, WU Shun-ke, QIN Wen-qing, MA Xi-hong,NIU Yin-jian, LAI Shao-shi, YANG Cong-ren, JIAO Fen, REN Liu-yi. Reductive leaching of gallium from zinc residue [J]. Hydrometallurgy, 2012, 113−114: 195−199.[18]LIANG Duo-qiang, WANG Ji-kun, WANG Yun-hua.Shuai RAO, et al/Trans. Nonferrous Met. Soc. China 31(2021) 555−564 564Difference in dissolution between germanium and zinc during the oxidative pressure leaching of sphalerite [J].Hydrometallurgy, 2009, 95(1): 5−7.[19]ZHANG Li-bo, GUO Wen-qian, PENG Jin-hui, LI Jing, LINGuo, YU Xia. Comparison of ultrasonic-assisted and regular leaching of germanium from by-product of zinc metallurgy [J]. Ultrasonics Sonochemistry, 2016, 31: 143−149.[20]HARBUCK D D. Optimization of gallium and germaniumextraction from hydrometallurgical zinc residue [J]. Light Metals, 1989: 984−989.[21]HARBUCK D D. Increasing germanium extraction fromhydrometallurgical zinc residues [J]. Mining, Metallurgy & Exploration, 1993, 10(1): 1−4.[22]TORMA A E. Method of extracting gallium and germanium[J]. Mineral Processing and Extractive Metallurgy Review, 1991, 3: 235−258.[23]RAO Shuai, WANG Dong-xing, LIU Zhi-qiang, ZHANGKui-fang, CAO Hong-yang, TAO Jin-zhang. Selective extraction of zinc, gallium, and germanium from zinc refinery residue using two stage acid and alkaline leaching [J]. Hydrometallurgy, 2019, 183: 38−44.[24]HURŞIT M, LAÇIN O, SARAÇ H. Dissolution kinetics ofsmithsonite ore as an alternative zinc source with an organic leach reagent [J]. Journal of the Taiwan Institute of Chemical Engineers, 2009, 40(1): 6−12.[25]LIU Fu-peng, LIU Zhi-hong, LI Yu-hu, WILSON B P,LUNDSTRÖM M. Extraction of Ga and Ge from zinc refinery residues in H2C2O4solutions containing H2O2 [J].International Journal of Mineral Processing, 2017, 163: 14−23.[26]DING Yun-ji, ZHANG Shen-gen, LIU Bo, LI Bin. Integratedprocess for recycling copper anode slime from electronic waste smelting [J]. Journal of Cleaner Production, 2017, 165: 48−56.从锌置换渣中分段浸出锌、铅、镓和锗饶帅1,2,3，刘志强1,2,3，王东兴1,2,3，曹洪杨1,2,3，朱薇1,2,3，张魁芳1,2,3，陶进长1,2,31. 广东省科学院稀有金属研究所，广州510650；2. 广东省科学院稀有金属分离与综合利用国家重点实验室，广州510650；3. 广东省科学院广东省稀土开发及应用研究重点实验室，广州510650摘要：采用分段浸出方法从锌置换渣中选择性提取锌、铅、镓和锗。
碱浸-还原挥发工艺回收镓锗置换渣中镓、锗
碱浸-还原挥发工艺回收镓锗置换渣中镓、锗
周科华;刘野平;梁彦杰;宋家琪
【期刊名称】《中国有色冶金》
【年(卷),期】2024(53)2
【摘要】镓、锗是重要的稀散金属,从锌冶炼过程中综合回收镓、锗成为该原生金属产量的重要来源。
目前主要采用酸浸工艺从镓锗置换渣回收镓、锗,回收率较低,资源利用率低。
本文利用镓、锗两性物质的属性,采用碱浸-还原挥发工艺进行了回收镓锗置换渣中镓、锗的试验研究,得到以下主要结论。
碱浸试验单因素最佳工艺条件为NaOH浓度4 mol/L、反应温度90℃、液固比8 mL/g、搅拌速度400 r/min,在此条件下,镓锗置换渣中镓、锗浸出率分别达到91.25%和78.95%;强化球磨浸出对镓、锗的浸出率没有改善作用;还原挥发试验的单因素最佳工艺条件为温度1200℃、粉煤配入量30%、挥发时间4 h,在此条件下,碱性浸出残渣中锗的挥发率达到91.02%。
该工艺产生的挥发残渣和砷酸钙渣返回火法炼铅系统综合回收铜、砷等有价金属,实现了渣的无害化处理。
本文回收镓、锗的方法可为同类企业从锌冶炼工序中回收镓、锗提供参考。
【总页数】7页(P49-55)
【作者】周科华;刘野平;梁彦杰;宋家琪
【作者单位】深圳市中金岭南有色金属股份有限公司;中南大学冶金与环境学院【正文语种】中文
【中图分类】TF813;TF843
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2.从高压浸出镓锗液中回收镓锗的试验研究
3.锌粉置换镓锗渣高压酸浸的浸出机理
4.锈蚀法从浸锌渣还原铁粉中分离镓锗的基础与应用
5.从锌浸渣中回收镓和锗的研究及实践
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锌粉置换渣浸出过程中镓的溶解行为及改善方法
锌粉置换渣浸出过程中镓的溶解行为及改善方法
张伟;饶帅;李立清;宫晓丹;吴才贵;胡东风;曹洪杨;刘志强
【期刊名称】《Transactions of Nonferrous Metals Society of China》
【年(卷),期】2024(34)3
【摘要】针对丹霞冶炼厂锌粉置换渣浸出过程中镓浸出率偏低问题,采用ICP-AES、XRD与SEM-EDS对不同批次锌粉置换渣化学成分、物相与形貌进行详细分析。
与正常生产锌粉置换渣相比,异常锌粉置换渣中镓主要赋存于黄钾铁矾之中,造成镓
浸出困难。
对锌粉置换渣氧压浸出过程进行分析,镓、砷和铁溶出规律较为一致:增
大硫酸浓度和液固比有利于镓、铁和砷的浸出,但提高温度和氧气分压对镓、铁和
砷溶出不利。
依据上述研究结果,提出强化镓浸出效率的改善措施,弱化一段氧压浸
出(分别降低反应温度和压缩空气总压至90℃和0.2 MPa)与强化三段常压浸出(分别提高硫酸浓度和反应温度至160 g/L和85℃),镓的浸出效率由77.83%提高至96.46%。
【总页数】11页(P1016-1026)
【作者】张伟;饶帅;李立清;宫晓丹;吴才贵;胡东风;曹洪杨;刘志强
【作者单位】江西理工大学材料冶金化学学部;深圳市中金岭南有色金属股份有限
公司丹霞冶炼厂;广东省科学院资源利用与稀土开发研究所
【正文语种】中文
【中图分类】TF8
【相关文献】
1.锌粉置换镓锗渣草酸浸出过程
2.锌粉置换镓锗渣硫酸浸出过程
3.锌粉置换镓锗渣高压酸浸的浸出机理
4.锌粉置换镓锗渣加压氧化浸出的生产实践
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简析锌粉置换渣中镓锗浸出工艺
简析锌粉置换渣中镓锗浸出工艺作者：钟湘来源：《中国化工贸易·下旬刊》2017年第03期摘要：镓、锗这两种材料是高尖端设备中的重要材料，被人们广泛应用在各高技术领域中，并成为这些领域中重要的材料。
但是，由于镓、锗本身的特殊性，对这两种元素的提炼是一个非常困难的事情，这便需要通过不断实验研究出新的浸出工艺，来促使这两种元素更加容易被人们提炼出来。
基于此，本文就对锌粉置换渣中镓锗浸出工艺进行探讨。
关键词：镓；锗；浸出工艺根据相关数据显示，在世界范围内镓的存储量仅为100万吨，我国约有15万吨，而且绝大多数都存在于铝矿中，但是锗的存储量则为3.6kt。
然而，这两种元素自身很难够形成独立的矿床，其主要是离子或是化合物的形式存在于锌、铝等矿床中，所以需要采取有效措施和工艺的镓、锗进行提取和分离，以满足人们在这两种元素材料上的需求。
下面笔者就对镓、锗的相关内容进行探讨。
1自然界中镓锗的形态镓、锗这两种元素均是稀散元素，在自然界当中很难够找到独立的矿床，也对无法对这两种元素进行开采。
从镓、锗以及锌这三种元素的原子半径来看，分别为0.127nm、0.146nm和0.137nm，而且所呈现出来的是四面体，在构造上为闪锌矿型。
锗元素其主要是以类质同象而存在于闪锌矿中，也存在于煤矿、铝土矿等矿床中。
而镓元素除了如同锗元素存在闪锌矿中以外，其还存在于Al2O3矿床中。
要想利用闪锌矿将镓、锗这两种元素分离出来，则需要利用湿法炼锌，在该工艺流程中会使镓、锗出现在浸出渣中，然后再利用有效的方法和手段来将镓、锗分离出来[1]。
2锌粉置换渣中镓锗浸出工艺2.1液膜分离法利用此方法对镓、锗进行分离提取十分类似于萃取，而且在提炼过程中也包含了反萃取和萃取这两个阶段。
由于在分离模式当中有水相和油相之分，所以在乳状液膜上也将划分为水包油与油包水两种。
如果在提炼时选择油膜分离法，那么在油膜的两侧将会同时进行反萃取和萃取两种反应过程，如果金属离子从膜的一侧转入到另一侧时，通过反萃取实验转入到的接收相当中，以此来有效实现反萃取和萃取两者之间所存在的内耦合[2]。
用稀硫酸-有机酸体系浸出锌粉置换渣中的锗试验研究
的影响。结果表明:在硫酸初始质量浓度 70g/L、温度 55 ℃ 、浸出时间 1h、液固体积质量比 10mL/1g、酒石
/mi
酸 加入量 10g/L 和搅拌速度 300r
水的草酸浸出锌粉置换 渣,锗 浸 出 率 可 达 98% 以
收稿日期:
2023
01
18
文章编号:
1009
2617(
2023)
03
0241
06
上 [15],但草酸再生困难,生产成本较高。
针对现有方法 存 在 的 设 备 要 求 苛 刻、回 收 成
本高、液 固 分 离 困 难 等 问 题,试 验 研 究 了 用 稀 硫
(H4S
iO4)胶体形成,因锗、硅 性 质 相 似,锗 易 被 硅
酸选择性吸附,导致锗 浸 出 率 降 低 [14]。综 合 考 虑
锗、铜、锌 浸 出 率 和 悬 浮 液 过 滤 情 况,确 定 硫 酸 初
始质量浓度以 70g/L 为宜。
2.
2 温度对金属浸出率的影响
取锌 粉 置 换 渣 10 g,在 硫 酸 初 始 质 量 浓 度
属浸出率的影响,试验结果如图 2 所示。
海精密科学仪器有限公司),循环水式多用真空泵
感耦合等离子体发射光谱仪(
Th
ermBiblioteka Scien
t
i
f
i
c )。
主要试剂:硫酸、有机酸等,均为分析纯,购自
/mi
25 ℃ 、搅 拌 速 度 300r
n、液 固 体 积 质 量 比
锌粉置换镓锗渣草酸浸出过程
。但由于该含镓锗物料中还含有锌、硅、
铜、铁、砷、铅等成分，且物相较为复杂，所以， 实 现镓、锗的高效回收面临着较大挑战。 还原或硫化挥发等火法工艺存在投资大、 能耗高、 污染重等缺点 ，因而，湿法回收技术是当前处理含 镓、锗物料的主要工艺。TORMA 和 LEE 等
[9−10] [8]
采
用碱浸工艺处理含锌冶炼渣，虽然该工艺可实现部分 金属的选择性浸出，但由于浸出液中硅、铅和铝的含 量较高，使得后续镓、锗回收较难。所以，目前多采 用“硫酸浸出−萃取分离”的工艺处理锌冶炼渣。但 采用常规硫酸浸出工艺时， 锗浸出效果较差， 仅为 60% 左右[11]。为了提高镓、锗的浸出率，KUL 等[12]采用了 氧化浸出工艺处理锌冶炼渣， 锗的浸出率达到 90%左
基金项目：中国博士后科学基金面上项目(2012M521544) 收稿日期：2016-07-21；修订日期：2017-01-20
通信作者：刘志宏，教授，博士；电话：0731-88830478；E-mail: zhliu@
第 27 卷第 10 期
刘付朋，等：锌粉置换镓锗渣草酸浸出过程
作为高新技术支撑材料的镓和锗，因其优良的光 电和化学性能，被广泛应用于军事、光纤通讯、催化 自然界中极少存在单一的 剂、 电子和医学等领域[1−3]。 镓、锗的工业矿床，镓、锗主要从锌、铝、铜等有色 金属冶炼的副产物中回收。 锌粉置换镓锗渣作为一种典型的含镓、 锗的物料， 其镓、 锗含量分别为 0.2%~0.4% 和 0.2%~0.5%(质量 分数)，具有较高的综合回收价值，目前在全球引起了 广泛关注
锌粉置换镓锗渣主要化学成分 Main chemical composition of the zinc powder
Table 1
锌Ⅰ系统氧化锌浸出及铟锗富集工艺操作规程4(改)
Q/ZYJ 株洲冶炼集团有限责任公司企业标准Q/ZYJ 05.01.12.04—2005代替Q/ZYJ 05.01.12.04—2004锌Ⅰ系统氧化锌浸出及铟锗富集工艺操作规程2005-09-05 发布2005-10-08 实施株洲冶炼集团有限责任公司发布Q/ZYJ 05.01.12.04—2005前言本标准是对Q/ZYJ 05.01.12.04—2004《锌Ⅰ系统氧化锌浸出及铟锗富集工艺操作规程》的修订。
编写规则符合GB/T1.1—2000《标准化工作导则第1部分：标准的结构和编写规则》的要求。
本标准从实施之日起，原Q/ZYJ 05.01.12.04—2004《锌Ⅰ系统氧化锌浸出及铟锗富集工艺操作规程》同时废止。
本标准由株洲冶炼集团有限责任公司产品与工艺技术标准化工作分会提出。
本标准由株洲冶炼集团有限责任公司标准化管理委员会办公室归口。
本标准起草单位：湖南株冶火炬金属股份有限公司锌浸出厂本标准主要起草人：易雄辉刘文敏袁建明本标准主要审核人：刘朗明陈爱国朱北平苗华磊肖康谷卫胜周新海唐守层唐凌本标准主要审编人：钟鸣谭仪文本标准批准人：王辉本标准1995年12月30日首次发布，2000年6月12日第一次修订。
IQ/ZYJ 05.01.12.04—2005 锌Ⅰ系统氧化锌浸出及铟锗富集工艺操作规程1 范围本标准规定了锌Ⅰ系统氧化锌浸出及铟锗富集工艺流程、基本原理、原材料质量要求、工艺操作条件、岗位操作法、产出物料及质量要求、主要技术经济指标和主要设备。
本标准适用于锌Ⅰ系统氧化锌浸出及铟锗富集工艺操作过程。
2 规范性引用文件下列文件中的条款通过本标准的引用而成为本标准的条款。
凡是注日期的引用文件，其随后所有的修改单（不包括勘误的内容）或修订版均不适用于本标准，然而，鼓励根据本标准达成协议的各方研究是否可使用这些文件的最新版本。
凡是不注日期的引用文件，其最新版本适用于本标准。
GB/T 13940 聚丙烯酰胺Q/ZYJ 04.02.05—2002 工业用布技术条件Q/ZYJ 06.05.01.04—2005 氧化锌焙砂Q/ZYJ 06.05.02.02—2005 氧化锌中性上清Q/ZYJ 06.05.02.07—2005 铟锗富集渣Q/ZYJ 06.05.02.12—2005 氧化锌浸出渣Q/ZYJ 06.05.02.13—2005 自用锌粉Q/ZYJ 06.05.03.02—2005 锌电解废液3工艺流程（见图1）4基本原理利用氧化锌作原料，采用浸出和置换等工艺，达到分离铅、锌和富集铟锗的目的。
氧化锌烟尘不同浸出体系锗提取行为
第14卷第5期2023年10月有色金属科学与工程Nonferrous Metals Science and EngineeringVol.14，No.5Oct. 2023氧化锌烟尘不同浸出体系锗提取行为廖彬， 刘付朋*（江西理工大学材料冶金化学学部，江西 赣州 341000）摘要：以含锗氧化锌烟尘为原料，研究了硫酸、草酸、酒石酸、硫酸-酒石酸混合循环浸出工艺中Zn 、Fe 、Pb 、Ge 等有价金属的浸出行为。
结果表明：硫酸浸出工艺可实现Ge 、Zn 的高效提取，在硫酸浓度100 g/L 、液固比10 mL/g 、温度90 ℃、反应时间120 min 的条件下，Ge 、Zn 的浸出率分别可达86.12%、93.13%；草酸浸出工艺可实现Ge 、Fe 与Zn 、Pb 的选择性分离，在最优条件下Ge 、Fe 的浸出率分别为92.32%、67.30%，Pb 、Zn 基本不被浸出；酒石酸浸出体系下，Ge 的浸出率较低，最高只达76.15%，并且Zn 、Fe 的浸出率维持在较低水平；硫酸-酒石酸混酸浸出体系下，Ge 的浸出率明显改善，最高可达99.42%，同时Zn 、Fe 的浸出率分别可达89.53%、68.56%。
通过四段循环浸出的方式，Ge 富集后浓度可达152.93 mg/L ，经N235萃取分离处理，Ge 的萃取率接近90%。
关键词：锗；氧化锌烟尘；浸出；选择性分离；萃取中图分类号：TF803.21 文献标志码：AExtraction behavior of germanium in different leaching systemsfrom zinc oxide dustLIAO Bin, LIU Fupeng *（Faculty of Materials Metallurgy and Chemistry ， Jiangxi University of Science and Technology ， Ganzhou 341000， Jiangxi ， China ）Abstract: The leaching behaviors of valuable metals such as Zn, Fe, Pb and Ge in the cycle leaching processes of sulfuric acid, oxalic acid, tartaric acid and the mixture of,sulfuric and tartaric acid were investigated, with germanium-containing zinc oxide dust as raw material. The results show that the high-efficiency extraction of Ge and Zn can be achieved by using a sulfuric acid leaching process. Under the conditions of sulfuric acid concentration of 100 g/L, temperature at 90 ℃, liquid-solid ratio of 10 mL/g, and the reaction time of 120 min, the leaching ratios of Ge and Zn can reach 86.12% and 93.13%, respectively. The selective separation of Ge and Fe from Zn and Pb can be achieved by the oxalic acid leaching process, and under optimal conditions, the leaching ratios of Ge and Fe are respectively 92.32% and 67.30% while Pb and Zn are essentially not leached. The leaching ratio of Ge in the tartaric acid leaching process is relatively low, reaching a maximum of 76.15%, while the leaching ratios of Zn and Fe remain at a low level. The leaching ratio of Ge in the mixed acid leaching process of sulfuric acid and tartaric acid improves significantly, up to 99.42%. Meanwhile, the leaching ratios of Zn and Fe are up to 89.53% and 68.56%, respectively. The concentration of Ge can reach 152.93 mg/L by four-stage cyclic leaching.收稿日期：2022-08-22；修回日期：2022-11-14基金项目：国家青年自然科学基金项目（51804141）；国家博士后基金面上项目（2019M662269）；江西省博士后择优资助项目（2019 KY07）；山东省博士后创新人才项目（2019-216）；江西理工大学清江优秀人才项目（JXUSTQJYX2019006）；江西省自然科学基金面上项目（20202BABL204030）通信作者：刘付朋（1985— ），副教授，主要从事稀有金属二次资源回收方向的研究。
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锌粉置换镓锗渣草酸浸出过程刘付朋;刘志宏;李玉虎;刘智勇;李启厚【摘要】The oxalic acid leaching of the zinc powder replacement residue containing gallium and germanium was carried out. The effects of oxalic acid concentration, leaching time, liquid-to-solid (L/S) ratio, leaching temperature, and hydrogen peroxide concentration on the leaching of gallium and germanium, together with the filterability of the leaching residues were investigated. The effective mechanisms of improving the leaching through adding hydrogen peroxide in oxalic acid leaching system were found out. The results show that using oxalic acid and hydrogen peroxide as leachant can effectively promote the leaching of Ga and Ge. Moreover, the filterability of leaching residues also can be obviously improved in the oxalic acid leaching system. These could be attributed to the fact that hydrogen peroxide oxidize elemental gallium and germanium, as well as their sulfides, while the oxalic acid promotes the formation of gallium and germanium complex, and oxalic acid has negligible effects on silica, thus the leaching of gallium and germanium and the filterability of the leaching residues were improved. The optimal leaching conditions are as follows: oxalic acid concentration of 110 g/L, hydrogen peroxide concentration of 0.12 mol/L, L/S ratio of 8, temperature of 40℃, stirring rate of 300 r/min, and leaching time of 30 min. Under the optimal conditions, 99.32% of Ga and 98.86% of Ge were leached out, while the leaching of Zn, Cu and Si were 0.815%, 0.842%and 0.430%, respectively.Moreover, the filtration rate of the leaching slurry increases from 0.48mL/min in atmospheric pressure acid leaching system to 100 mL/min.%考察锌粉置换镓锗渣草酸浸出过程中,草酸浓度、浸出时间、液固比、浸出温度、双氧水浓度对镓、锗、锌、铁、铜、硅浸出率及浸出料浆过滤性能的影响,揭示在草酸浸出体系下添加双氧水促进镓、锗浸出的作用机理.结果表明,采用草酸和双氧水为浸出剂,不仅可实现镓、锗的选择性浸出,还可显著改善浸出料浆的过滤性能.双氧水促进镓、锗浸出的机理为其作为氧化剂使镓、锗单质及其硫化物氧化为可溶的氧化物;草酸与镓、锗可生成稳定络合物,而与硅的作用较弱,从而促进镓、锗的浸出,同时使浸出渣的过滤性能得以改善.在草酸浓度为110 g/L、双氧水浓度为0.12 mol/L、液固比(L/S)为8、搅拌速度为300 r/min、浸出温度为40℃、浸出时间为30 min的条件下,镓和锗浸出率分别为99.32%、98.86%,而铜、锌、硅的浸出率分别在0.82%、0.84%、0.43%,且浸出料浆的过滤速度由常压硫酸浸出体系下的0.48 mL/min提高到100 mL/min.【期刊名称】《中国有色金属学报》【年(卷),期】2017(027)010【总页数】10页(P2154-2163)【关键词】镓;锗;草酸;双氧水;浸出【作者】刘付朋;刘志宏;李玉虎;刘智勇;李启厚【作者单位】中南大学冶金与环境学院,长沙 410083;中南大学冶金与环境学院,长沙 410083;中南大学冶金与环境学院,长沙 410083;中南大学冶金与环境学院,长沙 410083;中南大学冶金与环境学院,长沙 410083【正文语种】中文【中图分类】TF803.21作为高新技术支撑材料的镓和锗，因其优良的光电和化学性能，被广泛应用于军事、光纤通讯、催化剂、电子和医学等领域[1−3]。
自然界中极少存在单一的镓、锗的工业矿床，镓、锗主要从锌、铝、铜等有色金属冶炼的副产物中回收。
锌粉置换镓锗渣作为一种典型的含镓、锗的物料，其镓、锗含量分别为0.2%~0.4% 和 0.2%~0.5%(质量分数)，具有较高的综合回收价值，目前在全球引起了广泛关注[4−7]。
但由于该含镓锗物料中还含有锌、硅、铜、铁、砷、铅等成分，且物相较为复杂，所以，实现镓、锗的高效回收面临着较大挑战。
还原或硫化挥发等火法工艺存在投资大、能耗高、污染重等缺点[8]，因而，湿法回收技术是当前处理含镓、锗物料的主要工艺。
TORMA 和 LEE 等[9−10]采用碱浸工艺处理含锌冶炼渣，虽然该工艺可实现部分金属的选择性浸出，但由于浸出液中硅、铅和铝的含量较高，使得后续镓、锗回收较难。
所以，目前多采用“硫酸浸出−萃取分离”的工艺处理锌冶炼渣。
但采用常规硫酸浸出工艺时，锗浸出效果较差，仅为60%左右[11]。
为了提高镓、锗的浸出率，KUL等[12]采用了氧化浸出工艺处理锌冶炼渣，锗的浸出率达到 90%左右，但硅的浸出使得浸出料浆的过滤性能严重恶化。
为了消除硅对镓、锗浸出的不利影响，HARBUCK[13−14]和王继民等[15]分别采用硫酸与氢氟酸混合酸浸出高硅锌浸出渣中的镓、锗，两者的浸出率均可达98%以上，但氟离子对设备腐蚀严重，且含氟废液难以处理。
LIU等[16]采用高压酸浸工艺处理锌粉置换镓锗渣，镓、锗的浸出率分别可达98%、94%以上，矿浆的过滤速度较常规酸浸提高了近20倍。
但由于高压酸浸设备复杂、投资及运行成本较高，难以工业化。
为此，刘付朋等[17]又开展了在常压硫酸浸出体系添加硝酸钠及十二烷基磺酸钠助浸的研究，尽管镓、锗的浸出率分别达97%、90%以上，且浸出料浆的过滤性能得到明显改善。
但仍有约10%的锗损失在渣中。
综上所述，虽然针对锌冶炼渣的硫酸浸出工艺展开了广泛研究，并取得了一定进展，但对高硅含镓、锗物料的处理工艺仍有待改进。
采用硫酸强化浸出体系，虽然可提高镓、锗的浸出率，并改善浸出料浆的过滤性能，但锌、铁、铜和硅等也会相应大量浸出，使得后续镓、锗回收更加困难。
此外，虽然研究人员针对锌冶炼渣硫酸浸出液中镓、锗的回收开发了多种萃取剂，但大多存在成本高、选择性低、水溶性强、来源不广泛等缺点[18−20]。
为此，本文作者在已有工作的基础上，研究了锌粉置换镓锗渣的草酸浸出工艺，实现了镓、锗选择性浸出；而且更为重要的是，由于镓、锗在草酸浸出体系中以配合离子存在，所以采用价格低廉、来源广泛、性质稳定的萃取剂N235即可实现镓、锗的高效回收[21−22]。
实验所用锌粉置换镓锗渣产自国内某冶炼厂，经干燥、磨细、混合后用作试验原料。
物料化学成分、化学物相分析结果分别列于表 1 和 2。
湿筛粒度分析结果如表 3所列。
物料的XRD谱如图 1 所示。
物料EPMA 定量分析结果如图 2 和表 4 所示。
物料中镓、锗、铁、硅的元素面分布图如图 3 所示。
由表1可知，实验所用锌粉置换镓锗渣主要成分为锌、硅、铜、铁、砷、铅等，其中Fe(Ⅱ)含量为3.74%(质量分数)，占原料总铁含量的47.66%(质量分数)；其镓和锗的含量分别为0.266%和0.362%(质量分数)。
同时渣中二氧化硅的含量高达9.14%(质量分数)，这使得镓、锗的回收较难进行。
由表2可知，锗主要以MeO·GeO2、GeO2形态存在，少量为Ge、GeS、GeS2；而镓主要以Ga2O3、MeO·Ga2O3形态存在，少量为Ga、Ga2S3。
XRD分析结果表明，锌粉置换镓锗渣中主要物相为金属锌、硫酸锌，也有少量铁酸锌、硅酸锌存在，由于含量较低，未见含镓、锗物相的衍射峰(见图1)。
由表3可知，实验所用锌粉置换镓锗渣粒度较细，75%(质量分数) 以上的粒度小于45 μm。
由表4 的电子探针定量分析结果可知，图2中点1主要物相为硫酸锌，该物相中基本不含镓、锗；图2中点6、11、13和点3、8分别为铁酸锌和硅酸锌物相，这两种物相中镓、锗的含量明显高于硫酸锌物相，另外，硅酸锌中镓、锗的分布要高于铁酸锌中。
图2中其余的点主要为含有锌、铅、铜、钙等金属的铁、硅的胶体化合物。
从图 3 所示的锗、铁、镓、硅元素在锌粉置换镓锗渣中的分布图可知，镓、锗主要以弥散状态分布在整个物料中，在含铁、硅的区域中均有分布。
为了证实锌粉置换镓锗渣中锗、镓与硅、铁的关系，利用表4中的数据，对渣中锗、镓、硅、铁的含量进行了线性拟合，其拟合结果如式(1)~(4)所示。
从以上线性拟合结果可知，锌粉置换镓锗渣中锗的含量与硅(见图4)、铁的含量均具有较好的相关性。
而渣中镓的含量与硅、铁的含量的相关性较差。
由此可知，在锌粉置换富集镓、锗的过程中锗主要以共沉淀的形式(MeO·GeO2) 进入到渣中；而镓主要是经锌粉还原后经氧化以Ga2O3存在渣中。
量取一定体积已知浓度的H2C2O4 溶液于500 mL三口瓶中，将三口瓶置于恒温水浴中，升温至实验温度，然后按照预定的液固质量比加入一定量的双氧水和锌粉置换镓锗渣，开启搅拌，搅拌速度为300 r/min，保温一定时间。