The Extraction Of Germanium By Microemulsion

microemulsion is a kind of thermodynamically stable, homogeneous and optically isotropic solutions, which is consisted of surfactant, cosurfactant, organic solvent and water. The diameter of microemulsion varies from 10nm to 200nm, and the interfacial tension of microemulsion is very low. In this paper, the study is focesed on the characteristic of microemulsion and the application of microemulsion on the extraction of germanium.In the paper, we choosed AOT as surfactant, n-butanol as cosurfactant, n-heptane as organic solvent and the Na2SO4 solution to preparation microemulsion. The pseudo-ternary diagram of the microemulsion was prepared th study the structure and forms of different kind of microemlsion. Through investigating the varieties of the pseudo-ternary diagram after injecting n-butanol and N235, reserched the effect of injecting n-butanol and N235. We can see that the n-butanol and N235 could make a contribution to the stable of microemulsion, which is in favor of the extraction of germanium. The conductivity of the microemulsion with/without N235 was investigated. The results showed that the microemulsion with N235 has lower conductivity than the microemulsion with N235, which might because the N235 has high viscosity.On the basis of the study on the property of microemulsion, microemulsion without extractant was used to extract germanium. First, the system AOT/n-butanol/n-heptane/water was made to extract germanium. This system was not stable enough to avoid demulsification in the process of extracting, only if injecting a lot of n-butanol and the feed solution having high value of pH. The the maximum extraction efficiency of this system was 63.5%. Second, the system AOT/NaOL/n-butanol/n-heptane/HCl was used in the extraction of germanium, which has higher extraction efficiency(71.4%) than the first system. The result of investigation of the extraction of germanium use microemulsion without extractant showes that the emulsion without extractant was not stable enough, and the extraction efficiency was low.With the purpose of increasing the extraction efficiency of germanium, the extractant N235 was injected, which is an amine extractant, and must be acidulated with 0.25 mol/L H2SO4. the system AOT/n-butanol/n-heptane/N235/Na2SO4 solution was used to extact germanium. This system has enough stability in the process of extraction, and the extraction efficiency could be close to 100%. The influence of equilibration time,R,the concentration of Na2SO4 solution,the concentration of n-butanol,the concentration of the tartaric acid in feed solution,the pH value of feed solution and the temperature were investigated to make sure the optimal condition. The system has lots of advantages than other system used in extraction of germanium, such as the wide pH value,the good stability and the high extraction efficiency, and so on.