Study On Separation And Recovery Of Germanium And Silicon From High Silicon Containing Materials

As a scarce resource,germanium is an important strategic reserve material of various countries.As the largest country in the production and consumption of germanium resources,how to optimize the production process and the recycling of germanium resources has become an important means to alleviate the shortage of germanium resources.At present,the germanium resources in our country are mainly obtained from the fly ash from the burning of lignite,the tailings of zinc smelting and waste optical fibers.This dissertation focuses on the current low germanium leaching rate in the extraction of germanium from fly ash,poor separation of germanium and silicon from fiber solid waste,and heavy environmental pollution.The main research contents and results are as follows:(1)The fly ash was leached using different types of acids,and it was found that tartaric acid was used for leaching,and when the concentration of tartaric acid in the solution was 80g/L,the leaching temperature was 50?,the leaching time was 2h,and the solid-liquid ratio was 10,The leaching rate of germanium in fly ash reaches the maximum under this system(about 74%).When studying the influence of different leaching aids,it is found that when the leaching aid H₂O₂is used,the above conditions remain unchanged and the concentration of H₂O₂in the solution is 0.1%,at this time the leaching rate of germanium in the fly ash reaches the maximum under this system(About 85%).When studying the influence of surfactants,when the concentration of anionic surfactant sodium dodecyl sulfonate in the solution is 3.33g/L,the above conditions remain unchanged,and the leaching rate of germanium in fly ash reaches the maximum under this system Value(around 84%).For the filtered germanium-containing solution,the precipitation of germanium in the fly ash leaching solution is achieved by tannic acid.When the amount of tannic acid in the solution is 1.2g/L,the precipitation rate of germanium at this time reaches 97%,and it passes XRD at the same time.And XRF characterization analysis,the germanium element successfully entered into the precipitated product.(2)When the pH value is alkaline,the self-made resin starts to adsorb germanium in the solution.When the pH is greater than 10,the adsorption rate can reach more than 99%.The increase of temperature can promote the adsorption rate of germanium by the self-made resin.Under static adsorption conditions,the unit saturated adsorption capacity of the self-made resin is 47.5mg/g.By fitting the kinetic and isotherm adsorption model,the adsorption is more in line with the quasi-second-order kinetics and Langmuir isotherm adsorption model.Under the dynamic adsorption system,the dynamic saturated adsorption capacity per unit volume of the self-made resin is measured to be 17.2mg/g;and through the response surface analysis of Design-Expert software,it is concluded that the three factors have an effect on the adsorption of germanium on the resin in order of initial solution Germanium concentration>flow rate>temperature,and the actual experimental data is in good agreement with the response surface analysis prediction data.Regarding the recycling performance of the self-made resin,after 5 cycles,the germanium adsorption rate is above 99%,and the germanium desorption rate is above 90%.Through SEM analysis,the surface of the self-made resin is mesoporous;and through FT-IR analysis,it can be concluded that the meglumine functional group on the resin surface has a significant complexation with germanium.For the self-made resin eluent,when the pH value is 10,the adsorption rate of MgO on germanium reaches the best,and the saturated adsorption capacity of MgO on germanium per unit volume is 3811mg/g.