Research On Ultrasonic Enhancement Technology For Germanium Extraction By Tannin Precipitation From Germanium-containing Leachate

Germanium is an important strategic reserve resource,In recent years,With our Solar cells,Infrared thermal imaging technology and 5G-tech national development strategy,the demands of optical fibre keep rising,which has led an increasing demand of germanium products.At present,the process of tannins precipititation of germanium is usually used to enrich germanium from non-ferrous smelting soot,but the traditional process has some defects such as unclear process,serious local flocculation,large consumption of tannins and germanium concentrate is of low grade,which limits the development of germanium industry.This paper focused on the problem of germanium recovery with tannins from zinc leaching lixivium,proposing precipitation of Germanium with Tannins under ultrasonic intensification process and studied influence factors and the reinforcement mechanism.The main conclusion is summarized below:1.The reaction mechanism of tannins with germanium was studied with ideal solution of germanium and tannins.According to the experimental results,the optimum tannins dosage and germanium precipitation rate at 30 multiples(tannins and germanium mass ratio),the normal condition were obtained,and the precipitation rate of germanium was98.84%.According to the microstructure and internal structure analysis of germanium-tannins:The deposition mode of germanium-tannins is layer polymerization.And the germanium-precipitation reaction is hexa-coordinate of Ge⁴⁺and O-phenolic hydroxyl group,occurs sp³d² hybridization,the coordination forms a Ge-O covalent bond.2.Using the actual germanium-containing leaching solution as the research object,the optimization conditions of ultrasonic enhanced germanium deposition process of tannins were studied.The germanium precipitation rate is 99.01%when precipitation temperature is 60?,reaction times is 30 min,p H is 2.50,ultrasonic power is 30 W,tannins is 22multiples(tannins and germanium mass ratio),which is 4%higher than conventional method.Meanwhile,the concentration of germanium after precipitation can be reduced to0.6 mg/L,which met the requirements of zinc electro-deposition(0.8 mg/L).3.By investigating the interaction sequence between metal ions and tannins in the germanium-containing leaching solution and the characterization and analysis of the germanium-tannins precipitation under ultrasonic conditions,the mechanism of the germanium precipitation process of tannins in the germanium-containing leaching solution strengthened by ultrasonic external field was clarified.The binding energy orders of metal and tannins is Ge⁴⁺>Fe³⁺>Mg²⁺>Zn²⁺>As⁵⁺.Ultrasonic can enhance the ion mass transfer and promotes the ionization equilibrium of phenolic hydroxyl groups and generates more H⁺and R-O^-,then increase the coordination reaction between Ge⁴⁺and tannins,thus reducing the complexation probability between tannins and impurity metal and improving the grade of germanium slag.At the same time,low frequency ultrasonic vibration can refine the particle size,reduce the direct flocculation of germanium-tannins,and then reduce the consumption of tannins.The study on the process parameters and mechanism of germanium precipitation formed in this paper can provide clear theoretical guidance for the current process of germanium precipitation tannins,and provide a feasible technical scheme for reducing the dosage of tannins and improving the grade of germanium concentrate,which is of great significance for the efficient utilization of germanium containing dust and the sustainable development of germanium industry.