Of Germanium From Germanium-containing Slag Leaching Pilot Study

Germanium is scattered metal, low levels in the crust, has no economic value and independent of the deposits, the majority of compounds present in the form of silicate and sulfide minerals. As the excellent physical and chemical properties of germanium, is widely used and more importance in the national economy and the military in recent years. With the information industry and the rapid development of new energy sources, along with global demand for the rapid growth of germanium, researchers have more attention and concern of germanium recovery. A Yunnan company leaching residue of germanium with sulfuric acid, leaching rate is only about 55%.It is the low level of resource utilization. In order to improve the comprehensive utilization of resources of germanium, this paper used mixing acid and curing to improve the leaching rate of germanium and germanium integrated recycling.The first part of this paper analysis the theory of germanium leaching thermodynamics, kinetics, and SiO2 in concentrated acid changes, supporting the concentrated acid leaching germanium in theory. Then study the concentrated acid curing-flooded germanium process, examine the different factors on aging effects of concentrated acid, through selecting important factors, using center of rotation response surface design to optimize the design of the experiment to optimize the concentrated process and establish an appropriate leaching model. Examine a variety of factors of flooding leaching process and Analysis follow-up treatment leaching solution containing germanium. The main contents of this paper are as follows:First, draw the water E-pH diagram of germanium, analysis the E-pH diagram, the raw material of germanium oxide can be dissolved in acid. Increasing the reaction rate by increase the concentration of sulfuric acid, and the leaching kinetics of conventional kinetic experiments come to sulfuric acid leaching of germanium-containing slag is generated such a solid product. Germanium leaching kinetics equation can be expressed as:Kc=K0·r-1·[H2SO4]1.654·exp[-10640/RT].By SiO2 in dilute acid and concentrated acid changing obtained SiO2 in form of a stable form under the conditions.Mixing acid and curing factor experiments show that, the optimal conditions for the aging mixed acid:weight of 40g, under the conditions of grinding time of 4min, plus the amount of water and acid are 20g, curing temperature of 80℃, curing time 3h, the leaching rate of 71.6%.It can be seen by analyzing the size and the amount of sulfuric acid leaching rate of germanium greater impact, Curing temperature and curing time is less. Mainly because in the course of acid mix, the temperature reached a high moment, concentrated sulfuric acid and materials mainly in response to this stage.Through center of rotation the combination of response surface methodology modeling concentrated acid leaching germanium regression mathematical model: Y=72.63+21.65χ1+0.53χ2+1.06χ3-0.100χ1χ2-0.24χ1χ3+0.12χ2χ2-11.27χ12-1.25χ22-1.47χ32. Correlation coefficient R is 0.9067, precision 33.979 is greater than4, R2adj= 0.9765, found that the sulfuric acid affected the leaching rate of germanium significantly. Obtained the best optimization parameters by Design-Expert software, are:weight of 40g sulfuric acid 30g, aging time 44.52min,43.56℃higher leaching rate of germanium, Leaching rate of 79.14%. While this process in a short time under the conditions of aging, curing temperature is low. Experimental verification of this prediction by and experimental values of a better match.Flooding process parameters:leaching time of 1h, acid concentration Og/L, leaching temperature 90℃, liquid-solid ratio of 4, the leaching rate of 78.88%.Therefore, under the general terms of concentrated acid curing the leaching rate of 78.88% germanium. By the acidity of the solution after flooding and analysis of deposition of germanium on the industrial production process research, solution after concentrated acid aging-flooding leaching for the flooding precipitation process.In short, based on the leaching process of germanium-containing thermodynamic and kinetic experiments, through the center of rotation through the combination of response surface methods to optimize the experimental design. Germanium has been such a high residue leaching rates, proof of strong acid curing process in dealing with this type of residue has obvious advantages, this study extends the curing process in concentrated acid metal scattered field applications.