Separation Of Germanium And Comprehensive Utilization Of Germanium Containing Fiber Solid Waste With High Silicon Content

Germanium,an important dissipated metal,is widely used in semiconductor,aerospace,nuclear physics detection,optical fiber communication,infrared optics,solar cells,chemical catalysts,biomedicine and other fields.Among these industries,germanium used in optical fiber accounts for the largest proportion of germanium industrial consumption,about 30%.With the application of 5th-Generation communications,the demand for germanium in optical fiber further increases,along with a large number of abandoned optical fiber processing problems.Therefore,it is of great social significance and economic value to recover germanium from solid waste of optical fiber contained germanium and further utilize it comprehensively.The recovery of germanium from solid waste contained high silicon germanium has always been an important issue to be addressed in related industries.So far,there has no efficient and economical waste fiber disposal technology at home and abroad,which causes certain environmental pollution and resource waste.This paper focuses on the study of the solid waste of optical fiber contained germanium,aiming to recover the germanium from optical fiber and reuse the solid waste after germanium extraction,so as to further improve the economic value of the solid waste of optical fiber.In this paper,the recovery of germanium was successfully realized by alkali leaching under low temperature and high pressure,adding alkali metal in the process of neutralization and aging,and then chlorinating distillation.The experiments showed that:（1）The method of alkali leaching under low temperature and high pressure can effectively dissolve all germanium in fiber contained high silicon germanium;（2）The addition of sodium chloride to the mixture of sodium silicate and sodium germanate during the neutralization and static aging process can significantly affect the polymerization of silicate acid in the solution,thus it can grow into nano-silica nanoparticles instead of forming silica gel;（3）The maximum germanium recovery efficiency was 98.338%when the sodium chloride content was up to 4%of the solution mass.In addition,with the addition of sodium chloride,the resulting silica changes from a highly agglomerated globule to an irregular spherical mesoporous silica with improved dispersion.When the sodium chloride content was 4%,the maximum specific surface area of mesoporous silica was 409m²/g,and the corresponding pore size of BJH was5.56nm.The Ag/SiO₂ nanocomposite catalyst was prepared by a simple chemical reduction method using the residual nano-amorphous SiO₂ after germanium recovery as the carrier.The effects of different silver loads on the catalytic performance of Ag/SiO₂ catalyst were evaluated by using Na BH₄ to reduce 4-np.It was found that with the increase of silver loading,the catalytic performance of the catalyst increased first and then decreased.When the silver content was 1.5%,the nanocomposite catalyst had the best catalytic performance,the corresponding catalytic constant of 24.54min^-1·g^-1.The catalytic reduction process was combined with a first-order kinetic reaction model,and the fitting constant was 0.989.However,further increase the amount of silver loading the catalytic efficiency reduced,which was believed to be caused by the aggregation and growth of silver nanoparticles on the catalyst surface.In addition,the study on the cyclic stability of the catalyst showed that after the catalytic efficiency of the catalyst was still above 97%after 7 cycles,suggesting its excellent stability.