Improve subsequent leaching efficiency and extraction rate of germanium in optical fibre cables with pre-treatment

Abstract

Germanium is an important and rare material which widely used in fibre optic industry, accounting for about 40% of the total germanium product usage. Due to the rarity of germanium, developing an effective recycling process of recovering germanium metal from waste fibre optical cables is significant. Fibre optical cables was arranged to do characteristic analysis, pre-treatment and dissolution in this study. In the characteristic analysis, the content of germanium dioxide in the glass fibre was 0.15%, and the remaining components were all silicon dioxide. In the pre-treatment part, it consists of two steps which are the solvent treatment and roasting. At the solvent treatment step, glass fibre can be separated by acetone with a concentration of more than 50% and ethanol with concentration of more than 75%. At the roasting step, NaOH was used as a roasting additive. Adding 5 molar ratio of NaOH/SiO2 at 500 °C for 2 hours can totally convert the optical fibre into the silicate. After roasting, it could be leaching by dilute H2SO4 and its leaching rate is higher than 99.5%. This study can provide a process to recovery germanium from optical fibre effectively. According to the optimal conditions, the recovery of germanium could be up to 99%.