Optimization of germanium enrichment from waste optical fibers: A validation experiment using a hybrid approach

A batch-type and lab-scale germanium recovery method was developed via a hybrid approach combining pyro-and hydrometallurgical reactions to prove the feasibility of mass production and economic recovery of germanium from waste optical fibers. More specifically, the extent of pyro-metallurgical separation reaction was carefully examined to determine by trial and error its completion time which was 2 h at 700 degrees C. The post pyro-metallurgical reaction product was leached at 50, 65, and 80 degrees C for a maximum 8 hr retention at each temperature, using an optimized composition of aqueous HCl solution: maximum germanium recovery of 26 ppm was thus experimentally substantiated by using the ICP-OES method. XRF analysis was performed on the post-hydrometallurgical leaching residue to detect any significant composition of remaining Ge: The confirmation of Si, Cl, and Na as sole residual elements thus cogently substantiated the complete separation of germanium in accordance with the present hybrid approach. The present research thus casts very promising insight into a hybrid recovery method, suitable for mass production, for subsequent elemental germanium recovery of waste optical fibers by means of cementation and electro-reduction.