A process for recovering germanium from effluents of optical fiber manufacturing

Germania is the primary dopant used to control the refractive index profile in optical waveguides. However, its poor efficiency of incorporation and its high cost create a need for recovery. This paper describes a system to recover the unused germanium from the manufacturing effluents. Briefly, the process includes 1) a gas scrubber to incorporate the unreacted germanium into solution, 2) a recirculation system to increase the germanium concentration, 3) a reaction to form a germanium precipitate, and 4) a filtration step to isolate the germanium-containing solids. The process is capable of recovering greater than 95 percent of the unreacted germanium.