Elemental distributions of solid waste collected from the germanium extraction process.

Area of Science:

• Environmental Science
• Geochemistry
• Materials Science

Background:

• Solid waste from germanium extraction is a potential secondary resource.
• The elemental distribution and occurrence in this waste are not well understood.

Purpose of the Study:

• To investigate the elemental distribution and occurrence in solid waste from germanium extraction.
• To determine the leachability of various elements from this waste.

Main Methods:

• Sequential extraction procedure
• X-ray Diffraction (XRD)
• Fourier-Transform Infrared Spectroscopy (FTIR)
• X-ray Photoelectron Spectroscopy (XPS)
• Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS)
• X-ray Absorption Fine Structure (XAFS)

Main Results:

• Ca, S, Fe, and Si were identified in crystalline forms (e.g., calcium sulfate, iron oxide hydroxide, quartz).
• Si and Al were found in amorphous structures.
• Ca and S leached easily in water or weak acid; Fe, Al, and Si leached in reducible/oxidizable conditions.
• Ge, As, and Cr were predominantly in the residual fraction, with Ge associated with Si/Al amorphous structures, Cr with silicates, and As with iron minerals.

Conclusions:

• The study clarifies the elemental occurrence and leachability in germanium extraction waste.
• Understanding these characteristics is crucial for efficient resource recovery and waste management.
• Ge, As, and Cr are primarily in recalcitrant forms, requiring specific strategies for extraction.