Mechanochemical sulfidization of lead oxides by grinding with sulfur

Lead oxide was co-ground with sulfur to investigate the possibility of stimulating a solid-state reaction to form lead sulfide. The formation of both lead sulfide and lead sulfate was confirmed, even without any other additive such as iron powder. The necessary conditions for sulfidizing the oxides can be explained based on thermodynamic considerations, namely a negative change in Gibbs free energy. This method can be applied to treat leaded glass by co-grinding it with sulfur to form sulfide as well as sulfate, so that current mineral processing techniques, such as flotation separation, might be used to recover lead from various kinds of leaded glass wastes.

Lead oxide and lead dioxide as starting materials were co-ground with sulfur, respectively. X-ray diffraction analysis showed lead sulfide and lead sulfate were generated in the ground samples.Figure optionsDownload as PowerPoint slideHighlights
► Mechanical grinding of lead oxide and lead dioxide with sulfur was conducted.
► Mechanochemical reaction between lead oxide (lead dioxide) and sulfur happened.
► The formation of lead sulfide accompanied by lead sulfate was confirmed after grinding.
► Sulfidization reaction for lead dioxide was much easier than lead oxide.
► The reaction could be applied to treat lead glass by co-grinding sulfur with glass.