Mineralogical characterization and speciation of sulfur, zinc and lead in pyrite cinder from Bergvik, Sweden

Roasting of sulfide ores to produce sulfuric acid began on an industrial scale in the middle 1800′s and is still used extensively worldwide. The residual, pyrite cinders, have commonly been disposed environment where they pose a potential serious threat aquatic life. In this project, two profiles cinder deposit Bergvik, Sweden, sampled comprehensive mineralogical characterization carried out. objectives were investigate composition morphology grains speciation sulfur, Pb Zn solid phase. Scanning electron microscopy showed with core ore minerals sphalerite enclosed layers iron oxides/hydroxides (mainly hematite). XANES analysis, supported by X-ray diffraction SEM-EDS bulk element that content residual sulfur mainly sulfides, 55–80%, predominately sphalerite. remaining mass assumed be adsorbed or precipitated as secondary sulfate minerals, predominantly associated grain surfaces. Calculated saturation indexes indicated barite, anglesite perhaps aluminite. EXAFS spectroscopy about half was bound O S. LCF analysis spectra main species (40–50%) franklinite (10–20%). like hydrozincite possibly zinc oxides. precipitate located both surface interior inclusions. analytical interpretation anglesite.