Beneficiation of pyrite from coal mining

An abundant mineral in nature and despite its potential as raw material for different segments of industry, when it comes from coal mining, pyrite (FeS2) is treated as waste, and its disposal culminates in environmental problems for the coalfields. Increasing the purity of pyritic tailings, increasing its iron disulfide content, strengthen the possibility of turning it into a value-added by-product. In this work, an analysis of impurities in the pyrite of southern Santa Catarina (Brazil), including organic matter, sulfates, iron oxides, calcite, clay and sandstone, suggests a processing route for pyrite based on separation by density in bromoform and subsequent leaching in water and acetone solution. Statistical methods were applied to set the leaching parameters, and the process efficiency was evaluated and confirmed by fluorescent X-ray (XRF) elemental analysis (CHNS/O), X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR). The proposed method extracted ferrous sulfate, calcite and quartz present in clayey and sandy fractions.