Characterization by FTIR of Oxidized Pyrargyrite with Sodium Sulfide

Pyrargyrite is a silver-rich sulfosal of formula Ag3SbS3, considered a refractory species to leaching with cyanide solutions. In this research work, the characterization by infrared spectroscopy by Fourier transform and X-ray diffraction (XRD) of the oxidation of pyrargyrite with sodium sulfide is presented. The XRD results of the oxidation with sodium sulfide show that the pyrargyrite PDF 00-019-1135 is transformed into silver sulfide acanthite identified with PDF 96-901-1415, and the rosinckyite phase was also detected PDF 96-901-2782 as well as Ag2O3 PDF 96-150-9693. The characterization by FTIR shows the absorption bands in 534, 760, 1019, and 1384 cm−1 characteristics of the presence of Sb–O bonds of Sb2O3, and these oxides decisively influence the leaching of silver, due to the formation of a passivation layer on the mineral affecting the success of the leaching.