Please use this identifier to cite or link to this item:
Title: Process mineralogy of bacterial oxidized gold ore in São Bento Mine (Brasil).
Authors: Márquez, Marco
Gaspar, José
Bessler, Karl Eberhard
Costa, Geraldo Magela da
Keywords: São Bento
Bacterial oxidized
Gold ore
X-ray diffraction
Issue Date: 2006
Citation: MÁRQUEZ, M. et al. Process mineralogy of bacterial oxidized gold ore in São Bento Mine (Brasil). Hydrometallurgy, Amsterdam, v. 83, p. 114-123, 2006. Disponível em: <>. Acesso em: 02 fev. 2015.
Abstract: The São Bento deposit (Santa Bárbara, MG) occurs in the middle portion of the Quadrilátero Ferrífero (latu sensu), hosted by the São Bento iron formation. The most important minerals in the deposit are arsenopyrite, pyrrhotite, chalcopyrite, sphalerite, galena, electrum, magnetite, ilmenite, siderite, ankerite, calcite, quartz, chlorite, stilpnomelane and muscovite. A mineralogical characterization of samples from the bacterial oxidation process at the São Bento gold mine (MG) was performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), Mössbauer spectroscopy and electron probe microanalysis (EPMA). Samples were collected in four different dates: one sample from the flotation concentrate and four from the bacterial oxidation system (BIOX) (TK2, TK4/TK68 bioreactors and TK28 thickener). Pyrrhotite was completely oxidized and arsenopyrite, pyrite and chalcopyrite were only slightly oxidized in the BIOX. Siderite occurs in small concentration in BIOX. Quartz, chlorite, and muscovite were slightly affected along the process. In BIOX, amoniumjarosite and hydroniumjarosite in lower abundance are the main phases formed. Native sulfur was detected in significant concentrations. Goethite and hematite are the main oxyhydroxides and an unidentified hydroxide containing up to 10wt.% MgO was observed. Subordinate phases in BIOX samples are fibroferrite, zykaite, bukovskyite, sarmientite, tooeleite, alunite and gypsum. Chemistry of the iron sulfates shows that there are two amoniumjarosites in the BIOX, high and low- As jarosites. Low-As amoniumjarosite contains 10wt.% As2O5 in average; while the high-As one contains 20wt.% As2O5 in average. As-to-S substitution ratio is 1:1 suggesting a solid solution series toward an “As jarosite”. Their crystallization seems to be controlled by a solvus.
ISSN: 0304-386X
metadata.dc.rights.license: O periódico Hydrometallurgy concede permissão para depósito deste artigo no Repositório Institucional da UFOP. Número da licença: 3577160218530.
Appears in Collections:DEQUI - Artigos publicados em periódicos

Files in This Item:
File Description SizeFormat 
ARTIGO_ProcessMineralogyBacterial.pdf349,5 kBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.