Microprobe Techniques for Speciation Analysis and Geochemical Characterization of Mine Environments: The Mercury District of Almadén in Spain
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- 作者：Anna Bernaus ; Xavier Gaona ; José ; Maria Esbrí ; Pablo Higueras ; Gerald Falkenberg ; and Manuel Valiente
- 刊名：Environmental Science & Technology
- 出版年：2006
- 出版时间：July 1, 2006
- 年：2006
- 卷：40
- 期：13
- 页码：4090 - 4095
- 全文大小：433K
- 年卷期：v.40,no.13(July 1, 2006)
- ISSN：1520-5851
文摘
Metallurgic calcines with very high mercury and methylmercury content from the Almadén mining district wereanalyzed by synchrotron-based microprobe techniques.Information about mercury speciation was obtainedby 
-EXAFS (microscopic extended X-ray absorption finestructure) spectroscopy, whereas elemental associationswere evaluated by -XRF (microscopic X-ray fluorescenceanalysis) mapping. Complementary characterizationmethodologies, including X-ray diffraction (XRD), inductivelycoupled plasma-optical spectroscopy (ICP-OES), as wellas a sequential extraction scheme (SES), were used to predictthe potential availability of mercury. Analysis of totalmetal content revealed extremely high concentrations ofmercury and iron (between 7 and 35 and 65-70 gkg-1, respectively) and high zinc concentrations (2.2-2.5g kg-1), whereas other metals such as copper, nickel, andlead were found at low concentration levels (30-300 mgkg-1). -EXAFS results indicate that cinnabar (HgSred) is oneof the main species within the studied mercury-richparticles (5-89% of total mercury content), together withmore soluble mercury compounds such as Hg3(SO4)O2(schuetteite) and HgO (5-55% of total mercury content).Additionally, element-specific -XRF maps of selectedmercury-rich particles in the studied samples revealed anevident correlation among Hg-Pb-Ni (and S), indicatinga possible geochemical linkage of these elements. Correlationswere also found among Fe-Mn and Hg, which havebeen attributed to sorption of mercury onto oxyhydroxidesof Fe and Mn. This finding was supported by resultsfrom a sequential extraction scheme, where a significantamount of Hg was extracted with the fraction soluble in 6M HCl.
-EXAFS (microscopic extended X-ray absorption finestructure) spectroscopy, whereas elemental associationswere evaluated by -XRF (microscopic X-ray fluorescenceanalysis) mapping. Complementary characterizationmethodologies, including X-ray diffraction (XRD), inductivelycoupled plasma-optical spectroscopy (ICP-OES), as wellas a sequential extraction scheme (SES), were used to predictthe potential availability of mercury. Analysis of totalmetal content revealed extremely high concentrations ofmercury and iron (between 7 and 35 and 65-70 gkg-1, respectively) and high zinc concentrations (2.2-2.5g kg-1), whereas other metals such as copper, nickel, andlead were found at low concentration levels (30-300 mgkg-1). -EXAFS results indicate that cinnabar (HgSred) is oneof the main species within the studied mercury-richparticles (5-89% of total mercury content), together withmore soluble mercury compounds such as Hg3(SO4)O2(schuetteite) and HgO (5-55% of total mercury content).Additionally, element-specific -XRF maps of selectedmercury-rich particles in the studied samples revealed anevident correlation among Hg-Pb-Ni (and S), indicatinga possible geochemical linkage of these elements. Correlationswere also found among Fe-Mn and Hg, which havebeen attributed to sorption of mercury onto oxyhydroxidesof Fe and Mn. This finding was supported by resultsfrom a sequential extraction scheme, where a significantamount of Hg was extracted with the fraction soluble in 6M HCl.