Metallurgic calcines with very high mercury and methylmercury content from the Almad&
eacute;n mining district were
analyzed by synchrotron-based micro
probe techniques.Information about mercury s
peciation was obtainedby
-EXAFS (microsco
pic extended X-ray absor
ption finestructure) s
pectrosco
py, whereas elemental associationswere evaluated by
-XRF (microsco
pic X-ray fluorescence
analysis) ma
pping. Com
plementary characterizationmethodologies, including X-ray diffraction (XRD), inductivelycou
pled
plasma-o
ptical s
pectrosco
py (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, res
pectively) and high zinc concentrations (2.2-2.5g kg
-1), whereas other metals such as co
pper, nickel, andlead were found at low concentration levels (30-300 mgkg
-1).
-EXAFS results indicate that cinnabar (HgS
red) is oneof the main s
pecies within the studied mercury-rich
particles (5-89% of total mercury content), together withmore soluble mercury com
pounds such as Hg
3(SO
4)O
2(schuetteite) and HgO (5-55% of total mercury content).Additionally, element-s
pecific
-XRF ma
ps of selectedmercury-rich
particles in the studied sam
ples 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 sor
ption of mercury onto oxyhydroxidesof Fe and Mn. This finding was su
pported by resultsfrom a sequential extraction scheme, where a significantamount of Hg was extracted with the fraction soluble in 6M HCl.