MINERALOGY AND GEOCHEMISTRY OF OCHREOUS SEDIMENTS FROM VARIOUS SB DEPOSITS (SLOVAKIA)

9th International Multidisciplinary Scientific GeoConference - SGEM2009, www.sgem.org, SGEM2009 Conference Proceedings/ ISBN 10: 954-91818-1-2, June 14-19, 2009, Vol. 2, 579-584 pp

ABSTRACT

The objective of our study was to examine the mineralogy and chemical composition of
ochreous sediments accumulated in the area of four abandoned Sb deposits from
Slovakia. Each of them is from different geological settings and there are also
differences between types of mineralization and mine processing. Samples were
collected mainly from mine drainages and fraction under 0.063 mm was analyzed
using conventional methods, including X-ray diffraction, IR spectroscopy, transmission
electron microscopy and sequential extractions. Schwertmannite was identified as
predominant mineral phase in acidic conditions, but while carbonates are very common
in most of the studied localities, neutral pH prevails and therefore ferrihydrite is
precipitating most often. In older sediments ferrihydrite transforms to more stabile
goethite. Total content of As is 2128 mg/kg in case of schwertmannite sample and
varies from 433 mg/kg to 134 g/kg in ferrihydrite samples; Sb content in
schwertmannite is 35 g/kg and in ferrihydrite samples is in range from 893.2 mg/kg
to19 g/kg.

Keywords: Sb deposit, Fe ochre, As, Sb