Mineralogy and Weathering of Realgar-Rich Tailings At a Former As-Sb-Cr Mine At Lojane, North Macedonia

Autor(en)

Tamara Đorđević, Uwe Kolitsch, Todor Serafimovski, Goran Tasev, Nathalie Tepe, Stöger-Pollach Micheal, Thilo Hofmann, Blazo Boev

Abstrakt

In the Lojane area (North Macedonia) ores of Sb (stibnite), As (realgar), and Cr (chromite) were mined and processed in a
metallurgical plant until 1979. Over one million tons of flotation tailings containing As, Sb, and other hazardous substances are
located in an open dump site for flotation waste created by the mine. The tailings site is completely unprotected, and its orange
color reflects a very high concentration of arsenic (fine-grained realgar superficially altered to pararealgar). In order to better
understand the weathering behavior of these tailings, which is necessary to evaluate the environmental risks (mainly from the this oxide also form larger homogeneous grains up to 500 lm in size, characterized by broad dehydration cracks suggesting
original formation as a gel. Both As-rich and -poor variants were identified as members of the rom´eite group. EELS showed that
all the Fe is ferric. Further secondary phases originated from the weathering of realgar, stibnite, and other primary phases are
As-bearing sulfur, scorodite (often slightly Sb-bearing, locally common), arsenolite, ‘‘limonite’’, pickeringite (Ni- and Febearing),
alunogen, and annabergite. The weathering of primary sulfides in the flotation tailings at Lojane proceeded under
mostly oxidizing, acidic, and temporarily wet conditions. Highly acidic conditions on the surface of the tailings dump imply
dissolution of arsenolite and scorodite, thus causing contamination of the environment and high mobility of arsenic.
mobilization of As-Sb-Cr), solid waste material was sampled and studied from the chemical and mineralogical point of view.
The material was characterized by inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasmaoptical
emission spectrometry (ICP-OES), X-ray diffraction analysis (both single crystal and powder), scanning electron
microscopy (SEM) with energy-dispersive microanalysis (EDX), Raman spectroscopy, and transmission electron microscopy
(TEM) with selected area electron diffraction (SAED), energy-dispersive X-ray analysis (EDX), and electron energy loss
spectrometry (EELS). The studied tailings material is comprised mostly of well-crystallized realgar, gypsum, and quartz, and
minor amounts of stibnite, pararealgar, chromite, and sulfur. Very minor pyrite is found within quartz aggregates. The most
abundant secondary phase, which forms thin coatings around realgar and stibnite grains, is an As-Sb-Fe-Ca-(Ni)-oxide/
hydroxide in which the As:Sb ratio varies from ca. 2:1 to 1:2.2 and Fe contents are variable. Antimony-dominant variants of

Organisation(en)

Institut für Mineralogie und Kristallographie, Department für Umweltgeowissenschaften

Externe Organisation(en)

Naturhistorisches Museum Wien (NHM), Goce Delčev University of Štip, Technische Universität Wien

Journal

The Canadian Mineralogist

Band

57

Seiten

403-423

Anzahl der Seiten

21

ISSN

0008-4476

DOI

https://doi.org/10.3749/canmin.1800074

Publikationsdatum

05-2019

Peer-reviewed

Ja

ÖFOS 2012

105116 Mineralogie, 105105 Geochemie, 104023 Umweltchemie, 105906 Umweltgeowissenschaften

Schlagwörter

ASJC Scopus Sachgebiete

Geochemistry and Petrology

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/c3f8f9e9-ea06-4c25-ad68-1c341fe5f516