Mineralogical study of archaeological copper slags found in the area of Krushevets Village, SE Bulgaria

Article in Press
Pages: 
pp. 3-23
Department of Mineralogy and Petrography, University of Mining and Geology “St Ivan Rilski”, 1700 Sofia, Bulgaria
University of Chemical Technology and Metallurgy, 8 Kl.Ohridsky Blvd, 1756 Sofia, Bulgaria
Abstract: 

In this article, we present the results of our study on archaeological slags found near the village of Krushevets, Southeast Bulgaria. Chemical analyses of the slags show a high Fe2O3 (40.11–54.57%) and SiO2 (29.32–42.28%) content, increased CaO content (3.01–6.51%), as well as very low quantity of SO3 (from 0.20% to 0.52%) and P2O5 (between 0.23% and 0.30%). The unbound residual copper in the samples is in an amount of 0.41% to 1.07%. The main phases composition of the slags are as follows: fayalite-type silicate phases with impurities, kirschsteinite and laihunite; pyroxenes of the augite-type and amorphous hosted glass; iron-oxide phases (magnetite and maghemite); and copper-containing phases (drops of unbound copper, relicts of ore minerals such as bornite, chalcopyrite), as well as newly formed phases, such as chalcocite, and copper-containing spherical aggregates. The studied samples are a by-product of copper extraction metallurgical activity. The raw material used was of copper-sulfide type with impurities of manganese-, calcium-, magnesium- and aluminium-containing minerals.

Keywords: 

Archaeological copper slags, SEM CDD-EDS, X-ray powder diffraction, old copper mining, SE Bulgaria

VOLUME 49 (2)/August 2020

Department of Mineralogy and Petrography, University of Mining and Geology “St Ivan Rilski”, 1700 Sofia, Bulgaria
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University of Chemical Technology and Metallurgy, 8 Kl.Ohridsky Blvd, 1756 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria