Phase and chemical composition of historical Zn-Pb slag from the dump in Ruda Śląska (Silesian Province, southern Poland)

exploitation and processing are found in numerous southern Poland
regions, especially Silesian Province. The Zn-Pb slag dump in Ruda
Śląska, which is over one hundred years old, is an example of such
a location. Chemical composition tests have exhibited that the slag
is characterized by a relatively rich mineral composition with Si and
Fe's dominant content. Impurities in the form of heavy metals, i.a.
Zn, Pb, Cd, As, and rare earth metals: La, Dy, and Y, have also been
identified. The components of which the slags are comprised
include near-equal amounts of silica glass and crystalline phases
represented by oxides (hematite, spinel, magnetite, and hercynite)
and by silicates (fayalite, forsterite, augite, anorthite, mullite, and
quartz). The crystalline phases rarely form euhedral shapes and are
mostly found in fine glass-surrounded crystallites. Based on the
conducted mineralogical and chemical analyses, it has been
established that the tested slags are a waste material resulting from
the processing of locally found oxidized Zn-Pb ores – so-called
calamine – rich in iron impurities.