Mineralogy and origin of coarse-grained segregations in the pyrometallurgical Zn-Pb slags from Katowice-Wełnowiec (Poland)

Abstract

The unique among pyrometallurgical slags, coarsegrained (up to 2.5 cm) segregations (up to 40 cm long) rimmed by Baplitic^border zones occur within holocrystalline historical Zn-smelting slag in Katowice, S Poland. Slag surrounding the segregations consists of olivine, spinel series, melilite, clinopyroxene, leucite, nepheline and sulphides. Ca-olivines, kalsilite and mica compositionally similar to oxykinoshitalite occur in border zones in addition to olivine, spinel series and melilite. Miarolitic and massive pegmatite-like segregations are built of subhedral crystals of melilite, leucite, spinel series, clinopyroxene and hematite. Melilite, clinopyroxenes and spinels in the segregations are enriched in Zn relatively to original slag and to fine-grained border zones. The segregations originated as a result of crystallization from residual melt rich in volatiles (presumably CO 2 ). The volatilerich melt was separated during fractional crystallization of molten slag under the cover of the overlying hot (ca. 1250°C) vesicular slag, preventing the escape of volatiles. That unique slag system is analogous to natural magmatic systems.

Geochemistry, petrology and evolutionary computations in the service of archaeology: restoration of the historical smelting process at the Katowice–Szopienice site

“…The large amount of iron in the glass and the presence of Fe-depleted spinel are typical of undercooling conditions, where Zn and Al are preferentially bounded into spinel structure. This observation is in agreement with common spinel zoning in pyrometallurgical Zn-Pb slags, where the core is rich in Mg, Zn and Al, whilst the rim has a composition close to magnetite (Kucha et al 1996;Ettler et al 2001;Warchulski et al 2015Warchulski et al , 2016.…”

“…The slag sample is composed mainly of Si (19.26 wt.%), Fe (10.95 wt.%), Ca (9.62 wt.%), Al (5.91 wt.%), Mg (3.48 wt.%), S (2.09 wt.%) and Zn (1.34 wt.%) ( Table 3). In general, the slag composition is similar to that of other pyrometallurgical Zn-Pb slags from Upper Silesia (Puziewicz et al 2007;Warchulski et al 2015Warchulski et al , 2016. Normalization of the investigated slag to roasted ore (Fig.…”

“…Sybilski et al 2004). Slags, as analogues of silicate melts, also offer the possibility of describing the unique process of melt crystallization (Puziewicz et al 2007;Warchulski et al 2016).…”

Pb-Rich Slags, Minerals, and Pollution Resulted from a Medieval Ag-Pb Smelting and Mining Operation in the Silesian-Cracovian Region (Southern Poland)

“…The historical metallurgical slags are good materials for providing information on former metal smelting methods and their contemporary mining ore quality [10][11][12][13][14]. The examination of slags can provide significant information about chemical transformation rates and the metal stability associated therein [15][16][17][18][19][20]. Multiple geochemical investigations show that, historically, lead production has had an impact on environmental pollution since the Roman times, e.g., in England [21], Sweden [22], and Spain [23].…”

Understanding Heterogeneity of a Slag-Derived Weathered Material: The Role of Automated SEM-EDS Analyses

“…Even in a single heap, phase composition of slags [21,27] and proportions of primary and secondary phases [19,20] may vary strongly. Additionally, the relationship between primary and secondary phases may be disturbed by hydrothermal crystallization from hot fluids remaining in the slag heap shortly after the slag deposition [22,28]. All these processes contribute to the complexity of the weathered zone developing on slag heaps.…”