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

• Published in: Mineralogy and petrology Vol. 110; no. 5; pp. 681 - 692
• Main Authors: Warchulski, R., Gawęda, A., Janeczek, J., Kądziołka-Gaweł, M.
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.10.2016
• Subjects: Earth and Environmental Science; Earth Sciences; Geochemistry; Inorganic Chemistry; Mineralogy; Original Paper; Olivine; Hematite; Bi2Te3; Nepheline; Galena
• ISSN: 0930-0708; 1438-1168
• DOI: 10.1007/s00710-016-0439-1

The unique among pyrometallurgical slags, coarse-grained (up to 2.5 cm) segregations (up to 40 cm long) rimmed by “aplitic” 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 volatile-rich 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.