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Geochemistry and mineralogy of metallurgical slag

August 13, 2021

Slag is a waste product from the pyrometallurgical processing of natural ores or the recycling of man-made materials. This chapter provides an overview of the geochemical and mineralogical characteristics of different types of slag. A review of the analytical methods used to determine these characteristics is also provided. Ferrous slags include blast furnace, steelmaking, and ferroalloy slags; the compositions of these slags are generally dominated by Ca and Si, some with significant Al, Fe, and/or Mg. Whereas, the composition of non-ferrous slags, mostly from base-metal production, are generally dominated by Fe and Si with significant but lesser amounts of Al and Ca. As for primary mineralogical phases, olivine-group phases, spinels, and glass are common among all types of slag. Other silicates such as melilite, pyroxene, feldspars, and oxides also occur. Sulfides are more common in non-ferrous slags and metals and intermetallic compounds can be found in both base-metal and ferrous slags. Carbonates are generally exclusive of ferrous slags. The chemical composition of slag depends on the furnace feed, fluxes, fuel source, and furnace conditions and efficiency of metal extraction. The chemistry and texture of mineralogical phases found in slag reflect melt composition and cooling rates. Overall, the mineralogy and chemistry of slags will determine its fate as an environmental liability or a valuable resource.

Publication Year 2021
Title Geochemistry and mineralogy of metallurgical slag
DOI 10.1039/9781839164576
Authors Nadine M. Piatak, Vojtech Ettler, Darryl Andre Hoppe
Publication Type Book Chapter
Publication Subtype Book Chapter
Index ID 70224568
Record Source USGS Publications Warehouse
USGS Organization Eastern Mineral and Environmental Resources Science Center; Geology, Energy & Minerals Science Center