Abstract
Blast furnace slag from the steel industry is commercially utilized as a cement replacement material without major processing requirements; however, there are many unutilized steel production slags which differ considerably from the blast furnace slag in chemical and physical properties. In this study, calcium sulfoaluminate belite (CSAB) cement clinkers were produced using generally unutilized metallurgical industry residues: AOD (Argon Oxygen Decarburisation) slag from stainless steel production, Fe slag from zinc production, and fayalitic slag from nickel production. CSAB clinker with a target composition of ye'elimite-belite-ferrite was produced by firing raw materials at 1300 °C. The phase composition of the produced clinkers was identified using quantitative XRD analyses, and the chemical composition of the clinker phases produced was established using FESEM-EDS and mechanical properties were tested through compressive strength test. It is demonstrated that these metallurgical residues can be used successfully as alternative raw materials for the production of CSAB cement that can be used for special applications. In addition, it is shown that the available quantities of these side-streams are enough for significant replacement of virgin raw materials used in cement production.
Highlights
Population growth and urbanization increases the demand to expand our built environment (Miller et al, 2016) in which concrete is the fundamental building material (WBCSD, 2009)
The visually observed melting or more advanced sintering behaviour in AOD_C (Fig. 1) can be explained with presence of fluorine, which is known to work as flux or mineralizer in Portland cement and modified Portland cements (Blanco-Varela et al, 1995; Odler and Zhang, 1996; Shame and Glasser, 1987)
The title study reveals how the impurities in metallurgical industry residue materials affect the properties of calcium sulfoaluminate belite (CSAB) cement clinker
Summary
Population growth and urbanization increases the demand to expand our built environment (Miller et al, 2016) in which concrete is the fundamental building material (WBCSD, 2009). Cement is the key binding component in concrete, and global cement production was estimated to be 4.1 billion tons in 2017 (Cembureau, 2018). The most commonly used binder is Portland cement (PC), in which the major and characteristic mineral phase is alite (C3S) (Taylor, 1997). The UNEP SBCI-report concludes that the most promising ways to decrease CO2 emissions related to cement production are 1) increased use of supplementary cementitious materials (SCM's) and 2) more efficient use of PC (UNEP, 2017). Alternative non-Portland clinkers were proposed to provide substantial reduction of CO2 emissions (Scrivener et al, 2018)
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