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. 2020 Mar 26;13(7):1529.
doi: 10.3390/ma13071529.

Effect of Cr on the Mineral Structure and Composition of Cement Clinker and Its Solidification Behavior

Haihong Fan  1 , Mengqi Lv  1 , Xiaosha Wang  1 , Jianmin Xiao  1 , Xiaofan Mi  1 , Luwei Jia  1
Affiliations

Effect of Cr on the Mineral Structure and Composition of Cement Clinker and Its Solidification Behavior

Haihong Fan et al. Materials (Basel). .

Abstract

In order to reveal the solidification behavior of Cr in the cement clinker mineral phase, 29Si magic-angle spinning nuclear magnetic resonance, X-ray diffraction, and scanning electron microscopy with energy-dispersive X-ray spectroscopy techniques were used to analyze the morphology and composition of the cement clinker mineral phase doped with Cr. The results showed that the addition of Cr did not change the chemical environment of 29Si in the clinker mineral phase, and it was still an isolated silicon-oxygen tetrahedron. Cr affected the orientation of the silicon-oxygen tetrahedron and the coordination number of calcium, leading to the formation of defects in the crystal structure of the clinker mineral phase, by replacing Ca2+ into the mineral phase lattice to form a new mineral phase Ca3Cr2(SiO4)3. Cr acted as a stabilizer for the formation of β-C2S in the clinker calcination. As the amount of Cr increased, the relative content of C3S decreased and the relative content of C2S increased. Further, Cr easily dissolved in C2S, while it was not found in C3S. This study is conducive to further research on the mechanism of heavy metal solidification in cement clinker. Furthermore, it is important to evaluate the environmental risk of heavy metals in the process of sludge disposal through cement kiln and promote the utilization of sludge resources and the sustainable development of the cement industry.

Keywords: 29Si MAS NMR; Cr; clinker; heavy metal; solidification.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
29Si MAS NMR spectrum of clinker with different Cr content.
Figure 2
Figure 2
29Si MAS NMR spectrum after fitting peaks of different Cr doping clinker.
Figure 3
Figure 3
XRD patterns of clinker with varying Cr content.
Figure 4
Figure 4
Crystal structure of silicate minerals.
Figure 5
Figure 5
SEM spectrum of Cr-doped cement clinker. (a) with 0.8% Cr; (b) with 1.0% Cr; (c) with 5.0% Cr.
See this image and copyright information in PMC

References

    1. Huntzinger D.N., Eatmon T.D. A life-cycle assessment of Portland cement manufacturing: Comparing the traditional process with alternative technologies. J. Clean. Prod. 2009;17:668–675. doi: 10.1016/j.jclepro.2008.04.007. - DOI
    1. Finnveden G., Johansson J., Lind P. Life cycle assessment of energy from solid waste—Part 1: General methodology and results. J. Clean. Prod. 2005;13:213–229. doi: 10.1016/j.jclepro.2004.02.023. - DOI
    1. Yang Q., Lv Z.F. Technical Analysis of Cooperative Disposal of Municipal Solid Waste by New Dry-process Cement Kiln. Chem. Eng. Equip. 2012:195–197.
    1. Xiang C.Y. Ph.D. Thesis. Wuhan University of Technology; Wuhan, China: 2015. Curing Behavior of Heavy Metal Ions in Portland Cement Hydration Products.
    1. Wang M.G., Wang F.Z., Shang D.C., Hu S.G. Effect of CdO on the formation of tricalcium silicate and its solid solution effect. J. Mater. Sci. Eng. 2016;34:208–212.