Substitution preference of chromium ions in the clinker phase of ordinary Portland cement.

The use of industrial solid waste to produce a cement clinker can not only effectively reduce the consumption of natural resources, but also reduce the pollution of waste. In this paper, the solidification trend of Cr ions in the clinker phases of ordinary Portland cement (OPC) was studied by combining experiments with theoretical simulations. The results from energy dispersive spectrometry, X-ray diffraction, and density functional theory (DFT) simulations suggests that Cr ions will preferentially enter the mineral C₄AF by displacing Fe ions. Further analysis of the bond length and bond order, electron density differences and partial density of states suggests that this phenomenon is mainly due to the similar electronic contributions of the host and guest ions. These insights will provide important fundamental guidance for understanding the doping behaviour of chromium ions in an OPC clinker and the utilization of Cr-containing industrial solid waste, thus paving an efficient way for the treatment of Cr-bearing industrial solid waste. [ABSTRACT FROM AUTHOR]