Application of first-principles theory in ferrite phases of cemented paste backfill

New paper published on Minerals Engineering

Paper Title: Application of first-principles theory in ferrite phases of cemented paste backfill

Authors: Chongchong Qi*, Andy Fourie, Qiusong Chen, & Pengfei Liu

Abstract: Cemented paste backfill (CPB) plays a vital role in mineral engineering and understanding the cement hydration is crucial for its successful application. As an important constituent in ordinary Portland cement (5-15 wt%), ferrite is heavily used in CPB without being fully demonstrated due to its composition complexity. In this paper, the structural and electronic properties of Ca2Fe2O5 (C2F), Ca2AlFeO5 (C4AF) and Ca2Al2O5 (C2A) were investigated using first-principles calculations. The results indicated that lattice parameters and bond length decreased with increasing substitution of the smaller Al3+ for the larger Fe3+. The chemical reactivity of the unit cell was derived mainly from O 2p, Fe 3p, Fe 3d, and Al 3p orbitals. The O atoms were prone to electrophilic attack with cations such as H+. In contrast, the Fe/Al atoms were prone to nucleophilic attack with anions such as OH- and the Fe atoms were more reactive than the Al atoms. This study provides new insight into the structural and electronic properties of ferrite at the atomic level, which will provide a better understanding of cement hydration and promote the application of CPB.

Keywords: Cemented paste backfill; Ferrite hydration; Structural properties; Electronic properties; First-principles calculations.

Reviewer 1: It is interesting to apply first-principles calculations in investigating the properties of CPB. The authors modelled the lattice parameters and bond length when Al3+ replaced Fe3+ in different positions. However, the following issues should be considered before further processing. 

Reviewer 2: In this paper, the authors presented results of an original experimental work dedicating to the structural and electronic properties of ferrite phases in cemented paste backfill. The topic addressed is interesting, within the scope of the journal. The overall technical quality is quite good. I believe that the presented data may be useful to other researchers.

Representative figure from this paper:

Plot of the structure of C4AF with the I2mb space group.

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