ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Effect of Na⁺ ion on the formation and hydration of ye’elimite containing Fe

Guofa Zheng, Xiaolei Lu, Qiang Li, Peng Du, Lina Zhang, and Xin Cheng

Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, Jinan, China

E-mail: mse_luxl@ujn.edu.cn

Received: 29 December 2021  Accepted: 25 March 2022

Abstract:

The effect of Na₂O-doped on the formation and hydration properties of ye'elimite containing Fe (C₄A_2.8F_0.2$) was focused on this study. A combination of x-ray powder diffraction (XRD), infrared spectrum (IR), differential scanning calorimetry (DSC)-thermogravimetric (TG) analysis, and SEM–EDS were used to investigate the microstructure and morphology of C₄A_2.8F_0.2$ with doping Na₂O. Hydration kinetics tests were conducted to study the effect of Na₂O on the C₄A_2.8F_0.2$ by the isothermal calorimetry and the electrical conductivity. The results show that Na₂O-doped promotes the phase transition of ye'elimite from orthogonal to cubic phase. The amount of Na⁺ ions substituted for Ca²⁺ ions reaches the limit doping Na₂O with a dosage of 0.8 wt%, and the crystal structure of C₄A_2.8F_0.2$ mineral tends to be stable. When the amount of Na₂O is more than 0.8 wt%, the formation of C₄A_2.8F_0.2$ is hindered and its content decreases. Besides, adding Na₂O promotes the grain growth of the C₄A_2.8F_0.2$, which doubles its average size, and makes the morphology of C₄A_2.8F_0.2$ change from an egg-like shape to an irregular shape. In addition, the hydration process of C₄A_2.8F_0.2$ doping with Na₂O is accelerated, the induction period is significantly shortened or even disappeared, indicating Na₂O facilitates the exothermic concentration of C₄A_2.8F_0.2$ hydration. However, the addition of Na₂O has no obvious effect on the total hydration heat release of C₄A_2.8F_0.2$.

Keywords: Na2O; Doping; Ye'elimite; Crystal structure; Hydration properties

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02199-9

Chemical Papers 76 (7) 4531–4539 (2022)