ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty 64, (3) 338 - 347 (2020)


PHASE FORMATION MECHANISM AND KINETICS IN SOLID-STATE SYNTHESIS OF Ba-DOPED YE′ELIMITE: THE EFFECT OF Ba-DOPING CONCENTRATION ON C4-xBxA₃$ SYSTEMS
 
Bao Xingyuan 1, Zhao Piqi 1, Liang Chen 2, Li Quanwei 1, Wang Shoude 1, Cheng Xin 1
 
1 Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, Jinan 250022, China
2 School of Materials Science and Engineering, University of Jinan, Jinan 250022, China

Keywords: C4-xBxA₃$, Ye'elimite, Kinetics, Rietveld, Solid-state reaction
 

Calcium barium sulfoaluminate (abbr. C4-xBxA₃$), one of the special cementitious minerals originated from ye'elimite (abbr.C₄A₃$), has superior hydration and hardening performance. In this paper, a series of C4-xBxA₃$ with different Ba-doping concentrations (x=0, 0.5, 1, 1.5 and 2) were prepared, and the effect of the Ba-doping concentration on the formation was systematically investigated by the Rietveld/XRD quantitative phase analysis. The results show that BaSO₄ is the essential intermediate phase for the formation of the Ba-doped ye'elimite. The solid-state reaction process of C4-xBxA₃$ is separately expressed as two main forms, corresponding to the cases in which the Ba-doping concentration (x) is larger than and less than "1", respectively. The Jander diffusion model shows the optimal fitting for C4-xBxA₃$ and it clearly proves that the C4-xBxA₃$ formation becomes increasingly difficult as the Ba-doping concentration increases. The correlation between the apparent activation energy (Ea) and the Ba-doping concentration is positively well related, which can be expressed as 'Ea) =71.9x+304' (kJ/mol).


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doi: 10.13168/cs.2020.0022
 
 
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