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Effect of MgO calcination temperature on the reaction products and kinetics of MgO–SiO 2 –H 2 O system
Author(s) -
Li Zhaoheng,
Xu Yudong,
Zhang Tongsheng,
Hu Jie,
Wei Jiangxiong,
Yu Qijun
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16201
Subject(s) - calcination , sodium hexametaphosphate , magnesium , kinetics , materials science , hydrate , mineralogy , reaction rate , chemical kinetics , grain size , inorganic chemistry , chemical engineering , nuclear chemistry , chemistry , sodium , catalysis , metallurgy , organic chemistry , physics , quantum mechanics , engineering
MgO‐based binders have been widely studied for decades. Recently, the MgO–SiO 2 –H 2 O system was developed as a novel construction material, however, its reaction mechanism remains unclear. This paper investigated the reaction products and kinetics of MgO/silica fume ( SF ) pastes with MgO calcinated at different temperatures. The results indicate that MgO presented larger grain size after calcination at higher temperature. Mg( OH ) 2 and magnesium silicate hydrate (M–S–H) gel were formed when using MgO calcined at 850, 950, and 1050°C. However, only M–S–H gel was formed when using MgO calcined at 1450°C. The reaction kinetics of MgO could be described using α = 1 − e − k * t . The reaction rate of MgO increased with decreasing calcination temperature, increasing SF dosage, and the addition of sodium hexametaphosphate. Only M–S–H gel was formed when the reaction rate of MgO was below the demarcation line (about 0.250 × 10 −6 s −1 ), and the corresponding demarcation area was around 14 days.