养护温度对高温煅烧MgO水化反应产物组成的影响

Effect of Curing Temperature on the Hydration Products Composition of MgO Calcinated at High Temperature

以TG-DSC和TG-FTIR联用,研究了轻质MgO在不同实验条件下的水化性质和水化产物。结果表明,900℃煅烧的MgO在室温下容易发生水化,温度升高可显著加快MgO的水化速率。常压高湿条件下,1300℃煅烧MgO的水化和碳酸化作用同时进行,产物为六方Mg(OH)2和无定型的碳酸化产物,两类产物的生成量随养护温度升高而显著增加,生成的碳酸化产物的热解温度在300～450℃范围内,基本覆盖了Mg(OH)2的热分解温度范围。高于1300℃煅烧的MgO有较强的稳定性,室温下几乎不发生反应,但温度提高到40℃以上时,水化和碳酸化作用又显著进行。

Hydration properties and hydration products of light magnesium oxide were investigated under different experimental conditions by means of TG-DSC and TG-FTIR. The results show that magnesium oxide calcinated at 900 ℃ tends to hydrate even at ambient temperature. Hydration can be significantly accelerated with increasing temperature. Under the atmospheric pressure and high humidity,hydration and carbonation were both exist when MgO was calcinated at 1300 ℃. The productions of reaction are hexagonally Mg（OH）2 and amorphous carbonate. Production quantities of these two kinds of product increase obviously along with rising of curing temperature. Pyrolysis temperature of the carbonate generating in this experiment is within 300-450 ℃,which almost covering up the range of decomposition temperature of hexagonal Mg（OH）2. After calcinated at higher than 1300 ℃,MgO has a great stability that it hardly react with H2O or CO2 at room temperature. But it still tends to hydrate and carbonate when curing temperature rises up to 40 ℃ or higher.