Performance and Microstructure of Carbonated MgO Samples under High Temperatures

Abstract

This study investigated the changes in the performance and microstructure of carbonated MgO samples subjected to 40°C–550°C in water, oven, and furnace conditions. Although sample strength remained relatively stable until 80°C, an obvious reduction was observed in higher temperatures. This performance decline was attributed to the changes in the content and morphology of the strength providing carbonate phases (hydromagnesite). Phase quantification results revealed lower hydromagnesite content with smaller crystal sizes at ≥150°C. The decarbonation of hydromagnesite, followed by dehydration of brucite to MgO at higher temperatures of 550°C, revealed the relationship between the stability of major phases and sample performance.