Thermodynamic variations in the decarbonation of low calcium fly ash-cement raw mix

Abstract

In this paper, the authors analyse the decomposition of a low lime saturation factor (LSF) raw mix -obtained by adding low calcium fly ash to standard portland cement- when heated to around 1000 °C. The decarbonation temperatures and variation in enthalpy taking place during calcite decomposition were determined by DTA and isothermal calorimetric measurement. The resulting belitic clinker had a LSF factor ranging from 75 to 85%. The presence of fly ash was observed to retard the onset of decarbonation and lower the peak and final decarbonation temperatures. Decarbonation enthalpy was also found to decrease with fly ash content

Keywords

• fly ash
• decarbonation
• thermal analysis
• isothermal calorimetry