According to the test results, for all six W/S ratios, the CO2 pressure inside the reactor decreases gradually with time until it reaches the equilibrium. In order to explain this pressure reduction from a chemical point of view, ideal gas law is applied. According to ideal gas law, the pressure of the gas is proportionate to the number of gas Tolvaptan when the temperature and the volume are constant (Levine, 1985). Therefore, this reduction of CO2 pressure can be considered as a reduction in the number of CO2 molecules present inside the closed reactor at the beginning of the test. The CO2 molecules may be reduced for two reasons: 1) dissolution in water in the mixture and 2) carbonation of oxides in fly ash. Only the CO2 involved in the carbonation reaction can be considered as sequestered, since the CO2 dissolved in water may be released when the pressure is released. Therefore, a correction should be made for CO2 dissolved in water. For that purpose, another series of tests was carried out using the same amount of water added to fly ash in each test and under the same set of reaction conditions (3 MPa, 40 °C, 60 rpm), and the pressure drop with time was recorded. In these control tests, the pressure reduction caused solely due to the dissolution of CO2 in water was estimated.