In this paper, the hydration kinetic process of free CaO in system containing high calcium fly ashH 2O has been studied under different temperatures.

Results show that the crush value,free-CaO content,invariability and innocuousness of the slag are all in conformity to the national standards and related trade criterion when the slag is put in storage for 12 months.

However,the free lime content of the fly ash is higher.

Hydration of free lime often leads to a volumetric expansion of hardened cement pastes.

The effects of various mineral additives such as fly ash, blast furnace slag and silica fume on the action of free lime in cement, and the mechanism of their effects on the cement soundness and expansion behaviors of HCP have been studied and discussed.

The main cause leading to the disqualification of cement soundness in hardened concrete is excessive f-CaO or magnesia in the cement mixture.

In the cement production process it is hard to develop an accurate mathematical model for both f-CaO and stack bed thickness which characterize the key technical indices in the cooling process with a grate cooler.