Studies on Dehydration, Reduction, and Hot Strength of Cement Bonded Cold Pellet

Abstract

The dehydration and reduction behaviour of cement bonded cold pellets and their effects on the cold and hot strength were investigated.
The results are as follows.
(1) The dehydration of cement bonded cold pellets begins to proceed at about 320°C and the compressive strength at room temperature decreases remarkably after the dehydration at above 600°C, and it increases after the complete dehydration at 900°C, probably owing to the sintering of materials in the pellets.
(2) The reduction of cement bonded cold pellets is generally faster than fired pellets at above 900°C because of larger chemical reaction rate constant, which, naturally, depends on the reducibility of raw materials and may be affected by some structural factors peculiar to cold bonding.
(3) At high temperature, cement bonded cold pellets tend to deform more easily than fired pellets and the highter reduction degree and temperature is, the more remarkable the deformation is. It is necessary to define hot strength taking the deformation into account.
(4) The hot strength of cement bonded cold pellets partially reduced at 700°C800°C is lower than that of fired pellets, but the difference in the hot strength becomes very little after the complete reduction at 900°C1 000°C.