Durability characteristics of the hydration of magnesium oxide under repetitive reaction

The durability of the magnesium oxide/water reaction system under repetitiv e reaction conditions was examined experimentally to demonstrate the operab ility of a magnesium oxide/water chemical heat pump. Changes in the reactiv ity in the hydration of magnesium oxide, which was the most sensitive proce ss in the repetitive reaction, were measured at hydration temperatures from 90-170 degrees C and pressures from 31.2-70. 1 kPa. A lower temperature an d a higher pressure for the hydration reaction were effective in maintainin g reactivity. The effect of different reaction conditions experienced durin g repetitive cycles to the standard repetitive cycle was discussed. From mi croscopic observations, nucleation in primary particles of the material ind uced by the structure change during repetitive reaction was an important fa ctor in the enhancement of durability. (C) 1999 Kluwer Academic Publishers.