Preparation and crystallite growth measurement of active magnesium aluminate spinel

MgAl₂O₄ was prepared by cocrystallizing and decomposing Al(NO₃)₃.9H₂O and Mg(NO₃)₂.6H₂O mixture. The crystallite growth of the resulting powder was studied in the temperature range 500 – 1000 °C. It was found that the equation governing the process is D² – D²₀ = KT. Two activation energies for crystallite growth were obtained, 22 kcal and 44 kcal for the temperature ranges 500 – 785 °C and 785 – 1000 °C respectively. It was noted that rapid increase in crystallite size occurred on soaking at a temperature > 800 °C.