No crystalline CaO phases were detected up to 20 wt% of CaO loading, however a broad reflection was clearly observed at 2⍬ range of 30.0–37.0◦ for 20% CaO/n-Al2O3 which, supports the presence of highly dispersed CaO on n-Al2O3. At 25 wt% of CaO loading, crystalline CaO phase was detected at 2⍬ angle of 32.0◦.