Calcium oxide, which is prepared from chicken egg shell, the egg shell cleaned in tap water firstly, then remove
of the internal protein layer from the shell after that the shell crashed and heated to 900oC (1173 K) for one hour
by furnace (Manfredi / Italy), at this temperature the shell becomes porous, fragile and very white in color. It is
concluded from this fact that the egg shell CaCO3 decomposes (decarbonation process) and gave CaO and CO2,
according to the reaction:
CaCO3 → CaO +CO2
(11)
(100grams of egg shell give us 64 grams of CaO).