Answer to Question #74102 in Organic Chemistry for David Hein

Question

Issue: removing through dissolution a thin (2-4 mm) iron carbonate crust covering fossilized bone without damaging the bone. Microblasting with conventional baking soda ineffective; removal of iron carbonate with mini-pneumatic air chisel also removes top layer of bone with the iron carbonate crust. Any solutions would be appreciated.

Answer 1

On heating FeCO3
FeCO3 = FeO + CO2
CO2 gas and is remove
FeO has heigh melting point , decrease melting point by the use flux SiO2
FeO this oxide is formed slag with SiO2
FeO + SiO2 = SiFeO3
Here FeO act as impurity and SiO2 act as flux formed a fusible product which is separate out from Bones