Desorption of carbonate from aluminum hydroxycarbonate gel by nitrogen purging

Carbonate was completely desorbed from amorphous aluminum hydroxycarbonate gel by purging with nitrogen. The reversibility of carbonate adsorption suggests that aluminum hydroxycarbonate particles are composed of planes of aluminum hydroxide with carbonate adsorbed at edge aluminum sites. A slow-reacting phase which was identified as a precursor of gibbsite, formed when the carbonate/aluminum molar ratio was less than 0.20.