ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 21, Number 1
JKCSEZ 21(1)
February 20, 1977 

A method of synthesizing NaAlCO3(OH)2 (Dawsonite) and KAlCO3(OH)2, was investigated by blowing CO2 gas into sodium and potassium aluminate solutions. The reactions were accomplished at a temperature of 80 to 90℃, while CO2 gas was blowing into the solutions which the molar ratios of Na2O/Al2O3 and K2O/Al2O3 were 6 to 8 and 8 to 10, respectively. It was observed that highly purified Dawsonite and KAlCO3(OH)2 are produced when Alumina is present in Boehmite at an equilibrium solid phase with a large amount of HCO3- in the solutions. The rational formulas of Dawsonite and KAlCO3(OH)2 synthesized under the conditions should be expressed as NaAlO(OH)HCO3 and KAlO(OH)HCO3, respectively, by IR analysis. In addition, electron microscopic observation also indicated that Dawsonite in a fibrous crystal and KAlCO3, (OH)2 in a needleshaped crystal.