Synthesis and crystal structure solution of potassium dawsonite: An intermediate compound in the alkaline hydrolysis of calcium aluminate cements
Potassium dawsonite is formed as an intermediate compound during the alkaline hydrolysis (AH) in calcium aluminate cements (CACs). A synthesis method of potassium dawsonite has been developed. The crystal structure of potassium dawsonite KAl(CO{sub 3})(OH){sub 2} has been solved by direct methods from X-ray powder diffraction data and refined with the Rietveld method. It crystallises in the orthorhombic Cmcm space group with unit cells parameters a=6.3021(3) A, b=11.9626(5) A, c=5.6456(3) A and Z=4. The structure consists of carboaluminate chains, formed by the basic unit [Al{sub 2}(OH){sub 4}(CO{sub 3}){sub 2}]{sup 2-} arranged along the c axis. The carbonate groups are placed in an alternate manner at both sides of the carboaluminate chains. The carboaluminate chains are also held together by the K{sup +} cations that are located in the middle of three such chains. Finally, the chemical reactions explaining the AH process in CACs are postulated.
- OSTI ID:
- 20702130
- Journal Information:
- Cement and Concrete Research, Vol. 35, Issue 4; Other Information: DOI: 10.1016/j.cemconres.2004.04.018; PII: S0008884604001723; Copyright (c) 2004 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0008-8846
- Country of Publication:
- United States
- Language:
- English
Similar Records
The controlling role of atmosphere in dawsonite versus gibbsite precipitation from tetrahedral aluminate species
A high-pressure X-ray diffraction study of the crystalline phases in calcium aluminate cement paste