Chemical Composition of Solution in Hydrothermal Reaction of Lime-Quartz-Water System
1977 Volume 85 Issue 982 Pages 281-286
Details
1977 Volume 85 Issue 982 Pages 281-286
The chemical composition of solution was measured in hydrothermal reaction of lime-quartz-water system. In this reaction the effects of particle size of quartz and added kaolin were discussed. Quartz powder with 2-3μm and 5-10μm in particle radius were suspended with lime in pure water in molar ratio of 1:0.8, and autoclaved at 181°C for 3-8 days. Changes in the concentration of SiO2 and CaO in solution were analysed. Identification of products were performed by means of X-ray powder diffraction and scanning electron microscope (S. E. M.).
It was found that
1) The solubility of quartz at 181°C was 205mg/l.
2) It took rather long time to reach equilibrium in Ca(OH)2 dissolution.
3) CaO concentration was high at first, in lime-quartz-water reaction, and the products in this period was lime rich phase. The transformation of the products was represented by the following reaction. α-C2SH→C-S-H(I)→tobermorite C-S-H(II)→C-S-H(I)→tobermorite Concentration of SiO2 increased until all the quartz had reacted, suggesting that the dissolution of quartz was faster than the consumption by reaction.
4) Added kaolin retarded the dissolution of quartz.
5) The presence of kaolin retards the lime-quartz-water hydrothermal reaction. This effect was supposed to be originated by the retardation of quartz dissolution by aluminate.
