The System Calcium Oxide-Silica-Water at 30°. The Association of Silicate^* Ion in Dilute Alkaline Solution

Abstract

Knowledge of the compounds of hydrated calcium silicate and their equilibria is important in cement technology and in regard to the use of siliceous minerals in cement.Hydrated calcium silicate is gelatinous at room temperature, regardless of method of preparation or time. However, the units of physical structure may be well-organized and definite, since X-ray analysis has shown that most inorganic gelatinous or amorphous materials are in reality crystalline, while all are crystalline (to X-rays) whose atoms or radicals are dior monovalent.1 A diffraction pattern has in fact been reported by Chassevant2 for Paul S. Roller and Guy Ervin, Jr.Vol. 62 coagula.7,8 A third method of experiment consists in precipitating hydrous calcium silicate and treating this with lime water. Because in this method the initial solid phase is a hydrous compound more or less closely related to the final products of equilibrium, a comparatively rapid approach to equilibrium would be expected. This in fact has been realized in the present work.Chemical analysis has in the past frequently neglected the correction due to dissolved silica.The association constant, solubility product constants, and one of the ionization constants, were calculated to a known precision. A high tendency toward association is evidenced.College Park, Md.

Effect of temperature and aluminium on calcium (alumino)silicate hydrate chemistry under equilibrium conditions

“…However, there is not a clear dependence of the measured Ca concentrations on temperature. This result is consistent with published solubility data for C-S-H systems [5,7,8,22,23,[45][46][47][48][49]. In both the C-S-H ( Figure 4A) and C-A-S-H ( Figure 4B) samples, the concentrations of Ca, Si and OH -species in the filtrates change by less than an order of magnitude between 7°C and 80°C (Table S2 in Appendix S3, Electronic Supporting Information).…”

“…[21]. Previously published C-S-H solubility data for systems with solid-phase Ca/Si ratios = 1 ±0.1 [5,7,8,22,23,[45][46][47][48][49] are shown as small white and grey symbols in A), with shapes corresponding to the coloured points for the new data. The data measured here (relative error = ±10%) are tabulated in Table S2 (Appendix S3, Electronic Supporting Information).…”

Solubility and structure of calcium silicate hydrate

“…Curve C".-This is drawn from the data of Greenberg and Chang [52] (lime-silica, prepared at 50 °C, equilibrated at 25 °C) and that of Roller and Ervin [76] (double decomposition, 30 °C). The remaining 3 points from Greenberg and Chang [52] for mature C 3 S paste lie on curve C" or between it and curve A. C-S-H samples equilibrated at the intersection of curve C" with A have Ca/Si ratios near 1.3.…”

A study on the synthesis of porous silica from a sodium silicate

“…이러한 중화반응에 의해 졸 상태의 실리카 입자는 입 자 사이에 중축합과정을 거쳐 겔 상태의 실리카 망목구 조를 형성하며, 수용액 중에서는 다음과 같은 반응들이 평형을 이루게 된다 [ 8 ] . H P C (1 .5% )+ P E G (1 .5% ) H P C (2 .5% )+ P E G (2 .5% ) H P C (5% )+ P E G (5% ) H P C (5% ) P E G (5% ) …”