Abstract
The behavior of sodium silicate solutions in an alkaline medium has been studied in the 11.56–9 pH range by adding different amount of hydrochloric acid into a concentrated commercial solution ([Si] = 7 mol/L, Si/Na = 1.71, pH = 11.56). The formed products and their evolution during long ripening (up to 150 days) have been characterized by cryo-SEM, elementary analysis (ICP-AES), X-ray diffraction and surface area and relative density measurements. In the studied narrow ranges of pH (11.56–9) and silicon concentration (7–0.2 mol/L) four different situations have been observed: (i) a stable and clear solution, (ii) a reversible and transparent physical gel; (iii) a soluble white gel characterized by a significant contraction during ripening and (iv) an irreversible gel which presents a slow syneresis leading to a consolidate solid. The characterizations of the different solids, liquids and gels have shown that the observed behaviors were the results of the formation of nanometric soluble NaSi1.87O4.24 particles and/or insoluble silica-like (NaSi12.66O25.82) grains and of the contribution of a dissolution/precipitation mechanism.
Similar content being viewed by others
References
WH Engelleitner (1990) Glossary of agglomeration terms, powder and bulk engineering. AME Pittsburg, New York
Viallis-Terrisse H (2000) Interaction des silicates de calcium hydratés, principaux constituants du ciment, avec les chlorures d’alcalins. Analogie avec les argiles. PhD thesis, Université de Bourgogne, France
Davidovits J (1991) J Therm Anal 37:1633–1656
Phair JW, Van Deventer JSJ (2002) Ind Eng Chem Res 41:4242–4251
Phair JW, Van Deventer JSJ, Smith JD (2000) Ind Eng Chem Res 39:2925–2934
Tognonvi MT, Massiot D, Lecomte A, Rossignol S, Bonnet J-P (2010) J Colloid Interface Sci 352:309–315
Merrill RC, Spencer RW (1950) J Phys Chem 54:806–812
Iler RK (1979) The chemistry of silica. John Wiley and Sons, New York
Fernández-Barbero A, Suárez IJ, Sierra-Martín B, Fernández-Nieves A, de Las Nieves FJ, Marquez M, Rubio-Retama J, López-Cabarcos E (2009) Adv Colloid Interface Sci 147–148:88–108
Tognonvi MT (2009) Physico-chimie de la gélification du silicate de sodium en milieu basique. PhD thesis, Université de Limoges, France
Brinker CJ, Scherer GW (1985) J Non Cryst Solids 70:301–322
Tanaka T (1981) Sci Am 244:124–138
Sosman RB (1965) The phase of silica. Rutgers University Press, New Brunswick
Randell MG (1985) Liquid phase sintering. Plenum Press, New York
Wijnen BPWJG, Beelen TPM, Rummens KPJ, Saeijs HCPL, Van Santen RA (1991) J Appl Cryst 24:759–764
Christy AA (2008) Colloids Surf A Physicochem Eng Asp 322:248–252
Author information
Authors and Affiliations
Corresponding author
Appendix
Appendix
-
1)
Volume of the solid skeleton VS
where MS is the mass of the solid skeleton. 2.2 corresponds to an estimate solid density (g/cm3). [Na°] and [Si°] are respectively the sodium and silicon initial concentrations in the solution before gelation. \( {\text{M}}_{{{\text{SiO}}_{2} }} \) = 60 g is the mass of SiO2 per mol of silicon and \( {\frac{{{\text{M}}_{{{\text{Na}}_{ 2} {\text{O}}}} }}{2}} \) = 31 g the mass of Na2O = 31 g per mol of sodium. Eq. 3 becomes:
-
2)
Si/Na atomic ratio (Si/Na)S
In the solid skeleton, we have
and
The combination of relations 6 and 7 leads to Eq. 8
Rights and permissions
About this article
Cite this article
Tognonvi, M.T., Rossignol, S. & Bonnet, JP. Physical-chemistry of sodium silicate gelation in an alkaline medium. J Sol-Gel Sci Technol 58, 625–635 (2011). https://doi.org/10.1007/s10971-011-2437-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10971-011-2437-4