How can I make water glass out of silica gel?

Answer 1

Water glass is the generic term for any of a variety of sodium silicates (or aqueous solutions of such compounds). There are several stoichiometric compounds that can be called sodium silicate, including Na4SiO4, Na2SiO3, Na2Si2O5, Na2Si4O9, Na6Si2O7, etc. Their solubilities in water vary, and solutions with a range of Na:Si ratios can be made by dissolving appropriate amounts of different composition sodium silicates in water.

Normally, one uses sodium silicate solutions to *make* silica gel, not the other way around. Nevertheless, To convert your silica gel to sodium carbonate, you would need to combine it with sodium carbonate, and heat the mixture until it fuses. Carbon dioxide will be given off and the remaining solid product will be a sodium silicate. (You will also evolve some water vapor during the early stages of heating because your silica gel almost certainly contains some water.) The Si:Na ratio in the final product will be determined by the ratio of Si gel and Na2CO3 you mix together (less whatever Na is lost from the system by volatilization). Sodium silicate is made commercially this way, using high-purity silica (quartz) sand as the source of silica.


Why would you want to do this? Water glass, both as powders and as prepared solutions, is cheap and readily available commercially.

Answer 2

try heating it. if the silica melts it should form glass

Answer 3

make refractory binder