Gearhead_Shem_Tov
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Refs and ideas for soluble silicates
In a separate thread in the technochemistry forum RepRap, Lawrence Welk, and Bubbles, oh my! I've been digging into using bubbles/foams of sodium silicate solution gassed with CO2 as a
printing medium for new type of additive 3D printing process, along with ideas about electroless and electrolytic plating of metals onto the resulting
silicate/carbonate (silica gel?) substrate.
I've found some interesting material about the myriad ways good old-fashioned waterglass can be used, including the manufacture of catalytic beds.
Frankly, the uses are so diverse it's quite daunting to sift through it. The diversity of applications are beyond what I'm looking at in the other
thread, so even folks who aren't into blowing tiny bubbles of sodium silicate might find useful information.
Two sources in particular have caught my attention:
Sodium Silicate as a Versatile Structural Material by Herbert I Hoffman, 1965
and
THE CHEMISTRY OF SILICA: Solubility, Polymerization, Colloid and Surface Properties, and Biochemistry by Ralph K. Iler, 1979.
The latter reference is on a Venezuelan site in the form of partial chapter pdfs from the Wiley Interscience book. Does anybody know if a complete
version is available online? And what other references should I be looking at?
-Bobby
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Mesa
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Somewhat related to this; I made some silica gel by dissolving pool cue chalk in aqueous NaOH, then adding sulfuric acid. It was set aside to
evaporate at room temp for a few days.
When it had become far too viscous to evaporate naturally, I fashioned a crude hotplate from an aluminium coke can(using the parabolic underside of
it,) and washed it with hot concentrated NaOH solution and a sponge.
After rinsing a few times to get rid of the excess NaOH, I poured the silica gel onto it and heated with an alcohol burner. The gel started
extruding/bubbling while slowly developing a translucent grey color. I'm assuming I'm getting a mix of Al2O3/SiO2, which, due to the difference in
thermal expansion, is developing into a pretty porous membrane. Perhaps a possible solution to a DIY cell divider for electrolytic cells?
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bbartlog
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No quantities anywhere?
Anyway, I would assume that your product is heavily contaminated with Na<sub>2</sub>SO<sub>4</sub>, since you took no steps to
remove it. Not going to make for much of a cell divider given that the sodium sulfate would dissolve, likely making the whole structure crumble.
The less you bet, the more you lose when you win.
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S.C. Wack
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More complete. Google hit #5. Not from the publisher.
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Mesa
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Quote: Originally posted by bbartlog  | No quantities anywhere?
Anyway, I would assume that your product is heavily contaminated with Na<sub>2</sub>SO<sub>4</sub>, since you took no steps to
remove it. Not going to make for much of a cell divider given that the sodium sulfate would dissolve, likely making the whole structure crumble.
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I figured the fact that I was using a butchered coke can as a hotplate and pool chalk as starting material
was indicative of a fairly trivial procedure(trivial perhaps the wrong word to use.)
Sure, this specific example would not function as a cell divider, but the idea of using SiO2/Al2O3 to create a porous membrane may still be valid.
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