I've been messing around with isolating impurities form municipal water. I don't know what it is, but there very fine suspended brown matters in water
collected from the drainage spigot on bottom of my water heater.
So, I'd collect it into a bucket and the murky material is almost colloidal but after letting it sit for a while, it settles out. I'd repeat the
process and had the settlements from 15 gallons of water collected in this manner.
The final matters was a mixture of colloid and suspensions as when I allowed it to dry to solid in a drinking glass, it formed a gel. Anyways, the
pint glass I used to do this drying now has a layer of silicate. I'm guessing the water treatment silicates was bound up to these suspended matters.
Its just a pint glass, so the prudent thing to do is to throw it away but I've been trying a means of improvising a means of removal.
I've read up on some materials online and none have worked, including dilute caustic at 50-60C, and a 1-2% solution of HF, but neither of these are
good anyhow.
If this silicate was dissolved in glass to begin with, why is it so hard to remove? Does dissolved silicate attach to glass on molecular level? How
can I remove it without damaging the glass? I can see this kind of build-up being an issue on distillation apparatus and such.
Now I know how water deposits on windows don't come off easily at all! blogfast25 - 20-12-2013 at 05:45
[...], the pint glass I used to do this drying now has a layer of silicate.
How do you know it is silicate? What empirical evidence tells you that?
The fact that it resists wash attempts, solvents and common mineral acids. I guessed silicate, and when I searched Google, precipitation of dissolved
silica is a fairly common issue on boilers and such. blogfast25 - 20-12-2013 at 09:39
Water treatment plants should take care of such impurities quite easily. I could be dead wrong here but potable water should contain very little stuff
like silicates. Your water heater has of course boiled up gallons and gallons of water, that's probably how you ended up with a build up. Are you
using a 'natural' source of feed water to your boiler, like well water?
If the deposit on the glass really is silicate and mechanical removal is impossible then you're basically stuck with it because any chemical agent
(think HF) that attacks the silicate will also attack the glass.
[Edited on 20-12-2013 by blogfast25]bfesser - 20-12-2013 at 15:52
How do you remove silly cats on glass? Have you tried water?IrC - 20-12-2013 at 18:47
I always found a can of tuna off to the side worked well at kitty relocation.
I think along with silicates you should consider carbonates of Ca and Mg along with various other chemicals. Would seem boiler cleaning methods would
work, I know back in the 50's muriatic acid worked to clean the water cooling towers at a big theater complex (few locations had central air). Time
is important, let it soak a good long while.
You might get a few ideas reading the links above.
Polyolefin - 22-12-2013 at 03:28
Amounts of non-volatiles in water is surprisingly high and can easily exceed 100mg/L. Potable water treatment may include filtration, but it does
nothing to remove dissolved solids.
I don't really get how the silicate that was dissolved in water that deposits on glass can't be removed by simply leaving in water. Maybe someone
knows more on this?
[Edited on 22-12-2013 by Polyolefin]Mesa - 22-12-2013 at 09:12
Water absorbs atmospheric CO2, any water that isn't kept under an inert gas will eventually become(slightly) acidic.
Acid + silicate = precipitated SiO2.
1500 grit wet'n'dry sandpaper, some water, some hand soap, some elbow grease. The abrasive is far too fine to cause any structural damage or stress
points in the glass.
I would like to point out, however, that this may not be the case with laboratory glassware intended for high temp/high pressure reactions. AJKOER - 9-1-2014 at 13:46
Try in increasing order of strength: acetic acid (vinegar), Citric acid and finally Muriatic acid (if fuming, safety gear required) as these have been
used to clean the scale from boilers (and/or toilets). Give the acid at least 2 hours. Drain the acid solution and flush the system.
If the brown residue is Iron based, Oxalic acid may also work, as in sufficient amounts, it will also form a soluble complex with Iron salts. Caution:
this acid is poisonous and will cause burns, so use appropriate safety equipment.
By the way, the answer to your problem, IMHO, lies not so much on acid strength as on the ability to form a soluble complex (which is why Acetic,
Citric and Oxalic acid are on the list).
[EDIT] You may also add significant NaCl to the HCl to raise the acid's activity level. Good luck!
[Edited on 9-1-2014 by AJKOER]hyfalcon - 9-1-2014 at 14:28
HCl and Hydrogen peroxide should dissolve just about anything.blogfast25 - 10-1-2014 at 05:12
