m1tanker78
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Fused NaCl + Silica (Sand) + Electricity??
This time, I wasn't fooling around with trying to extract Na from molten salt. I was under the impression that electrolyzing fused NaCl and sand would
yield sodium silicate (among other things). I was hoping to see some white crystals/powder but ended up with a black mass instead which I mixed in
some water and filtered. The filtered solution is almost syrupy and precipitates tiny crystals. It's somewhat basic at pH ~9. Copper sulfate crystals
don't "grow" in this solution.
The weird thing is that the black filtrate smells of HCl when heated and sure enough, indicator paper indicates acidic. The black stuff emits an
orange flame when passed in front of the torch (hydrogen?) There's also some muddy dark red sludge among the filtrate. I took 3 chunks of the black
stuff and subjected one to ammonia solution, another to hydrochloric acid and the final one to dilute H2O2. The only one that reacted at all was the
peroxide one. It fizzed a tiny bit but not immediately.
Even though I failed to produce sodium silicate, I'd still like to know what I produced. Any help would be much appreciated.
Also, Is there a way to produce sodium silicate using NaCl? I know about the molten NaOH and silica process but would like to produce larger
quantities.
Tom
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bbartlog
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What was your source of sand? What anode and cathode materials? What temperature did you run this at? Voltage? Current density? What did you use for a
container?
Black and dark red don't sound like silica or sodium compounds; I would suspect iron contamination. But without knowing more about your setup I have
no idea whether that's plausible.
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m1tanker78
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Update: The black 'rock' sample that I placed in the weak H2O2 solution actually dissolved. Acid and ammonia sample are unchanged.
@bbartlog:
There -is- quite a bit of iron contamination since I used a steel crucible (anode) and steel electrode for the cathode. I varied the current widely
throughout the melt in order to keep the melt from sputtering too much. I don't have a figure on the temp except that it was 'pretty dang hot'. Well,
more than hot enough to keep the silica sand and salt mixture brilliant red and at times even boiled some. The voltage was also widely variable; seems
my DC welder is constant current but current can be varied from 10 - ~200 amps. I believe the open circuit voltage to be around 80V. That obviously
drops under load to keep a CC.
Tom
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blogfast25
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m1tanker78:
What's the PURPOSE of your experiment? What are you trying to ACHIEVE? Make sodium silicate? That can be done in jiffy, not need to electrically
torture seemingly arbitrary mixtures of NaCl and sand. Don't tell me you're trying to make gold (the recipe for that is sand + p*ss + heat, every
alchemist knows that!)...
[Edited on 28-1-2011 by blogfast25]
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ScienceSquirrel
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I would guess that you have an indefinite mixture of all sorts of things.
Really heating silica and sodium hydroxide is the way to go to make sodium silicate, the ingredients are cheaply available on a kilo scale.
How big do you want to go?
Sodium silicate is cheaply and readily available as well so is it really worth making on a big scale?
Some people on here seem intent on doing loads of work and using up expensive chemicals and / or power to make something they could buy cheaply and
readily.
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m1tanker78
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Gold from sand + urine??
@blog:
It'd be nice to have some gold around the house but no, I'm not trying to produce gold. I'm trying to produce sodium silicate (or metasilicate) from
NaCl + silica sand + heat + electricity. I'm not trying to electrolyze the ingredients. It's my method of heating (fusing) salts.
I'm aware that fusing salt by this method tends to move the ions toward their respective electrode but I figure that at such a high temperature, the
sodium quickly recombines with the melt - if it even gets stripped to begin with.
I realize that one can take silica gel and NaOH solution and easily make sodium silicate. It seems molten NaOH and/or sodium carbonate also reacts
with quartz/silica sand to produce the same. My goal is to use table salt (cheap as hell) and silica sand (free) to produce a most-likely dirty sodium
silicate solution to have around the shop. I'll hopefully be making some sand cores for some aluminum pours in the near future and like the idea of
using the silicate as a binder. I've also used sodium silicate in the past to extend the useful life of steel parts in corrosive environments with
great success.
So, to sum it up:
1. Can salt + sand + heat by electric current (not carbon arc) produce sodium silicate? If so, are there any special considerations that need to be
observed in doing so (besides safety).
2. Any thoughts on the product of my last attempt (my OP)?
3. Is there a relatively easy way to clean the crud out of a steel crucible after a salt melt? Good Lord! I've spent 2-3 hours clearing out my
crucible with a hammer, screwdriver and a chisel. HCl - no good. Adding NaOH before I cut the current - helped a little but too pricey. Boiling water
in the crucible for 30+ minutes - no good. Hammer and chisel - still sore and somewhat deaf.
Tom
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m1tanker78
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Quote: Originally posted by ScienceSquirrel  | I would guess that you have an indefinite mixture of all sorts of things.
Really heating silica and sodium hydroxide is the way to go to make sodium silicate, the ingredients are cheaply available on a kilo scale.
How big do you want to go?
Sodium silicate is cheaply and readily available as well so is it really worth making on a big scale?
Some people on here seem intent on doing loads of work and using up expensive chemicals and / or power to make something they could buy cheaply and
readily. |
@ScienceSquirrel:
True. But buying the chemicals won't teach me anything about how they're made. I'm a non-conformist hands-on kind of guy. A theory is just a theory
until I've tried it myself. I'm doing all of this more out of curiosity than saving or earning money so I can't justify buying lab grade or bulk
chemicals.
Tom
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garage chemist
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Sodium silicate is made by melting soda with sand. NaCl has no place in any commercial processes for sodium silicate production- guess why.
To make it at home, NaOH is a better precursor than soda because less heat is needed to make it react with sand. In industry, the lower price of soda
compared to NaOH is the better argument.
The crude silicate melts are generally dissolved with water at temperatures far above 100°C and under pressure.
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ScienceSquirrel
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| Quote: Originally posted by m1tanker78 | | Quote: Originally posted by ScienceSquirrel | I would guess that you have an indefinite mixture of all sorts of things.
Really heating silica and sodium hydroxide is the way to go to make sodium silicate, the ingredients are cheaply available on a kilo scale.
How big do you want to go?
Sodium silicate is cheaply and readily available as well so is it really worth making on a big scale?
Some people on here seem intent on doing loads of work and using up expensive chemicals and / or power to make something they could buy cheaply and
readily. |
@ScienceSquirrel:
True. But buying the chemicals won't teach me anything about how they're made. I'm a non-conformist hands-on kind of guy. A theory is just a theory
until I've tried it myself. I'm doing all of this more out of curiosity than saving or earning money so I can't justify buying lab grade or bulk
chemicals.
Tom |
That's OK but you should try and give yourself a decent chance of success.
Following or adapting previous recipes is a good way to start.
Molten sodium hydroxide and silica will make sodium silicate. Get that to work and then try something more adventurous.
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blogfast25
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'Nuff said about this one, I feel...
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m1tanker78
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They say "you get what you pay for." Oh well, I'm still working on figuring out what I DO have. I was able to reproduce this stuff through aqueous
electrolysis of salt and sand. I'm leaning toward saying I ended up with some type of silica gel/silicic acid although the pH is dead neutral. I could
swear I smelled HCl being evolved from the solution and my nose usually knows. This may help me figure out what reaction(s) are taking place. I'm
going to perform a few experiments to see if I can narrow it down.
Tom
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m1tanker78
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Filtered = Concentrated Sodium Chlorate solution. Filtrate = Silica suspension of some sort. Filtrate combines readily with aqueous sodium hydroxide
to produce sodium silicate at room temp. Finer silica = faster reaction. And this sodium silicate filters crystal clear unlike the molten NaOH + sand
which had a yellow/brown tint no matter what I did. As a bonus, I have a method of producing ultra fine and pure quartz from crap sand.
All I needed was a few beers to get the gears turning... 
Tom
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