Varmint
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Thoughts on using flocculating agents...
Considering using a carbon anode for Chlorate production, and I was wondering what the more knowledgeable thought about using a flocculating agent to
clean up the carbon mess?
Seachem makes a fantastic agent I've used in both salt and fresh water. The hinge point for me right now is not knowing the PH of the post-production
liquor. I could envision adjusting the density to match the salt-water aquarium environment, but might be worried about try to adjust the PH to give
the agent "familiar territory" to work in.
So, best to filter/filter/filter, or does this proposed flocculant approach have some merit? My hope is it would make filtering many times easier,
perhaps one pass might capture everything?
http://www.seachem.com/Products/product_pages/Clarity.html
DAS
[Edited on 25-7-2013 by Varmint]
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watson.fawkes
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Here's what the
MSDS says is in it: | Quote: | | Proprietary aqueous solution of inorganic precipitating agent and organic flocculating polymer. |
It might
work, if the organic polymer isn't chewed up by the chlorate, and the "inorganic agent" isn't some unwanted impurity.
Try it and report back.
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papaya
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Why not add H2O2 to form basic piranha solution that will eat carbon?
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testimento
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I use sand filters to clean all my solutions that are just suitable with quartz sand. It won't clog even under extreme filterings(glue-paste like
greasy mess of inertized consumer grade fertilizers consisting of about 50% inert stuff that wont dissolve), and fine sand really filters up even the
finest particles. Coffee filters and filter papers will get clogged within few secons and virtually no liquid flow through them at all, even under
vacuum pump.
I use a 50mm layer of quartz sand with which will definitely do the job. Just take some plastic jar and drill dozens of holes to the bottom, place a
piece of cotton rag and pour sand over it, put another rag over the sand to prevent the sand cratering when you pour the liquid, and it's ready for
work. I recently put nearly a 100 liters of liquor through a single 50mm layer filter in a 10-liter bucket and it gave a crystal clear liquor from the
fertilizer goo.
It's a good idea to still let the solids settle from a liquid and carefully decant off the clear solution as far as possible, and then put it through
a couple of cotton sheets before applying it to the sand. The sand won't clog, but it will definitely slow down the filtration process. It took me
about 12 hours to get 10 liters of liquid through the filter and leave a solid cake on top of the cotton sheet over the sand. When I did another
filtration with very little solids(PbO2 and other impurities from my electrode tests) and one-cotton-sheet pre-filtration, the liquid went through the
renewed sand layer within 5 minutes.
If you use potassium salt for chlorates, bring the solution boiling and then filter it to get the potassium chlorate dissolved. On the same time you
make a recrystallization which will further stabilize and purify the chlorate.
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Varmint
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testimento:
I like the idea of the sand bed filter. Cheap, easy, and can even back-flush it to get like-new performance.
I'll try that first, and if I need better results then I'll try the flocculant approach.
DAS
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testimento
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Easiest way to recover the filter is to scrape off few millimeters of the top surface of the sand where most of the solids will stay, and the filter
is like a new again. I did this a couple of times with the fertilizer goo to speed up the process a little due to my impatience. 
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Varmint
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Clarity:
A success!
I did another run of KCl --> KClO<sub>3</sub> with my dry cell carbon anodes.
I dumped the entire contents of the 400ml cell through a reusable coffee filter similar to the one here:
http://www.easycomforts.com/easycomforts/images/p129205b.jpg
Most of the mother liquor and carbon flowed right through of course, but I was left with a pile of KClO<sub>3</sub) obviously "stained" with
residual carbon.
I could have done a cold water, or even a cold KClO<sub>3</sub> saturated solution wash at this point, but the purpose of the excercize
was to test the Clarity product mentioned above.
The filter contents was slightly over 15g dry weight.
Considering I was unaware of the high ph and hypochlorite smell (and therefore oxidation potential) on the Clarity, I decided to disolve the filtrate
in a beaker using distilled water, bringing the level up to 250ml.
To this I stirred in (3) drops of Clarity, after which the solids immediately began to precipitate and clump together, within 2 minutes the top 1/2 of
the solution column in the beaker was nearly water clear. I shined my green laser through the top part of the column, this is my old standby check
for suspended solids. The brighter the beam, the more particles.
The result indicated still more suspended solids, so I added (5) more drops of Clairity, bringing the total to (8). After a brisk stir, and 10
minutes or so of settling, the top portion was so clear, I had to dim the lights in order to detect the beam!
I rinsed the reusable filter, and dropped in a new coffee filter, then poured the beaker contents into the filter. At the very beginning of the
filtration there was a solid stream, which very quickly tapered off to really little more than a drop or two per second, eventually becoming even
longer between drops. All told, it took 25 minutes to filter the 250ml.
As the last drop fell from the filter, I tried the laser test again, now even with the lights out, I had a hard time seeing the beam. Clarity has an
orange color, but I was seeing no coloration to the filtered contents, so I was pretty certain the Clarity locked both the particulates and itself up
well enough that none of it made it through the filter.
I transferred the contents to a boiling flask and boiled it down to 100ml or so, let it cool, and harvested about 7g using the disposable filter,
giving the filtrate a quick rinse with chilled distilled water, which I returned to the flask. The crystals were dried then powdered, absolutely pure
white with no hint of color or contamination.
I boiled the rest down until crystals just began to form, added back 10ml of distilled water (this was done to capture any KCl that might have been
formed with the presumed hypochlorite decomposition due to boiling), returned to a boil for a few seconds, then removed from the heat, let cool, then
ultimately transfered to the freezer to get out the last KClO<sub>3</sub>.
This second batch was harvested/dried/powdered like the first, and again, no hint of color or contamination.
Now keep in mind, this was ONE filtration. Had I not used the Clarity, I would have went through at least 8 filters, losing
KClO<sub>3</sub> at each filter, and still would have ended up with carbon contaminated final product.
It is entirely possible that some small colorless fraction of Clarity made it through to the final product, but given the boiling and crystalization,
the contamination level has to be very small indeed, if any at all.
So, I declare a resounding success. If I had a friend in the business I'd consider having them run an assay, but I'm confident enough that the
product is pure enough I'd feel like I was wasting their time.
In no way am I advocating the use of Clarity in any other procedure, but if any of you are using carbon anode electrolysis and what to drop the sludge
in one pass, Clarity seems to do the job nicely.
DAS
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watson.fawkes
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Congratulations. Given your description of your procedure, I'd have to guess that the organic
polymer component is all filtered out, having acting as seed nuclei for flocculation. So that's good.
As for the inorganic part, 8 drops (~ 0.4 ml) in 250 ml of solution isn't much contamination in the worst case. Flocculants and deflocculants work by
manipulating surface charge, so I'd guess that either an anion or cation from the inorganic part is adsorbing onto particles, assisting with
deposition onto the polymer. If you're lucky, the inorganic component is either a simple acid or base, so the only counter-ion is H+ or
OH-. It might be a salt, though, in which case the counter-ion would largely be left in solution.
Disclaimer: This is my surmise about how this product works. I've read up on how deflocculants work in slip casting, but I'm by no means an expert in
the subject.
Therefore, given that you've had a success, I think you're in a good position to talk to the manufacturer about potential residual contaminants for
your application. I doubt that there's any particularly useful trade secret in them revealing if there's a contaminating counter-ion in their product.
If there is (and it's sodium), it would at least be good to know.
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hyfalcon
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Flame test a sample of your product. If there's any appreciable sodium in it, it will show up in the flame.
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phlogiston
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Nice work Varmint, I wandered about this many times but never tried it.
-----
"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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