testimento
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Filtering colloidal sludge
I recently bought some cheap fertilizer which I need to get ammonia compounds out, but the nitrate is, as usual, filled with what seems to be like
calcium carbonate, and maybe even with some gelatinizers. I've put a sample in a bottle for gravity filtering, and the colloid just sits there. I've
tried using sand filters with two harshness, one with 1-10mm granulates and one with 0.05-0.7mm granulates, but it just stucks up these all. A
centrifugal filtering would help, I'm sure, but I dont have a device for making even a small centrifuge(may build one in future, perhaps).
Just a though, does anyone have experience filtering these, probably intentionally difficult-made compositions into clear liquid? The sludge literally
clogs all filters within seconds, no matter how harsh they are, a cotton sheet lets few drops of mere moisture through and that's it.
Diatomaceous earth could help. Maybe even some coagulants which would clog the particles into large chunks and fall to the bottom, easy to separate by
gravimetric means, this is used in yeast removal from alcohol products.
<!-- bfesser_edit_tag -->[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: corrected
subject typo(s)]
[Edited on 7/10/13 by bfesser]
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Random
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You will need to let it settle down then decant clear solution from above.
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testimento
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I actually made some tests with following setup:
I first solved it in hot water as far as it go. Then I put a cloth on a bucket with holes at the bottom, poured 5cm layer of fine sand, put another
cloth and poured another 5cm layer of harsh sand and poured the shitty gunk on the filter. It drips now at a rate of about 5-10ml per minute, so I
should get it done within few hours maybe. Filters havent clogged yet, although I tested if the drip rate would increase by changing the topmost cloth
and washing the sand, but it didnt affect it.
I have a batch in few bottles which have settled pretty nicely so far, about 50% settlement done. Wait till it goes down to 70-80% until I flow the
top layer and put it through the sand filter.
Btw the sand works like a dream, the liquid coming through is crystal clear. I robbed my local beach armed with buckets, washed the sand thoroughly
which removed all water soluble and light enough impurities, then flowed some water through is at filter media, dried it at 350C and filtered it
through 1mm mesh net to get 1 grade of 0.05-1mm sand and the leftovers which are coarse stuff. Fine for me not paying shitloads for those quartz
filter sands 10 bucks a kg bag for pool filters. 
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Boffis
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I'd experiment a bit with dilute solutions of fertilizer and various coagulants like aluminium sulphate. If the colloid is one of the PEG XXXX type
polyols boric acid usually works a treat. Ground chalk is fairly coarse and will usually settle but the PEGs and similar polymers can inhibit this so
you will need a coagulant. Other possible coagulants are ammonia, tannin (for protein type and soluble amide polymers), gelatin and isinglass for
tannins and a few manmade polyols etc. Try aluminium sulphate first then boric acid, you done need much probably 0.1 or less of the weight of
fertilizer, if its not enough you can always repeat the process. Then allow to stand for a few days and finally decant and filter. Keep the solution
of fertilizer fairly dilute and then wash the residue and let it settle to recover most of the remaining soluble material.
One other material comes to mind, used by wine makers, is bentonite. This is used in higher concs say about 0.2 to 1%, disperse into water first and
then poor into your solution. Don't try to filter this stuff just let it settle for a week or two and decant.
On final idea is to add a collector and then a precipitant, say aluminium sulphate, if no ppt, then add home brew wine makers tannin or isinglass.
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testimento
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I already filtered it out.  I just poured it into cotton bag and put it upon
the sand filter and clear liquid came through and white paste was left over. Filtered 10 liters of it in 12 hours. I think centrifugal separation
could be best, Ive got 1kW electric motor and just need to lathe a joint for 4x2l soda bottles and make it run like hell for a while and it should
give nice clear liquid.
Btw...
Does anyone have any ideas how to get urea and ammonium nitrate and potassium nitrate separated from each other?
[Edited on 11-7-2013 by testimento]
[Edited on 11-7-2013 by testimento]
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