Apologies on the liberty with K2Co3 - I've been writing as KCo in my notes, which is sloppy. Again, not a chemist by trade.
Point well taken on playing with baking soda and vinegar (or drano and aluminum foil...) I had hoped that the simpler experiments I mentioned would
be more interesting for a budding young pyrotechnician. Then again, I think balancing diffeqs can be stimulating, so take what I say with a grain of
salt (your choice which kind)
So far as My KNO3 experiment goes I'm going to repeat it before I make a "real" post because it was 4 years ago and I wasn't taking great notes at the
time. As I recall:
My main twist was using precomposted manure to assure the nitrification had already been taken care of, thus avoiding the real wait.
I made a large filter by flipping over a plastic carboy and cutting off the bottom. I stuck a microfibre colth over the mouth on the inside so the
cloth lay well on both side s of the mouth. then I filled it with about 3" of mason sand. I ran water through this until the pH of the exit water
was unchanged.
Then I made a slurry of the manure with limewater in a 5 gal pail (can't remember the ratios but it shouldn't be signifigant, so long as there's
enough water to not get saturated. maybe 3 gal manure:2 gal limewater seems to make sense). I stuck a fishtank heater in it set to 70F (probably
unnecessary) and let it sit overnight, stirring whenever I felt like it.
Next Day I poured the gack(no better word for it) through the sand filter. This is messy and I needed to muck out the filter a few times before I was
done. I added a bunch of K2Co3 ( Actually, crude potash I had made earlier. The recipe. stipulated wood ash.). I stirred it and waited and hour for
precipitation. I think I decanted it and left the last 1" or so of solution above the precipitate. It could just as easily have been filtered.
Then crystalized the KNO3. I can't recall the yield. It wasn't much but it was enough to make a couple of firecrackers (which I did later).
I took a twirl around the web, just now, to see if I had made any gross errors in recall. I'm surprised to have not found this method anywhere. I'm
not sure where I got it from, now. It certainly isn't mine! (I'd love to take credit but I know I got it from someone else) . Iit seems a little
modern for a "grandaddy's saltpeter" recipe.
Basically, the Calcium Carbonate goes to Calcium Nitrate and then swaps places with potassium as the K2Co3 is added, which immediately drops out of
solution. I'll run the experiment again when I get time and post some pictures and proper quantities. It only took a weekend and it did work pretty
well.
EDIT: Just worked out the metathesis (I get paranoid when I don't see lots of others doing something I've taken for granted these past few years)
Here we go:
1. NH4NO3 (already present in composted manure) dissolves in the limewater.
2. 2NH4NO3(aq)+Ca(OH)2(aq) => Ca(NO3)2 (aq) + 2NH4OH(aq)
3. filter and add K2CO3 (ash or chemical)
4. K2CO3(aq) + Ca(NO3)2(aq) => 2KNO3(aq) + CaCO3(s)
5. filter evaporate slowly, separate, recrystallize, etc etc etc.
I feel better now that I've worked out the reactions. As Mentioned I've done this but, well, you are a tough room  I'll do it again and post more rigourous details when I get some free time
<rueful sigh>
[Edited on 30-8-2011 by polaris96]
Last few edits werte to clear up my awful arithmetic in the metathesis coefficients
[Edited on 30-8-2011 by polaris96]
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
