metalresearcher
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Li2CO3 red colorant (vid) ?
Here I did an experiment with .three mixtures:
KClO3 + sugar
same with CaCl2
same with Li2CO3
The first one has a real purplish K color, the second one an orange red color , the third one was not much difference of the first one despite Li2CO3
is described as a 'red colorant'.
I added in weight parts 2 KClO2 + 2 sugar + 1 Li2CO3.
With CaCl2 the color is orange red (not shown very well in this vid as the Powershot G9 displays red as orange).
Is the ratio wrong ? Adding more Li2CO3 slows down reaction considerably.
<iframe sandbox width="425" height="349" src="http://www.youtube.com/embed/vSIo0KCyar8?hl=en&fs=1" frameborder="0"
allowfullscreen></iframe>
[Edited on 2011-10-5 by metalresearcher]
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Bert
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Lithium is a poor and expensive red colorant for solid pyrotechnic mixes. Strontium is your best choice there.
Some use Lithium chloride in methanol colored flame mixes, however. Look here-
http://www.skylighter.com/skylighter_info_pages/article.asp?...
[Edited on 5-10-2011 by Bert]
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quicksilver
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I agree w/ Bert. It could be the video but it looks orange to me. (Pretty - but muy expensiveo). But you didn't have any strong compression there,
correct? An interesting experiment would be to determine what effect compression has on light output wavelength.
I came up with some red stars some years back with strontium nitrate, strontium carbonate (more for the chlorate as an anti-acid if you use a coating
or 1st fire of BP), chlorate, lactose, & a small amount of 60 mesh magnesium that with a varying amount of sodium could be altered from an deep
scarlet to an orange.
I wish I had enough lithium to have fun with. Even at a surplus buy it's about 3x as much as the alternatives. There's a guy here who does some
professional pyro shoots and has some shell techniques that are frankly as good as any I have seen from Japan. I hope he chimes in. He can get some
very nice colors. My favorite is a deep (yet bright) blue.
It's nice you put up a video however. But it's too bad you could do a "freeze-frame" - w/ multi frame comparison. The eye can become overloaded to
distinguish the subtle colors if they are fast: back to back.
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Erbium_Iodine_Carbon
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Lithium is indeed an effective red colorant; however the color that you see comes from both the lithium and potassium. In the video I noticed that the
lithium carbonate containing pile did burn with a purple-red color. This would be the result of lithium's red being added to the violet of potassium,
of which there was more.
If you wanta purer red color, use a lithium or strontium salt as your oxidiser so that there aren't any other elements adding their color to the mix.
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PHILOU Zrealone
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My 5O cents on this:
1°) Sugar is not the best thing for such experiments because, it holds a lot of naturally occuring sodium cation... This is trapped into its cristals
during the cristallisation process. Your sugar is certainly not chemically pure and several times recristallised to avoid sodium!
As a first rule...sodium is a poison for color effects because its yellow glow surpasses all other colors...even your pinkish potassium glow is
polluted by a lot of yellow.
2°) Sugar/KClO3 in close to stoechiometric ratio burns too fast and too hot to get any correct color expression.
If too hot a burn all colourizers will shift to the white and thus display very pale.
Better work a bit out of stoechiometry with excess fuel, but another fuel than suggar...you should try carbon black of fumes, sulfur and KNO3 (or
KClO3 but then add some 1-2% K2CO3 for stabilisation of the KClO3 vs acidic S, otherwise you would have a risk of spontaneous ignition).
The alcool dissolution burns low enough a temperature and is poor enough at sodium owing to its previous distillative isolation. Thus for some colour
pre-testingss you can dissolve some flame colourisers into aceton, ethanol or methanol...they all allow some good dissolution of the salts.
3°) The salt and the temperature makes it all...it must be hot but not too hot for the best expression and each color and composition has its best
ratios...
-While CuCl is the responsible of the blue-green color, it can be produced in situ by reaction between CuO, Cu(OH)2 or CuCO3 and the chloride
generated by the KClO3 decomposition...But of course if you have CuCl2 or even better Cu(ClO4)2...then the composition is richer at it and displays
very bright and powerfull colors.
-On the other hand CaCl2, SrCl2 and BaCl2 are good and realtively volatile for colorisation into orange, red and granny smith green.
-For Li the chloride works, but the best color is obtained from the hydroxyde...the coloriser is not Li(+) but ionised LiOH and the heat must be low
enough to stabilise LiOH and hot enought to make it volatile...
4°) If you want to make color tests, you must have your tests separated enough a distance so that ions of burning pile will not pollute the next
unreacted pile. Also the place must be "virgin" of any rest of previous tests/experiments...especially if it goes about other colorizing cations. You
would be surprised how traces of sodium or of burned carbon (coke/wood ashes) will make everything yellow-orangish.
[Edited on 10-10-2011 by PHILOU Zrealone]
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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