10 replies to this topic

[pyrotechnist]

Does anyone know if Calcium Nitrate may be of any use as an oxidizer in fireworks? seems like an interesting chemical.

[knackers]

Yes, no its quite hygroscopic

Edited by phill 63, 02 April 2009 - 10:00 PM.

[MDH]

It'll work but it will need to be in a warm, dry place at all times, with compositions stored in airtight containers. If that doesn't inconvenience you it might be worth trying, but nonetheless don't use magnesium or aluminum with it -- it'll become damaged over time.

[Pretty green flames]

It'll work but it will need to be in a warm, dry place at all times...

No, It won't work, I dried this stuff on a gas burner and the moment I took it of the flame it absorbed so much moisture from the air it was rendered useless. Don't waste your time with this stuff. The only useful thing you can do with it is fertilize your garden....

[seymour]

I'm with PGF. By the time it has cooled from your drying of it, you need to dry it again!!!

Things might be different if you live in such locations as Australia's Simpson desert, California's Death Valley, or the Sahara.

I am sure one can make a composition using it that works, but the lengths needed are not worth it. Calcium carbonate or sulfate both work absolutely fine, and need no special treatment.

[Mumbles]

To properly dry it, you either need to cool it in a vacuum, and back fill with dry or inert gas, or cool it in a dessicator/dry box. Even then, working with it in the open air, in anywhere but the desert, will likely render it useless. This is especially true with anything less than lab grade.

[Asteroid]

Why would lab grade wet faster than the pure product unless the impurities were more hygroscopic than the calcium nitrate itself?

[Mumbles]

I meant more impure than lab grade. Synthetic calcium nitrate, or fertilizer grade tends to contain very hygroscopic impurities. Ammonium nitrate, nitric acid, phosphoric acid, small amounts of calcium chloride, etc.

[a_bab]

Would you buy a 50 kgs sac of Ca nitrate fertilizer if it would be damp and drippy? I don't think so.

Calcium nitrate for fertilizers is actually mixed with some calcium carbonate that sticks to the nitrate and makes a compound that's no longer hygroscopic.

[Mumbles]

My experience is that they just coat the prills with calcium carbonate, or hydroxide, or something to that effect to seal it off. I've never tried to crack them to see if they absorb water. I'd imagine that they're already the tetrahydrate, and I'm not sure if the go farther or are deliquescent. The prills/granules will obviously have to be crushed, thus removing the protective coating to be used in anything.

Edited by Mumbles, 07 April 2009 - 02:12 PM.

[Gary]

You could use the calcium nitrate as a starting material for the preparation of potassium nitrate- just add a concentrated solution of potassium sulphate to a concentrated solution of the calcium nitrate, then filter-off the white precipitate of insoluble calcium sulphate ('gypsum'). Purify the potassium nitrate by 2 or 3 recrystallisations from water.
I would'nt bother using calcium nitrate in pyro- it is pretty much useless. Unless it could be sealed in wax or Vaselline to protect against moisture, but why go to such lengths when calcium sulphate, carbonate or oxalate salts can be used to produce a 'brick-red' colour?
Calcium oxalate, which is used in some orange colour/glitter comps, can be made quite easily- add a concentrated solution of the calcium nitrate to a concentrated solution of oxalic acid (often used as a rust remover), sodium oxalate or potassium oxalate, then filter-off the calcium oxalate precipitate.
Be careful- oxalic acid and oxalate salts are poisonous. Avoid skin contact or ingestion. Wear vinyl gloves.