35 replies to this topic

[jcow]

i have recently ordered 6kg of sodium nitrate, ?7- you cant go wrong! i know that it oxidises about the same speed as potassium nitrate. when making rocket propellants with the NaNO3, do i use the same ratios/proportions as i would with KnO3 (ie. 75:10:15 for BP)?

Edited by jcow, 15 March 2006 - 05:39 PM.

[BigG]

i have redcently ordered 6kg of sodium nitrate, ?7- you cant go wrong! i know that it oxidises about the same speed as potassium nitrate. when making rocket propellants with the NaNO3, do i use the same ratios/proportions as i would with KnO3 (ie. 75:10:15 for BP)?

You can try - but discussion on the matter took place before. Sodium Nitrate is hygroscopic and is not suitable for usage in climates such as in the UK. Is becomes useless rather quickly.

[alany]

To maintain the same oxygen balance you should use 0.84 times as much NaNO3 as KNO3.

That would make "BP" approximately:

72 NaNO3
17 C
11 S

It is perhaps no suprise that the PFP lists a BP variant from Allen:

71 NaNO3
16.5 C
12.5 S

For core-burning rocket propellant I'd suggest trying:

56 KNO3
33 C
11 S

Sodium Nitrate's hygroscopicity should be no worse than Strontium Nitrate, it actually has a better Hygroscopic point and sealed up inside a rocket it should be fine.

Edited by alany, 14 March 2006 - 09:05 AM.

[BigG]

To maintain the same oxygen balance you should use 0.84 times as much NaNO3 as KNO3.

That would make "BP" approximately:

72 NaNO3
17 C
11 S

It is perhaps no suprise that the PFP lists a BP variant from Allen:

71 NaNO3
16.5 C
12.5 S

For core-burning rocket propellant I'd suggest trying:

56 KNO3
33 C
11 S

Sodium Nitrate's hygroscopicity should be no worse than Strontium Nitrate, it actually has a better Hygroscopic point and sealed up inside a rocket it should be fine.

No Alany. I know the Simazu text, but in practice this does not seem to work ? even in laboratory quality chemicals. Both Sodium and Strontium nitrates do not store well in the UK. There are number of university studies on the subject. Burning rate of strontium based compositions fell by 50% in 1 year in GOOD storage conditions. Sodium nitrate fared a bit better but not much. Tubes do provide some protection, but rockets performance fall dramatically over time. Sodium nitrate flares (with magnesium), were manufactured in the UK (Perhaps still do), but the casing was FULLY SEALED.

In practice, sodium nitrate has little use around this part of the world, and indeed is not commercially used. I guess small quantities you can mix and shoot, but for quality pyrotechnic probably better to find those compositions you can work with for the long duration (I use sodium nitrate in my garden, and I can tell you, it a dump mess by years end)

[jcow]

Thanks for the advice.

But surely the damp NaNO3 can be revitalised if i was to heat it in small amounts and evaporate the water?
also, would the NaNO3 BP or sugar propellants be powerful enough to launch lightweight homemade 'estes' style rockets?

[BigG]

Thanks for the advice.

But surely the damp NaNO3 can be revitalised if i was to heat it in small amounts and evaporate the water?
also, would the NaNO3 BP or sugar propellants be powerful enough to launch lightweight homemade 'estes' style rockets?

There was quite a discussion about this in the BP forum, so I?ll try to stick to ?new? discussion.

First, yes, Sodium Nitrate, Charcoal and Sulfur (let?s call them Sodium Nitrate based propellant. Calling them BP does not sound right), will lift a rocket.

Second, yes ? heating will help ? but if you heat the mixture, do it in the sun or using hot air. In fact, heating was a common practice for sailors who kept BP at sea. After a few weeks bobbing around, the BP become much less efficient, so stops were made, and the BP was laid on the beach in the sun to dry.

Third ? No, it does not make a good repeatable practice. Quality pyrotechnic is made by the ability of repeating a procedure accurately over and over again. If damping and drying become a regular exercise, then the composition will behave differently as time passes (Plus, I?m sure there will be some crystallization process happening when you dry a mixed composition).

To sum it up ? by all means, use it to learn the basics ? but don?t make it your regular practice. Sodium Nitrate has little regular use in the UK (Simazu also has Yellow stars made with sodium nitrate, but a few British publications suggest companies here has to resort to other yellows).

[littlejohny]

Well from what I can gather you can't get pottasium nitrate. why not try to get some pottasium chloride, its used in substitute salt. Then you can convert your sodium nitrate into pottasium nitrate .

you should search it if your interested,

Sorry BigG for going of topic again.

Edited by littlejohny, 19 March 2006 - 01:58 AM.

[BigG]

Well from what I can gather you can't get pottasium nitrate. why not try to get some pottasium chloride, its a substitute salt. Then you can convert your sodium nitrate into pottasium nitrate .

No no no no no?.

Salt substitute is a mixture of potassium and sodium chloride. Littlejohny, if you don?t have a full understanding of your suggestion, please don?t suggest it.

There are about 100 posts about where to get potassium nitrate. We are not going to start this discussion again. This thread is about sodium nitrate type propellant, and should remain like that.

[EnigmaticBiker]

Second, yes ? heating will help ? but if you heat the mixture, do it in the sun or using hot air. In fact, heating was a common practice for sailors who kept BP at sea. After a few weeks bobbing around, the BP become much less efficient, so stops were made, and the BP was laid on the beach in the sun to dry.

I agree with your comments on the hygroscopic nature of NaNO3, I've almost given up trying to make various metal nitrates because of this. (Zinc Nitrate was a real swine to dry)

If jcow is really dedicated to trying this, a large container of silica gel (preferably indicating) might help. I've used this sucessfully to dry chems at room temp. Any composition or rocket motor could be stored in this prior to use.

jcow, it wouldn't be a good idea to mix any metals with NaNO3, given that it isn't really feasible to exclude all moisture.

Simon

[jcow]

I was considering buying the potassium nitrate as well from gardendirect. i was a bit worried that the authorities may get concerned and not believe my 'growing tomatoes' alibi in january! Has'nt anyone else bought large amounts of nitrate off the net and worried about the police getting involved? hopefully i will buy some KNO3 next time i order. Im the kind of person who makes the fireworks then lets them off soon after, so it doesnt really matter about the hygroscopic nature of NaNO3, as i dont store them for long.

Also, im not going to attempt to dry any sodium nitrate compostions (i've had bad experiences before), ill only dry nitrate when it is on its own.

[BigG]

Come on - read through the supplier thread. Discussion about buying nitrates and the such took place many times. Don't start this again. All your questions have been answered before in some detail.

[jcow]

i have ordered the sodium nitrate off gardendirect.co.uk, it is in the form of large granules.i havent yet tried it, but does anyone know if the nitrate has any other substances added to it that will affect its performance. i know that ammonium nitrate which is also hygroscopic has a coating to stop w**kers from blowing up things. does this apply the the 'nitrate of soda' on garden chemicals?

thanks

[EnigmaticBiker]

i have ordered the sodium nitrate off gardendirect.co.uk, it is in the form of large granules.i havent yet tried it, but does anyone know if the nitrate has any other substances added to it that will affect its performance. i know that ammonium nitrate which is also hygroscopic has a coating to stop w**kers from blowing up things. does this apply the the 'nitrate of soda' on garden chemicals?

thanks

I can't be 100% sure but I doubt it. Is there no data sheet with it?

You could try very simple purity tests to get an idea:-

Dissolve in water to find insoluble additives.
Filter if cloudy, dry and weigh any residue caught to get a rough percentage of impurity, a fire retardant is likely to be present in fairly large quantities. Some garden chems are from natural minerals and have lots of insoluble stuff present (One Sulphate of Potash, for instance has a few % of clay-like material + rocks!)

Take a very small quantity on a spoon or spatula and heat slowly and evenly on a hotplate (not flame) until it just melts, then slowly cool it until it solidifies.
Pure crystalline chemicals tend to have sharp melting/solidifying points, if heated carefully it should appear to melt/solidify almost instantly.

Hope that's useful.

[jcow]

i have just tested the sodium nitrate, it came in two 3kg bags. they did not have any oxidiser symbols, so i was a bit worried that it would be useless. the nitrate disolves in water, it was a bit cloudy and i didnt give it time to settle, so i will try this again later. i made some BP and nitrate and sugar mixtures which were both finely powdered and when burned, left a large amount of residue.they burnt fast, but not as good as expected. i tried several ratios of fuel to oxidiser and there were small improvements, but i was still left with this white residue.

i powdered some cool residue and tried mixing it with sugar, but nothing happened. some american sites say that KNO3 'prills' can be washed in alcohol, possibly removing the fire retardant. Does this apply to the nitrate?
the granules i have are not shiny.

would it be possible to fractionally crystalise the 'nitrate of soda' i have to separate the nitrate from the fire retardant?

[EnigmaticBiker]

i powdered some cool residue and tried mixing it with sugar, but nothing happened. some american sites say that KNO3 'prills' can be washed in alcohol, possibly removing the fire retardant. Does this apply to the nitrate?
the granules i have are not shiny.

would it be possible to fractionally crystalise the 'nitrate of soda' i have to separate the nitrate from the fire retardant?

You can try to clean the nitrate of soda by recrystallisation but it may be hit and miss if you don't know what the contaminant is and wether it is more or less soluble.

The residue after burning is probably a mixture of compounds, mostly NaNO2, this is where knowing the chemistry of what you're attempting is essential to understanding why.

For example: (runs to chemical dictionary )

Sucrose is C12H22O11

So, assuming all the sugar is burned to CO2 and H2O:-

1 mole Sucrose will need 24 moles of NaNO3

C12H22O11 + 24(NaNO3) --->12(CO2) + 11(H2O) + 24(NaNO2)

This is a really simplified way of looking at it, depending on the temperature achieved, how well mixed etc, a whole range of compounds will be produced.

Which is why Pyrotechnics is an art as much as a science.

(IMHO of course )