Does KNO3 expire?

[Blinky]

I managed to get a hold of some KNO3 - my mom had some, but it's VERY old - the expiry date on the bottle says February 2002. I'm wondering if saltpetre can expire, or if there are just regulations stating that they have to put a date on it.
This bottle says it's for internal use (??) - the label says:
"Saltpetre Potassium Nitrate BP Saline Diuretic DIN 00448214" and I'm hoping this is what I've been looking for, the 'BP' threw me off a bit.
Thanks for any info, I'm off to look this stuff up online some more before I try using it

 

[Hydro]

I haven't used saltpetre, so can't help with that. But have you looked into using "stump remover"? I got mine from a local gardening store. It's made by Laters in British Columbia. Here's a link to their website and the material safety data sheet.

http://www.laters.com/MSDS/2002 Msds-English/Laters Stump Remover.PDF

It's 100% KNO3. I've been using it for 2-3 months and it seems to work fine.

Hope this helps.

 

[Darkblade48]

I haven't used saltpetre, so can't help with that. But have you looked into using "stump remover"? I got mine from a local gardening store. It's made by Laters in British Columbia. Here's a link to their website and the material safety data sheet.

http://www.laters.com/MSDS/2002 Msds-English/Laters Stump Remover.PDF

It's 100% KNO3. I've been using it for 2-3 months and it seems to work fine.

Hope this helps.

I've called quite a few number of Home Depots around my area (Toronto) and apparently the Stump Remover is a seasonal thing, so they don't happen to carry any more of the good stuff.

Blinky, I'm not sure if KNO3 would have an expiraton date, as normally, chemicals shouldn't have expiration dates. However, what I would be careful of is the "BP Saline Diuretic". It might be nothing, or it might not be...maybe someone else can give a better answer than I can

 

[djlen]

If it is Salt Petre it is OK for use in dosing KNO3. It won't go bad over time, but might lose some of it's potency.
Ask mom where she got it and get a fresh batch when you can.

Len

 

[happychem]

No, it doesn't expire. Some chemicals will dissociate over time with light and heat, the chelates in trace element mixes are a good example. But KNO3 (aka saltpeter and/or stump remover). It is possible that the crystals will pick up water from the air and hydrate them, decreasing the actual amount of KNO3 per gram or tablespoon, but the compound itself will be fine.

 

[Blinky]

Thanks guys!
Len - I do have a source now (Thanks Darkblade48 , and will be getting some this weekend - the bottle my mom had is small, and won't last long, but she thought it might just do the trick for the time being