Sciencemadness Discussion Board

Can I store nitric acid safely?

jgourlay - 9-7-2008 at 15:54

Some of you have responded to my earlier posts, for which I thank you. As you know from them, I'm a homeschooler, but this is off the topic of my immediate homeschooling needs.

After browsing the forum and poking around on line I've come to the conclusion that nitric acid is both useful and likely to be banned from private purchase. I don't need it now, don't really want it now. But I am looking 3 or 4 years ahead and can see where it will be useful to have around for the science curriculum.

So, I want to get some now, but I am concerned. Many years ago, back when I was using a mix of nitric/sulphuric in conjunction with jewelry etching of gold and silver, I had a gallon. I kept this gallon in my garage in the 1 gallon plastic jug in which it was shipped. Note that I am in houston and temperatures here range from "hotter 'n hell" on up to 110 deg in the shade.

I went on a 2 week vacation, and came back to find both the nitric acid jug cracked and empty, and $4000 worth of high end wood working tools covered with an impressively horrific layer of rust.

Now, because I have little kids, I have two choices of storage locations. 1. in a shed which I can lock, and which can get up to 120 degrees for days on end. 2. in a refrigerator in this shed. That fridge, however, is used to store other things I'm sure I don't want to store with the acid, such as Tung Oil, Boiled Linseed Oil, and various varnishes.

I snapped enough now to realize that I should have transferred that original gallon to a glass jug. But do these glass jugs hold that pressure that I assume will develop as the acid wants to outgas in the outdoor temperatures? Is it safe to store the acid in a (plastic lined) refrigerator with other non-food items? The fridge, by the way, does have a freezer section-but it's quite skinny. If that's safe, does the nitric acid bottle sit above the sulfuric acid bottle or vice versa?

Btw, one application I'm looking forward to now is helping my budding-photographer-son prepare his own photographic "plates" from egg whites, silver, nitric acid, et. al. and making film for some cameras I inherited from my dad and for which film is no longer available. :D

Jor - 9-7-2008 at 16:09

If you buy it in a amber glass bottle with a good cap from a reputable supplier and keep it cool, I think you can keep it for a long time.
Keeping it in the fridge is possible, but in time your fridge might start to rust.
I have a liter of 63% nitric from Acros, and it's in a brown bottle, with a large red cap, with some plastic inside. I keep it quite cool, and it's still completely colorless.

pantone159 - 9-7-2008 at 16:26

I live in a similar climate (Austin), and I really wouldn't consider storing anything in a non-cooled environment.

HydroCarbon - 9-7-2008 at 17:21

Be sure if it's in the fridge/freezer the liquid isn't touching the cap as it could corrode. I would keep it in the fridge or in a locked cabinet in the house to keep it away from the kids.

Also towards Jor's post that said the fridge can rust. Is it really possible for the molecules to escape a tightly sealed bottle? Through the cap?



[Edited on 9-7-2008 by HydroCarbon]

woelen - 9-7-2008 at 23:21

yes, even thick caps are somewhat permeable for acids. I have HCl and HNO3 and around those bottles I always see a kind of 'frost' due to escaping gas. This 'frost' is very corrosive and makes iron tools rusty within a few weeks.

ProChem - 10-7-2008 at 04:44

I am beginning to stock my home lab with reagents and the acids I have are stored in 1/2 gallon plastic coated glass jugs and the jugs are never more than 3/4 full. I would not store any acid in a plastic container unless it was teflon. If I had to use plastic I would put the jug in a plastic pail and cover the jug uo to the neck in vermiculite. My garage is connected to the house so to keep the Mrs. Happy I am building a storage box out back (looks like a big dog house).

jgourlay - 10-7-2008 at 06:09

Thanks for the replies gents. I'll keep in the fridge, and instead of 1 big gallon jug, I'll use 4 or 5 smaller glass containers. Less chance of a slip and "oops" and less horror if that happens.

Are there better ways than glass funnel and "glug glug glug" to transfer the acid from the big jar to the small ones?

pantone159 - 10-7-2008 at 06:14

Quote:
Originally posted by jgourlayAre there better ways than glass funnel and "glug glug glug" to transfer the acid from the big jar to the small ones?


See this thread re use of a glass stirring rod to aid in pouring to avoid drips...
http://www.sciencemadness.org/talk/viewthread.php?tid=9889

Also keep a box of baking soda (NaHCO3) in the fridge, it ought to help absorb acid fumes.

DJF90 - 10-7-2008 at 07:12

A glass stirring rod wont help much for a gallon :P A glass funnel is probably the best way to do it, just be careful, wear goggles and gloves etc, and when the kids arent around, just incase you spill it.

The_Davster - 10-7-2008 at 11:02

I have the opposite problem, my acids would freeze if kept outside! Only HCl is safe from freezing in the winter. I therefore keep almost all chemicals indoors. The acids are kept in a lockable wooden cabinet with bottles of baking soda around them incase of a spill, and to absorb fumes. Hinges in this wooden cabinet are covered in ducttape as the hinges in the last cabinet rusted very badly.

S.C. Wack - 10-7-2008 at 15:56

I have used plastic coolers of all sizes for storage in the past. If you want cooling, well I guess $80 is a little pricey for one of those thermoelectric coolers...I seem to recall that the one that I have was a lot cheaper than that as bought 5 years ago.

I've wondered about the diffusion of things like HCl through plastic, not the cap - hardware store bottles themselves.

pantone159 - 10-7-2008 at 16:28

Quote:
Originally posted by S.C. WackI've wondered about the diffusion of things like HCl through plastic, not the cap - hardware store bottles themselves.


I used to keep a plastic bottle of hardware store 'muriatic acid' under the sink, back before I realized much the fumes corroded stuff. After a year or two, I noticed that the bottle was getting chalky, and stuff was starting to rust, so I got rid of it, and use only glass bottles for the stuff now.

jgourlay - 14-7-2008 at 05:39

Quote:
Originally posted by The_Davster
I have the opposite problem, my acids would freeze if kept outside! Only HCl is safe from freezing in the winter. I therefore keep almost all chemicals indoors. The acids are kept in a lockable wooden cabinet with bottles of baking soda around them incase of a spill, and to absorb fumes. Hinges in this wooden cabinet are covered in ducttape as the hinges in the last cabinet rusted very badly.


Is freezing bad?

woelen - 14-7-2008 at 06:01

Freezing itself is not bad for the acid, but the water in the acid may expand so much that the bottles crack.

The_Davster - 14-7-2008 at 10:32

Exactly, I was unable to find expansion/compression data for freezing acids, so I decided not to risk it. 2.5L of nitric or sulfuric in the garage would make a very bad day.
Keep in mind in my location in Canada, things that will not freeze for you may freeze for me.


[Edited on 14-7-2008 by The_Davster]

Engager - 14-7-2008 at 17:04

Highly concentrated or anhydrous nitric acid is unstable and decomposes slowly under ordinary conditions, seals must not be tight because decomposition products will generate pressure and bottle will finaly crack and spill acid all around. However this acid can be safely stored in glass container with tight glass lid in deep freeze section of home refrigirator. Decomposition is slowed greatly at this conditions, and NO2 gas cannot generate pressure because it liquifies at this temps. Liquid NO2 reacts with water contaminants in acid to form more nitric acid, so some kind of constant equilibrium exist. I stored concentrated HNO3 in this way for more then 2 years without any problems and degree of decomposition was low (very slight yellow color).

70% nitric acid and below can be stored forever in dark glass bottles with plastic lid, without any decomposition at ordinary temperature.

[Edited on 15-7-2008 by Engager]

Picric-A - 18-7-2008 at 14:18

I had a 1L bottle of i think 52% Nitric acid. I thought at this concentration it wouldnt release fumes. wrong. it eventually ate up the plastic coated paper lining in the lid. (considering this was the bottle i bought it in from some hypodermic supplier.) and after a while the nitric acid was contaminated with crud.
My soloution was to buy a 25m roll of PTFE tape for about £1 and put it on the tip of the bottle then screw the lid on it again.
It worked wonderfully, about 5 months on and no corrosion.! :)

[Edited on 18-7-2008 by Picric-A]

jgourlay - 23-7-2008 at 13:38

Quote:
Originally posted by Engager
Highly concentrated or anhydrous nitric acid is unstable and decomposes slowly under ordinary conditions, seals must not be tight because decomposition products will generate pressure and bottle will finaly crack and spill acid all around. However this acid can be safely stored in glass container with tight glass lid in deep freeze section of home refrigirator. Decomposition is slowed greatly at this conditions, and NO2 gas cannot generate pressure because it liquifies at this temps. Liquid NO2 reacts with water contaminants in acid to form more nitric acid, so some kind of constant equilibrium exist. I stored concentrated HNO3 in this way for more then 2 years without any problems and degree of decomposition was low (very slight yellow color).

70% nitric acid and below can be stored forever in dark glass bottles with plastic lid, without any decomposition at ordinary temperature.

[Edited on 15-7-2008 by Engager]


Engager: thanks.

BlackDragon2712 - 28-5-2014 at 16:53

Hey guys, I have a problem. I'm new to nitric acid and the last week I bought one liter of 68% acid but today I noticed that in the surroundings of the bottle there was like some kind of liquid with a smell of chlorine... the nitric acid came in a plastic bottle. I bought today a reagent amber bottle and I wanted to know if storing the nitric acid there would be enough to store it for like a year?

Thank in advance guys

btw I don't know if I should be asking this in here... sry if I shouldn't, I didn't know

thesmug - 28-5-2014 at 16:57

Some nitrogen compounds smell like chlorine but I don't have any idea what that could be (maybe the plastic reacted). Anyway storing in a glass bottle should (ideally) last forever.

Zyklon-A - 28-5-2014 at 19:05

The plastic likely contains chlorine, but I doubt it could be liberated.
Glass will never deteriorate, but what's the lid made out of? If not Teflon, or ground glass, you might want to seal it with Teflon.

BlackDragon2712 - 28-5-2014 at 21:18

It is made out of ground glass... the weird thing is that the nitric acid came in a HDPE bottle and as far as I know nitric acid will not react with that... maybe it was the polymer of the lid with which it reacted? Idk but anyway tomorrow I'll transfer the acid and clean the area, it wasn't very much but there's a soft smell similar to chlorine there and I have no other reagent in that location so I know it couldn't have been anything else...

Rogeryermaw - 2-6-2014 at 11:40

i routinely store ~200 ml of fuming HNO3 in an amber glass bottle in my freezer for up to 4-5 months or until i can afford other reagents that i can use with nitric. even around -10 it still builds up pressure. i'm not sure where the post is, but i remember woelen recommending venting your nitric bottles every couple of weeks or so. i have done so religiously since i read his post and have never had a problem.

Zyklon-A - 2-6-2014 at 13:55

Yeah. It is generally advised to vent often and keep the bottle filled only half way to allow plenty of room for gasous built-ups.

zirconiumiodide - 6-6-2014 at 11:43

Yeah i agree. When i first made Nitric Acid by bubbling NO2 through Hydrogen Peroxide i thought a few hours would be enough to vent it. But after storing for just a couple of hours upon removal of the top i could here fizzing and gas was evolved. The only time i smelt NO2 during the whole procedure of making NA! I vented often for a few days. After that it was fine - but still vent once a month or so. :)

Pyro - 8-6-2014 at 16:52

you could keep the bottle in a bucket of water, that way it will stay cool. gases will be neutralized and if it cracks it will be neutralized so much that it's practically harmless

zenosx - 8-6-2014 at 18:35

Just my two cents but I had issues with my `90% HNO3 until it was stored in an amber bottle with a greased glass joint. Otherwise it would tend to creep out of the top and stain my hands with dilute acid when picked up. This is in a non-refrigerant environment, in a dark steel drawer. 70% may store better.

Texium - 9-6-2014 at 14:18

Quote: Originally posted by Pyro  
you could keep the bottle in a bucket of water, that way it will stay cool. gases will be neutralized and if it cracks it will be neutralized so much that it's practically harmless


And if you were still concerned, you could even put some bicarbonate into the water bucket to ensure neutralization of vapors.

prof_genius - 27-6-2014 at 12:29

I would recommend keeping acids in underfilled plastic coated glass bottles (some Aldrich and Merck acids come in them), I would also recommend having a strip of parafilm or some other sealing foil around the cap, for extra protection you could keep the bottle in a heat sealed plastic bag for long term storage.

greenlight - 4-11-2014 at 07:26

I have had 10 litres of 70% Nitric acid stored in a cool cupboard in a black 15 litre HDPE (high density polyethylene) container for four years now. The acid is fine and the container undamaged but the screw cap has had to be changed twice as it has a seal which the acid slowly eats through.
The 99% Nitric acid i have is stored in a 250ml amber glass jar with a glass stopper in the refrigerator. The glass stopper has also been wrapped once with plumbers PTFE thread seal tape from the hardware store which holds up okay.

DrMario - 4-11-2014 at 09:22

Quote: Originally posted by zirconiumiodide  
Yeah i agree. When i first made Nitric Acid by bubbling NO2 through Hydrogen Peroxide i thought a few hours would be enough to vent it. But after storing for just a couple of hours upon removal of the top i could here fizzing and gas was evolved. The only time i smelt NO2 during the whole procedure of making NA! I vented often for a few days. After that it was fine - but still vent once a month or so. :)


Are you sure it was NO2 and not oxygen from the H2O2, which was building up?

DrMario - 4-11-2014 at 09:44

I'm a little bit dubious about nitric acid attacking HDPE. As far as I could see, our 69% nitric acid has never had any effect of the HDPE bottles from Sigma Aldrich. These are 2.5 L and 5 L bottles. True, mostly the acid is used up in about a week or two, but I am sure I've seen a 2.5 L nitric acid bottle outside the cleanroom (another lab) which stayed there for weeks, maybe months, due to lower consumption. Room temperature.

So.. what are you guys doing that your nitric acid eats through HDPE.. assuming your plastic is indeed HDPE?

Mabus - 4-11-2014 at 10:58

At my uni the fuming/concentrated nitric acid bottle was stored under sand in a metal container. Apparently it's pretty effective way of storage.

[Edited on 4-11-2014 by Mabus]

DrMario - 4-11-2014 at 11:37

What is the metal? Aluminium is, apparently, perfectly safe from nitric acid, so it could be that. In fact, I've done a few experiments in which I treated various aluminium alloys with nitric acid, and they didn't etch at all. This is due to the fact that HNO3 by itself is unable to etch alumina (Al2O3).

What's the function of the sand, though?

Mabus - 4-11-2014 at 12:24

IIRC, I think it's supposed to absorb the nitrogen dioxide gases that inevitable escape. Natural sand has a small percentage of carbonates and oxides, so there's no need to add neutralizing agents.

Don't recall what metal is made of, I'll check out tomorrow.

Metacelsus - 4-11-2014 at 12:26

Concentrated nitric acid might passivate aluminum, but I would think dilute nitric acid would corrode it.

DrMario - 4-11-2014 at 12:29

Quote: Originally posted by Cheddite Cheese  
Concentrated nitric acid might passivate aluminum, but I would think dilute nitric acid would corrode it.


Well, I've done the experiments, and the results are in: 7% HNO3 does not etch aluminium 1050 A, which is 99.5% aluminium.

I have not tested other alloys with diluted HNO3, but I have no reason to think that purer aluminium would behave any differently.

macckone - 4-11-2014 at 12:39

6061 is by far the most common aluminum alloy.
It is only 95.85 - 98.56 % aluminum, and usually more around 96 - 97%.
I don't know how it reacts to dilute nitric but it probably isn't as good as 1050A.

DrMario - 4-11-2014 at 12:40

Quote: Originally posted by Mabus  
IIRC, I think it's supposed to absorb the nitrogen dioxide gases that inevitable escape. Natural sand has a small percentage of carbonates and oxides, so there's no need to add neutralizing agents.


At least carbonate sands do contain a lot of calcium carbonate, so I can see how that would help. Is the bottle completely immersed in the sand, though, or is the cap protruding out?

DrMario - 4-11-2014 at 12:42

Quote: Originally posted by macckone  
6061 is by far the most common aluminum alloy.
It is only 95.85 - 98.56 % aluminum, and usually more around 96 - 97%.
I don't know how it reacts to dilute nitric but it probably isn't as good as 1050A.

I'll do the experiment tomorrow and satisfy both our curiosities. I have many 6061 samples which I etch with a phosphoric acid-based etchant (it uses HNO3 as an oxidant, interestingly enough).

But at least with concentrated HNO3 (69%), aluminium 6061 does not react at all.

[Edited on 4-11-2014 by DrMario]

Mabus - 6-11-2014 at 06:33

OK, so here's what I got:
-The metal container is made of steel, has some rust on the container joints, but other than that, it shows no signs of degradation.
-The nitric acid is no longer stored in the sand container, now it's the acids cabinet. The plastic lid show some signs of corrosion.
-When it was stored in the sand, the sand level was up until the bottom of the lid.

DrMario - 6-11-2014 at 08:23

And I forgot to test the 6061 etching in diluted HNO3. I had a very rubbish couple of days, crowned by an accident where a car has hit me while bicycling (I was nicely and slowly crossing the road at a designated crossing - but the b**** was out for my blood).

Mabus - 6-11-2014 at 11:52

Oh no, that's terrible. I hope you're alright.

DrMario - 6-11-2014 at 12:03

I hope I am. There seem to be no major bones broken. I'll know more tomorrow. My work keeps me so busy, I can easily forget about the pain.

TGT - 12-11-2014 at 20:44

This summer I saved about 5 gallons of pure white fuming nitric acid from my fathers house. He use to work in a metal plating factory and when they closed he brought it home. This was way back in 1990 or so. It was stored in a blue plastic bottle that was designed for acids, but it was now 2014 and the many years of cold winters and hot summers had changed the bottle to a light powder blue and the plastic was very brittle. Not to mention they were stored under a pool deck with no protection from the outside other than the deck floor. I knew it had to be saved before it leaked so I transferred the acid to amber glass bottles. I was disappointed that I only got a small amount of fuming as it was supposed to be white fuming nitric acid. I continued filling and brought them inside to a more stable temperature. When inside I did a titration and also a weighing to judge the percentage. To my amazement I still had slightly over 70% nitric acid and it was still clean and clear. This acid is anywhere from 25 to 30 years old and still retains a moderate amount potency! I am sure if it was stored for the same amount of time an a cool basement in the dark it would still be very potent. I have used it many times now with great success.

I thought this would be interesting to others as it shows how long nitric can be stored for even in the worst conditions possible. I think the deciding factor for it to last as long as it did was that there was a whole 5 gallons and not much air in the bottle. If it were 1 litre in the same bottle I am sure the results would have been different.

On a side note, there also was a 5 gallon bottle of Muriatic Acid of the same age. It's container was way worse condition than the nitric acids, but the acid itself was as strong as it was when it was first placed there. I saved that too.

TGT

DrMario - 12-11-2014 at 23:20

Quote: Originally posted by TGT  
This summer I saved about 5 gallons of pure white fuming nitric acid from my fathers house. He use to work in a metal plating factory and when they closed he brought it home. This was way back in 1990 or so. It was stored in a blue plastic bottle that was designed for acids, but it was now 2014 and the many years of cold winters and hot summers had changed the bottle to a light powder blue and the plastic was very brittle. Not to mention they were stored under a pool deck with no protection from the outside other than the deck floor. I knew it had to be saved before it leaked so I transferred the acid to amber glass bottles. I was disappointed that I only got a small amount of fuming as it was supposed to be white fuming nitric acid. I continued filling and brought them inside to a more stable temperature. When inside I did a titration and also a weighing to judge the percentage. To my amazement I still had slightly over 70% nitric acid and it was still clean and clear.


Could it be that you didn't actually have fuming (near 100%) HNO3, but standard 69%?

TGT - 13-11-2014 at 17:33

No, it was fuming Nitric at the time it was bottled because my father remembers well and that is the only concentration used. But it was never 100%, more close to 94% from what my father says.

TGT