thermochromic
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Storing Sodium in Aluminum Bottle
So I bought some Potassium metal a little while back and it came in this aluminum bottle with a separate stopper (looks to be LDPE) as well as a
tamper evident screw-on cap. So i suppose if it is good for potassium then it should be good for sodium right (in a second bottle and not combined in
the same one with the K, and submerged in mineral oil of course)?
I only ask because I know NaOH is obviously is not compatible with storage in Al so any Na2O, and consequently NaOH, on the surface of the
metal would cause issues if it came in contact to bottle wall I would think; however this looked to be a professional supplier I purchased the K from
and no issues have occurred with it (it was sealed very well with no doubt an inert atmosphere inside) but still I wanted some other opinions. Is it
standard for Na or K to come in metal containers? Does anyone think this is a bad idea? I searched here and google but couldn't really find anything
pertaining to the metal, everything was trying to warn me about NaOH + Al.
Thanks
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JJay
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NaOH is a problem with aluminum in the presence of water. I don't think small amounts of it without water will be a huge issue, but I don't really
recommend storing sodium in aluminum either.
[Edited on 18-8-2020 by JJay]
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Dr.Bob
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I find it very useful to be able to see some things before I open the bottle. So for reactive metals, it would be useful to be able to tell what was
in the bottle, how much and in what condition before opening. I have never seen any reactive metals shipped in aluminum, so that is new to me, but
I would not use aluminum to store much of anything reactive or of concern. It is fine for storing alumina and other solids. I have seen ether
shipped in aluminum cans, which I don't prefer, but have gotten used to, but it makes it impossible to tell if any peroxides have precipitated in the
liquid before opening. Should not be an issue with good storage and labeling, but I don't want to be the person dealing with an old bottle found
stored improperly when I can't see inside.
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j_sum1
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I bought 100g of sodium one time. It came in an aluminium can with folded metal seal.
Apparently it was considered stable enough to post internationally like that.
It stayed in its can for 2-3 years before I had a need to open it. I had lost probably around 2-3% due to an imperfect seal but it was otherwise ok.
I don't think the can would have lasted too much longer though. There were signs of corrosion on the aluminium.
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macckone
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Sodium is ok for short storage in aluminum.
It isn't good for long term storage due to the possibility of moisture getting in, which leads to corrosion.
Glass is ok but it is subject to attack, at least it is visible.
Stainless steel is probably better for long term storage as it isn't attacked by sodium hydroxide below 80C at any concentration according to
literature.
Sodium hydroxide pellets are shipped in HDPE but are subject to air infiltration which isn't good for sodium.
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thermochromic
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Thanks everyone for all your input. Now I am torn between glass and HDPE. Perhaps fluorinated HDPE would be better, it is quite a bit cheaper than the
true fluoropolymer containers but supposedly provides a less permeable barrier than regular HDPE (interesting to note I just ordered some fluorinated
gallon jugs and the recycle code still lists them and the standard number "2" HDPE, I am now wondering if they are the real deal.)
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Stainless steel is probably better for long term storage as it isn't attacked by sodium hydroxide below 80C at any concentration according to
literature.
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Well honestly now you have me thinking that the K I received came in stainless steel instead of aluminum. Here is the K on the left and the Aluminum
container I originally got for the Na on the right. Notice how much more shiny it is? That could just be a more polished finish however; I suppose I
could test a small corner or something... unless any of these markings give it away that I am unaware of...
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macckone
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Stainless steel is considerably heavier and harder than aluminum.
The usual test for metal type is to use a metal hardness tester aka durometer.
The potassium container does look like stainless steel.
Since it was packaged in the US I doubt it is aluminum.
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Morgan
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Some stainless steel that isn't typically magnetic can sometimes be magnetic around the stressed bends and edges of the container.
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unionised
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I can see how aluminium would not be compatible with NaOH in the presence of water.
Does anyone know a much better way to ensure that water is absent than bottling it up with sodium?
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macckone
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unionised,
You can dry NaOH with aluminum, it reacts in the presence of water, including bound water with the NaOH.
A melt of NaOH will react violently with aluminum releasing hydrogen gas.
This will form sodium aluminate.
Assuming sodium aluminate is an acceptable contaminant, you can get very dry sodium hydroxide this way.
It makes a better drying agent than sodium hydroxide alone.
If you are just worried about storage then stainless steel or hdpe is the way to go.
If you have a water sensitive reaction that requires hydroxide then drying with sodium is the way to go.
If you want to use NaOH as a drying agent then drying with aluminum is the way to go.
Stainess steel water bottles are $10 or less and perfect for storage.
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Mateo_swe
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I have bought some sodium and it came like this:
Pure Sodium in secure AL/PE foil in argon atmosphere, protected from air, light and humidity.
When i open this i will put it in a container that let me see the condition of the sodium as i think this give me a instant info on the condition of
the metal.
Either a glass container, some transparent plastic container or a vacuum sealed bag with some oil.
Oil is going to cover the sodium whatever enclosure i use.
Dont you think visual confirmation on the status of the metal is very valuable?
Whatever problems with the metal can be seen and i can take action before it gets real bad.
Stainless steel enclosures is probably very good or (any compatible metal container) but it lacks the transparent visual status indicator.
[Edited on 2020-8-20 by Mateo_swe]
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Herr Haber
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How long do you plan to live ?
The little NaOH that will be formed will never be a problem to glass in your lifetime. The only problem with glass is that it can break.
And there I was thinking the most legitimate use of mason jars in a lab was to store alkalis 
The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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macckone
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Herr Haber,
It takes a couple of years, not a lifetime.
Yes it depends on the amount of NaOH present.
If it is directly against the glass it will form damage over time.
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morganbw
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Just keep it dry, within the foil wrap you have or under some oil.
Moisture is your enemy but under some mineral oil and a lid, no worries.
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Dr.Bob
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I have seen sodium stored in many forms over 30+ years. The material in glass bottles has done pretty well, most is still pretty good. What has
happened sometimes if that the lid or cap was not put on tight or worse yet cracked over time, as many caps are cheap plastic. Then the material has
often turned into a mass of white or yellowish crud that muct be destroyed very carefully. Worse yet one chunk of sodium, a full pound, was sealed
in a metal (steel) can. The can eventually corroded some and or the seam leaked, allowing some water vapor to get in, which caused so much sodium
hydroxide to form as to bulge the can and break the can open in places. This can was years old, and had been stored in a cabinet behind other stuff.
It stayed there until the person left and someone tried to clean out their lab area, which contained old metals, old ethers, and many other nasty
things. That sodium can had to be carefully opened and put into a large metal drum in a large hood and slowly quenched with ethanol over a week or so
in small aliquots, and keep the can covered and purged with nitrogen the entire time.
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j_sum1
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Quote: Originally posted by Dr.Bob  | | Worse yet one chunk of sodium, a full pound, was sealed in a metal (steel) can. The can eventually corroded some and or the seam leaked, allowing
some water vapor to get in, which caused so much sodium hydroxide to form as to bulge the can and break the can open in places. This can was years
old, and had been stored in a cabinet behind other stuff. It stayed there until the person left and someone tried to clean out their lab area, which
contained old metals, old ethers, and many other nasty things. That sodium can had to be carefully opened and put into a large metal drum in a large
hood and slowly quenched with ethanol over a week or so in small aliquots, and keep the can covered and purged with nitrogen the entire time.
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Aaah Dr Bob. That sounds like the wussy way to dispose of Na. Here's the manly way of doing it!
https://www.youtube.com/watch?v=mNWTpfHovHM
(gulp!!)
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Dr.Bob
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I would have been happy to toss it in our storm water pond, but the dept head and safety people were a pain. Same way, pyrophorics should be short
with a rifle from a safe distance, but instead we have to quench slowly. I do know people who used to 1) burn waste organics in a metal drum, 2)
toss old butyl lithium reagents into the Hudson River (Burroughs Wellcome before it moved to RTP), and likely GE back a few years, 3) drain sinks into
a deep hole and pour acetone down them. These were all done by people I have meet in real life, but all would be illegal now, might have been then,
but few knew or cared 40 years ago, including our own government. (Seen that video before, even watched it before we did the sodium quench for some
ideas..., it is a great one.)
But I have found a glass bottle with a good cap to work find for storing sodium.
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Heptylene
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I store my sodium (100 g) in a glass jar with mineral oil. The type of jar with a rubber seal and lever to close the lid. It's absolutely airtight,
been sitting for 2 years in the jar and the surface of the metal is still shiny.
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monolithic
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Are there any safe ways to quench sodium metal? I made sodium with the NurdRage method but quenching 100 ml or more of mineral oil with small amounts
of sodium in it makes me nervous. (The bulk of the sodium is recovered, obviously.) My current method is to very slowly pour it into a bucket of water
-- is there a better way?
[Edited on 8-25-2020 by monolithic]
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Heptylene
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Sodium reacts more slowly with ethanol than with water. You can put the sodium pieces in ethanol. Another option is to burn the sodium with a
blowtorch. It lights up like magnesium without exploding.
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