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While performing an inventory of my school's chemical storage closet today, my fellow teacher and I found some sodium tucked away in the back corner of our flammables cabinet. One container appears to have leaked the oil the sodium was being stored in, and we aren't sure about the second container. We don't know how long it's been there, but neither of us is going to use it, and, honestly, we don't want it. How do we dispose of this? Can someone with a little more chemistry know-how point me in the right direction? Are we stuck with this?

Or...

In the event that the administration won't let us dispose of the sodium, can you tell me how to remedy the storage situation? We don't feel that there is an adequate amount of oil in the container for proper storage of the remaining sodium, and if we have to keep it I want to make sure it is being stored correctly.

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  • $\begingroup$ 3g of sodium + water youtu.be/_WY7ayBipBM, keep in mind if wish to dispose it using open water. Small pieces (about 0.1-0.2 g) dies without such pornography, but it will be loooong. $\endgroup$ – permeakra Aug 21 '12 at 8:13
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    $\begingroup$ It might be useful to know how much sodium we are talking about, a few grams or much more? $\endgroup$ – Mad Scientist Aug 21 '12 at 8:17
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    $\begingroup$ @permeakra ..."pornography"? $\endgroup$ – immibis Jul 19 '15 at 5:24
  • $\begingroup$ You can use what's left as lye if it has oxidized all the way $\endgroup$ – James Oct 1 '16 at 1:08
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If you handle sodium, the first thing you need is a way to extinguish it if it catches on fire. You should have a bucket of sand ready to use, and additionally a class D fire extinguisher, if available. I'm assuming you know this, but don't let the sodium come into contact with water.

You always want the sodium stored in an inert liquid, usually mineral oil is used for that. Organic solvents like n-hexane are also used for short time periods. You should refill the mineral oil immediately.

The usual way to neutralize sodium is to put small pieces in an organic solvent like n-hexane and slowly add either isopropyl alcohol or ethanol to it. Isopropyl alcohol reacts slower, and is therefore a bit safer. When all the sodium is dissolved, you can add water to make sure there is no elementary sodium left.

How dangerous this is depends a lot on the scale, it's easy to do if you are only getting rid of a bit of sodium you haven't used in your reaction. I have no experience with neutralizing large amounts of sodium, this method should still work but it might take a long time if you are careful as you'll have to do it in small batches.

To be honest, the fact that you asked this question here on the internet indicates to me that you should at least let someone more experienced supervise the procedure.

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  • $\begingroup$ I just wanted to comment I cannot agree more. If neither you nor your teacher are sure how to handle the disposal, neither of you really should be doing it. $\endgroup$ – J M Aug 21 '12 at 14:12
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    $\begingroup$ I would only add that if the school does not have a designated person to handle this, the best option is probably to call the local fire department. They will either be able to dispose of the sodium, or will put the OP in touch with someone who will. $\endgroup$ – Colin McFaul Aug 21 '12 at 14:42
  • $\begingroup$ If there is a nearby college or university with a chemistry department, someone at that department would likely be willing to help with disposal. $\endgroup$ – Ben Norris Aug 21 '12 at 15:58
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    $\begingroup$ Yeah...I'm a biology teacher and have absolutely zero use for pure sodium. It's only a few grams and is probably left over from a previous chemistry teacher who no longer works with us. There is no way I'm undertaking a neutralization like this on my own--and quite honestly I don't have the time to really do this properly. For all of sodium's interesting properties, I have no desire to blow up my classroom/science lab. We have permission to dispose of it and Emory University is right around the corner. We might get some help from them. Thanks, guys! $\endgroup$ – Meg Coates Aug 22 '12 at 2:48
  • $\begingroup$ $+1$ for the last paragraph. $\endgroup$ – Jan Feb 13 '17 at 22:46
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Roesky published a wounderful method based on flowerpots and dry sand, and a shallow tray of water. I regard this as my excalibur for slaying even the worst and most disgusting alkali metal monsters.

What you do is to put some dry sand in a large flower pot. Add the sodium or potassium scrap. Next fill the pot up with dry sand. Now stand the flower pot in a shallow tray with a little water. The water slowly rises up inside the flower pot over several days. The sodium is quenched by the water, the sodium hydroxide tends to react with the sand to form solid silicate. If something happens then this method has far less flammable matter which can become involved in a fire. This is why I like it. With the IPA method the use of IPA greatly increases the size of the fire which you can have if something goes wrong.

I hate the disposal method based on isopropanol / ethanol with a deep passion. I have had to fight a fire resulting from when this method went wrong. One of my lab mates added some sodium scrap to a large bowl of IPA and which already contains a lot of sodium scrap. The whole lot went up like the olympic torch.

I was out of the lab at the time going to see my PhD supervisor, I wanted him to buy me a chemical. He was out of his office, as I turned around to go back to the lab I saw the yellow flames licking up to about waist height. I rushed back to the lab.

Knowing that the bowls in question were typically used for the disposal of sodium, I grabbed a dry powder extingisher. A young lady with a CO2 extingisher came at the fire at a path at 90 degrees from mine. She gave the fire a squirt of CO2. The fire meekly complied and died. But as soon as she stopped discharging CO2 it jumped back up and continued its reign of chaos.

I then set to work upon the vile monster with my ABC powder extingisher, I had pulled the safety pin (droped it) and I took aim at the vile dragon and I squaezed hard on the levers. to my horror the bowl started to slide backwards away from me as soon as my jet of white powder hit the fire. I stopped my discharge and quickly reconsidered what I was doing. I then looked at the still burning fire and then I squezed more in a more gentle way and I let out a gentle stream of powder into the fire. I laid down white powder into the fire and as the fire became smaller I stepped closer and closer until I was right at the edge of the bowl which was the size of a frying pan. As I covered the fire with powder it died out and I found myself standing next to bowl of white solid in a christmas card scene. The floor around me was covered in white powder.

Chubb sell a special metal fires extingisher under the name "Pyromet" this is a special dry powder system which applies powder in a very gentle way. It uses graphite which is delivered with a special lance. I was impressed when I saw a film of it being demonstrated on a pile of burning magnesium turnings.

My own cheap and cheerful version of the pyromet system is to fill a polyethene bag with dry sand. I keep a bucket of loose sand in my lab and a bucket filled with these sand bags. If you have a sodium fire then lift one of these sand bags onto the fire with tongs or some other method which keeps your hands away from the fire. The heat of the fire will melt the bag and the sand comes out onto the fire thus covering it with sand.

I think that this is much more easy than trying to deliver sand with a spade or a large spoon onto a fire. I have used this method to control burning sodium during what I regard as controlled sodium burns while disposing of the residues from using sodium sand to convert ethyl esters into TMS protected hydroxy ketones.

My method is to remove the sodium and sodium chloride from the reaction mixture by filtration through celite under nitrogen gas using schlenk methods to handle the mixture. After finishing the workup and using the vacuum pump to remove solvents from the celite pad. I would clear all flammables from the workplace and deal with the leftover sodium sand. I would use a large steel can with a hole in the bottom as my flower pot. I would put in some dry sand. I would then unstopper the schlenk filter and with great care tip the solid residue out into the steel can. A few times it ignited during this operation and then started to burn in the can. I would then normally add a bag of dry sand to the top of the steel can and then wait. This method quickly brought the burning sodium under control.

Looking back I think that with 20 years of experience and my sandbag method I would have managed the sodium fire I put out as a postgrad a lot faster and with greater ease. But it was the first fire I had to fight in my life as a chemist. I hold the view that when you have had to use a fire extingisher for real that you will become a better chemist. I also hold the view that practise fires do not count, when you fight a practise fire you have someone who is experienced in fire control with you. If things get out of hand then they will step in.

I was taught a few simple rules when fighting a fire

  1. Always approuch a fire in a direction which allows you to escape, it is best to be between the fire and the door to the room. Rather than have the fire between you and the door.

  2. If the fire gets worse despite your best efforts, then retreat away from it.

  3. Before you do battle with the monster, give your extingisher a quick squirt at a direction away from the fire. If it fails to operate then check the safety pin is out and with dry powder then give it a mighty shake. Also if something unexpected comes out of the extingisher then retreat away from the fire. I have heard of horror stories of fire extingisher service workers who fail to add the chemcial additives to the water placed in a foam extingisher.

  4. If you develop any breathing difficulties while doing battle with the fire then retreat away, stop doing your St-Geroge act and leave the dragon alone.

  5. If you see gas cylinders threatened by the fire then back away, make sure you tell the fire fighters when they turn up about the cylinders.

  6. If it is a fire which involves escaping gas then do not use an extingihser, doing so will set you up for a gas explosion. Instead if you can disconnect the gas supply by closing the valve on the cylinder or the main gas valve for the lab. Then if the fire is still burning then use an extingisher on it. If you can not put out the fire by cutting off the gas supply then leave the fire to a professional firefighter.

  7. If in doubt then retreat away from it.

  8. If in further doubt then see rule 7.

I later managed to see my PhD supervisor and he did buy me that chemical, and I was able to use the chemical to do a reaction which was the basis of a good paper. One of the best chemcials I have ever asked someone to buy for me.

Like the person who gave the other answer I strongly hold the view that if you have to ask a basic question on sodium metal disposal it suggests to me that you need to ask someone who is more trained / experienced than you to deal with the problem. One of the greatest books I have ever read on radiation safety has the simple crisp advice of "refuse any work which you are either not trained for or equipped for". While this advice was targetted at industrial radiographers, it also applies to unwanted sodium metal.

A final warning, while I have chosen to share some of my experience of sodium (and potassium) and fire control, when you choose to deal with these things you have be fit to do what you need (or want) to do. Before you work as a chemist you should learn how to put out fires and manage accidents / mishapes. If you do not know how to then you should stop work and seek expert advice / training. Also if you apply fire control methods wrongly or handle sodium wrongly you endanger yourself and others, so I would suggest you think long and hard before either choosing to be willing to fight fires or work with sodium metal. I accept no responsibility for what happens to your with either fires or sodium metal.

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  • $\begingroup$ Your hatred about the isopropanol method is not a criticism of the method but of the way it was performed. It is a safe method as long as you don't try to dispose of large quantities in one go. Adding small quantities of the metal to the liquid is relatively safe. $\endgroup$ – matt_black Apr 16 '18 at 8:20

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