Australia's Science Forum

Hi Guys, Has anyone had any success in drying out chemicals such as Magnesium nitrate that have deliquescent ie absorbed moisture to the point of being liquid I must have a very damp storeroom, and have a number of chemicals that making any solution of known concentration is impossible because of the unknown volume of water they have absorbed. It is frustrating as we use so little of these chemicals but my only alternative is to buy fresh and use a tiny amount and watch they rest turn to mush! Ive tried sealing with parafilm with limited results more interested in resurrecting the chemicals I have Any hints ?

MariaC

Aside from using an evaporating basin to boil them dry, I don't know how you would go about it. Perhaps you could store some of those bead things that absorb moisture from the air? I can't think what they are called but I can picture them! lunch box sized plastic containers, I think clear with a pink lid. Sorry I can't be more helpful than that. Otherwise keeping lids tight is the only thing I do to prevent this. Oh! Perhaps you could run some plumbers tape around the top of the bottle when you first get it and then screw the lid back on? Just another thought...

I had this problem with a nitrate at the start of the year (zinc?) and there were lots of great replies. Maybe do a search????

It was zinc nitrate. Good luck, and tell us how it goes, I too, need to dry some chems out.

Maybe what your thinking of is a dessicator. I'm sure you could google it. you need to put some silica gel or some other substance in the bottom to absorb moisture. it has a tight fitting lid so you create a dry atmosphere. if you use one, make sure you grease the seal between lid and base, otherwise you may have trouble sliding the lid off.

hope you have some success

Sharon

OR we put a piece of cling wrap over the opening of the bottle, small silica gel, bag. (We ask for these via our news letters to staff & students, they come in all sharpes and sizes, some with shoes, some with herb tablets) on top of the cling wrap. Put the lid on, and twist it down. I have done this for a few years, now and so far so good. Yes some times the little silica gel bag, has fallen into the chemical, but that ok. My sodium Hydroxide has lasted that way for a few years now, which is great.. Twist the long pieces of cling wrap around the lid or over it. See if that helps.

Does that dry them out though once they have absorbed the water??

The silica gel has the ability to absorb any moisture in its environment. you can't see inside the little pillows but when it's saturated the silica gel turns pink. when it's bright blue it has capacity to absorb moisture. you can dry out pink silica gel by putting it in the oven and watch it turn blue again. (unsure of temp but shouldn't have to be too hot - maybe less than 60deg????). i havent dried the little pillows so don't know what temp the pillow fabric can stand. i use bulk silica gel and just fill up an evap basin and stick it in the oven. voila!!!!!!

Calcium chloride anhydrous lumps used in dessicator.

Descication is definitely the way to go. You don't want to heat nitrates, or you'll end up with oxides, ... and nitrogen dioxide gas!

2 Mg(NO3)2 + heat → 2 MgO + 4 NO2 + O2

Thanks for all the replies! I didn't think the desiccator would work with that amount of fluid but Ill give it a try and let you know the results MariaC

Hi MariaC
I have several dessicators for hydroscopic ( or is it deiquescent ) chemicals. I keep litmus paper in them also. They're not very expensive and worth investing in to avoid future problems.
Judy