Sciencemadness Discussion Board

Chemical storage and ZnSO4

Copper - 24-10-2015 at 17:31

Currently I store solids in glass containers, and liquids in HDPE containers. I'm thinking of placing 4 molar sulfuric acid into the HDPE container, but I'm not sure about leakage. Also what would be best to store hazardous solids?

Also, I'm trying to make ZnSO4. I plan to make it through Zn + H2SO4 (dilute). I would do that in a glass container. Then I need to evaporate it, but I run into a problem. If I let is sit outside, it will gather dust and become impure. If I boil it, the glass may crack (I'm using a glass jar), and it might burn the ZnSO4. Otherwise the ZnSO4 may spit out like the time I tried to boil off water from a salt solution.

Any help would be appreciated. Thanks

Deathunter88 - 24-10-2015 at 19:22

Solids in glass and liquids in HDPE seems ok. On rare occasions concentrated acids will slowly degrade HDPE but that is very rare. 4molar sulphuric acid is even fine in PET containers so storing in HDPE is fine. Just leave your solution of zinc sulphate in a corner of a room and cover a with loose sheet of paper towel.

Copper - 24-10-2015 at 19:48

Thanks for the help, I'm wondering if the paper towel might seal off the container and set up equilibrium though?

cyanureeves - 24-10-2015 at 19:51

do ground glass botles with stoppers really work for nitric acid? does any one here use these?there a couple of bottles on ebay right now for sale but i dont know.i have a bunch of those qorpak but the lids even though have teflon do eventually leak. i noticed the bottles sold by finn scientific have a teflon rim on top of the bottle itself.that teflon rim is what i think make these containers work as opposed to just a teflon liner on a qorpak lid.finn scientific only sells to teachers and schools too,i have even thought about buying a bottle of nitric acid just for the bottle.i can make nitric acid though.

greenlight - 24-10-2015 at 20:44

I used to use glass reagent bottles with ground glass stoppers for 98% Sulphuric and 70% Nitric acid.
They work but I used to wrap a layer of PTFE plumbers thread tape around the stopper which would makes it airtight and change the tape every couple of months.

cyanureeves - 25-10-2015 at 10:28

thanks greenlight for your answer as i was just about to delete my question above.of course teflon tape will make a good gasket wrapped around the ground glass.problemo solved.

maleic - 28-10-2015 at 01:01

HDPE can accommodate 100% and strong acid between 20-60, all have good corrosion resistance。

greenlight - 28-10-2015 at 02:53

This is correct, I have a large HDPE container for 62% HNO3 that is from 2006 which I use to store it and distribute smaller portions into glass reagent bottles for refrigerator storage when needed. I only just had to change to a fresh HDPE container as the plastic was getting quite brittle.

[Edited on 28-10-2015 by greenlight]

agent_entropy - 28-10-2015 at 05:46

@ Copper The paper towel might slow the evaporation slightly, but it's more than porous enough to let water vapor escape.

ahill - 11-11-2015 at 02:56

@cyanureeves I keep my >90% nitric acid in ground glass stoppered bottles which are then kept in ziplock plastic bags. After a few months, the bags always have a little acid in the bottom - so its far from optimal.

I've started using PTFE tape on the stoppers, and that seems a little better - but really, I'm still not very happy with it.

These days, I just keep conc H2SO4, and make what nitric acid I need as I need it, and only ever store what is left over.

annaandherdad - 11-11-2015 at 08:15

Copper, a problem you may have with making ZnSO4 from Zn + H2SO4 is that there will always be a bit of H2SO4 left over (of course less and less the longer you leave the Zn metal in there). But one way to take care of this is to take a small sample of your ZnSO4 solution (presumably with some H2SO4 still in it), add Na2CO3. This will neutralize the excess acid and precipitate ZnCO3. Filter, wash and dry the ZnCO3, then add to the ZnSO4 + H2SO4 mixture. This will neutralize the excess H2SO4. Then filter to remove the excess ZnCO3 and what's left is pure ZnSO4 solution. It crystallizes just fine when you dry it.