Sciencemadness Discussion Board

Liquid Mercury

Steveboy25 - 8-12-2015 at 09:23

Hello new to the forum just wondering is ther a safe way to make Hg salt out off liquid Mercury yes I have seen the post by another member and used search bar to find answers but ther must be a safer way to do it.
Thanks in advance

Detonationology - 8-12-2015 at 09:32

What kind of salt do you wish to make? A safer to handle Hg salt? Typically, soluble Hg compounds are MUCH more dangerous to handle than metallic, liquid mercury.

Steveboy25 - 8-12-2015 at 12:30

Safe as possible kind really it's for a aluminum amalgam

chemrox - 8-12-2015 at 13:15

I would buy HgCl2. Seems like a waste of valuable metal to salt it. However, Hg & HCl should give a result. Waffen is one of the guys that could help with stoichiometry and conditions.

Steveboy25 - 8-12-2015 at 13:23

I have 3kg off it couldn't buy it in a salt just liquid form cheers for the help

Detonationology - 8-12-2015 at 13:35

"Aluminum amalgam may be prepared by either grinding aluminum pellets or wire in mercury, or by allowing aluminum wire to react with a solution of mercury(II) chloride in water." (Wikipedia) I don't have experience with any mercury compounds, but I wonder what what happen if you were to melt some aluminum in a crucible with a fairly insoluble mercury (II) salt until it was mixed consistently throughout the aluminum. Perhaps, at elevated temperatures the mercury salt would be more likely to attack the aluminum.

Metacelsus - 8-12-2015 at 16:19

For amalgam, just use the liquid Hg. It's less convenient, but safer than having to prepare a salt.

careysub - 8-12-2015 at 17:39

From my (online) investigation of the uses if mercury I gather that aluminum amalgam for reductions can be prepared using mercury(II) nitrate instead of mercury(II) chloride.

While equally toxic it seems much safer to prepare and work with - it does not sublime like the notorious "corrosive sublimate", and is easily made (at least, if you have some nitric acid).

Direct combination of mercury and aluminum sounds like a good idea (no soluble mercury compounds) but the actual procedure sounds difficult:

"The most direct way is to grind aluminum pellets or wire
in mercury. This is not a particularly easy method to
control or standardize, and ideally it should be performed
in an inert atmosphere to prevent the amalgamated aluminum
from reacting immediately. "
http://www.clays.org/journal/archive/volume%2019/19-5-337.pd...

Fine aluminum powders are available (down to just a few microns) which seem like they would amalgamate very readily. The inert atmosphere would make things more difficult, but how about performing this under a liquid to exclude air contact, both mercury and aluminum being dense.

byko3y - 9-12-2015 at 02:35

Sulfates and nitrates love to decompose and hydrolyze
2Hg(NO3)2 --> 2HgO(s) + 4NO2(g) + O2(g)
that's why they don't sublime, so you need to add a small amount of acid to a solution of an old salt until all the HgO percipitate is dissolved
To prepare both chloride and nitrate you need to oxidize the mercury with nitric acid, because neither HCl nor dillute H2SO4 can oxidize the mercury.
So, the simplest way to obtain mercury salt is to make a nitrate in a hot 40% nitric acid.
Elemental mercury vapor is thought to be as toxic as organomercury compounds.
You can't make aluminium amalgam with elemental mercury - they just don't react easily because of aluminium oxide layer, which is not a problem for pitting corrosion when using mercury (II) salt.

[Edited on 9-12-2015 by byko3y]

hissingnoise - 9-12-2015 at 03:17

Aluminium versus mercury!


byko3y - 9-12-2015 at 06:15

AFAIK it's 40 seconds of the video are 40 minutes of real time - you can clearly see why it's not suitable for amalgam preparation.

careysub - 9-12-2015 at 07:21

Quote: Originally posted by byko3y  
AFAIK it's 40 seconds of the video are 40 minutes of real time - you can clearly see why it's not suitable for amalgam preparation.


Thanks for your very informative comments.

And the video does show why aluminum airplanes and mercury do not mix.

Although ~2 hours (according to the text) elapses, and the amalgamation process was kickstarted by "scratching gallium into the surface", this does make it seem like some procedure using a little gallium to get the process started might be viable. An hour or two for a preparative procedure to complete is not unreasonable (if if works).

I see comments here about using gallinstan in amalgamations, but little or no experimental, so I can't tell if this really viable or not.

Steveboy25 - 12-12-2015 at 08:17

Cheers for that fellas