Sciencemadness Discussion Board

How to separate mercury and water soluble metal salts?

laguzaza - 24-8-2018 at 21:48

Can you separate mercury from water soluble metal salts, say potassium nitrate, with just water?

Here's what I thought about the process.
1.Pour water into the mixture and shake it until metal salt is dissolved.
2.Wait until mercury and metal salt solution are separated due to sedimentation.
3.Pour out the solution to get the remaining mercury.

Do you think this will work?

unionised - 25-8-2018 at 01:18

Usually.
It's possible that some metal salts will react with the mercury.

Sulaiman - 25-8-2018 at 01:23

I'm fairly confident that a few washes with tap water, then a rinse with distilled water, will remove all of the highly soluble nitrate salt.

Metallic mercury is insoluble in water so you can wash as many times as you feel necessary,
the less water/solution remaining after each rinse/decant operation,
the quicker the salt will be diluted to negligible levels.

A quick rinse with dilute nitric acid (if available) will leach out most other metals,
and finally squeezing the mercury through cloth or cotton wool removes any remaining solids.

fusso - 25-8-2018 at 02:49

Quote: Originally posted by Sulaiman  
I'm fairly confident that a few washes with tap water, then a rinse with distilled water, will remove all of the highly soluble nitrate salt.

Metallic mercury is insoluble in water so you can wash as many times as you feel necessary,
the less water/solution remaining after each rinse/decant operation,
the quicker the salt will be diluted to negligible levels.

A quick rinse with dilute nitric acid (if available) will leach out most other metals,
and finally squeezing the mercury through cloth or cotton wool removes any remaining solids.
I think it's best not to wash with tap water or the chemicals will react with mercury. Who knows how much Ag and Au (both less reactive than Hg) is dissolved in the water? They will probably be reduced to metallic form and dissolve in the mercury and will be difficult to remove even with HNO3.

unionised - 25-8-2018 at 04:09

Quote: Originally posted by fusso  
Who knows how much Ag and Au (both less reactive than Hg) is dissolved in the water?

Practically none because they would have been removed in passing through copper pipes.

However there may be copper in the water (albeit at less than 1 ppm for drinking water).
The elctrochemistry of amalgams is tricky, so I'd not like to have to say whether or not that will react with mercury.

Incidentally, mercury is slightly soluble in water to the extent of about 6 ppm.
Not enough to make a difference to washing it, but enough to make it environmentally unhelpful to do lots of washes.

Sulaiman - 25-8-2018 at 06:13

I live in a poor area where we can't afford to gold plate the insides of water reservoirs, tanks, pipes and taps :(

If there are metals in your water supply that can't be dissolved/oxidised by nitric acid then I suggest that you relocate to a safer area :o

Or start recovering PGMs from your water supply :P

[Edited on 25-8-2018 by Sulaiman]

fusso - 25-8-2018 at 06:49

Quote: Originally posted by unionised  
Quote: Originally posted by fusso  
Who knows how much Ag and Au (both less reactive than Hg) is dissolved in the water?

Practically none because they would have been removed in passing through copper pipes.
I don't even know what metal(s) my local water pipes are made of, I just know they aren't made of lead and cadmium:o

[Edited on 25/08/18 by fusso]

fusso - 25-8-2018 at 08:57

Quote: Originally posted by laguzaza  
Can you separate mercury from water soluble metal salts, say potassium nitrate, with just water?

Here's what I thought about the process.
1.Pour water into the mixture and shake it until metal salt is dissolved.
2.Wait until mercury and metal salt solution are separated due to sedimentation.
3.Pour out the solution to get the remaining mercury.

Do you think this will work?
Actually is this a hypothetical problem or a real trouble you made?

laguzaza - 25-8-2018 at 16:32

Thanks guys, your answers really helped me a lot!
Quote: Originally posted by fusso  
Quote: Originally posted by laguzaza  
Can you separate mercury from water soluble metal salts, say potassium nitrate, with just water?

Here's what I thought about the process.
1.Pour water into the mixture and shake it until metal salt is dissolved.
2.Wait until mercury and metal salt solution are separated due to sedimentation.
3.Pour out the solution to get the remaining mercury.

Do you think this will work?
Actually is this a hypothetical problem or a real trouble you made?


A hypothetical problem. I was wondering if just water is enough to break bonds of water soluble metal salt amalgam and free mercury from it. By the way can you call such mixture an amalgam?

[Edited on 26-8-2018 by laguzaza]

DraconicAcid - 25-8-2018 at 16:50

Mercury will not amalgamate with ionic compounds, only with metals.