H2O/gold solution will not boil

[SCHROEDERFPM]

TL;DR

Hi!

So I have been experimenting with different fluid/metal mixes.
I first took a handful of gold coated computer pins, put them in salt water, applied a current.
This corrosion and I was able to seperate the copper diluted liquid using a slow oil and water seperation leaving tap water and the "gold flakes".

I then tried to boil off the water, by sitting the glass bottle in a pot of salt-water and bringing it to boil but the gold would not boil, about 45 minutes & till as a pond.

Any ideas?

This is my solution and it remained still and did not bubble once while the pot boiled . I realise salt and oil impurities may increase the boiling point but I wouldn't imagine to this extent, and when I filtered the solution the oil seemed to collect the copper and other dissolved metals turning green before I removed it from the clear water and yellow gold solution you see here. It really withstood a lot of heat.

 

[.Scott]

A saturated aqueous salt solution will boil at 108.7C. If you limit the temperature that you are applying to the water to 108.7, it will evaporate - but probably not boil.

 

[jack action]

I then tried to boil off the water, by sitting the glass bottle in a pot of salt-water and bringing it to boil but the gold would not boil, about 45 minutes & till as a pond.

Why do you put the glass bottle in another salt-water pot? If the boiling point of the water in the pot is a fraction of a degree below the one for the water in the glass bottle, the water in the glass bottle will never boil.

Possible solutions are:

• Use a liquid with a higher boiling point in the pot;
• Pressurize the pot as in a pressure cooker. You will have to isolate your glass bottle and somehow vent it outside the pressurized pot.

It really withstood a lot of heat.

It did not. The "lot of heat" was used almost exclusively to boil the salt-water. It never reached the glass bottle and its content other than the heat transfer due to the initial temperature difference between the two liquids.

 

[russ_watters]

Why do you put the glass bottle in another salt-water pot? If the boiling point of the water in the pot is a fraction of a degree below the one for the water in the glass bottle, the water in the glass bottle will never boil.

Below? Above? I have my doubts that boiling is even possible in this setup with what is working against it:

1. Open-top container loses significant heat due to evaporation at near boiling temperatures.
2. Poor thermal conduction of glass.
3. Low delta-T - even boiling saturated salt and trying to boil pure water in the glass, you have a delta-T of only 8C.

 

[SCHROEDERFPM]

Why do you put the glass bottle in another salt-water pot? If the boiling point of the water in the pot is a fraction of a degree below the one for the water in the glass bottle, the water in the glass bottle will never boil.

Possible solutions are:

• Use a liquid with a higher boiling point in the pot;
• Pressurize the pot as in a pressure cooker. You will have to isolate your glass bottle and somehow vent it outside the pressurized pot.

It did not. The "lot of heat" was used almost exclusively to boil the salt-water. It never reached the glass bottle and its content other than the heat transfer due to the initial temperature difference between the two liquids.

I added salt to try and raise the boiling point of the pot water above that of the liquid in the bottle, which is tap water for the most part.
I will try a pressurized system or a different container.

 

[SCHROEDERFPM]

Below? Above? I have my doubts that boiling is even possible in this setup with what is working against it:

1. Open-top container loses significant heat due to evaporation at near boiling temperatures.
2. Poor thermal conduction of glass.
3. Low delta-T - even boiling saturated salt and trying to boil pure water in the glass, you have a delta-T of only 8C.

Thankyou.

A saturated aqueous salt solution will boil at 108.7C. If you limit the temperature that you are applying to the water to 108.7, it will evaporate - but probably not boil.

I did not even observe any water loss from evaporation the liquid just did not get hot enough inside the bottle.

From reading responses possibly due to the nature of the glass or the setup. I will try some other methods.

 

[SCHROEDERFPM]

Below? Above? I have my doubts that boiling is even possible in this setup with what is working against it:

1. Open-top container loses significant heat due to evaporation at near boiling temperatures.
2. Poor thermal conduction of glass.
3. Low delta-T - even boiling saturated salt and trying to boil pure water in the glass, you have a delta-T of only 8C.

Below/above what sorry?Thankyou. I will try some other setups, although I did not observe any evaporation inside the bottle the liquid just didn't get hot enough. It remained still and in a liquid form .

 

[russ_watters]

I did not even observe any water loss from evaporation the liquid just did not get hot enough inside the bottle.
From reading responses possibly due to the nature of the glass or the setup. I will try some other methods.

Is the container open? If so, there's evaporation and if then, it's exactly in the amount of the input heat, which is very low. You might be able to watch it for an hour and not notice a level change.

Below/above what sorry?

Temperature. Jack said if your solution's boiling point is a fraction above the bath's there will be no heat transfer. But even if the solution's boiling point is below the bath's, the maximum temperature difference is 8C which is exceptionally small to try to transfer heat.

 

[jack action]

Jack said if your solution's boiling point is a fraction above the bath's there will be no heat transfer.

No, I said it wouldn't boil but there still can be a heat transfer.

even if the solution's boiling point is below the bath's, the maximum temperature difference is 8C which is exceptionally small to try to transfer heat.

But it will boil.

Still, I was curious and experimented with a bain-marie made of stainless steel with tap water in both cans.

While the water in can 2 was boiling hard, the water in can 1 barely had small bubbles at the bottom with a little steam floating away. Even by putting the lid on it, it wouldn't change much, certainly not making the lid "dance" under pressure like it was doing in can 2.

 

[russ_watters]

No, I said it wouldn't boil but there still can be a heat transfer.

I misstated: not enough heat transfer to boil no matter the real configuration. No heat transfer would require no heat loss by the inner vessel (it would level-off at the temperature of the outer bath and be insulated above).

But it will boil.

Still, I was curious and experimented ...

While the water in can 2 was boiling hard, the water in can 1 barely had small bubbles at the bottom with a little steam floating away. Even by putting the lid on it, it wouldn't change much, certainly not making the lid "dance" under pressure like it was doing in can 2.

I really don't want/see a need to quibble about this. PF likes to go down the rabbit hole of additional nuance and confounding factors. Sure, you can make a pot boil with an 8C delta-T if you work hard enough. Heck, the ultimate would be a covered inner vessel that you blast with steam so the condensation transfers more heat than a water bath would. Heck, even in a nice rolling boil a lot of the heat transfer will be via steam condensation not water convection. But that doesn't seem to match what we have here.

 

[SCHROEDERFPM]

So the inner pot will never reach the temperature of the outer because of the heat loss?

 

[russ_watters]

So the inner pot will never reach the temperature of the outer because of the heat loss?

Correct. And how close they can get to each other depends on how well you can restrict the heat loss.

 

[SCHROEDERFPM]

Ok Thankyou.

 

[nasu]

Why do you want to boil the water in the first place?

 

[SCHROEDERFPM]

Why do you want to boil the water in the first place?

I don't know I'm just messing around