Boiling AR Gold Solutions

[NoIdea]

Hi Harold, Yep I am boiling a AR solution …… for science. 8)

In trying to capture as much of my acid as possible, the unit that performs this task is semi-sealed condenser/receiver, the receiver has wet cotton wrapped around it to trap any vapours that may want to escape after dissolution of NOx gases.

The AR gold solution was boiled, more of a rolling boil; I was not concerned about losing gold as it would end up in the condensed solution



The point Harold, God bless his persistence, has regurgitated over and over again is NOT to BOIL your AR solutions, so I took this opportunity to discover what does in fact happen when you do not heed to Harold’s valued warnings.

Result: I found no evidence that gold chloride distilled over while boiling a dilute solution, note that a degree of reflux is apparent and may prevent Au from carrying over, however, once the NOx gases became visual, so did the gold chloride, condensing higher up on the wall of the boiling vessel. And after a time gold was found in the distillate.

The two pictures show the apparatus I’m using and a close up of the condensed gold chloride on the wall of the vessel.



I use and aquarium air pump to blow air into the condenser instead of water because it is around 10deg.C here at the moment.

So, in conclusion: DO NOT BOIL YOUR AR solutions.

Can’t imagine how much gold has already gone up and out of refiner’s beakers :roll:

Regards

Deano

 

[Harold_V]

So, in conclusion: DO NOT BOIL YOUR AR solutions.

Can’t imagine how much gold has already gone up and out of refiner’s beakers :roll:

In my case, it was enough to turn the side of my travel trailer a nice purple color. A nice circular fan pattern, the result of evaporating too quickly, with a fan in the garage window directly above my hotplate. The end of my too fast evaporation and the beginning to my understanding of the value of a proper hood.

That was the day I came to understand that Hoke knew what she was talking about! 8)

Harold

 

[4metals]

It is common for gold to pass off the reaction in the vapors even if you don't boil the solution, but boiling surely speeds things up.

I like to set up scrubbers with condensed reactions so the condensate falls back into the reaction, this serves to lessen the NOx load and recycle some acid. Some acid always passes out of the condenser as well and it is picked up by the low CFM drops I like to put into the exhaust hoods and connect to the scrubber.

Usually 2 or 3 times a year it pays to flush out the ductwork and collect the liquid coming out of the drops. The acid from these rinses always leaves a stain when testing with stannous, even the drops which exhaust reactions which are not heated.

 

[butcher]

Thanks for the post of your experiment NoIdea.

I would like to remind members that you can also lose gold in roasting them with chlorides or even salt, If I have a powders with gold and chlorides I will neutralize them with sodium hydroxide and wash out the salt that is formed from neutralization reaction.

 

[qst42know]

Thanks for the post of your experiment NoIdea.

I would like to remind members that you can also lose gold in roasting them with chlorides or even salt, If I have a powders with gold and chlorides I will neutralize them with sodium hydroxide and wash out the salt that is formed from neutralization reaction.

I wonder if this would be beneficial when dealing with your filter paper storage?

If you dropped your papers directly into a lye solution, silver chloride would get converted while wet, and the volume of paper reduced. The resulting sludge could be washed dried and incinerated without losses in silver or gold.

Anyone see any issues with this idea?

 

[glondor]

RE: filters in lye....I think there are issues with this but I will let some one who knows for sure. I think the term is "wet ashing" and I understand it is very dangerous. I was told doing this with sulfuric was bad, I do not know if it is the same with lye.

Please clarify this before trying anything. You don't want to make things that go boom.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=10360&p=99940&hilit=wet+ashing#p99940

 

[butcher]

I think the concentration of lye solution should be a considered, to concentrated and silver may become a hydroxide (? Soluble?), instead of an silver oxide,

We are going to need to incinerate the paper to ash anyway (volume of paper does not concern me), and we will need to rinse the sodium chloride that forms. so I see no problem with a dilute hydroxide solution, but I prefer to store my papers dry.

I cannot think of anything that would go boom.
And qst42know did state wash and dry sludge, (so qst42know is not talking about hot NaOH which would be nasty if it splashed on you or would blind if it got to your eyes)