boilng point of HAucl4 [missing gold]

[slouma37]

Hi Richard,
if u noticed, i try to focus the maximum on the gold reactions and today i learned that all gold chlorides : AuCl, AuCl4-, HAuCl4, AuCl3 and Au4Cl8 are also subject to light dissociation. Yes the simple day light can let the gold goes out , evaporates (of course specially) if the beacher is not COVERED.

It's a bit comprehensive as the Cl2 molecule is subject to dissociation when exposed to light.

Let's say w'll work from now on on a candel light by night...to resolve this problem definitly. and secondly COVER always any gold chloride solution to avoid any evaporation.

Now about Urea, i was incriminating urea for a while to be the most step ruining me...after some essay's i noticed that i can recover 98% of my dissolved buttons recovered with the use of urea to neutralyse the NOx's AND any excess of HNO3. why the HNO3 ? i insist on this coz steve says somewhere that Urea only react to eliminate's the NOx's and not the HNO3. It's false. (forgive me Steve if it was not u who said that)...
Coz Urea reacts with HNO3 like this:
5 (NH2)2CO + 6 HNO3 ---------> 8 N2 + 5 CO2 + 13 H2O
and also can react this way giving urea nitrate in solution :
(NH2)2CO + HNO3 ------------> CO(NH2)2.HNO3

So Urea swing both ways...

and why it's my favorite way of denoxing , it's coz it reduce the TIME of denoxing especially when we used an excess of HNO3, in the case we don't know the exact mass of gold we expect. + The reason of we cant denox with heat without letting the solution UNCOVERD.

Ok here i follow the advices to put cristal urea in hot water before adding it little by little in my AR to denox tille it stops fizzing definitly.

hope all this helps

 

[butcher]

I really do not think the light vaporizes gold, but bielieve that it can change the gold salts state, like HAuCl4 to AuCl4, not loosing any gold just loosing hydrogen.
again this is just the way I understand it, and I am just learning also.
and if any gold actually did evaporate my guess it would be hard to measure the weight difference without scientific atomic scales, again my speculation.

using urea is up to you, but here is an Idea that works for many members here, only use the nitric to get the job done, that way you will have none to very minute excess nitric to eliminate, also another trick is adding gold button to use up any excess nitric in solution. I am not saying the urea will not work, I just believe their are better way's, but each of use may choose to recover and refine our gold differently, that does not make either of us right wrong or left.
but if it is high quality gold you seek then I would read some of the older posts of Harold, and GSP on eliminating the nitric from aqua regia, between these two professional refiners I think we can learn the best of two worlds, and gain from almost a century ogf their combined expierience.


slouma37, my friend, please spend some time reading the posts on this forum, their are some professional refiners that can teach us more than we dreammed of learning

 

[philddreamer]

Butcher wrote:
"Phil, on your Inquartation notes you made up, it say's boil, can you edit it to say slow evaporation?"

I fixed it. Thanks!

Phil