questions about hcl/cl process

[Traveller11]

Two questions about the HCl/Cl process:
Will it dissolve PGM's, as well as gold?
After all of the gold is leached, and prior to precipitating gold from the leach solution, is it necessary to neutralize the surplus bleach (NaOCl) in the solution?
What are the methods for neutralizing bleach, if necessary?

 

[Geo]

it will evaporate out just sitting expose to the air. the bleach is sodium hypochlorite, this gets dissolved by the hcl and is converted to chlorine gas. the chlorine will gas off at atmospheric pressure slowly (over night), but if you warm the solution below 100 degrees C for a couple of hours, the chlorine will evaporate faster.

 

[AztekShine]

Do you guys prefer this method over AR?

 

[Photobacterium]

What I've been wondering about the HCl-Clorox method is -

Since Gold does not normally dissolve in HCl, but will dissolve in HCl in the presence of Chlorine - when the Chlorine dissipates from the solution, what is there to keep the Gold in Solution ?

That is, if you do not use SMB, but are just patient and wait for the chlorine to dissolve, or perhaps accelerate the dissipation of the chlorine by heating the solution - will some or all or the Gold precipitate ?

 

[Geo]

when you dissolve gold with chlorine in hcl, the gold is converted to auric chloride (gold(III) chloride) or (Au2 Cl6). the hcl holds the gold in suspension. the reaction to do this is a mile long and im not a chemist. all i know is the result is auric chloride and gold will not self precipitate as its been stated by members that i trust that auric chloride is stable by itself for decades if not longer as long as no organics are involved.

AR is recomended for disolution of gold solids while hcl/cl works well with foils or powders or any finely divided gold and even some PGM's.