Final ammonia water wash necessary ?

[Martijn]

The washing step should only be done on the final refined gold ! Why do you say that Lou ?

Because it makes no sense to wash recovered gold that needs refining, you can't 'wash' a solution (kind of obvious) and you have fine powder that is contaminated with just traces of other metals.
These can be easily washed out when in powder form.
If you have a second refine, the traces will be reduced by the second refine. The last bits still have to be washed out.
Washing in between refining can still be done, but not sure if it makes a lot of difference.

 

[justinhcase]

Washing in between refining can still be done, but not sure if it makes a lot of difference.

I actually wash my recovered gold before putting it back into solution.
My thinking is the fewer impurities present at the time of digestion the better.
Fewer impurities will be present to be dragged through.
Every percentage counts.

 

[orvi]

Because it makes no sense to wash recovered gold that needs refining, you can't 'wash' a solution (kind of obvious) and you have fine powder that is contaminated with just traces of other metals.
These can be easily washed out when in powder form.
If you have a second refine, the traces will be reduced by the second refine. The last bits still have to be washed out.
Washing in between refining can still be done, but not sure if it makes a lot of difference.

Actually, when I drop gold from base-metal saturated AR solution, I wash the gold with HCl, and it is very clear that immense ammount of junk go away. Better to deal with it beforehand in my opinion. Then after this very simple operation, you will continue with much purer feed for final refinement.

I am not a fan of ammonia in all, maybe only in a situation with just too high silver content. But this can be reduced by other means. And as we had smoke detectors in every room on my previous work site - I simply avoided any chance of making the smoke show

 

[Martijn]

I thought he meant after precipitating as in 'final refined gold'

Edited to take out wrong reply.