Need help dropping gold from solution

[donl001]

I have processed several batches of gold filled scrap using the process outlined on Lasersteve's "Processing of Gold Filled Scrap" video. All of the previous batches have been processed smoothly. On one batch, however, I am having a little issue... .
After completely dissolving the base metals with nitric acid, a large percentage of the gold refuses to settle out of the solution. I have attempted to dilute the solution with 3x volume of water and then boil, but, the majority of the gold still remains in suspension as it has been for approx. 2 weeks.

Any help would be appriciated.

Thanks again to all that contribute to this forum and all of the assistance / information that you have provided!!

 

[2002valkyrie]

Any advise by myself should be overlooked if beter advise has been posted. Which has been.

 

[2002valkyrie]

Deleted by 2002valkyrie

 

[Harold_V]

Any help would be appriciated.

In this case, I expect that there is no purple color to the solution, but that fine particles, resulting from the gold filled material breaking down after base metals have been removed) are in suspension.

That condition may be reversed by adding a little nitric, or even sulfuric, then boiling once again.

As my response by PM indicated, if this material can be separated from the solution, it would be important that it got incinerated, then given a boil in HCl and water. That will insure that the material that is present that is causing the gold to stay in suspension is eliminated. Otherwise, when the values are dissolved, they may be (and probably will be) impossible to filter.

Harold

 

[donl001]

Hi Harold,

Actually, the material in suspension and the small percentage that has settled appears to be all purple, colloidal gold.

Thanks,

Don

 

[Lino1406]

If it is really gold...(which I suspect)
you can use some water purifying agent
to flocculate, agglomerate (precipitate)