How to increase the carat of alluvial gold?

[sugianto]

Yes, you are right.
My point now is if the other content of gold is PGM, then I will save the solution after using AR. But, if the content is merely silver and copper, than it is not worth enough to spend too much time and effort.
I think, maybe, I should make some assay, but before that, I will try to find some silver to do Hoke's trick first.

I plan to make 6k Gold by adding some silver, then boiled with nitrate. The left over metal, I will weigh first. If it is indeed 89-92% of weight. I will try to leach it with cold AR. After all the yellow metal gone, I will try to boil the left over with hot AR.
Then I can be sure, whether the other content is just base metal + silver, or some PGM.

 

[FrugalRefiner]

I plan to make 6k Gold by adding some silver, then boiled with nitrate. The left over metal, I will weigh first. If it is indeed 89-92% of weight. I will try to leach it with cold AR. After all the yellow metal gone, I will try to boil the left over with hot AR.
Then I can be sure, whether the other content is just base metal + silver, or some PGM.

Keep in mind that one of the reasons for using silver when inquarting is that when you process the alloy in nitric, platinum will dissolve along with the silver. While platinum will not normally dissolve in nitric alone, when it is combined with silver, it will "follow" the silver into the nitric. Palladium will also dissolve in nitric, with or without the silver.

You can still get a rough idea of the gold content using your procedure (within the accuracy limits of your scale), but you'll want to test the nitric leach for any platinum or palladium, as that's where you'll likely find them. Iridium and rhodium would not dissolve, but you're much less likely to encounter them.

Dave

 

[etack]

why inquart at all? This gold should just be melted, shot, and put into AR. The resulting AgCl filtered and tested for other metals. The gold will come out .98+like this if washed well before melting.

If your unsure of AR then dont put it into any acids and sell it like it is.

Eric

 

[sugianto]

I inquart, because the content is 89-92% Au. If I use AR at first step, I can't take out the Silver. I just want to make sure, if there is silver, then I take out the silver+base metals.
After that, I assumed the left over is Gold+Pt. Then with cold AR, I leach Au, then rinse the leftover and boil in hot AR to leach the Pt.

 

[Barren Realms 007]

I inquart, because the content is 89-92% Au. If I use AR at first step, I can't take out the Silver. I just want to make sure, if there is silver, then I take out the silver+base metals.
After that, I assumed the left over is Gold+Pt. Then with cold AR, I leach Au, then rinse the leftover and boil in hot AR to leach the Pt.

You can run material directly in AR (no need to inquart ). Drop out the silver as silver chloride by diluting the solution with ice. Then drop your gold out of your solution with copperas. Evaporate your solution down and adjust the PH and drop out your Pt.

Your use of copperas to drop your gold out of solution on your first run should give you a purity of .99 to .9996 once you are use to the process.

Refine your gold a 2nd time if you feel it needs it or that your extra time spent with material costs justifies the expense.

And then the same thing with your Pt.

Your Pt and silver chloride I would save up and accumilate a sizeable amount to justify reprocessing them since your gold is what you are mainly after.

 

[nickvc]

It would be worth your time dissolving a small sample in AR to find out what you actually have.
Silver wil not dissolve in any significant amount so any white sediment left could be tested for silver easily, drop your gold and then test with stannous to see that all the gold is out and if any other values remain in solution.
This test will give you the answers you need as to if its worth your time and effort.

 

[g_axelsson]

Inquarting with silver will remove most of any platinum, it follows the silver in the inquartion process. (I don't know if it will follow copper too, it might do it)

I mainly suggested inquartation since you never loose the sight of the gold and it easily gets the gold to 99+% purity.

No problem with denoxing or melting power. No gold lost in filters.

Göran

 

[sugianto]

Oh, great information, Sirs.

I never know, if I inquart all, the Platinum will follow the silver. So, if we put the all in AR, i must tested all the PGM with stannous chloride, right?
Then precipitate the gold and platinum and silver separately, if it has Platinum and Silver, right?

 

[nickvc]

When you inquart you normally then dissolve off the base metals plus any silver in nitric, that is the process that will carry any PGMs , if you try to dissolve inquarted metals in AR it won't due to the presence of silver which will form an insoluble coating around the other metals.
If you just dissolve yor metal in AR any silver will form silver chloride which will settle at the bottom of your vessel but the gold, PGMs and most base metals will dissolve, you can then precipitate your gold but if there is any PGMs they will need cementing out of the solution using copper and agitation.
That's the reason we use silver it carries the PGMs into nitric, you can then either create silver chloride by adding HCl which will leave the PGMs in solution or cement the silver out the PGMs will follow and can be recovered by use of a silver cell.
I advise most people not to create PGM salts they are nasty, toxic and unpleasant to deal, they also are not keen to precipitate unless in concentrated solutions, so either cement from the AR or recover from the cell as metals.
As I said earlier your first job is to dissolve a small amount of your metal say 10 grams and filter, any white sediment may be silver you can test this, then precipitate the gold and then test the remaining solution with stannous which will tell you whether you have all the gold out and what other values may be there.

 

[sugianto]

Yes, your solution is very logical. If we inquart with silver, will all the PGMs go into the solution?
I think, I will follow your advice.

 

[nickvc]

Yes, your solution is very logical. If we inquart with silver, will all the PGMs go into the solution?
I think, I will follow your advice.

Yes they will up to I think 10% or there a outs of the silver volume.
Before you even try that do that sample run and find out if it is worth the effort, no PGMs or silver is it worth refining?