Inquart dental gold

[rustyle]

I did inquart process on my 108 grams dental gold which I had XRF assay before process. Alloy = 59% Au, 1.3% Pt, 13% Pd, 23.2% Ag, and other base metal.

I alloy 108 grams dental gold with 170 grams of 80 grs sterling and 90 grs refined silver before do the inquart. I use 260 ml nitric with equal amount distill water. When finish, I cover the gold with nitric and little water to clean the gold. Wash/make sure no more nitric (wash then check pH level), boil with HCL, wash again, dry, and melt the gold, then have it XRF. I did get all gold as expected which including the platium in the gold.

Now in the solution still have silver (about 185 grs) and palladium (14 grs). I know silver can drop with clean copper but it will also drop some of palladium too.

Question is how do I drop all palladium out the solution? And how do I drop all silver without palladium go down with it?

Please help!

 

[4metals]

You have to drop the silver as a chloride and wash it well. Then reduce it back to metal. This leaves the Pd in solution. You can then cement the Pd with copper and re-digest to clean it up and concentrate it.

Another option would be to drop the Pd from the acid with DMG first and then cement the silver.

 

[nickvc]

I suspect that you might well have platinum with the silver and palladium. If instead of melting after the Hcl wash you had dissolved the material in AR you could have precipitated the gold out and then cemented the platinum out with copper.

 

[4metals]

If the platinum was low in concentration compared to silver the nitric will indeed take in Pt. Generally if the silver content exceeds 10 times the Pt content you will have Pt in the nitric.

I would then drop the silver as a chloride and cement the balance of the solution. In this case the low quantity of Pt in there to begin with the silver can carry the majority of it into solution on parting so it will be in the nitric.

Another option would be to kill the nitric acid (after dropping silver chloride) with sulfamic acid, then drop platinum with ammonium chloride and palladium with sodium chlorate. This will eliminate the tedious boil down to rid the nitric from solution but some concentrating may be necessary to drop the salts more efficiently.

 

[rustyle]

You have to drop the silver as a chloride and wash it well. Then reduce it back to metal. This leaves the Pd in solution. You can then cement the Pd with copper and re-digest to clean it up and concentrate it.

Another option would be to drop the Pd from the acid with DMG first and then cement the silver.

Thank You for all your help and advises!

I will try drop palladium out first with DMG then cement the silver. Is that the best and simple way to do? Please advise the process.

DMG solution = 4 grams NaOH + 100 ml water + 5.8 Dimethylglyoxime
Each 43 ml of this solution will drop a gram of palladium

Is this calculation correct? Please advise.

Reason I pick this process because this refine silver will be reuse as alloy so it can be contaminate little bit copper when cement it using copper. My main thing is get all Palladium out.

I'm not worry about platinum because it's only about 1grams. And XRF show some platium already in the melted gold so I don't think it's enough for any to drop out solution.

Again, Thank You for all your help and advise.

 

[rustyle]

Please any one help me to let me know my DMG mix are correct or not. And what is correct process using it.. Thanks

 

[lazersteve]

I use my DMG as described by Freechemist here:

Freechemists Palladium Test

Steve

 

[rustyle]

I use my DMG as described by Freechemist here:

Freechemists Palladium Test

Steve

Thank you! Steve,

I will do that tomorrow.

 

[rustyle]

I use my DMG as described by Freechemist here:

Freechemists Palladium Test

Steve

Hi every one,

I let it sit for more than 24 hrs, and try to filter it out. It's very hard (unable to filter) to filter even with vacuum filter. Is that normal?

Also, it's color is not yellow but it's more likely green.

 

[rustyle]

I use my DMG as described by Freechemist here:

Freechemists Palladium Test

Steve

Hi Steve,

What should I do with this very hard to unable to filter solution.

In this solution have around 200 grams of silver and around 14+ grams palladium from 108 grams dental gold. And 100+ grs silver and 9 grams palladium from another 58 grams also dental gold. So total 300+ grams silver and 23+ grams palladium in this beaker.

Please help me save it.

Thanks,

I had filter small amount and test the liquid. It have no more palladium in the filtered liquid so I add small piece copper to see silver drop. And it do drop out silver.

When I able seperate the liquid and palladium, do I just dry and melt it? or do I need to go any more step before melt it?
I saw your video, your palladium look yellow then dry/heat for it turn to gray. And then melt it.

But my look like it's green???....

 

[samuel-a]

Pd- dmg is best filtered by gravity filtration. use fluted paper.
Instead of cementing with copper (which you say doesn't happen) try precipitating with HCL and treat the cloride salt.

DMG is good to scavenge traces of Pd from solutiones of other metals, but not for an actuall recovery of large amounts... unless you have filter press + very cheap DMG.

 

[freechemist]

Hi rustyle,

In your post from March 26th you write the following:

Now in the solution still have silver (about 185 grs) and palladium (14 grs).

Judging the colours of solution and of precipitated material in pictures, you posted later, this solution contained also Cu, and may be some Pt, which (slower, than Pd) precipitates on addition of DMG, too, causing the now dark coloration of the solid material. In my practice, on several occasions, I have obtained similar, quite dark precipitates on treating used silver-electrolytes, containing too much Pd with DMG.

In this case, after my opinion, it would have been the best, like 4metals proposed it, to precipitate silver quantitatively as AgCl, leaving Pd (and eventually Pt) in solution. Regarding the composition of your solution, this would have been done best by slow addition of the combined Ag/Pd-solution to a big excess of hot aqueous HCl, more than stoichiometrically required, to precipitate AgCl quantitatively and let react all Pd to PdCl₄^2-.

Regards, freechemist