I'm having trouble cementing Palladium, help...

[orvi]

DMG is very good tool for Pd scavenging, but it does not work well in all circumstances.

I found that too much residual nitric acid tend to decompose DMG and forming Pd complex, so I always neutralized majority of free nitric in the solution using sodium hydroxide. pH must stay low tho. Aim for pH slightly above 0. Then, I usually filtered the solution from any undissolved junk and added DMG. You do not need to prepare a solution, if you have good mechanical/magnetic stirrer. Just add it in as powder with vigorous mixing.

Reaction of DMG with Pd in nitrate solutions is usually faster than in HCl solutions - DMG has somewhat better solubility in nitrate media in my experience. It can take one hour or even more to precipitate all of the Pd if solid DMG is used -- but I just usually let it stir and came back hour or two later to filter it.
That mixing and constant agitation is very important.

Never try to drop Pd with DMG from non de-NOx-ed AR solutions. DMG is severly decomposed in these, and precipitation is always incomplete. And in addition, decomposition products from DMG disintegration can be dangerous.

I always de-NOx-ed the solution, then dropped the gold, and finally scavenged Pd with DMG (AR solution, AuPd scrap). I just added some excess of it and let it stir vigorously overnight in a beaker on magnetic stirplate. Filter the precipitate in the morning, wash with some few % HCl...

 

[amirfmpz]

Thank you.

 

[amirfmpz]

Hello budy, how are you ? Whenever I used DMG, there was nitric in the solution too and yes it dilutes the solution (if you don't do this the acid redilutes the pDMG). I've never done it with hydrochloric alone. But you can try to hurry up.

Great, how are you? Yes, I have to do the same thing. Thank you for your help.

 

[Yggdrasil]

Hi .dmg in concentrated hydrochloric acid
Does it precipitate the palladium or should the hydrochloric acid be diluted??

What about replying to the initial comments?
As said DMG solution is prepared best in NaOH.
If you search the forum there are good description on how to prepared it.

 

[Yggdrasil]

DMG is very good tool for Pd scavenging, but it does not work well in all circumstances.

I found that too much residual nitric acid tend to decompose DMG and forming Pd complex, so I always neutralized majority of free nitric in the solution using sodium hydroxide. pH must stay low tho. Aim for pH slightly above 0. Then, I usually filtered the solution from any undissolved junk and added DMG. You do not need to prepare a solution, if you have good mechanical/magnetic stirrer. Just add it in as powder with vigorous mixing.

Reaction of DMG with Pd in nitrate solutions is usually faster than in HCl solutions - DMG has somewhat better solubility in nitrate media in my experience. It can take one hour or even more to precipitate all of the Pd if solid DMG is used -- but I just usually let it stir and came back hour or two later to filter it.
That mixing and constant agitation is very important.

Never try to drop Pd with DMG from non de-NOx-ed AR solutions. DMG is severly decomposed in these, and precipitation is always incomplete. And in addition, decomposition products from DMG disintegration can be dangerous.

I always de-NOx-ed the solution, then dropped the gold, and finally scavenged Pd with DMG (AR solution, AuPd scrap). I just added some excess of it and let it stir vigorously overnight in a beaker on magnetic stirplate. Filter the precipitate in the morning, wash with some few % HCl...

He has another thread on his material and have not showed positive Stannous test.
But to settle matter a DMG test would be conclusive even if he do not precipitate, right?
Say in a teaspoon or so?

 

[amirfmpz]

What about replying to the initial comments?
As said DMG solution is prepared best in NaOH.
If you search the forum there are good description on how to prepared it.

I precipitated the orange salt from my nitric acid solution with aluminum.
Then I took some of this sediment and dissolved it in concentrated hydrochloric acid.
Then I dissolved 1 gram of dmg in 50 ml of hot water (it did not dissolve / I added sodium hydroxide until it dissolved).
Then I added this solution to that solution > but the palladium did not precipitate!!!!!
That's why I asked if my hydrochloric acid solution should be thick or dilute?
And I found out that dmg works in a solution containing nitrate>!!

 

[Yggdrasil]

I precipitated the orange salt from my nitric acid solution with aluminum.
Then I took some of this sediment and dissolved it in concentrated hydrochloric acid.
Then I dissolved 1 gram of dmg in 50 ml of hot water (it did not dissolve / I added sodium hydroxide until it dissolved).
Then I added this solution to that solution > but the palladium did not precipitate!!!!!
That's why I asked if my hydrochloric acid solution should be thick or dilute?
And I found out that dmg works in a solution containing nitrate>!!

That means you do not have Pd in solution, as long as you did not add so much that the pH got too high.
Add a bit of the DMG solution to the solution you are testing, like a drop or two in a full teaspoon.
What color was the solution before the DMG?

 

[amirfmpz]

Red

That means you do not have Pd in solution, as long as you did not add so much that the pH got too high.
Add a bit of the DMG solution to the solution you are testing, like a drop or two in a full teaspoon.
What color was the solution before the DMG?

 

[amirfmpz]

When we deposited palladium with dmg.
If nitric acid is present in the solution.
Does it dissolve palladium again????

 

[Yggdrasil]

When we deposited palladium with dmg.
If nitric acid is present in the solution.
Does it dissolve palladium again????

To some degree I guess, but not instantly.
So far there is nothing indicating that you have Pd in solution.
And you can not precipitate what is not there.
Redo the Stannous on paper/cotton bud and the DMG test in a spoon full of solution, then one drop of DMG solution in there.

 

[amirfmpz]

To some degree I guess, but not instantly.
So far there is nothing indicating that you have Pd in solution.
And you can not precipitate what is not there.
Redo the Stannous on paper/cotton bud and the DMG test in a spoon full of solution, then one drop of DMG solution in there.

OK, I'll do it, I'll send the movie. Thank you

 

[amirfmpz]

With dmg it was colored.

 

[Yggdrasil]

With dmg it was colored.

Keep your posts regarding the same in one thread please!

 

[amirfmpz]

Keep your posts regarding the same in one thread please!

ok