# Palladium on MLCC - am I doing it wrong?



## Wingedcloud (Aug 18, 2016)

Hello everyone,

A few days ago, I decided to venture on new ground and try and get a bit of Pd from MLCC. I've never tried this before, so, since I am a complete newbie on this field, bear with be a little :s
I hand picked 100g of them (took me 2 days  ) and followed the procedure presented by samuel-a on his website.
A first HCl leach, followed by a AR leach, followed by Zn shavings addition for Pd recovery.
Had no trouble at the first 2 steps, but struggling at the final step.

I started the zinc additions and between each addition, I tested the solution with stannous to see how I was doing.


As you can see, in all tests I get this orange color, that does not represent the positive result of Pd with stannous. I read in Hoke that a gree-blue color is to be expected.
After some Zn additions, neither the solution nor the material that is expected to deposit had the expected characteristics.



Also, there is a lot of foam as you can see. I took a bit of that foam, rolled it on a piece of paper and after adding stannous, I got this result.



Here we can see the green-blue area, indicating I definitely have some Pd in there (I guess). The thing is I don't know what to do next.
Should I add more zinc? Should I filter the solution to get rid of that white powder and add more zinc after that?

If someone can shed some light on this subject, would be much appreciated.

Kind regards,
Winged


----------



## stefano (Aug 19, 2016)

If you have denoxxed completely the solution after the AR-leach, then the SC-test gives you positive on Pd, if there was any Pd in the mlcc`s. A SC- test with Q-tip gives a almost black color at the beginning, which gets green in a few minutes, when there is a lot of Pd in the solution. If there is few Pd in the solution, the SC-test gives a brown color, and the color disappears in a dozens of minutes.
If there is almost no color, it means that there was no Pd in the mlcc`s.

If you have not denoxxed the solution after the AR-leach, then the SC-test surely gives you nothing, or a false result. You have then to denoxxing the solution.


----------



## Topher_osAUrus (Aug 19, 2016)

How much Pd are you expecting from 100g of them?

1-2 grammes?


----------



## Wingedcloud (Aug 21, 2016)

stefano said:


> If you have denoxxed completely the solution after the AR-leach, then the SC-test gives you positive on Pd, if there was any Pd in the mlcc`s. A SC- test with Q-tip gives a almost black color at the beginning, which gets green in a few minutes, when there is a lot of Pd in the solution. If there is few Pd in the solution, the SC-test gives a brown color, and the color disappears in a dozens of minutes.
> If there is almost no color, it means that there was no Pd in the mlcc`s.
> 
> If you have not denoxxed the solution after the AR-leach, then the SC-test surely gives you nothing, or a false result. You have then to denoxxing the solution.


The Denoxxing part makes sense, but...doesnt the added zinc firstly removes excess nitric and then cements our Pd ?



Topher_osAUrus said:


> How much Pd are you expecting from 100g of them?
> 
> 1-2 grammes?



Since I read that Pd content on MLCC amounts for 2% of weight, I was waiting for something around 1-2 g, yeah.

Winged


----------



## stefano (Aug 22, 2016)

Yes, adding zinc to the AR-solution which contains free nitric results that the free nitric is consumed. But the salt which forms contaminates the solution. And more contaminated is the solution results that the refinig of the PM gets much more difficult and complicated. 
Much more simple is the denoxxing of an AR-solution, when it contains only a few or better nothing of base metals.


----------



## anachronism (Aug 22, 2016)

Winged

How do you know that the MLCC you used were the Pd containing ones and not the more common base metals ones?


----------

