Pd cementing not working

Gold Refining Forum

Help Support Gold Refining Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

uzi

Member
Joined
Nov 6, 2018
Messages
15
Hi to everyone.

I have tried to find a topic with same problem as I have but still after many attempt, problem remains.

I have pins covered silver, palladium and base metal is copper. I treated them with nitric acid and recovered silver with HCL to silver chloride. Now I am tried to cement Pd with copper. I add copper bar to solution but it does not cement the Pd. I tested the solution in testing tube with DMG and I saw yellow salts (as cottage cheese) but after I mixed it well all was gone. Same is with stannous .. it show brown. I cant understand why it is not reacting as it should. Is it active nitric acid in my solution the problem?

Maybe somebody had same problem and can give me a advice.

Regards

Rayn
 
Hi Lino1406


Thanks for reply.

I have 1l solution and expected palladium is 7gm.
 
As well I tried to separate Pd from nitric solution with SMB and got light yellow sediment, after what I washed it and added distilled water and added small amount NH3 until salt become darker yellow and solution dark blue. I repeated process .. removed dark blue liquid ...added water and small amount NH3 ... salt was very dark yellow. After several times repeating this all remain same ...dark blu solution and quantity of yellow was same. I decide to wash this salt and add HCL so I can separate with zinc ...but after I did it I only got copper red sediment.

Is there any simple way as cementing to separate Pd and how its done.

Regards
Rayn
 
No I did not. I have ph papers but they are very complex. I go and buy digital one.

What additive is best to change ph of solution.

Thanks in advane Lino1406.


Rgards
Rayn
 
If you are lucky, the sodium acetate by itself will give you the palladium acetate, ready for melting
 
Thanks Lino1406

Luck sounds as russian roulette in my case. What condition must solution have to use sodium acetate. Do it separate Pd from solution where other base metals are present?


Thanks in advance

Rayn
 
Hi Platdigger

Yes, as after that solution lost hes green color.

Maybe you know why this appeare?

Regards
Rayn
 
Can someone just give tips how concentrated solution must be and what is best ph to cement Pd to copper.

Really all other chemical reactions and options are not for me.


Regards
Rayn
 
Hi Lino1406

Strange is that I left this solution with AR to the vessel and some metal is growing but it is red/pink as copper. As I understand next metal that cementing should be after copper as silver ..palladium etc. Why is copper growing?

As well I ordered PH digital meter as ph papers dont work to try sodium acetate


Regards

Rayn20181119_200956.jpg
 
You did dissolve some copper, then the zinc in the alloy the pins are made from or steel parts will cement out the copper from solution.

Nothing strange with that.

Göran
 
Hi Göran

I put these pins in HCL and start to add small amount nitric acid to remove coating. I removed one solution as it become dark red/brown and then added again HCL and started to add small quantities of nitric acid bud reaction did not start as it was with first solution so I left it. But these pins should be copper and no steel or zinc.

I go and melt some pins tomorrow to bar to make analysis for metal content. Seems these stannous and DMG showing something other then Pd. Maybe some basemetal give false results.


Regards
Rayn
 
I'm quite sure these are not copper pins. Copper based alloy but probably brass or phosphor bronze, pure copper is too soft to make good springy connectors.

Göran
 
Back
Top