# Pd cementing not working



## uzi (Nov 14, 2018)

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


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## Lino1406 (Nov 14, 2018)

How much palladium is expected from the batch you treated? (seems negligible)


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## uzi (Nov 15, 2018)

Hi Lino1406


Thanks for reply. 

I have 1l solution and expected palladium is 7gm.


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## uzi (Nov 15, 2018)

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


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## Lino1406 (Nov 15, 2018)

Did you control pH at 4 (or saturate with sodium acetate) before DMG?


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## uzi (Nov 15, 2018)

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


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## Lino1406 (Nov 15, 2018)

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


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## uzi (Nov 16, 2018)

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


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## Lino1406 (Nov 16, 2018)

YES if silver is already gone


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## Platdigger (Nov 16, 2018)

uzi, did you treat all of your solution with zinc?

I am curios about this "copper red sediment"
Did you check to prove it is only copper?


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## uzi (Nov 19, 2018)

Hi Platdigger

Yes, as after that solution lost hes green color. 

Maybe you know why this appeare?

Regards
Rayn


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## uzi (Nov 19, 2018)

Pic of strange cementing


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## uzi (Nov 19, 2018)




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## uzi (Nov 19, 2018)

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


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## Lino1406 (Nov 19, 2018)

What is strange here?


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## uzi (Nov 19, 2018)

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

Rayn


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## g_axelsson (Nov 19, 2018)

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


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## uzi (Nov 19, 2018)

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


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## g_axelsson (Nov 19, 2018)

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


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## Lino1406 (Nov 20, 2018)

The white metal objects, what they are doing?


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## uzi (Nov 20, 2018)

Hi Lino1406

On whit pins don´t grow copper on them, only darker pins.

It seems I am one step closer. I found that best ph for cementing on copper is 2-3. At the moment I made solution ph4 and sms that most of copper and nickel is removed from solution. Ph treated solution is still red coffee color as it should be?

Rgards
Rayn


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## Lino1406 (Nov 20, 2018)

Sorry I don't get you. Do you expect palladium after copper and nickel are gone?


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## DNIndustry (Nov 24, 2018)

Are you sure these are not military beryillium copper or phosphor bronze.? The white is fire suppression. Used in airplanes. Civilian as well.

https://en.m.wikipedia.org/wiki/Beryllium_copper


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## uzi (Feb 26, 2019)

Hi.

I find a way how remove plating from pins so I don´t need to dissolve all metals. I removed plating in NaOH and SMB solution used 3.0V (graphite anode and stainless steel cathode). It took 4 days to remove plating of these soviet pins. 

After that I got about 200gm of black powder. I treated it with diluted aqua regia so silver will be left behind. After aqua regia there was only about 30 gm light grey powder left. As I tested AR solution with stannous there was light orange/red result. As solution is green I tested with ammonia and it show that copper is in it as well changed hp with ammonia and checked nikel with DMG and there was light rose sediment. 

Thing is that this aqua solution have some kind of grey crystals after it become in room temperature and these crystals are growing. Can it be that silver went to AR solution and it coming out now. Or is some other metal behave like that. If someone can give me a little information as if it is Osmium or some other kind of dangerous metal then I leave it and not dealing with it.

I add a pictures of process 

1. deplating pins
2. collected plating in filter
3. powder treated with Nitric (test)
4. AR test with stannous
5. Crystals after AR cooling to room temperature.
6. Crystals pic 2 in test tube 

Please if someone have information of situation then please let me know.

Regards

Ain


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## uzi (Feb 26, 2019)

Pics of process


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## uzi (Feb 27, 2019)

Hi.

Today I tested my grey sediment what was left after AR treatment with Ammonia so I can recover silver as chloride. As AR was first treatment of collected black mud from electrolysis then I was sure that this light gray mud left after AR is silver as chloride. 

After treatment with Ammonia I found that it does not dissolve in it. Seems this gray powder is not silver chloride but silver as metal. As well was copper in it as ammonia turned blue. If it´s metallic, seems that other option is test it with nitric, to find out is it silver. As I understand Ammonia nitrate and nitric can make a explosion so good wash is needed. 

Hook don´t give much about rare PGM´s and stannous don´t give any indication of metal presented. Maybe somebody have knowledge how to test Iridium. As i read Iridium powder can be flammable so this I want to avoid.


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