# Cemented palladium



## Geo (Aug 17, 2018)

I had enough free time to work on some secondary stuff I have been collecting. I process whole boards, such as ram, video and sound cards, some CPU's, and a few other high end boards in AP to both liberate the foils as well as chips and SMD's. Through a screening process, the chips are removed and anything larger than the smaller tantalum capacitors. Anything smaller goes on to the next process where I dissolve the gold foils from the remaining solids with HCl and bleach. I enjoy pretty good success doing this and it leaves the MLCC's and film resistors virtually intact. The leech is not on the material long enough to dissolve any PGM's and any that it does comes out in the stock pot. 

So I rediscovered a container of mixed SMD's that has gone through this process and decided to give Pd another try. Only this time, I wasn't going to try and refine. I was going to make as pure a solution as I could and cement the Pd out using aluminium turnings. I then cleaned the cemented powder with a boiling, dilute HCl bath. I followed this with a boiling Dilute sulfuric acid bath. I followed this with several boiling water rinses. All of this on a hot plate stirrer with good stirring. I dried the powder and roasted it over a camp stove flame. I then melted it using propane/oxy cutting tip in a high back melting dish. I will have it assayed Monday. I think it was a decent result.


----------



## FrugalRefiner (Aug 17, 2018)

Indeed! Nice little bar!  

Dave


----------



## nickvc (Aug 18, 2018)

Nice Geo.
You may have lost a little in the Hcl wash but as it was dilute it would be a small amount, be very interesting to see what the assay says.


----------



## Geo (Aug 18, 2018)

I get a report. I'll scan it and post it here.


----------



## Geo (Aug 21, 2018)

The assay was 69.3% palladium. I'll get the report scanned in and post it tomorrow. It wasn't super easy but it is doable. I am going to start taking SMD's on toll refines. I'm sure I can get the purity up to 90%.


----------



## cosmetal (Aug 21, 2018)

Geo said:


> The assay was 69.3% palladium. I'll get the report scanned in and post it tomorrow. It wasn't super easy but it is doable. *I am going to start taking SMD's on toll refines.* I'm sure I can get the purity up to 90%.



Geo,

Definition of SMD Devices from Euro Circuits:
https://www.eurocircuits.com/smd-surface-mount-device/

*"SMD – Surface Mount Device. Surface-mount technology (SMT) is a method for producing electronic circuits in which the components are mounted or placed directly onto the surface of printed circuit boards (PCBs). An electronic device so made is called a surface-mount device (SMD)."*

Not trying to be a pain, but, which SMD components are you interested in toll refining? 

Peace,
James


----------



## Geo (Aug 22, 2018)

MLCC's and film resistors. Other surface mounted devices may have a small amount of precious metals but not really what I am after. I have video of the material this came from posted on my group. I didn't post it on youtube.


----------



## nickvc (Aug 22, 2018)

I know I don’t have to warn you but be careful when working with PGMs especially if you are working with them regularly.


----------



## Geo (Aug 22, 2018)

Thank you Nick. Yea, seems I am very popular now. Everyone has been stockpiling then and not knowing what to do with them. As soon as I posted my success, I've been flooded with request for tolls. Definitely going to have to be safety oriented all the time. I understand that it may have contributed to Frank's death as well as Freechemist. Certainly not something to take lightly.


----------



## Platdigger (Aug 22, 2018)

Hi Geo, say what if instead of using al turnings you used copper powder?


----------



## etack (Aug 22, 2018)

If you use Cu powder you will cement the Ni. Al wont cement Ni.

Additionally Al is cheaper and easier to remove from other metals.

Eric


----------



## Geo (Aug 25, 2018)

Eric is right. It's even cheaper than zinc powder. I bought my aluminum turnings but there is a machine shop close by that I can get them for free. I am just concerned about impurities in the aluminum.


----------



## 4metals (Aug 25, 2018)

> If you use Cu powder you will cement the Ni. Al wont cement Ni.



This statement flies in the face of cementation based on the normal electrode potentials as listed in the electromotive series. While it is possible that there are mitigating circumstances to this general rule, I hope you are willing to post some back up to this claim.


----------



## Geo (Aug 25, 2018)

Yea, I didn't say anything about it. I was agreeing that aluminum is easier to clean up after the drop. A simple HCl bath will remove any left over aluminum. As far as the nickel, it has been my experience that nickel can not be removed from solution through ionic exchange. It can't be cemented from solution. There are other metals that once it is dissolved in an acidic solution, can't be cemented back out. Aluminum is another.


----------



## Platdigger (Aug 25, 2018)

Ok, here is an abstract were they are cementing copper on nickel. https://www.tandfonline.com/doi/abs/10.1179/cmq.1971.10.3.165?journalCode=ycmq20
So either way nickel should not cement on copper.


----------



## snoman701 (Aug 25, 2018)

Geo said:


> Yea, I didn't say anything about it. I was agreeing that aluminum is easier to clean up after the drop. A simple HCl bath will remove any left over aluminum. As far as the nickel, it has been my experience that nickel can not be removed from solution through ionic exchange. It can't be cemented from solution. There are other metals that once it is dissolved in an acidic solution, can't be cemented back out. Aluminum is another.



Your statements are much to broad. Ionic exchange is one of the primary methods by which nickel is recovered from industrial waste. The nickel in solution from refining wastes is cemented just fine by the addition of iron. 

What happens is that the aluminum in solution interferes with the cementation of nickel in solution. 

https://www.jstage.jst.go.jp/article/nikkashi1972/1982/1/1982_1_44/_article/-char/en


----------



## Geo (Aug 25, 2018)

Thanks snoman701. I guess there are exceptions to every rule. I just don't happen to be working with sulfates. I just have never cemented nickel on iron or anything else I can think of. DMG will drop nickel from basic solutions. 
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=58&t=9158


----------



## Platdigger (Aug 26, 2018)

So Geo, what were the other metals and percentages that showed up in the assay?
Or was it xrf?


----------



## Geo (Aug 27, 2018)

It was an XRF. It's Elemetal Direct in franklin Tn. Large bench top machine.


----------



## g_axelsson (Aug 28, 2018)

snoman701 said:


> Geo said:
> 
> 
> > Yea, I didn't say anything about it. I was agreeing that aluminum is easier to clean up after the drop. A simple HCl bath will remove any left over aluminum. As far as the nickel, it has been my experience that nickel can not be removed from solution through ionic exchange. It can't be cemented from solution. There are other metals that once it is dissolved in an acidic solution, can't be cemented back out. Aluminum is another.
> ...


The article is discussing sulfate solutions and even with aluminium present 40% of the nickel did cement. Now the article were written in Japanese so I don't know a lot of the details about the experiment. For example I couldn't find the nickel concentration of the sulfate solution.

The copper added was added as a salt to the solution (0.2 g/liter) and that made the cementation work perfectly.

This is my impression of how the experiment worked out...

Adding metal iron to a nickel sulfate solution cements nickel while iron goes into solution.
If there is a small contamination of aluminium sulfate it will interfere with the cementation so only 40% of the nickel did cement out until it stopped working (under the same conditions as above).
Adding 0.2g of copper ions per liter of nickel solution lets the cementation of nickel on iron work again.

Nickel does not cement on copper, or every copper refinery would be out of business. The main contamination in copper sulfate electrolyte is nickel sulfate. The first step in electrolyte treatment is nickel sulfate removal by crystallization, showing that it is quite concentrated in the electrolyte without contaminating the electrolytic copper cathodes.

At least that is what I think happens in real life.

Göran


----------



## etack (Aug 28, 2018)

4metals said:


> > If you use Cu powder you will cement the Ni. Al wont cement Ni.
> 
> 
> 
> This statement flies in the face of cementation based on the normal electrode potentials as listed in the electromotive series. While it is possible that there are mitigating circumstances to this general rule, I hope you are willing to post some back up to this claim.




This was mentioned in a 2011 http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?t=9416

he refers to "reading it some place," this could be it.

however this feedstock was a nickel sulfate solution.

https://nepis.epa.gov/Exe/ZyNET.exe/30003TTI.txt?ZyActionD=ZyDocument&Client=EPA&Index=1986%20Thru%201990&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&UseQField=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A%5CZYFILES%5CINDEX%20DATA%5C86THRU90%5CTXT%5C00000006%5C30003TTI.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h%7C-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r85g16/r85g16/x150y150g16/i500&Display=hpfr&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=1


2013 discussion about MLCCs Lazorsteave mentioned it in his instructions.

I will however test this as I have some pure nickel.

Eric


----------



## g_axelsson (Aug 28, 2018)

The EPA project paper was a good read, it showed that aluminium doesn't cement nickel, at least not from a sulfate solution. But that can be the result of an over potential between nickel and aluminium.

Just as you can plate zinc onto a zinc cathode from an acidic sulfate solution while an iron cathode only produces hydrogen.

I wonder what would happen if you connected a nickel strip with an aluminium strip and put them into a nickel solution. Would it form a crude battery and cement nickel onto the nickel strip while aluminium went into solution?

I don't know and right now I'm only speculating.

Göran


----------



## snoman701 (Aug 28, 2018)

g_axelsson said:


> Nickel does not cement on copper, or every copper refinery would be out of business. The main contamination in copper sulfate electrolyte is nickel sulfate. The first step in electrolyte treatment is nickel sulfate removal by crystallization, showing that it is quite concentrated in the electrolyte without contaminating the electrolytic copper cathodes.
> 
> At least that is what I think happens in real life.
> 
> Göran



Nickel does plate out if the concentration gets high enough...as I like you thought it was handled differently. In practice, nickel content in electrolyte is maintained around 1,000 ppm. *edited*

The first step in electrolyte treatment is to decopper the electrolyte through electrowinning cells. Following, volume is greatly reduced through acid distillation. Clean acid is sent back to the electrolyte. Copper in electrowinning cells at this point is not anode quality. Impurities at this stage are all over the place, but bismuth and antinomy are also plated out as copper quantity decreases. Once they are plated out, the acid is further distilled until you have "black acid" which I guess can be as high as 60% nickel sulfate. It's at that point that it's dealt with, and how it's dealt with is going to depend on actual concentration. Often the black acid is used elsewhere in the refinery, guess it depends on the size refinery. In a smaller refinery, Id imagine they are now using an ion exchange resin to selectively adsorb the nickel because setting up to the point that you can distill acid is not exactly for the faint of heart. There are a lot of electrolyte purification resins out there that are designed just for this purpose. Elution of the nickel from the resin is accomplished with a stronger sulfuric acid.


----------



## g_axelsson (Aug 29, 2018)

Thanks for the clarification, but at least nickel doesn't plate out on copper by itself, it needs high enough concentration compared with copper and the voltage potential from the plating cell.

Göran


----------



## rusti2 (Apr 17, 2021)

Geo said:


> Eric is right. It's even cheaper than zinc powder. I bought my aluminum turnings but there is a machine shop close by that I can get them for free. I am just concerned about impurities in the aluminum.


You have to use scrap aluminum cable for high tension, they are wires of 1 to 2 millimeters in diameter and it is the purest aluminum called electrical grade


----------



## Geo (Apr 17, 2021)

rusti2 said:


> Geo said:
> 
> 
> > Eric is right. It's even cheaper than zinc powder. I bought my aluminum turnings but there is a machine shop close by that I can get them for free. I am just concerned about impurities in the aluminum.
> ...


Thank You. I have some EC wire. I never thought about that. I'm actually working with some catalytic material now. That will come in handy.


----------

