Cemented palladium

[etack]

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]

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]

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]

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]

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]

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

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.