Separating copper oxide from pgm black (mostly palladium)?

[Slaughlin79]

I did what was recommended on a screw up I made and dissolved all my collected metals, and after cementing pgms out on copper,I was left with a lot of fine copper. I used 2-1/2 copper pipe that I split and and bent into a square plate. There was also an amount of copper chloride mixed with the pgm black.

After many many boiling water washes and drying I put in a small Corning dish and heated to turn the fine copper into copper oxide. Following that I added around 25 ounces of distilled water and an a very small amount of HCl to hopefully dissolve the copper oxide and leave the pgms.
Well if hope was all I needed I wouldn’t be here asking.
But just like when I’m trying to cement the last bit of palladium from solution and it’s so saturated with copper, copper crystals start to grow on the copper metal,so I add a touch of HCl to remove crystals and start the reaction back up,the palladium starts redissolving.
Before you know it I back to square one or really it’s a way worse square one bc now the saturated copper sulution,now has a lot more copper In it copper the process a pain in the ass.

So I’m here to ask of a detailed way, if any exist, to seperate copper from pgm by electrolysis? I don’t know much about electrolysis except the basic understanding of using a cathode and anode and electricity to refine metals . I don’t know what to use for anode or cathode (for pgms) or the volts needed and many many hours of searching haven’t taught me much,bc there’s not much on this exact subject. I’ve been working on this for a few years (catalytic converters) and I’m at the end and just trying to get stuff cleaned up and finished so I can move on bc I have learned over the past 4 or 5 years this isn’t for me.
But being In ocd about finishing what I’ve started I need to finish so I can start on my building and cnc haas machining center. I’ll be honest I’m desperate for some help.

 

[Shark]

While it isn't electrolysis how would the pgm's react to sulfuric? While not a a great choice for removing copper, it will do it, if it leaves the pgm's behind, you should be good to go.

 

[Lino1406]

10NH4OH : 3.5H2O2:10H2O (copper etchant) may do the job, though slowly. Electrolysis does not work on powder

 

[Yggdrasil]

I don't know how AP works on CuO but as Lino says one of the copper etchants might work.
My own test on NH3OH was good for copper, but the smell was intense.
It was done in an closed (ish) box though.

Most of us are quite set up for AP anyway, so a test should be quick and easy.

 

[Jmk88]

Copper oxide will dissolve in ammonia hydroxide 10%. Dont need heat but a bit speeds it up.

 

[Geo]

I second the ammonia. Colorless household ammonia from the supermarket.

 

[Geo]

I don't know how AP works on CuO but as Lino says one of the copper etchants might work.
My own test on NH3OH was good for copper, but the smell was intense.
It was done in an closed (ish) box though.

Most of us are quite set up for AP anyway, so a test should be quick and easy.

In my experience, CuCl2 (while oxidized with atmospheric oxygen) will dissolve finely divided palladium metal dust.

 

[Geo]

While it isn't electrolysis how would the pgm's react to sulfuric? While not a a great choice for removing copper, it will do it, if it leaves the pgm's behind, you should be good to go.

Dilute H2SO4 will dissolve CuO while not effecting the PGM's while cool. The powder needs to be rinsed well of all other acid. The sulfuric acid will intensify the other acids capability of dissolving the finely divided powder.