Trying to think logically here but wouldn’t it pay to dissolve say 10 kilos and melt say 2 kilos into a bar and use that to cement the Pd and Ag using that bar, this will also recover the values contained in the bar for free, the value of the Pd if Arthur is correct in its percentage would make it financially viable, the other thought was to shred the wires and use AP to remove the copper but unless it was in very small pieces it might take some time.
wires containin pd---1100 kgs--no more detail at the moment
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arthur kierski
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Thanks Nickvc,you gave an excellent idea in cementing dissolved wire in a melted wire bar---using AP to dissolve the copper,is also a good idea---but as you say it takes along time----did you think of my idea of deplating de wires?
thanks for your informations
Arthur
thanks for your informations
Arthur
Arthur I don’t think cyanide will strip the palladium but I could be wrong and I can’t think of an easy way to strip the Pd completely or dissolve the copper base that is quick, 4metals idea is certainly worth a try but I suspect it will be a balancing act between heat and acid strength or you will have Pd cementing back into the copper.
The original patent for the electrolytic concentrated sulfuric cell we all use, US patent # 2,185,858, says that, besides Au and Ag, it can be used to strip Pd from Cu. The only difference in the one we use and the one in the patent is the strength of the sulfuric. Our baths are about 92% sulfuric and they don't attack the copper (I used tech. grade H2SO4 - about 96-97% - and added 5% water, to make it strip faster - measure out the water and add the H2SO4 to the water). The one in the patent says the specific gravity can be can be as low as 1.65, which is only about 73% sulfuric. In my experience, that will attack copper, especially when the temperature exceeds 37C.
It strips gold pretty fast. I have never tried it with silver or Pt. Au works good because,as you strip, the Au form a powder and falls to the bottom - no gold dissolves. I used the same 50 gallon stripping bath, daily, for a year or two before I had to make up a new bath. I just siphoned it off and harvested the gold every 3 weeks, or so, and reused the solution over and over.
I've never used it for Pd or Ag, so I don't know what happens. My guess, especially with the silver, is that it will dissolve until it is saturated. Nearly concentrated sulfuric, very hot, in a cast iron vessel, has been commonly used in the mining industry, for many years, to part the Ag from the Au in hi-Ag dore'.
I have no idea what would happen with the Pd. I know it would strip but getting it out of the H2SO4 could be a problem. You might try adding about 2-3%, by volume, HCl to the sulfuric. It would be fumey for a day or so. I have played around with Au, using the HCl, and it seemed to work fine. I don't think any of the Au dissolved as HAuCl4. The reason I suggest the HCl addition is that it may block the Ag from dissolving, due to formation of Ag Cl.
I do believe I could mess around and figure out how to get the Pd out of solution. The obvious problem is how to automate moving that wire through the solution. Maybe with the reel of wire, with a slight drag on it, on one end, and a take up reel on the other end. Probably need a rinse or 2 after stripping.
If you want to play with this, there are 2700 hits if you search for - sulfuric cell. I also tried - sulfuric cell .jpg and got about 80 hits. That brought up a few photos. Also search for - sulfuric stripper. If this interests you, let me know and I'll give you some pointers on experimenting with this.
Just thinking out loud.
It strips gold pretty fast. I have never tried it with silver or Pt. Au works good because,as you strip, the Au form a powder and falls to the bottom - no gold dissolves. I used the same 50 gallon stripping bath, daily, for a year or two before I had to make up a new bath. I just siphoned it off and harvested the gold every 3 weeks, or so, and reused the solution over and over.
I've never used it for Pd or Ag, so I don't know what happens. My guess, especially with the silver, is that it will dissolve until it is saturated. Nearly concentrated sulfuric, very hot, in a cast iron vessel, has been commonly used in the mining industry, for many years, to part the Ag from the Au in hi-Ag dore'.
I have no idea what would happen with the Pd. I know it would strip but getting it out of the H2SO4 could be a problem. You might try adding about 2-3%, by volume, HCl to the sulfuric. It would be fumey for a day or so. I have played around with Au, using the HCl, and it seemed to work fine. I don't think any of the Au dissolved as HAuCl4. The reason I suggest the HCl addition is that it may block the Ag from dissolving, due to formation of Ag Cl.
I do believe I could mess around and figure out how to get the Pd out of solution. The obvious problem is how to automate moving that wire through the solution. Maybe with the reel of wire, with a slight drag on it, on one end, and a take up reel on the other end. Probably need a rinse or 2 after stripping.
If you want to play with this, there are 2700 hits if you search for - sulfuric cell. I also tried - sulfuric cell .jpg and got about 80 hits. That brought up a few photos. Also search for - sulfuric stripper. If this interests you, let me know and I'll give you some pointers on experimenting with this.
Just thinking out loud.
arthur kierski
Well-known member
Thanks GSP---i asked if it was possible to obtain pd from plated copper wires,using a product similar to gold stripper for gold-----that is nacn+nmss oxidizer------gold stripper leaves de copper plated wires intact and the gold goes to solution,and precipitated by cementation with zin powder----Thanks for the attention----i have 1100kgs of plated pd wire--and doing the traditional method with nitric acid ,willtake a long time---thanks ------ Arthur
Arthur with over a ton to process I’d be tempted to go for the copper cell route and recover the Pd from the slimes, I’m guessing the owner would rather have a good result rather than a fast one as even using a cell won’t be quick, perhaps aim to give returns after each 100 kilos are processed and maybe suggest a100% return for the first 500 kilos with any balance at the end.
arthur kierski
Well-known member
Nickvc-----i decided to do the way that i did with paladium in other ocassions------i calculated that processing 20kilos a day ,it will take 55 days to proceess this Pd-----i thought it would take much longuer------i will now give a resume------i make a nitric solution and distilled water in a 20 liter plastic vessel-----in this vessel i add slowly the wires -----2to3kilos at a time---wait until all this dissolve,and add another2to3 kilos in 3or 4,hours 20kilos is dissolved ------after that ,i add sodium hipoclorite to the dissolved paladium solution,and then i add nh4cl and mix------imediatelly red paladium sal is formed and floats in rhe vessel--now i filtrate de solution and the red palladium salt stays in the paper----after this filtration and before continuing i test the mother liquid with stanous chloride-------if i find that there is still pd in the solution, i repeat ,hipockorite and nh4cl--and the red salt is added to the filter paper-----the red salt out with distilled into a becker add nh4oh that willdissolve the red salt ,and formed impurities in the bottonof the becker,is filtrate out-----from here on i have some options--by doing 20kilos,a day i expect to obtain 200grams of Pd dayly-----i might also add dmg to the nitric and obtain huge quantities of yellow fuffy pddmg salt and takes the pd from the yellow salt-----i already did this a few years ago--------thanks to you for all advices----but i willmake a test in deplating--the wires with nacn plus oxidizer solution
arthur kierski
Well-known member
LIno,thanks for the formulation for copper etchants--
regards,
Arthur Kierski
regards,
Arthur Kierski
Arthur,
Will the Hypochlorite react with the silver or does it stay in solution through the process? Or do you drop it separately prior to this?
Cheers Wal
Will the Hypochlorite react with the silver or does it stay in solution through the process? Or do you drop it separately prior to this?
Cheers Wal
arthur kierski
Well-known member
fishaholics---i did this process of obtaing the red impure pd salts many times(nh4pdcl4) and if agcl is mixed with the red salt,on the continuation of the process will be eliminated-----i really do not remember how i
dealt with agcl -----but with your question,i decided,that i will eliminate by making the initial nitric solution with tap h2o instead of using distilled water-and filtate the agcl out before making red salt with hypocloride and nh4cl------or add some nacl to the dissolved wire-and filtrate the possible agcl out and them continue the process to obtain the red salt------thanks for the alert-----
Arthur Kierski
dealt with agcl -----but with your question,i decided,that i will eliminate by making the initial nitric solution with tap h2o instead of using distilled water-and filtate the agcl out before making red salt with hypocloride and nh4cl------or add some nacl to the dissolved wire-and filtrate the possible agcl out and them continue the process to obtain the red salt------thanks for the alert-----
Arthur Kierski
Arthur wouldn’t it pay you to cement the values using some of the wire melted into bars at least that way some of the material will be recovered for free and you will have metallic values rather than salts, you can always test the solution using DMG to ensure you have all the Pd out and if not use ammonium chloride to drop any residues.
arthur kierski
Well-known member
Nickcv---before beginning the efetive extraction i will experiment your sugestion of cementation with a bar of the melted material--and tell you the results-------i will try also the nacn+oxidizer, that many years ago a member of our forum---Juan Manoel Arkos Frank,from mexico,told me that it works with plated wires -----not only gold----- I hope that one of this 2methods works because is quicker and cheaper---the method that i describe yesterday is the one that i used----many brown fumes in the dissolution with nitric---and much cl gas to make the red salt------Thanks and please continue to make sugestions and advises--it helps me a lot-
Arthur KiersKI
Arthur KiersKI
arthur kierski
Well-known member
Nickvc,after i wrote the last reply to you a few minutes ago,a question come to my mind-----WHEN cementingthe pd powder ,the nitric solution could redissolve the precipitated palladium again? i thought also that i could elevate the ph of the nitric solution and cemented with copper bars--the pd would precipitate?
Arthur
Arthur
The whole idea of cementation is to replace your target values or metals and replace them with another so you want a little free acid, not too much, and then place your bar into the solution, the solution would rather have the copper in solution than the Pd so it replaces the Pd with the copper from the bar, for this to work well I’d suggest adding an air bubbler, any Pd or silver in the bar will be released as the solution dissolves the copper to replace the values, even if it does dissolve them at first it will almost instantly release them with the copper.
