Non-Chemical Paladium from silver Paladium solution

[amitoha23]

Hi

i have an issue with extracting Palladium from silver Palladium solution .
i put the powder in Nitric Acid and used chloride method (salt to extract the silver out ) i was left with strong orange liquid .
i have seen that i need to vaporize all tne nitric ions by slow evaporation of liquid to liquor(concentrated liquid ) and add HCl.
repeat this steps a few time the extract the palladium using CL .

i hope i did not misunderstand the process . but the problem is when i slow evaporate the liquid salt Crystals are building up and some Palladium is dropping with it . (strong orange Powder )
i need to filter the salt and then keep the palladium , it a bit annoying , i did not reach the level needed to finish this process as i find my self playing with filtering salt from Palladium .

did i put to much salt in the silver extract process ? how can i drop salt of what can do to solve this issue ?
how can i refine the mentioned powder in a better way ?

Regards
Amit

 

[Marcel]

Dont use nitric where you dont have to. It makes it all more complicated.
HA (Hot Acid). Hot HCl alone will dissolve Pd and form AgCl. It may take hours for it to extract the Pd and maybe has to be repeated.
or
HAP (Hot AP) will also dissolve Pd very fast. Use 1:1 HCL and H2O2 (+12%) and heat it to 60° so it starts to foam and fizzle very strong. Takes only minutes. May have to be repeated (with fresh solution) several times.

Filter solutions. Solids bear the AgCl.
Take the orange solution and drop with copperwire or even aluminum,zinc etc. If your are absolutly sure that there is no other basemetal in solution.

 

[amitoha23]

Thank you ,
this will do the job before i used Nitric , what can i do now ?
can i drop the Palladium using Aluminum ? or something else ?
leaving salt in liquid .

Regards
Amit

 

[Lino1406]

What I recommend is increasing pH to around 3 before dropping
with Al or Zn (preferable for Pd).
Lino1406 author "29 recovery procedures"

 

[etack]

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=9477&p=90800&hilit=freechemist+DMG#p90800

This is the best way. Drops it out, filter, cement silver. I found if you remove the silver first the Pd nitrates can be hard to remove if it really concentrated.

Eric

 

[freechemist]

After my experience it is suitable to dissolve Ag/Pd-alloys or mixed Ag/Pd-powders in nitric acid. Hot hydrochloric acid alone will neither dissolve metallic Pd, nor will it form AgCl from metallic silver, whereas nitric acid will dissolve both metals, forming well soluble nitrates. These can be treated with a lot of excessive HCl in order to precipitate AgCl and keep Pd in solution as anionic chloro-complexes PdCl₄^2-, and eventually, some PdCl₆^2-. For each gram of silver 1 ml of 32% HCl, and for each gram of Pd 6 ml of 32% HCl should be used. Practically it is best done by diluting the calculated total volume of 32% HCl with an equal volume of water, heating the HCl/water-Mixture to ca. 80^oC, stirring constantly, and adding the mixed Ag/Pd-solution slowly. After complete addition, stirring and heating are continued to near boiling. The mixture is let stand to cool to room-temperature, and solid AgCl is separated by filtration. The filtered Pd-solution can be treated further, to crystallize intensely red K₂PdCl₆ or by cementing metallic Pd.

 

[Marcel]

. The mixture is let stand to cool to room-temperature, and solid AgCl is separated by filtration.

The filtration is a big problem for me. I have tried various methods but this ultrafine AgCl seems to slip through almost any filterapparatus that I have on hands. What would you suggest to trap AgCl?

 

[etack]

The filtration is a big problem for me. I have tried various methods but this ultrafine AgCl seems to slip through almost any filterapparatus that I have on hands. What would you suggest to trap AgCl?

Refiltering with the same paper. the first filtering will help filter out the smaller particles.

Eric

 

[Marcel]

Thanks Eric. I did try it the other way around and precipitated Pd right in the mix, then filtered the solution, but all I got was Pd with some AgCl and AgCl with some Pd (and some CuCl in both batches) :lol:
From there I tried to separate again both batches, but now I just redissolve the mess and start all over again. Will use you trick thsi time.