Palladium explosion!

[lazersteve]

How did you kill off the excess nitric acid from the original dissolution prior to precipitating the Au? If you used urea, your explosive could have been created with it.

DMG solution would be my first choice to scavenge the remaining Pd from the solution.

Steve

 

[jeweler1]

This liquid only contains Palladium , chromium, copper , and some iron . The gold has already been removed . Since The only thing I want is ($) I really don't care about the purity or what other metals drop out as long as all the Palladium drops I just want a powder I can send to a refiner. The Iron is fast , cheep, and takes far less time than Zinc, or Copper . I have used Chlorine in the past to produce Pure Palladium but If you read this post you can see what happened . And because I just want ($) and I have many gallons to process this is the most economical method for me. I do appreciate all the advice . Sorry I don't get on this forum more but I have a lot of refining to do $$$$$.
Earl
8)

 

[jeweler1]

I reduce the liquid by simmering it from 1400ml to 600ml than I add distilled water to 1000ml and all the nitric acid is gone.
Earl

 

[Synom]

maybe any aluminium in your mixture?
it is highly reactive with palladium and you should avoid putting both together not only in acids - this is very dangerous :idea:

 

[jonn]

I reduce the liquid by simmering it from 1400ml to 600ml than I add distilled water to 1000ml and all the nitric acid is gone.
Earl

I find that hard to believe... Maybe try simmering to 60ml then add Hcl, watch out for the red cloud.

 

[Rougemillenial]

I was reprocessing solution, which contained Palladium. This is a process I have done many times before
I learned the process from this forum and the video’s I had purchased. I am not a chemist so please bare with me. The solution had already gone through gold refining with poor mans Aqua Regia and precipitated with SMB. But it still contained a significant amount of Palladium along with Chromium, Nickel, and some Copper. This process I do outside because of the Chlorine gas. I first put the solution in a large plastic bowl and add powdered chlorine (pool chemical) it boils and gives off a lot of gas. Occasionally I return to stir it, which makes more gas. It was during one if these stirrings that the explosion happened BOOM!!!!. As if I put a firecracker in it. I was splattered with solution on my arm luckily not in my face. Now I have done this many times before and nothing like this has ever happened, What did I do wrong??

you must have had some perchlorate or chlorite in your pool chlorine. that produces chlorine oxides which are extremely unstable. that would certainly do it. i've made chlorine accidentally before and it's nothing compared to the oxides. it could have been far worse. probably should've stuck with zinc since this is clearly waste from a gold drop thus using hypochlorite instead of zinc is pointless

 

[Rougemillenial]

If it was a hypochlorite based pool chlorine, you could've generated dichlorine monoxide with the reaction of other acids to make hypochlorous acid which can be dehydrated in the presence of saturated solution. also chlorates, chlorites, and perchlorates produce chloric acid/chlorine dioxide/dichlorine trioxide, dichlorine pentoxide/ and dichlorine heptoxide. all of these chlorine radicals are highly reactive and can react with just about all organic materials as well as decompose in UV by a free radical mechanism to form chlorine and oxygen which takes up much more space. if it was a TCCA based pool chlorine, you could've had silver, or other metals that form unstable fulminates. :shock: The best way to drop palladium is chlorine/ ammonium chloride. this generates ammonium hexachloropalladate

 

[Lou]

No to the above.

The best way is to precipitate it as K2PdCl6 and skip using ammonium chloride. KCl is the stand in.

Often times what is causing the trouble is either too warm a solution with ammonium cation, or else too much chlorate which makes chlorine dioxide.

 

[Lino1406]

I think that SO3-- ion reacts readily with chlorine. Reducer + oxidizer can give explosion depending on concentration. Do not try for example to mix thiosulphate with hydrogen peroxide

 

[aga]

Would it be rude to ask why Rougemillenial has revived a 2014 thread without recounting their same/similar personal experience ?

If i had recently done something similar, and the only possible related thread was this one, it would make sense to revive it instead of making a new one.

Reviving and merely offering advice on a dead thread does not make any sense at all.

Edit: possibly googled advice perhaps ?