Birtan Varol
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My English is not very good, but I'm trying. How can I get the palladium in the silver chlorate left over from the stone separation process? Please help me with this, thank you.
extracting palladium from silver chloride
- Thread starter Birtan Varol
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Welcome.
I'm not sure I understand you.
Is this Silver Chloride from karat Gold?
If so why do you expect Palladium to be there?
Any way the safest way to do it is to cement on Copper.
Since you have processed it you nees to study these links before you proceed.
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I think you have silver chloride in an AR solution from stone recovery , if this is the case then simply filter and well rinse the silver chloride and then cement the palladium out using copper and aeration which will recovery your palladium and then convert your silver chloride back to metallic silver using the method of your choice.
Birtan Varol
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Hİ . Let me be clear. I dissolve mixed gold and some PGM jewelry in aqua regia to remove precious stones. and after the gold dissolves, I filter the silver. Of course, the gold dissolved in this acid is of various carats. During this dissolution, silver chlorate comes out of the gold and I filter it. While filtering, palladium rhodium and iridium silver get stuck on the filter papers that I filter and this rate is about 5% of the silver and I want to get these pgms from this silver chlorate. I want to learn this method, thank you.
Birtan Varol
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Thank you for the information you provided. Here's what I do .Let me be clear. I dissolve mixed gold and some PGM jewelry in aqua regia to remove precious stones. and after the gold dissolves, I filter the silver. Of course, the gold dissolved in this acid is of various carats. During this dissolution, silver chlorate comes out of the gold and I filter it. While filtering, palladium rhodium and iridium silver get stuck on the filter papers that I filter and this rate is about 5% of the silver and I want to get these pgms from this silver chlorate. I want to learn this method, thank you.
Birtan Varol
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How should I use copper to remove pgm from silver chloride or how should I wash it with nitric acid? I would be grateful if you explain this
Please get your chemicals straight. Silver Chlorate is a salt we "never" see since it is water soluble and do not form in our conditions.
Silver Chloride is another story we see that all the time since it is not soluble in any of the acids we use
and forms every time Silver salts come in contact with Chlorides.
Palladium dissolves easily in the AR so it will be in the solution.
Platinum dissolves in AR too though not as easy as Pd
Rhodium and Iridium do not dissolve well in AR.
Rhodium will often be in the plating of White Gold.
Iridium may be in alloy with Platinum but I'd guess it follows Pt into solution since it is in low percentage in the alloy.
And again Silver Chloride.
So what you will find in the solids in the filters will be solid Rhodium, Silver Chloride, maybe some fine Ir powder and bound up solution.
Wash it well with HCl until the wash is clear (keep the wash liquid in a container for later use or cementing),
then wash with water until it is no longer acidic.
Next the issue is the PGM particles.
You either need to dissolve the Silver Chloride or accept that they they end up as loss.
After proper AgCl conversion you may or may not be able to capture it in the filter if you filter the residue, but I doubt it.
Just my two cents
Is it a lot of Silver Chloride? Can you share a pic of how much?
The palladium salts can hang up mechanically in an excessive quantity of Silver Chloride, but as pointed out, they should have dissolved completely in aqua regia.
Your best bet is to take your insolubles from the stone removal and dissolve them in heated Ammonium hydroxide. This is a high fume reaction so a good hood is required. The Silver Chloride will dissolve back into solution and any bits of platinum that didn't dissolve from the aqua regia process will remain as solids along with any undissolved gold. This is not an often recommended method because of the heavy fume and the potential to form explosive silver compounds from alkaline ammonia solutions. Which is why I mention to acidify the solution sooner than later. For years I always referred to using ammonia followed by Hydrochloric Acid as the genie in the bottle. When you mix the two, you will see why!
Filter the solution to separate the metallic solids from the solution. Any Palladium that dissolved will be in solution now but often Platinum alloys contain Palladium so some of the undissolved Platinum metal may be Platinum Palladium. Separate the solids for re-dissolution in aqua regia.
Now add Hydrochloric Acid to the ammonia solution, do this quickly, not next week as we don't like to allow ammoniacal Silver solutions lying around in a refinery for safety reasons. The white precipitate will be Silver Chloride which you can filter, rinse and convert to metal for recovery. The remaining acidic solution can be cemented to recover any remaining values.
The original aqua regia solution from the stone removal process will also contain dissolved Platinum and dissolved Palladium which can also be recovered by cementation.
Your best bet is to take your insolubles from the stone removal and dissolve them in heated Ammonium hydroxide. This is a high fume reaction so a good hood is required. The Silver Chloride will dissolve back into solution and any bits of platinum that didn't dissolve from the aqua regia process will remain as solids along with any undissolved gold. This is not an often recommended method because of the heavy fume and the potential to form explosive silver compounds from alkaline ammonia solutions. Which is why I mention to acidify the solution sooner than later. For years I always referred to using ammonia followed by Hydrochloric Acid as the genie in the bottle. When you mix the two, you will see why!
Filter the solution to separate the metallic solids from the solution. Any Palladium that dissolved will be in solution now but often Platinum alloys contain Palladium so some of the undissolved Platinum metal may be Platinum Palladium. Separate the solids for re-dissolution in aqua regia.
Now add Hydrochloric Acid to the ammonia solution, do this quickly, not next week as we don't like to allow ammoniacal Silver solutions lying around in a refinery for safety reasons. The white precipitate will be Silver Chloride which you can filter, rinse and convert to metal for recovery. The remaining acidic solution can be cemented to recover any remaining values.
The original aqua regia solution from the stone removal process will also contain dissolved Platinum and dissolved Palladium which can also be recovered by cementation.
