Removing lead and tin from pregnant solution or stockpot

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Marcel

Well-known member
Supporting Member
Joined
Feb 18, 2012
Messages
523
Location
Europe/Germany
I had my low-yield Pd solution, which was made by extracting the Pd from MLCCs using dilute nitric acid, sitting outside for a few days. Since temperatures went around 3° Celsius and even a bit lower, the lead started to preticipate as fine white needles on the bottom of the vessel ( I always use transparent 5L ex-water bottles).
So after filtering the solution with a densly stuffed funnel, I got a cristal clear orange colored Pd nitrate solution.
Now this solved my old problem with the recovery of Pd when lead and tin is present - it is a nightmare.
This time it was different. I put the now clear but colored solution in a beaker, heated it to around 80°C and put a copper bar in it. Imm. the Pd precipitated and after a few hours the 3l solution was processed and nice black powder came down. I have not fully dried and melted it but I suppose it is around 1-2g.

So my tip for this season: Cool down your solution or stockpot by just putting outside in the cold, then have it filtered with a very fine filter (in the cold!). Use that- now free of most of base metals- solution and precipitate PMs using copper adding heat. No chemicals involved. Very few energy needed.

Edit: Here is a photo of the funnel how it looked after filtering the ice cold solution. Itw as stuffed, so only a few drips per second would pass through. The filterd remains look like glass fibers. They are most likely leadchloride cristals. Dont know where the Cl came in, but I received the MLCCs partly processed.

IMG_0405.JPG
 
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