Reclaim from chemical plating bath

[raffredo]

Hi all,
i am interested in learning about your opinion regarding different approaches to reclaim metal from chemical deposition bathes. Those bathes are intended for "electroless" plating. Instead of putting amps to work, the bath composition is slightly instable on purpose and will decompose just on the work piece surface in order to deposit (selectivly) metal. Either by difference in nobility (immersion plating) or when the work piece surface is catalytic active to support decomposition for a reductor specimen, which puts (locallly) charge on the surface that can reduce solubal metal down. Most prominent example would probably be electroless Nickel which is often based on hypophosphite as reductor.

Currently i am looking at a Pd deposition bath with app 2 g/L PGM complexed in solution, some hypophosphite and lead salt as stabilizer. pH about neutral and no other metal present in significant amounts. Processing would need to handle app. 100 L per month.

Possible ways to get the metal out:
1) Plating chemical "out of spec" further on some dummy material. Need heating, agitation, maybe even reductor replenishment... that does not sound smart.
2) Cementing Pd chemically out. Just dumping Cu or Zn powder in and filtrate anything out. Maybe a bit messy, but if the hypophosphite does not bother, a viable solution.
3) Galvanic plating with a simple setup. I just saw at an chinese marketplace a company advertising "reclaim" systems and they named one even for Pd. Pictures showed rotating steel cathode and graphite anodes. Voltage was (in a picture) adjusted to 2.3V. Metal could be scrubbed of the drum-cathode after some runs. Some papers i found talked about very high reclaim rates for Pd from wastewater, but i am not sure what unwanted specimen could form on the anode in this process.

Did i miss any other option? Do you see a flaw in either of those approaches?
Thanks for reading.

 

[Imalwaysañgie69]

What if not deposit of correctly? And what are the symptoms of silver copper lead poisoning of electrolysis I'm interested? What if a person gets poisoning from it what if they made a pendant of it and they were around their neck all the time and it seeped out on their neck and wasn't properly sealed what then? What if your solution was thrown out on the ground and a person went to pull the grass and dig in the sand what then what kind of poisoning would happen then? Tell me what kind of poisoning if over the months they had done this over a year they done this what kind of poisoning would they get what kind of a symptoms would happen would death happen they didn't figure it out till today after it's been over a year and a half what would happen in this patent

 

[Yggdrasil]

What if not deposit of correctly? And what are the symptoms of silver copper lead poisoning of electrolysis I'm interested? What if a person gets poisoning from it what if they made a pendant of it and they were around their neck all the time and it seeped out on their neck and wasn't properly sealed what then? What if your solution was thrown out on the ground and a person went to pull the grass and dig in the sand what then what kind of poisoning would happen then? Tell me what kind of poisoning if over the months they had done this over a year they done this what kind of poisoning would they get what kind of a symptoms would happen would death happen they didn't figure it out till today after it's been over a year and a half what would happen in this patent

To complicated to take here.
But a pendant of Copper or Silver is not toxic.
Even Lead metal will not be particularly Toxic, not very beautiful to look at though.
The most common adverse reaction on jewelry is allergies.

Solutions poured out on the ground is a completely other matter.
Those are almost always toxic and should be cleaned up asap.
Symptoms differs from substance to substance.

 

[raffredo]

Thanks for those responses, but it appears the topic shifted rapidly away towards general health concern.
Any opinions the best approach to reclaim complexed noble metals in presence of hypophosphit?

 

[Yggdrasil]

Thanks for those responses, but it appears the topic shifted rapidly away towards general health concern.
Any opinions the best approach to reclaim complexed noble metals in presence of hypophosphit?

Sorry about that, the thread was temporarily hijacked.
First why are you wanting to get the Pd out?
For reclaiming the material for further use in plating or for sale?
If it is not to be reused, plain cementing it in Zinc or Aluminum would suffice and the easiest option.

 

[raffredo]

Yeah, reclaim and sale is the intended path. Thanks for voting for path b from my start post.
Direct recycling into new bath batches is no option, because certified quality of pd-salt from commercial vendors is needed for this plating application.

Reading across the forum, getting fine powder zinc is probably the prefered method. Zn powder appears to be dirt cheap, so i would go with two times the mass of the anticipated Pd mass i want to drag out.
pH is already near neutral with few free acids. So mixing the powder in at room temperature with highest agitation, let it stirr over night and filter everything out. Washing it quick with technical concentrated nitric acid to get off any Zn should leave me with acepptable pure Pd powder, that can be given to professional reclaimer in exchange for purified salts.

 

[Yggdrasil]

Yeah, reclaim and sale is the intended path. Thanks for voting for path b from my start post.
Direct recycling into new bath batches is no option, because certified quality of pd-salt from commercial vendors is needed for this plating application.

Reading across the forum, getting fine powder zinc is probably the prefered method. Zn powder appears to be dirt cheap, so i would go with two times the mass of the anticipated Pd mass i want to drag out.
pH is already near neutral with few free acids. So mixing the powder in at room temperature with highest agitation, let it stirr over night and filter everything out. Washing it quick with technical concentrated nitric acid to get off any Zn should leave me with acepptable pure Pd powder, that can be given to professional reclaimer in exchange for purified salts.

I believe the best cementing will be at somewhat acidic solution, unless it is a Cyanide based solution.
DO NOT let Cyanide based solution get acidic.
Then it should have a pH around 10-11 or so.

When you have your powders, wash it well in water and then in dilute HCl until all the surplus Zinc is digested.