Thiourea plating process.

[kaisernine]

Curious if any of you have experience using thiourea to reverse electroplate ( gold and silver ) or have a link to the process I can research - I used to work with chrome, copper and nickel plating in a factory - but I was recently talking to a one of the engineers at my old job and he brought up them using thiourea for some new processes and kept saying it is very nasty to work with but never really stated as to why.

I mean is it really that bad? is it worse than using sulfuric, nitric, hcl and other pickling agents we already use in plating and plating prep?

Just curious - really do not recall ever using this stuff at work - it certainly sounds better than the cyanide they used for leaching tanks in the past.

 

[Yggdrasil]

Curious if any of you have experience using thiourea to reverse electroplate ( gold and silver ) or have a link to the process I can research - I used to work with chrome, copper and nickel plating in a factory - but I was recently talking to a one of the engineers at my old job and he brought up them using thiourea for some new processes and kept saying it is very nasty to work with but never really stated as to why.

I mean is it really that bad? is it worse than using sulfuric, nitric, hcl and other pickling agents we already use in plating and plating prep?

Just curious - really do not recall ever using this stuff at work - it certainly sounds better than the cyanide they used for leaching tanks in the past.

I think the issue is that it might be carcinogenic, which is a bit more scary than an acid burn.
A quick search said handle with care may also damage the bone marrow.

Should be reason enough I guess.

Edit spelling

 

[kaisernine]

That's what I read as well, just figured as sulfuric acid fumes, nitric and the like also can be, I appreciate the response.

I was curious of the mode of transport for issues.

Either case I don't need it was just interested if anyone used it.

 

[Martijn]

Most nickel salts are also carcinogenic.
Treat all hydrometallurgy as deadly.
Always. No touching that beaker that looks clean, small amounts can build up in your body qnd cause problems years later.
Pgm's are exceptionally dangerous.
You will get some exposure no matter what you do I guess, but be cautious handling everything chemical.

 

[kaisernine]

I know and I agree completely, it is not exactly the healthiest of careers/hobbies.

I worked with many of the chemicals we are discussing - just not this one.

I was just curious if any members use it and how / what for.

I've seen a video of someone using it for deplating and when I asked the engineer I worked with he didn't say too much about it but they are using it for a selective process in deplating/replating, and there are a large amount of hazards to it.

Thiourea is readily available so I was wondering about the process as I never used it when I was at the facility before I started my own business.
I wanted to know the pros and cons and maybe figure out why they adopted it.

I will just ask the engineer next time I visit in a month to pickup for my scrap contract with them.

Again I appreciate the reply, forum is a wealth of knowledge - I have been out of the plating career for a long time and started a scrap business when I realized how much was being thrown away by the plating facilities when there were errors.

I won't lie I have access to a lot of gold and silver plated material and have refined gold in the past (still do jewelry when I get it). I thought about processing this material in the future but I can do it with other types of cells that are safer and I still have a plating rectifier from the facility they tossed out after they got a upgrade. I had it refurbished with new diodes and it is read to go if I were ever to decide to do it.

I am so busy I'll probably just end up selling the material at some point but it sounded like a fun retirement hobby, but then again there is always fishing.

 

[Yggdrasil]

I know and I agree completely, it is not exactly the healthiest of careers/hobbies.

I worked with many of the chemicals we are discussing - just not this one.

I was just curious if any members use it and how / what for.

I've seen a video of someone using it for deplating and when I asked the engineer I worked with he didn't say too much about it but they are using it for a selective process in deplating/replating, and there are a large amount of hazards to it.

Thiourea is readily available so I was wondering about the process as I never used it when I was at the facility before I started my own business.
I wanted to know the pros and cons and maybe figure out why they adopted it.

I will just ask the engineer next time I visit in a month to pickup for my scrap contract with them.

Again I appreciate the reply, forum is a wealth of knowledge - I have been out of the plating career for a long time and started a scrap business when I realized how much was being thrown away by the plating facilities when there were errors.

I won't lie I have access to a lot of gold and silver plated material and have refined gold in the past (still do jewelry when I get it). I thought about processing this material in the future but I can do it with other types of cells that are safer and I still have a plating rectifier from the facility they tossed out after they got a upgrade. I had it refurbished with new diodes and it is read to go if I were ever to decide to do it.

I am so busy I'll probably just end up selling the material at some point but it sounded like a fun retirement hobby, but then again there is always fishing.

We answered this a few weeks ago, didn't we?
Do you really want to play around with carinogenic substances?
I would choose the Sulfuric stripping cell any day.

 

[goldandsilver123]

I have searched a bit about thiourea and it seems it is possibly carcinogenic, not proved carcinogenic (from what I read in 10 min searching)

Thiourea is used at 8% to remove tarnish from silver in jewelry, product sold at supermarkets.

Borax is carcinogenic if you read the msds


Keeping proper sense of how to deal with chemicals, gloves, etc, I wouldn't mind.

 

[kaisernine]

Appreciate it, I will research further in my free time. I would probably do sulfuric cell as well, as I have all the equipment already.

 

[kaisernine]

Most nickel salts are also carcinogenic.
Treat all hydrometallurgy as deadly.
Always. No touching that beaker that looks clean, small amounts can build up in your body qnd cause problems years later.
Pgm's are exceptionally dangerous.
You will get some exposure no matter what you do I guess, but be cautious handling everything chemical.

this is pretty much what I was getting at, was just curious if any members had experience with using it and results.

all of refining is deadly if handled improperly and exposure will happen even to the best of us.

 

[macfixer01]

I know that Geo did some experiments trying to strip gold with thiourea at one time. He questioned whether that was what some of the Youtube videos showed where some supposedly “safe to touch” chemical selectively strips only the gold. Instead of electrolysis he was oxidizing it chemically with sodium percarbonate (instead of H2O2) but he said it didn’t work as expected. It apparently stripped the solder off the pins but left the gold untouched? Anyway I don’t think he ever did any follow up on it though. There were a couple YouTube videos by Patnor and Owltech using stripping cells with thiourea. To adjust the ph I believe one added sulfuric acid and the other I think added citric acid.





Also see the photo for a little more info.

 

[kaisernine]

I know that Geo did some experiments trying to strip gold with thiourea at one time. He questioned whether that was what some of the Youtube videos showed where some supposedly “safe to touch” chemical selectively strips only the gold. Instead of electrolysis he was oxidizing it chemically with sodium percarbonate (instead of H2O2) but he said it didn’t work as expected. It apparently stripped the solder off the pins but left the gold untouched? Anyway I don’t think he ever did any follow up on it though. There were a couple YouTube videos by Patnor and Owltech using stripping cells with thiourea. To adjust the ph I believe one added sulfuric acid and the other I think added citric acid.





Also see the photo for a little more info.

interesting, thank you for the info.

I like the idea of it plating out rather than all of it ending up a sludge to filter, although I'd imagine it won't all deposit on the cathode it is still nice to see.