arthur kierski
Well-known member
I have 2 tons of iron wires plated with gold(strong Plating )--I want to recuperate these gold and need help of ways to recuperate this gold--arthur kierski--member since 2008--Any ideas are welcome
plated gold in iron wires
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Dissolve the iron in hot HCl maybe.
As Nick indicates one can dissolve the Iron if the thickness of the Gold allows it or one can dissolve the Gold.
HCl for the Iron, Cyanide for the Gold if you are set up for this. AR may run into issues with the Iron I guess.
Maybe it can be smelted as Gold and Iron is not very happy together.
I hope some of the smelting wizards chime in now.
My first choice would be cyanide stripping. Smelting would involve adding copper and oxidizing out the iron with O2. Two tons is a lot of material, CN would make quick work of it.
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Bang on the money. Arthur you've got access to cyanide haven't you? Jon
arthur kierski
Well-known member
Thanks for the first answers--i took some of the material and attacked with cianide,the goldissolved in the cianide was very little--the wire remains gold plated--with water and sulfuric,the reaction is very strong at the beginning,but soon become very weak(because only the tip of the wire is iron-the acid does not attack the gold plated wire
arthur kierski
Well-known member
Jon,i will repeat stripping with cianides--once,twice ,3 times,then i tell you the results--i will buy fresh cianide and prepare my gold stipping solutions--
You use the words sulfuric and acid in your answer. Never mix acid and cyanide. The cyanide will attack the plating with time and circulation, if you want it sped up add a little peroxide but only strip a small sample in cyanide peroxide. The reaction can get violent if you do not control portions. They call that process bombing in the jewelry industry for good reason.
Mix up your sodium cyanide at 4 grams per liter or potassium cyanide at 5 grams per liter. Use in a container that has air agitation. Allow room for the reaction to rise so, a deep container. Only turn the air on when stripping as it will break down the cyanide. Add between 0.5 and 1 ml per liter of 50% peroxide. Do not over add the peroxide. It reacts aggressively so start with small quantities until you are comfortable controlling the reaction.
Dip in the material to be stripped in a removable basket so you can pull it out when it gets aggressive. Rinse the stripped parts in water and save the rinse to process as you are rinsing off gold containing liquid.
Once you get the hang of it, it goes quickly and you will get a feel for how much you can strip before the solution needs replacement.
Dip in the material to be stripped in a removable basket so you can pull it out when it gets aggressive. Rinse the stripped parts in water and save the rinse to process as you are rinsing off gold containing liquid.
Once you get the hang of it, it goes quickly and you will get a feel for how much you can strip before the solution needs replacement.
arthur kierski
Well-known member
Dear 4metals,thanks for your explanation-i liked very much and i will begin do it tomorrow--then i will tell you how it went -once again thanks. i have to tell you that i do not mix ever acids with cianides-
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I've spent years building different varieties of leach tanks. The amount of mistakes I've made are enormous. Getting the mix of aeration, CN level, temperature and pH balance to get a respectable leach speed is an eye opener of a process. It's one of those things that's relatively simple at a basic level, however needs a lot of thought to weaponise into something that can do volume of ewaste items at a profitable/practical scale. It's a great journey.
The chemistry of Cyanide leaching is absolutely fantastic.
One thing to be aware of is that cyanide leaching will rarely recover all the gold , if done correctly and you get the mix right you should get 95% in a reasonable time, as Deano once pointed out virtually all recoveries are subject to give and take or wins and loses, finding that balance that gives decent returns for the effort is the art.
Many moons ago I ran a large electroplating shop in a connector manufacturers factory. We plated a lot of gold and silver connectors and contacts. As in any large plating shop, jobs that were out of spec required stripping and re-plating. Our strip of choice was cyanide peroxide. I never used the cyanide peroxide on e-scrap just on plated pieces, which were stripped in a basket provided a 100% coverage of gold on the pieces. This made for a quick and efficient reaction. To the point that the operator had to remain present to pull out the basket when the reaction was complete or getting too violent. I believe the efficiency came from every piece exposed to the cyanide was gold, not gold and solder and copper spaced out as in e-scrap. For e-scrap it may be viable and it just takes time so it is a different situation. Plated wire should behave like plated connectors did for me 50 years ago.
I believe the stripping process will get all of the gold off the substrate, it's the recovery from the solution where you can hang some values up.
Recently Kurt recovered some gold from cyanide plating salts, he got most of the gold by conventional cementation but he had a lot of solution to clean up with copper powder to get it all. I'm stumbling to find the thread, I'll keep looking.
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That's it Jon, thank you.
With two tons I’m guessing a lot of this material is going to be balled up or compacted getting the solution to all the pieces might not be easy and could be time costly to separate, it may pay to shred the material and use a rotating barrel to help expose the wires to the solution.
The plague of connector contacts (at least in the 1970's) was the solder hole where a connecting wire was soldered onto the connector. Some designs had a cross hole to vent the hole and make for better circulation and some did not. The most gold rejects were on the contacts for what quality control called black in the hole. A situation where solution did not flow easily into those gaps to deposit the plating. Barrel plating was better which is what Nick is saying. But we never used a barrel for the peroxide cyanide strip because of its tendency to react quickly (why it was called bombing in the first place) The reaction was controlled by lifting the pieces out of the solution, which is difficult in a barrel.
Although shredding may help for sure but shredding wire which is likely rolled into balls to drum it up may be a challenge as the material may tend to wrap around the cutters and make a huge knot.
When we plated small parts that would not plate well in a barrel, we had racks and the parts were hung on copper wire. We did a lot of wire plating and ended up with drums of the plated wire. It was a high yield scrap.
Although shredding may help for sure but shredding wire which is likely rolled into balls to drum it up may be a challenge as the material may tend to wrap around the cutters and make a huge knot.
When we plated small parts that would not plate well in a barrel, we had racks and the parts were hung on copper wire. We did a lot of wire plating and ended up with drums of the plated wire. It was a high yield scrap.
arthur kierski
Well-known member
Nickvc,a rotating barrel is an excellent idea--at the moment i am trying various ways to recuperate the gold from the wires--when i reach a decision, i will tell to the members of the forum--Specially to you, Jon and 4metals-by the way,4metals formulation worked very well---
If you are using cyanide a simple concrete mixer will provide you with that rotating barrel and fairly inexpensively.
