Silver Recovery with Reverse Electroplating
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- Опубликовано: 25 авг 2024
- Silver recovery from platted cutlery wasn't my priority for couple of years but today I found a box of plated forks and spoons and decided to check if I correctly remember the process. Played a little with the power supply to check different voltages ... still 1.8V looks best but if you are in a hurry go for as much as your power supply can give you :)
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I was an aircraft mechanic and worked in aerospace almost my entire career. All jet engine hot section components are fastened together with literally hundreds of nuts and bolts that are silver plated because the silver acts as a lubricant so they’re easier to disassemble. The fasteners can only be used once and then they’re discarded. I’ve thrown tens of thousands of them away over the years! If I only knew how simple it would have been to strip the plating away I’d have retired a wealthy man!
I fully understand you. If I have had the knowledge about eWaste I have now 20 years ago I would be able to retire at 42.
They still do 😂. It is crazy to me, our scrap guy must be a happy dude. Even the one time use crush gaskets are plated.
I learned how to do this about a year ago from watching you. I would like to tell you what I have discovered in the meantime. You said to use a piece of stainless steel as the electrode and I wondered, magnetic or non magnetic stainless steel? I searched for the answer and didn't find any info, so I experimented and found that magnetic stainless steel works far superior. What I then did was to get a full size commercial restaurant magnetic stainless tub and make that my cathode. The whole big tub. I further placed huge magnets obtained from electric motors around the stainless tub to increase its magnetism. I'm talking about magnets that are so powerful that they are dangerous and can injure one. For my anode I have silver plated buss bars attached to wood that I have across the top of the tub from which I attach and hang silverware and other silver plated items I wish to deplate. I use the salt that you recommend as well as the low volts you recommend. I keep the silverware in the solution for about 2 days and I don't have to use a brush at all, as all the silver is off, along with some base metal. Ramping up the size of my contraption allows me to deplate around 40 pieces of silverware at a time. I started off with just the glass like you are showing. When I do a clean up, I get a brown sludge which I dry, cupel to get rid of base metals and then remelt in a crucible and pour into an ingot to await further refining. Your video is what got me started. Thank you.
Wow! Happy rot see that this video was useful to you and thank you for sharing how you further improved the cell.
BREATH!!!!
Please make a video of it 🙏
It's nice to see this done by someone who acts like a chemist in a lab setting rather than someone in there garage with an overexposed camera.
Thanks!
I will be trying your process in the near future, I have around 90#s of silver playing and sterling silver to play with. All I need is the sodium sulfate and it's on
Hi, for the silver plating is fine, just takes time. Sterling silver has to be dissolved in nitric acid and refined - it is a different story 😀
Great tutorial! Thank you for sharing 👍
Thank you!
1.8V is the 'optimal' (minimum) voltage ONLY if using common steels as the anode. If using a different mental, check your standard galvanic potentials!
Also . . . if you let the reaction progress, the whole spoon will be gone. It doesn't stop at the silver unless you use the same metal for your anode as the metal in the original silver-plated object.
Current is optimal for steel anode. Correct.
you mean if I use pure silver instead of stainless I dont have to refine it after to get rid of anything?
That’s correct. Even on top of the stainless steel silver is 999 to 9999 pure.
thanks !@@escrapchannel
Hi, Thanks for sharing! very illustrative video !.. One question, Is the sodium sulphite electrolyte always selective for the Silver no matter what the base metal is?
Hi, I used sodium sufite for different silver plated metal objects. Always worked. But who knows :)
Works well for silver plated brass and on top of the object we have tin, iron ... so no issues.
@@escrapchannel would using a computer supply with 12 V make the process much faster?
Hi, when voltage is high reaction goes fast but also impurities are more. Also some foam spears on top that is quite unpleasant.
From my experience electrolytic processes are slow in general and pushing them is usually not successful.
@@escrapchannel what electrolyte do you use for gold plating?
@@FirstLast-tx3yj For gold plating I do reverse electroplating in 98% sulfuric acid.
Nice video sir
Thanks!
thanks for the information. my question is does the electrolyte go from a dilute sulfuric acid to more concentrated after you remove silver from many pieces? also, as i have been doing this, the brass and copper base metals eventually go into the solution as foam as the silver is removed. i am suspecting that some of the base metals go into solution along with the silver. how to you process the brass/copper materials that collect on the bottom of the container?
Hi, electrolyte is quite cheap and to be honest I never used it long enough to see a difference as you describe. Silver in solution I precipitate as silver chloride. Metal pieces on the bottom I dissolve in nitric acid first and then precipitate silver as silver chloride, too.
hello. Do that cell wokl on solid silver objects example a 90 percent scrap silver coin to get the silver out? good video
Hi, it is a very slow process for solid objects. I usually dissolve silver in nitric acid and recover pure silver from the solution.
what about a nylon brush to remove the loose silver instead if a spoon?
Hi, toothbrush works perfectly :)
for a container with a volume of 20 liters what voltage and current is needed? do you have any recommendations?
Hi, voltage should be same, and when you set-up the system you will test with a power supply working on constant voltage what is the current. You work at constant voltage and during the process current changes.
@@escrapchannel okkk. for the best current settings at what number ? If the cathode area is 450 cm²? Is there a contact that can be contacted to ask questions about this silver recovery?
Hi, voltage or potential difference between electrodes is important in reverse electroplating. When process starts at fixed voltage you will have maximum current for the cell and it will slowly go down. For 450cm2 should be more then enough a power supply I use: 30V /5A. When you work on 1.8V for example you can test current dependence on concentration, distance between electrodes, etc.
Just build the cell and the during testing it will be properly set-up.
How do you reverse electroplate rhodium? I have a lot of electronics that contain rhodium.
Hi, have never tried Rhodium reverse electroplating, but as all metals it is question of finding correct electrode and voltage to have it selectively recovered.
Do you use sodium sulphate or sodium sulphite?"The key difference between sodium sulphate and sodium sulphite is that the sodium sulphate has a sulphate anion, which has one sulfur atom and four oxygen atoms whereas sodium sulphite has a sulphite anion, which has one sulfur atom and three oxygen atoms" this is from Google. I ask to clarify for my personal use.
Sodium sulphite I believe is the better of the two
Hi, it is sodium sulphite.
@@escrapchannel ya I seen it in a comment on the very bottom. Thx for reply mate
Great Video, one thing I would like to ask, what difference would it make if I use sea salt instead of the sodium sulfite? and would it be the same amount if I did?
Hi, if you use salt you will end up wit a lot base metal dissolved and deposited on the stainless steel electrode.
@@escrapchannel thank you for the answer and for the quick response :)
Couldn't you just keep stripping the silver from items and plating it on a small silver bar to make it bigger?
Yes, can be fully stripped and melted.
Silver Spoon and What is second metal please
Silver plated spoon and stainless steel electrode.
Sir can I use sodium sulfite and distilled water for revers electroplating gold? Not a silver
Hello, no. It will not work as you will dissolve a lot of copper. Gold reverse electroplating is done in concentrated 94-96% sulphuric acid. I have such videos.
@@escrapchannel Sir I can't use sulfuric acid . Please tell a another chemicals. I like use distilled water and citric acid to my chemicals what do you think it's will work? Please reply.
Hi, citric acid method works well when used for thin gold plating like ram fingers, not that good for pins and gold plated metal objects.
What are you using and were Do I get it?
I use sodium sulphite.
Will sodium sulfate work?
Hi, I never tried, to be honest.
replace the stainless steel with a silver spoon?
Hi, never tried :) To be honest I always refine silver before melting it. Sreetips cell works well, also a cycle of nitric acid dissolving works. Just to go closer to 999. Silver spoon is an alloy - if sterling 92.5% if other can be 80% or in between ...so to get 999 in all cases one more refining is needed.
I like stainless as it is easy to remove silver from it’s surface and can be used almost forever :)
@@escrapchannel the problem i have is my refiner pays more for sterling than 999. i dont know why....
less steps and expense for me😃
@@tinsoffish1810 Because your refiner most probably directly uses sterling silver that is 925 silver for jewelry.
The point is that if you use spoon you will get pure silver on top.
If I was you - I will use the stainless electrode and get 99% silver. Then add copper to reduce the % to 92.5% and sell as sterling.
Is your buyer using any tool to check the silver content?
Also, don’t expect to get solid silver layer on top of the spoon. In home refinery you very difficult can keep the conditions to get solid silver on top.
Do you think magnesium sulfate would work as good as sodium sulfate?
Or possibly a potassium sulfate ?
Should be sulfite not sulphate. In general sodium cation is really small and moves fast in water when potential difference applied. Magnesium is a little bigger cation and two 2+. Sodium is 1+.
So, if you use magnesium salt you will have worse electro conductivity with same amount of salt.
@@escrapchannel Thank you for the correction and your advice. We have done reverse electroplating on Silver before using the sodium chloride and distilled water. I start seeing what appears to be a copper going into solution and the recommended clearing of this was a couple of drops of hydrochloric acid which appears to be producing copper (II) chloride. We've been definitely looking for a cleaner method with less by product.
When you do reverse electroplating you should consider the potential of the ions, so you calculate what will be the product on the electrodes - silver, hydrogen, etc.
If you have a lot of silver plated metal objects just use chemical stripping. Sulphuric acid 1 litter and 50 ml nitric acid. Both concentrated. Mix carefully! Removes silver plating really quickly and efficiently.
@@escrapchannel I'm a fan of the sulfuric/nitric recovery method, I'm trying to keep it as low toxicity as possible, something that my teenage son could participate in, with minimal hazards.
What about using a tungsten rod and sodium bicarbonate ?
Never tried this combination maybe because I never had a solid piece of tungsten.
Im just worried about creating chlorine gas from sodium chloride
@@matthewforgath5298 Reaction is slow so if done open air or under any ventilation - gas produced should not reach risky concentration.
@@escrapchannel if it's done fast does it affect the silver in anyway ? Will it burn it up ?
@@matthewforgath5298 when voltage is high and reaction goes fast there is a lot of base metal in solution and also starts bubbling and forming foam.
How does the quality of the silver change at higher voltage
Hello, usually when voltage is very high and there is foam on top we have not only silver but also all other metals dissolving and even small pieces falling from the surface, so silver is dirtier that we collect, In all cases needs refining to 999 so not a big issue.
@@escrapchannel could more than one piece be deplated at ounce
Could you just use a stainless steel bowl and attach the lead fill it with electrolyte to do this
Michael Madera: yes, you can use copper wire for example and put together many objects.
Michael Madera: yes, dirty silver can be purified as Sreetips shows in his videos or just dissolved in nitric acid and reduced to silver with copper or zinc.
Can you tell me if you get toxic fumes from this. Is it safe to do in the house
Hi, I can’t recall any fumes or bad smell. Actually it was done in-house without ventilation on.
Thanks for the reply
Sorry for the questions but how do you know when the silver is all spent on the item . I seem to have a creamy calcification on the item. When I scrap it off it still looks silver. Also does the solution have a shelf life? Do you need to filter off as I've a 2lt beaker and the water is cloudy? Dark brown to black. Any pointers will be appreciated 👍
Process is slow, so it takes long time to strip all silver especially when layer is thick. You are correct as long as you see the white layer on top you have silver on the object. Base is usually brass, so Color change is clear when silver stripped.
The fast way to strip silver is to use acids. 20 parts concentrated sulphuric acid and one part concentrated nitric acid. Heating needed but not boiling. Strips silver fast and you clearly see red colour of the base metal. Sulphuric acid blocks sipper/brass from dissolving. Silver is recovered from solution with table salt as silver chloride. Work with acids needs special equipment and unfortunately hood to ventilate poisonous gases. So, don’t do this if you cannot protect yourself.
The ‘charm’ of reverse electroplating is that you let the electricity do the work. Just connect and forget. It is slow but needs no effort. Silver drops as metallic silver pieces and also goes into the solution.
What is the material of the electrode you are using?
Stainless steel
@@escrapchannel thank you
You say "sodium sulfate" but show "sodium sulfite". Which is it? Sodium sulfite is a very smelly chemical!
Hi, it is the sodium sulfite Na2SO3. Usually sulfides are the smelly ones.
What would happen if you increased the power supply to 12v 6amp?
Hi, fast reaction, dirty foam on top, etc. Electroplating and reverse electroplating are slow processes and the slower the better quality result.
@escrapchannel I had a very very dirty solution doing the 12v 6amp. I did use salt and distilled water. It was horrible. So much base metal in solution. I have non-iodized salt and distilled water here. I am going to try the voltage you have recommended. How long should I let it deplate before removing it and brushing?
@@HardKnocksTime wait, please! Salt? It will never work with salt in the solution. Thats the reason for the base metal quickly moving to solution. Please use Na2SO3 - 60g per litre distilled water. It will keep reaction smooth at the. Outage in the video.
@@HardKnocksTime Sodium Sulphite is the chemical name
@escrapchannel I will get the sodium sulphite and give it a try. I can't thank you enough. Give me a week and I will be back to let you know how it turned out. Thank you again for all of your knowledge, time, and sharing with me!!!
It's all arrived now my friend. I accidentally mixed 60g in my liter. Is that okay or do I need to decant and make 50g?
@@HardKnocksTime hi, 60g per litre of water is fine.
@@escrapchannel Not having much luck getting any silver thus far. I'm set at 1.8v my amps are low and won't go higher then .9. I've been going about 2 hours now with no silver peeling maybe just a tiny dust when I brush the item. Almost as if it's not working at all. Any suggestions?
@@HardKnocksTime you may have silver in the solution. Take 1ml and add table salt. There are two parts of the process: silver goes to the solution and some parts of the plating may fall too.
@@escrapchannel how much salt should I add to the one ml of solution,?
Couple of crystals - silver chloride should instantly appear as white residue.