Keyboard Mylars, what method to choose ?

[kjavanb123]

The following links two homemade shredder and cutter that can be used for mylars or films.

https://m.youtube.com/watch?list=PLxXd0CgIkAPId55oGBeq2Dm1_IQfj5pWK&v=HT_7hMs3WBI

And
https://m.youtube.com/watch?list=PLxXd0CgIkAPId55oGBeq2Dm1_IQfj5pWK&v=4S2tKhAru2k

 

[dscrapper]

I process about 6 lbs of keyboard mylars with the Lye . 10% lye . all came clean then I incinerated . I smelt with borax and sodium carbonate as a flux to catch the ash. My problem is the silver looks as thou its got gold in it. Anyone ever heard of some keyboard from PCs mylars having both silver and gold ?

 

[Topher_osAUrus]

Id bet its firescale from a bit of copper contamination (somehow) over it being gold. Try putting a couple pieces in a small beaker with a little distilled water and then add some nitric. If its firescale the oxidation will quickly be removed and leave shiny silver.

Sulfuric can work too, just not as fast. It has the benefit though, of not dissolving a small bit of the silver with the oxidation.

Pictures would be cool.
I love me some pictures

 

[butcher]

I like the home made paper shredders, guards are also easy to make,that way even I could keep my fingers from being mistakenly shredded. for some reason my fingers are always attracted to fast moving objects.

 

[dscrapper]

Id bet its firescale from a bit of copper contamination (somehow) over it being gold. Try putting a couple pieces in a small beaker with a little distilled water and then add some nitric. If its firescale the oxidation will quickly be removed and leave shiny silver.

Sulfuric can work too, just not as fast. It has the benefit though, of not dissolving a small bit of the silver with the oxidation.

Pictures would be cool.
I love me some pictures

I think you may be right about the copper . I cant get and nitric to try . I do have more of this powder to smelt but am waiting until I figure out what to do with it . since it is copper can I use hcl in my powder and remove it ?

 

[Topher_osAUrus]

I think you may be right about the copper . I cant get and nitric to try . I do have more of this powder to smelt but am waiting until I figure out what to do with it . since it is copper can I use hcl in my powder and remove it ?

I wouldnt use HCl.
But I hate silver chloride.

I dont know how much AgCl would be created even, probably minuscule amounts, but thats still too much for my liking.

Can try to pickle it in battery acid, or after its melted quench it in dilute HCl

 

[lg701]

I use normal household bleach from Walmart (8.25% sodium hypochlorite). Biggest problem is it
takes quite awhile to get the silver off the mylars. Evidently the ink is the determining factor in how
long it takes. Some mylars take days, others take weeks. Agitation from time to time is required as it is with a lot of the processes we do.
Much safer process but patience is a virtue.

 

[kjavanb123]

I use normal household bleach from Walmart (8.25% sodium hypochlorite). Biggest problem is it
takes quite awhile to get the silver off the mylars. Evidently the ink is the determining factor in how
long it takes. Some mylars take days, others take weeks. Agitation from time to time is required as it is with a lot of the processes we do.
Much safer process but patience is a virtue.

You may also heat your lye solution that will shorten the time needed for mylars to get clean.

 

[rickbb]

When using bleach with x-ray film the process of stripping the silver bearing emulsion converts the bleach to lye eventually leaving only lye in solution and no bleach.

Could be something similar going on with the Mylar's, the bleach converting to lye before the stripping occurs, which is why it takes a long time.

 

[lg701]

Are we talking about the same thing here? I'm using sodium hypochlorite, not sodium hydroxide.
My apologies if I'm wrong, but I'm not sure normal bleach turns to lye under any circumstances.

 

[rickbb]

Are we talking about the same thing here? I'm using sodium hypochlorite, not sodium hydroxide.
My apologies if I'm wrong, but I'm not sure normal bleach turns to lye under any circumstances.

Yes, bleach, sodium hypochlorite, will be converted to sodium hydroxide in the process of dissolving the emulsion of x-ray film to release the silver salts. Several patents and papers published by Kodak back in the day talk about this.

I don't know if anything similar is happening on the resin, (silk screen ink), that is binding up the silver on keyboard Mylar though. Since you mentioned it took a very long time for the bleach to breakdown the bond of ink to Mylar. And since we know that lye works for breaking that bond, I thought about the conversion process that happens with x-ray film and bleach.

Was just thinking out loud on it, and could be completely wrong, (wouldn't be the first or last time I'm sure).

 

[lg701]

Thanks for the heads up about using bleach with x-ray film Rick. If I had access to any amount of
x-ray film I would have tried that next. I think I will pass on that adventure.
Besides the agitation I sieve the liquid and add fresh every 5-7 days. I figured if it evaporates
from our gold solutions before dropping, the same must happen here.
Even though we all use bleach for laundry and find it in lots of other cleaning products it goes
without saying that it should be kept out of reach of children and pets.

 

[kjavanb123]

Hi everyone

I happened to receive 822g (1.81 lbs) of mylars (with that blank sheet between them). There were 41 pieces.

I used 10% lye solution (that is 10g lye mixed with 100ml of water).

Here are some pictures,


Here is what mylar looks like after 1.5 hrs of boiling in lye solution.


This time instead of filtering the ink and silver and melting them, I washed them into a beaker and dissolved the silver in nitric then filtered and added hcl to drop the silver as silver chloride.


Here is the silver chloride. After being washed few times I sprinkled zinc powder and mixed it with silver chloride, then added hcl to convert to elemental silver.


And here is the final silver shots from that mylar batch.


So net weight of silver from this batch is 9.05g silver from 822g mylars (41 pieces).

This calculates to 11g of silver per kg of mylars. Or 6.1g silver per lbs of mylars. In my last batch I did direct melting the silver and ink I got 6.7g silver per kg.

So it seems filtering the liberated ink and silver, then dissolve it in nitric filter and drop with hcl or cement with copper would be a better option.

Locally I can get mylars for about the price of 4g of silver per kg, so if I can get 11g silver from a kg of them, seems like a good deal.

Also I used a centrifuge to separate the silver inks from the mylars.

Best regards
KJ

 

[rickbb]

In my opinion you went to a lot of extra work and chemical expense reducing your profit.

The silver in the ink/resin is almost pure as is. The last batch of Mylar's I did after I had separated the ink from the Mylar, after washing and drying, I simply melted it with some soda ash as a flux.

The melt process will carbonize the ink/resin and any bits of Mylar and that will either go up in smoke or get trapped in the soda glass which you can break off of the silver bar/button when cool.

My yield was approximately 1ozt per 10lbs of Mylar's.

 

[kjavanb123]

In my opinion you went to a lot of extra work and chemical expense reducing your profit.

The silver in the ink/resin is almost pure as is. The last batch of Mylar's I did after I had separated the ink from the Mylar, after washing and drying, I simply melted it with some soda ash as a flux.

The melt process will carbonize the ink/resin and any bits of Mylar and that will either go up in smoke or get trapped in the soda glass which you can break off of the silver bar/button when cool.

My yield was approximately 1ozt per 10lbs of Mylar's.

Hi Nick

The reason I did the extra step was to avoid the smoke from ink plastics in melting and dealing with lower volume of metals.

Based on my finding from 10lbs of mylars you should have gotten almost at least 2 ozt. Hence another reason for my extra step.

 

[kjavanb123]

Hi

Just finished processing 6kg (~12lbs) of mylars in 10% lye solution, boiled for 1.5 hrs.

Recovered 58.51g silver. This makes it close to my last yield of 10g per kg of mylars.






Best regards
KJ