# How to process ash from e-waste?



## Marcel (Apr 1, 2013)

I received 6.5Kg of incinerated and ball-milled ash back from a large refinery here in Germany. I was not satisfied with their work and this portion was not yet refined just made to ash and send back to me in a steel bucket.
Now this ash was made from transistors and similiar 3-legged components, they where factory new and the original weight was 24Kg.
I suspect the refiner to have kept all the sieved material, because the reduction of the mass, seems to be too much. 
I dont really mind that, because most of the material that could not be milled to fine powder should have been the copper leads, plated with tin.
So now I have a dry very fine concentrate. I tested it with magnets and only found very little magnetic material in it (maybe 5%).
I then dissolved 10g in Aqua Regia, tested it with SC and got a very strong reaction, but no color to it. (the greenish solution on the swap turned transparent). Further testing found the expected silver in it.
I boiled down the solution to a point where white crystals precipitated all at once. Filtered that and ran some water over them which made them dissolve and turn into the well known blueish solution.
So my assumption was that the crystals were made of AgNOx , because they are well soluable in water.
I even tried to put 200g in my furnace and roast it at around 1200°C, hoping for the metalparticles to get to each other and form larger nuggets, even if that would mean "dirty" alloys" . But the ash is just too fine and wont allow the mini silver particles to find each other.
Used a spyglass and a microscope and was able to see small balls of silver and what looked like gold (very little gold).
Now my question is, what would you suggest to to with this concentrate in order to recover the values effectively?
I suppose to have silver in a economic scale in that powder, very little gold and prob. very little Pd.
I do not care too much about the Au and the Pd, since I suppose it is not enought to set up a seperate process. But what about the silver?
Leaching such fine powder is a real pain. It takes long, it requires a lot of chemicals and has to be redone several times.


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## etack (Apr 1, 2013)

Get a propane melting furnace and add a sett amount of silver and melt it all together and mix it well for a while. then pour into a cone mold and reweigh it to see what you collected. You will need a flux that will collect and thin the silicon and carbon the rest should be base metales.

Eric


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## Marcel (Apr 1, 2013)

Dear Eric,
I know from some documents, that some of the large refiner use such methods. Ironpowder seems to be very popular in the US whereas others use copperpowder as collector material. Using silver itself sounds like a good idea to me (theoretically!) it just has to prove that it can be done that way. 
I will use some leftover silver as collectormetal, mix it with the ash and flux, then try to get it all melt together. If I stay below 1000° there should be no copper alloyed.
Will keep you updated if I succed in that direction.


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## FrugalRefiner (Apr 1, 2013)

Marcel,

I have a few comments:



Marcel said:


> I then dissolved 10g in Aqua Regia, tested it with SC and got a very strong reaction, but no color to it. (the greenish solution on the swap turned transparent). Further testing found the expected silver in it.


If you dissolved your sample in AR you shouldn't have had much silver in solution.



> I boiled down the solution to a point where white crystals precipitated all at once. Filtered that and ran some water over them which made them dissolve and turn into the well known blueish solution.
> So my assumption was that the crystals were made of AgNOx , because they are well soluable in water.


 AgNO3 in solution is clear. Cu(NO3)2 is blue.



> If I stay below 1000° there should be no copper alloyed.


 While copper by itself may not melt, remember that molten metals are powerful solvents of other metals. Once the silver becomes molten, it will likely dissolve any copper it contacts, so you will end up with some in your silver. On the good side, the silver should also dissolve any gold and palladium that may be present.

Dave


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## johnny309 (Apr 1, 2013)

Even solder ...at 300-400 degress celsius can "catch" some copper.....not to mention gold and silver.....


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## a_bab (Apr 3, 2013)

Hello,


can you please give me the yield for the transistors as refined from your refiner? Let me guess: 1 g/kg or less?

There are 2 solutions to your issue:
1. Pan the ash just like gold/sand - it may work
2. Time to build an electrostatic separator - it would certainly work well and separate the metal fraction.


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## Smack (Apr 3, 2013)

Did they incinerate? Two things lead me to believe they did, one is the loss in weight and the other is no mention of smoke when you tried to melt it. You said it didn't do anything when you tried to melt it, did you stir while heated? I'm guessing you didn't use any copper or silver to collect your material when heated? Those little particles of metal in your powder need to either come into contact with each other to grow in mass or add some silver or copper so it can collect and merge with that. Either way you need to stir the melt. If you add metal to the melt to make it more homogenous, make sure you weigh it so you can subtract it later.


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