Processing mobile phone parts

[Zolotov]

Hi,
to do my first gold refining test I want to process mobile phone parts (didn't get any fingers). After disassembling around 200 phones I got this pile

After sorting the pile I got these items:

2.7g of gold plated flakes (plated on steel I guess, because they can be attracted with a magnet):


179.2g of gold plated cables (with ferrous compounds in them)


35.5g of gold plated wires embedded in plastic



and 239.6g of random items with gold plated parts


From what I have learned so far, since my scrap is almost all ferrous I have to use aqua regia. But before AR I can filter out the stuff with 2 reactions:
1) Nitric acid. (AP)
or
2) Oxidizing. (Burning)

Which one is the best for this stuff?
Since there is plastics in cables and connectors, burning seems to be the right thing, but I am in doubt what to choose, don't want to make a mistake.

Will appreciate your comments very much.

 

[kernels]

Pretty much everything in those pictures will be simultaneously difficult and leave you with so little gold that you will not know whether or not it had been dropped from solution.

Did you already depopulate the boards and process the chips ? That is where the 'easy' gold will be.

 

[Zolotov]

Did you already depopulate the boards and process the chips ? That is where the 'easy' gold will be.

Yes, I depopulated with sand bath, 2kg of these boards, and this is what I have:

1,302.2g - depopulated PCBs without electronic components
108.3g - the chips (integrated circuits)
213.1g - aluminum
87.6g - metalic (gold plated) connectors
51.5g - plastic (gold plated) connectors
22.7g - cameras
99.6g - tiny items (impossible to sort): tny ICs , small resistors, capacitors , etc.
115g - lost material or ferrous junk

I am going to process the chips tomorrow.
I do not understand well why are you saying gold will not be visible. If I use nitric acid gold plated connectors will be visible. I can see them right now. Then, after I filter the black liquid processing with aqua regia should be much easier because all the plastic was removed. The nitric acid is just to get rid of the plastic. Right or wrong?

 

[kernels]

Trying to get rid of plastic using Nitric acid is a great way to create a big mess. You can use nitric acid on gold plated copper connector pins, but usually you will use a lot of acid to get rid of a lot of copper for very little gold.

From the 100g of chips, you can expect up to maximum 0.5g of gold when you get experience with processing, for the first time, usually people do not get such a good yield.

Some of the PCBs will appear to be gold plated, you won't believe me, but there is almost no gold there, hardly worth the acid and not worth the effort to process.

When I say that the gold will not be visible, I mean that when you dissolve the gold, then precipitate the gold (refine the gold), there will be such a small amount of gold in all those connectors that the gold will settle as a fine dusting on the bottom of the beaker.

 

[patnor1011]

Too much plastic there, it may get affected by nitric. You need to reduce plastic to almost zero either by sorting or incinerating(with a risk of values being blown off if not done correctly).

 

[Zolotov]

From the 100g of chips, you can expect up to maximum 0.5g of gold when you get experience with processing, for the first time, usually people do not get such a good yield.
.

Thanks for the input.
0.5 g of gold is very low, I am puzzled.
Lets say I processed it and got the 0.5g but I still wouldn't understand where the gold leak is.
This is my math:
One ton of mobile phones produces 300g of gold
One ton of mobile phones can contain maximum of 17,000 phones, minimum 10,000, suppose we have 17,000
Gold plated items (cables, plastics, cameras, etc) contain microscopic amount of gold per kg, so we consider it 0. Then all the gold must be located on the board in components.
1kg of mobile phones will contain 0.3 grams of gold (300/1000) and 17 mobile phone boards (17,000/1000) . (according to reported data)
Since I have already stripped off all the plastic parts, my kg of scrap contains only boards , I have counted them, and I have 120 boards in those 2kg, which means there is around 60 mobile phone boards per kg.
So, at least I must produce 3.52 (60/17) times more gold than the reported statistics, or exactly 1 gram of gold per kg (3.52 x 0.3g). If I would process 2kg, the yield must be 2 grams, but I got only 100g of chips, and as you say, there is not enough gold there to complete 2 grams, 1.5g is missing.
This is why I scratch my head and say, where is the gold leak ???? An enormous black hole in statistics , I would say

 

[patnor1011]

I cant see any IC chip in your pictures. Where are they? Most of gold will be in them.
All like these I marked in this picture:

 

[kernels]

If I do the math as per my physics textbook, then my car should have equal grip using very skinny tyres as it does when I have very wide tyres fitted. (Because friction is not dependent on contact area)

The reality is that there are losses in every process you will do and the smaller your input source is, the more the losses will be proportionally. I would personally not bother at this stage to process 100g of BGA chips by themselves, you are welcome to try it as an experiment, it is the only way you will really learn.

300g of gold per 1000kg of mobile phones seems very high to me, this makes raw cellphones 3 times better to process than some ICs. If you said that that is only for cellphone boards, then it is starting to sound more reasonable.

Remember when you read those statistics about xxg per ton of cellphones, the people doing that recovery used very different processes from what you will likely be using. As a home refiner, you will only be recovering the easy gold, the big companies are able to scale up and recover gold from every part.

 

[patnor1011]

If I do the math as per my physics textbook, then my car should have equal grip using very skinny tyres as it does when I have very wide tyres fitted. (Because friction is not dependent on contact area)

The reality is that there are losses in every process you will do and the smaller your input source is, the more the losses will be proportionally. I would personally not bother at this stage to process 100g of BGA chips by themselves, you are welcome to try it as an experiment, it is the only way you will really learn.

300g of gold per 1000kg of mobile phones seems very high to me, this makes raw cellphones 3 times better to process than some ICs. If you said that that is only for cellphone boards, then it is starting to sound more reasonable.

Remember when you read those statistics about xxg per ton of cellphones, the people doing that recovery used very different processes from what you will likely be using. As a home refiner, you will only be recovering the easy gold, the big companies are able to scale up and recover gold from every part.

This:
http://en.community.dell.com/dell-blogs/direct2dell/b/direct2dell/archive/2013/03/20/how-much-gold-is-in-smartphones-and-computers

o learn more about gold and how it is removed from discarded devices, I spoke to Sean Magann, vice president of sales and marketing for Sims Recycling Solutions—North America, a division of the global re-use and recycling firm Sims Metal Management.

How much gold is in a smartphone?

Magann: In very rough numbers, there are 10 troy ounces of gold (or about three-fifths of a pound) per ton of smartphones. Ten thousand phones weigh one ton. [With gold selling for about $1,580 per ounce, that would yield $15,800.]

How about a laptop?

Magann: Two hundred laptops would yield five troy ounces of gold.

How much is in an average desktop?

Magann: A PC circuit board, where the gold is, weighs about a pound. If you had a ton of those boards, you should have 5 troy ounces of gold.

 

[kernels]

OK, so that is interesting, 300g in a ton of phones, 10k phones in a ton of phones, that means 300g in 10k phones. That means 0.03g per phone. That seems much more reasonable to me.

0.03g I would expect from 6g of good high-yield ICs, which seems reasonable for the number of ICs in a smartphone. So yes, it looks like most of the gold in a phone does come from the ICs.

 

[Zolotov]

I cant see any IC chip in your pictures. Where are they? Most of gold will be in them.

this is the material I have got from the 2kg of the boards from depopulating them:

108.3 grams of ICs:


201 grams of aluminum:


87.6 grams of metallic connectors:


51.5 grams of plastic connectors:


22.7 grams of cameras:

 

[Zolotov]

and 99.6 grams of tiny material that went off the board (small ICs, resistors, capacitors, etc)




all this material is contaminated with sand tough

 

[Zolotov]

The reality is that there are losses in every process you will do and the smaller your input source is, the more the losses will be proportionally. I would personally not bother at this stage to process 100g of BGA chips by themselves, you are welcome to try it as an experiment, it is the only way you will really learn.

Yes, this is for learning. Becuase I have about 25kg of these boards right now, but I am afraid to screw it.

300g of gold per 1000kg of mobile phones seems very high to me, this makes raw cellphones 3 times better to process than some ICs. If you said that that is only for cellphone boards, then it is starting to sound more reasonable.

I got this data from here on 'Data' section, this is the thread:
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=33&t=20851

And I am ok with the losses, I just want to know where I am losing it and how much.
I was thinking to put the boards as they come (no preprocessing) into aqua regia (a sample of 1kg) and try to get the gold out of it. This way I won't lose anything since everything will be dissolved. I just have to extract aluminum, iron, copper, tin, lead individually until gold is left and then precipitate it with metabisullfite. Not sure how I am going to do this, but this video of aqua regia plant inspired me:
https://www.youtube.com/watch?v=ahVXhxDwmNg
if some guy can, then I also can do it, even if I have to try dozens of times.

 

[Zolotov]

I just turned off the incineration process. I processed the chips together with the small items (resistors, capacitors and other tiny stuff) and I have some substance of yellow color at the top. Is this some dangerous compound? Or maybe it is sulfur? I didn't see this yellow stuff on youtube videos, probably I did something wrong. I had it for 1 hour burning, at the beginning there was some small smoke, but after about 40 minutes smoke totally disappeared. Probably I shouldn't mix the chips with the small items.
Here is the pic:

 

[anachronism]

Can we inject a bit of reality here?

So Sims say I could have 300g per tonne of mobile phones That's based upon modern refinery techniques where every scrap of gold is collected. Your average guy at home as nowhere near the same tech available. This whole exercise, whilst interesting will be something that you look back on and say "never again, I could have sold them and bought loads of easily recoverable product with the proceeds."

 

[kernels]

Can we inject a bit of reality here?

So Sims say I could have 300g per tonne of mobile phones That's based upon modern refinery techniques where every scrap of gold is collected. Your average guy at home as nowhere near the same tech available. This whole exercise, whilst interesting will be something that you look back on and say "never again, I could have sold them and bought loads of easily recoverable product with the proceeds."

Yep,I have tried to say the same thing in a few different ways in this thread. It is quite difficult to explain to someone new that there is a big difference between theoretical recovery and real-world-at-home recovery.

 

[Topher_osAUrus]

Why did you mix them?

 

[Zolotov]

Why did you mix them?

because they contain gold. those chips are black, they are just of a smaller size. capacitors also contain gold. and any ferrous stuff will go out with a magnet, so i thought "why not?".

 

[Zolotov]

Can we inject a bit of reality here?

So Sims say I could have 300g per tonne of mobile phones That's based upon modern refinery techniques where every scrap of gold is collected. Your average guy at home as nowhere near the same tech available. This whole exercise, whilst interesting will be something that you look back on and say "never again, I could have sold them and bought loads of easily recoverable product with the proceeds."

You can collect every scrap of gold too. What tech do they have? The reactions work the same at big scale or small scale, so I don't see why an average guy at home can't do the same. Or, do you mean that they are using patented processes that we don't even know about? Then , that's different. But if they do it with aqua regia, then being big or small guy doesn't matter. Scale affects the volume only. So if I have 1kg of mobile phones, I should get 0.3 grams of gold

 

[Topher_osAUrus]

Yeah. I understand that train of thought.(..i once had it, sometimes still do...)
But, I know if I had some 18k green gold, 18k red gold, and 18k yellow gold, I wouldnt just throw them all into AR because "they all have gold".

Each type of feedstock requires it's own process. Sure, sometimes they get to a "point" in each of their processes where they can all get thrown in together. But, you must know each of their own idiosyncracies first. That way you aren't creating more work for one of the batches, by throwing it in with something that needs 3 more steps to get where it needs to be, to be "properly" mixed with the other lots.

I know you are working with escrap, and not karat gold, but the same principles hold true.