Mobile phone printed circuit boards analysis report

[kjavanb123]

All,

Today I smelted 211 grams of used mobile phone circuits, and that produced an alloy weighing 47.3 grams, I think some beads still inside the ash which shall be ball milled and separated, weighed then mix with other alloys for 100-element ICP assay. I shall post its result next week.

Here is photo of sample cell boards which I smelted,


And this is the smelt alloy,


Regards,
Kevin

 

[bswartzwelder]

Will be looking for the cell phone results. Presently, I have about 6 full 5 gallon buckets of boards only. No screens, no steel that could be removed, and no plastic other than what might be in the makeup of the circuit boards themselves. I also have about a 5 gallon bucket of screens and a 5 gallon bucket of lithium ion batteries. The batteries will go to Radio Shack for recycling. I plan to crush the screens down to a powder then melt the powder in my kiln. Hopefully, using a cone shaped mold, any metals etched onto the screens will sink to the bottom of the melt. After that, who knows. Home Depot likes to see me coming. They have the buckets with lids prominently displayed in their store.

Bert

 

[Pantherlikher]

Hi...
Questions for both.
211grams of boards...any guess as to how many boards?
Do you smelt everything just to find out PM/ton of material? Seems alot of work if just recovering.

If melting the glass, why grind to a powder? to fit more?
If grinding, why not process with nitric and then AR? Melting the ground glass would start you over if nothing seperates well enough.

Either way I'm courious enough to see results so please share.

B.S.

 

[kjavanb123]

Hi...
Questions for both.
211grams of boards...any guess as to how many boards?
Do you smelt everything just to find out PM/ton of material? Seems alot of work if just recovering.

If melting the glass, why grind to a powder? to fit more?
If grinding, why not process with nitric and then AR? Melting the ground glass would start you over if nothing seperates well enough.

Either way I'm courious enough to see results so please share.

B.S.

Yes my objective here is to find an assay on materials we collect in the market. So after that we can find the optimum options to recover metals from them.

Kj

 

[bswartzwelder]

Arthur Kierski left me a message saying he thought the idea of melting the glass to separate the PM might be interesting. Most of the "seasoned" members of the forum give very sound advice which I trust (Arthur being one of them). I have a rock polisher with about 5 pounds of 1/2 inch ball bearings and thought it might be an easy way to go, but I need to order some replacement parts for it first.

Also, most of the screens have a plastic layer either glued to them or somehow laminated to them. I want to get rid of as much of the plastic as possible before applying heat to it (FUMES), or make a mess by adding a bunch of chemicals to them. Obviously, with a 5 gallon bucket of screens, it will take quite a while to crush them all down, so I'll start out with a smaller sample.

Bert

 

[g_axelsson]

Reality check! How much metal do you think it is on a screen you could look through?

The classical material to use in screens is ITO (Indium Tin Oxide) which is conductive but still transparent. According to one reference I just read there are also some displays with a reflector in the back made up of 98% silver, 1% copper and 1% gold but only 0.3 um thick.
It's possible that with industrial scale there could be an economical way to recover indium and eventual precious metals by heap leaching, but I haven't heard about any.

Before grinding and melting do some tests to find out how much if any precious metals there are.
Grinding the glass would probably create a lot of fine metal or oxide particles which would be suspended in the melt, you need a collector in the melt and something to lower the viscosity of the melted glass.

Last but not least, you are talking about melting metals, smelting is the art of extracting metals from ore with heat and pyrochemistry.
If you want to collect the indium and tin in a melt you need some reduction agent to turn the oxides back into metals before they would come together... that's smelting!

Göran

 

[kjavanb123]

All,

The ICP result are finally here, the following is the analysis for mobile phone circuit boards smelted.

View attachment image.jpg

As it can be seen 211 grams of mobile phone circuits just like you see in the picture in the beginning of this post produced 47 grams of alloy metal, so 1000 kg would produce 222.748 kg of metal alloy, since 1 metric tonne of this metal alloy according to the assay would have 1033 grams of gold, therefore, 222.748 kg of metal alloy would have at 100% recovery rate, would produce 230 grams of gold, so one metric tonne of mobile circuit boards as you see in this post would have 230 grams of gold.

Please advise,
Kevin

 

[Anonymous]

Kevin

That's far too small a sample to base a calculation upon with regards to an overall yield per tonne for mobile phone boards.

Yes it's correct for the specific mix of boards you used but I would hazard a guess that your mix of boards covered a very small part of the types of mobile phones available. Did you keep a log of the make, model, and respective quantity of each type of board?

 

[kjavanb123]

Spaceship,

No I did not keep a log on different types of mobile boards I smelted, and I think it would be very difficult task to separate 1 metric tonne of mixed mobile phone boards into sub groups based on models and year of built and etc, the only problem I see with the assay result is that, somehow the lab may have missed some of the beads and that is where the missing gold is, or some of it might be in the carbon ash, as GoldSilverPro has mentioned in my other posts, since I just smelted the boards without any incineration first,
I incinerated 2 PC boards I am going to try it with them and hopefully use fire assay, as this lab used AR digestion followed by spectrometric on a homogenious sample from 47 grams of beads alloy.

Rergards,
Kevin

 

[Anonymous]

1 tonne of mobile phone boards is one heck of boards Kevin.

It's not difficult at all to separate some piles of boards out that are the same. You only used a small sample anyway so you could do this with ease. Collecting data is easy but collecting RELEVANT data is a lot harder, but it pays a lot better in the long term.

Respectfully (and I mean this to help and nothing more) you need to start putting some process into what you're doing here because it all appears (across the multiple threads) to be completely random. You're not going to get any genuinely useable data by doing things this way. You're just throwing you money away on useless assays that really contain no concrete and relevant data.

Now, my post here is designed to help, not to put you through the grinder so please take it in the manner it is intended Sir. You need to re-assess how you are doing this because it's just eating a hole in your money right now.

 

[bswartzwelder]

Kevin,

Thanks for the post. I was surprised to see there was 2.5 times more gold than silver. I would have thought the solder would have contained more silver. Also surprising was the fact there was NO nickel in the sample.

I have about 6 or so 5 gallon buckets of populated cell phone boards. Once springtime get here, I will start depopulating them outside. I can see where the amounts of gold could vary widely. Older boards would have thicker plating whereas the newer boards have thinner plating. Also, many of the newer boards have touch screens and do not have a traditional keyboard. Those keyboards usually have a lot of gold under the contacts.

Again, thanks for the information.

g_axelsson, I said I would be melting the glass portion of the screens, not smelting them, but at the present, I have a brand new kiln which has never been fired up. However, a kiln will not keep out the air and allow pyrolization. Perhaps I will need to use some flux in the mixture. I also know that the yields are most likely extremely low. It's just that I've never really seen them addressed on the forum and I have a bunch of them (probably at least a 5 gallon bucket) laying around. I thought it would be better to take a chance and see if there's anything of value in there BEFORE they go to a landfill or recycling center. Most of the connectors I have found which connect to the screens have a layer of gold plating on them. When I pulled the connectors off, I would bet there is some small amount of gold left behind. I can crush the screens into a powder without there being a lot of dust in the air.

 

[g_axelsson]

g_axelsson, I said I would be melting the glass portion of the screens, not smelting them, but at the present, I have a brand new kiln which has never been fired up. However, a kiln will not keep out the air and allow pyrolization. Perhaps I will need to use some flux in the mixture. I also know that the yields are most likely extremely low. It's just that I've never really seen them addressed on the forum and I have a bunch of them (probably at least a 5 gallon bucket) laying around. I thought it would be better to take a chance and see if there's anything of value in there BEFORE they go to a landfill or recycling center. Most of the connectors I have found which connect to the screens have a layer of gold plating on them. When I pulled the connectors off, I would bet there is some small amount of gold left behind. I can crush the screens into a powder without there being a lot of dust in the air.

I'm looking forward to see the results. My prediction is quite low but I'm hoping I'm wrong.

The conductive layer on the screens is called ITO, indium tin oxide, so actually what you plan to do requires smelting to recover tin and indium by adding a reducing agent to the melt.

I never said it was you that said "smelting", but watch this...

All,

Today I smelted 211 grams of used mobile phone circuits, and that produced an alloy weighing 47.3 grams, I think some beads still inside the ash which shall be ball milled and separated, weighed then mix with other alloys for 100-element ICP assay. I shall post its result next week.

Here is photo of sample cell boards which I smelted,
View attachment 1

And this is the smelt alloy,


Regards,
Kevin

Hi...
Questions for both.
211grams of boards...any guess as to how many boards?
Do you smelt everything just to find out PM/ton of material? Seems alot of work if just recovering...

The ICP result are finally here, the following is the analysis for mobile phone circuit boards smelted.

No I did not keep a log on different types of mobile boards I smelted, and I think it would be very difficult task to...

I rest my case! 8)

Göran

 

[kjavanb123]

Goran,

I was on the impression that producing an alloy of metals from printed circuit board is called smelting, once ball milled and separated the metal from ash, then you melt the metals.

Regards
Kevin

 

[g_axelsson]

http://en.wikipedia.org/wiki/Smelting

Smelting is a form of extractive metallurgy; its main use is to produce a metal from its ore. This includes production of silver, iron, copper and other base metals from their ores. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gasses or slag and leaving just the metal behind.

http://en.wikipedia.org/wiki/Melting

Melting, or fusion, is a physical process that results in the phase transition of a substance from a solid to a liquid. The internal energy of a substance is increased, typically by the application of heat or pressure, resulting in a rise of its temperature to the melting point, at which the ordering of ionic or molecular entities in the solid breaks down to a less ordered state and the solid liquefies.

If you are only using heat and no chemical reactions then it is just melting, not smelting.

Göran

 

[9kuuby9]

To put it simply; smelting involves a chemical reaction (and also a physical one)

But melting Only involves a Physical reaction.