My results of specific types of IC chips, flatpacks and BGA

[Tzoax]

This is my little contribution to the site, I have tested various types of chips for gold content using these steps:
1. Separation of the specific type of chips, removing paper stickers if any, removing wires from the edges of the chips with scalpel (*some types of chips are processed along with these wires and that will be indicated), weight them, and count the pieces of chips included.
2. Pyrolizing chips with butane torch.
3. Turning chips to ash on a hotplate
4. Shaking the chips inside of the glass jar and sieving the ashes
5. Repeating steps 3-5 until all of the white/grey powder goes through the sieve, and the resin consists of wires, silicon dies and heat spreaders
6. Washing with hot water until water is clear
7. Removing magnetic wires with neodymium magnet while still inside in water (*these wires are processed separately, I remove the basic metals with nitric acid and process them with aqua regia, for every 5kg of all kind of chips I recover 2-3 grams of gold only from these wires, so all of my results are not including gold from these wires, and not including the gold from the resins-wires, silicon dies and heat spreaders, it only relates to sieved ash).
8. Remove the basic metals from concentrate with nitric acid and washing again with water
9. Aqua regia, neutralizing excess nitric with urea, dropping the gold with SMB.
10. washing the gold powder 3xdistilled water 3xHCl, 3xdistilled water.
11. Weighting the gold and calculating the percentage of gold yields by kg of specific chips and even the gold yield of one piece of specific chip.

I will post one by one type of chips. This is a first type - SMALL VARIOUS CHIPS. You can see on the pictures shapes and the size of these chips. They have at least 6 wires, some of them are thinner then the others, also some of them are square and have wires of all 4 sides. Since their size are similar and very small, I decided to classify them as small various chips and process them together. Because they are very small I have not removed the wires.


The total weight is 747g, there are 6317 of chips, and the gold recovered was 1.0g.
Conclusion is:
1kg of small various chips contains 1.338688g of gold. (only from ash, not including magnetic wires with gold bonding wires trapped inside of them and resins-wires, silicon dies and heat spreaders)
Average weight of one chip is 0.118252335g.
Average gold content by one chip is 0.000158303.

 

[Tzoax]

The next type of chips are FLATPACKS 2S THIN. These are RAM type chips, they are all thin and have wires on 2 sides.
I removed the wires with scalpel.


Total weight of chips - 428.7g
Number of chips - 858pcs
Avg weight of 1 chip - 0.49965035g
Gold recovered - 0.3g
Avg gold per kg - 0.69979g
Avg gold per piece - 0.00034965g

 

[Tzoax]

IC CHIPS 4-SIDED 24x24mm
These chips are square, thick, 24x24mm, like shown on the picture, wires are removed.


Total weight of chips - 804.4g
Number of chips - 184pcs
Avg weight of 1 chip - 4.37173913g
Gold recovered - 0.4g
Avg gold content by kg - 0.497265g
Avg gold content by piece - 0.002173913g

 

[Tzoax]

FLATPACKS 4S RECTANGULAR THICK 20x13mm
These chips are thick, rectangular, they have wires on all 4 sides, 20x13mm, wires are removed.


Total weight of chips 502.6g
Number of chips 327pcs
Avg weight per 1 piece 1.537003058g
Gold recovered 0.7g
Gold per kg - 1.392758g
Gold per 1 chip - 0.002140673g

 

[Tzoax]

BGA VARIOUS CHIPS
All of the types og BGA chips, already separated from green bases with a heat gun. They do not have magnetic parts.


Total weight of chips - 456.9g
Number of chips - 286pcs
Avg weight of 1 chip - 1.597552448g
Gold recovered 5.2g
Gold content per 1kg - 11.381046g
Gold content per 1 chip - 0.018181818g

 

[Tzoax]

Flatpacks 4-sided square thick 27x27mm
Wires was removed.


Total weight of chips - 576.5g
Number of chips - 109pcs
Avg weight by 1 chip - 5.288990826g
Gold recovered - 0.7g
Gold content per 1kg - 1.214224g
Gold content per 1 chip - 0.006422018g

 

[Tzoax]

IC chips 2-sided Small var
Wires was not removed.


Total weight of chips - 407.2g
Number of chips - 460pcs
Avg weight of 1 piece - 0.885217391g
Gold recovered - 0.1g
Gold content per 1kg - 0.24558g
Gold content per 1 chip - 0.000217391g

 

[Tzoax]

Rectangle 2-sided 7x13mm
Wires was removed.


Total weight of chips - 789.5g
Number of chips - 1669pcs
Avg weight of 1 chip - 0.473037747g
Gold recovered - 0.3g
Gold content per 1kg - 0.379987g
Gold content per 1 chip - 0.000179748g

 

[Anonymous]

Thanks for sharing this information with us. 8) 8)

Jon

 

[Tzoax]

Flatpacks 4S Squ. + Rect. thin
All of the thin chips - square and rectangular that have wires on all 4 sides. Wires was removed.

Total weight of chips - 392.2g
Number of chips - 405pcs
Avg weight of 1 chip - 0.968395062g
Gold recovered - 0.9g
Gold content per 1kg - 2.294748g
Gold content per 1 chip - 0.002222222g

 

[Tzoax]

That was my tests so far, when i test again some new type of chips i will post it here, also if someone wants to share their results they can post here so we can compare results and get more accurate values. I hope these results will help someone to have some roughly view of gold content in specific types of chips.

 

[FrugalRefiner]

Very nice Tzoax. Thank you for sharing!

Dave

 

[Grelko]

Thank you very much for taking the time to do this, it will help alot.

 

[richard2013]

Hello and Thanks Tzoax

have you also tried cellphone bga chips?

 

[Tzoax]

Hello and Thanks Tzoax

have you also tried cellphone bga chips?

Hello, i never tried to test cellphone chips, all of my chip tests was from computer motherboards, PCI cards, graphic cards, hard drives, laptops and network boards and equipment. For me, the cellphones are not interesting, they are hard to find in some larger quantities, they are often overpriced, it takes a lot of time to take them apart, it takes too much of cellphones to collect several hundred grams of chips for testing. There are lot of other values inside of cellphones, but for me it is a waste of time comparing to the other electronic scrap that i could buy for the same money. For example, if 1 cellphone costs 0.4$ i will always buy 1 or two old graphic cards with big BGA chips for that money, it just saves me a lot of time and work.

 

[Tzoax]

I just tested a new type of chips - SMALL BGA chips, like in newer RAM memory types (DDR2/DDR3), and the similar chips from motherboards and cards. They are all small, square or rectangle shaped, and all of them have a foil base with solder balls.
I soaked the chips in concentrated HCl and bring them to boil 3 times, the most of the tin dissolved. I incinerated the chips and washed with water. This time i used poorman's AR with KNO3. There was still some tin left so it took me some time to filter the solution with metastannic acid. I dropped the gold with SMB and washed the gold powder with hot water. I redissolved the gold again with poorman's AR to be sure that all of the contaminants are gone. I waited until AR was crystal clear and the contaminants like silver chloride and metastannic acid was settled at the bottom, then i carefully decanted the AR solution through the filter paper and dropped the gold with SMB again. I rinsed the gold powder with hot distiled water 3 times/3 times with hot HCl/3 times with hot distiled water. i dried the gold, measured it and here are my results...

Total weight of chips: 233.7g
Number of chips: 919pcs
Average weight of one chip: 0.25429815g
Gold recovered: 1.1g
Avg. gold per 1kg: 4.706889g
Avg. gold per one chip: 0.001196953g

 

[g_axelsson]

That is a very good result! I was afraid that the short small gold wires in the BGA chips would mean less gold. It's quite a lot actually, compensating for the smaller component size.

I've just started going through boxes of memory sticks and was going to do a test as yours, but you beat me with a few weeks.
I will add my results when I have them.

Thanks!

Göran

 

[Tzoax]

That is a very good result! I was afraid that the short small gold wires in the BGA chips would mean less gold. It's quite a lot actually, compensating for the smaller component size.

I've just started going through boxes of memory sticks and was going to do a test as yours, but you beat me with a few weeks.
I will add my results when I have them.

Thanks!

Göran

I was surprised too with a gold content in this type of chips, i think that it is because of weight and surface area of the chips - one average big BGA chip weights 1.59g (without foil base and solder balls), and one average small BGA chip weights 0.25g (with foil base and solder balls). The small BGA chips are lot thinner and they have wide surface area. So my opinion is that big BGA chips have longer gold bonding wires, but small BGA chips have much greater number of gold bonding wires. Take a look at the picture with small BGA chips and count the solder balls on any chip, they have about 100-150 wires per single chip. In one kilogram of small BGA chips the number of chips are 4000, with minimum 400000 of gold bonding wires. In one kilogram of big BGA chips the number of chips are 629, and i think that they have much less number of gold bonding wires than 400000.
Thank You.

 

[patnor1011]

I just tested a new type of chips - SMALL BGA chips, like in newer RAM memory types (DDR2/DDR3), and the similar chips from motherboards and cards. They are all small, square or rectangle shaped, and all of them have a foil base with solder balls.
......
Total weight of chips: 233.7g
Number of chips: 919pcs
Average weight of one chip: 0.25429815g
Gold recovered: 1.1g
Avg. gold per 1kg: 4.706889g
Avg. gold per one chip: 0.001196953g

And there goes one of the last "secrets" in IC yields... :mrgreen:
They are second best after s/n bridge BGA, I mentioned that few times, weight/mass ratio and lack of other metals like pins in internal structure make them more valuable than other IC with pins.

 

[Grelko]

5. Repeating steps 3-5 until all of the white/grey powder goes through the sieve, and the resin consists of wires, silicon dies and heat spreaders

Do you happen to know the mesh size of the sieve you were using? I've been using a flour sifter, approximately 25-30 mesh? I believe I counted 27/inch. (The square holes are a bit smaller than 1mm by 1mm) I was wondering if I should keep going until everything is around -100 or smaller, either with my pipe crusher, mortar/pestle, or just re-burn it. I just sifted out 397g of black/grey powder from a batch I did yesterday.

I ran a small batch on an old scrap BBQ before, panned it a bit, then ground it up small enough to have the powder go through a coffee filter. I ended up with some copper and bonding wires, maybe 15 of each. Took a good while to get down to just the wires though.

I was wondering if it's possible to crush the pieces up enough, so that you wouldn't need to incinerate it at all? I have to buy coal/charcoal, but I can use my pipe crusher or mortar/pestle for free. I'm just seeing if I can save a couple dollars.


Edit - Nov 10th (Answered my own questions)

Over the last 2 days, I very slowly went through approximately 200 grams of the powder I had. The bonding wires must be around -150 or -200 mesh. I knew they were really small, but I didn't think they were quite this small. Just messing around with a makeshift goldpan, I spent atleast 10+ hours going through it. I used a hard drive magnet, and even went as far as using tweezers to pick out the copper wires. It might end up weighing 0.1g? (it's still wet and is probably around 80% gold, the rest is black). It was all mixed chips "even the 3 legged ones with the copper tops that have a hole in them", just the lowest recovery, no Ram, CPU, N/S bridge etc.

Yes, it is possible to crush the chips enough, that you wouldn't need to incinerate them. (Just incase you live in an area that doesn't allow fires) It'll take you a while if you use a pipe crusher and mortar/pestle though.

On a side note, panning bonding wires is probably about the same as panning "gold flour", except you might want to use an eye dropper instead of a snuffer bottle. I may just melt this down into a tiny picker, then dissolve and clean it after saving up more.