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

[Tzoax]

I dropped the gold, it took a whole day to settle to the bottom, there is a very little of gold, maybe around 0.1g in my opinion. For now i will leave it as it is and i will collect some more of silicon dies to make a test and then i will mix the gold and calculate the gold content.

68.4g that i processed seems to be very little of material to make a good test considering my scales have only 1 decimal. I started to separate the silicon dies from the incinerated chips and i will collect at least several hundred grams for testing.

 

[mls26cwru]

for 68 grams, that looks like a decent amount... pictures can always be deceiving, but it looks like you might have more that 0.1g. Did you have any problems with silver? did you find any other PMs?

I have a shipment of chips coming in in the next couple days, Ill keep close track of weights and recoveries from the silicon dies and add it to this thread.

 

[Tzoax]

mls26cwru, yes it looks promising, maybe there is more than 0.1g. In case there is less than 0.1g it will be not detectable with my scales since it has only one decimal. So, i will test some more and merge the gold. This is a very slow, for 2 hours of work i collected 40g of silicon dies so far. I wonder is there a better way for separating silicon dies from wires.

I had no problem with silver chloride, everything was left inside a double filter papers. If there is anything left of precious metals in AR, it will be recovered later, it goes to stockpot. Thank you for furure sharing of your results, how are you planning to separate the silicon dies from wires?

 

[g_axelsson]

Instead of measuring the weight on a small amount of gold it can be melted and the diameter measured. From the volume and density a more exact weight can be calculated.

Göran

 

[Tzoax]

Göran, thank you for this information, i will keep that in mind. I have no experience in melting, and it is a small amount of gold for induction furnace i use for melting. I would say there is a very little gold here because it took 1 day to settle and there was no visible forming clumps of gold when stirring (comparing to AR solution that i used couple days ago with 0.2g of gold inside and even larger volume of AR solution - the clumps of gold was forming while stirring).

 

[mls26cwru]

After I roast my material (This is only for BGA style, nothing with metallic legs) I grind them and pass them through a number of sieves... I would have to double check, but i think its 1/2", 1/4", 1/8", and 1/16" sieve for a rough sieving... that allows me to get out heat-spreaders in the first rack, most dies in the second rack, most broken dies in the third rack. Of course there is a little bit of hand separation that goes on, but the different sieves will sort 90percent of the material for me. The wires/ash break off and pass through the sieve and I just put the whats left in a container for processing later.

After a couple attempts, I settled on using an initial nitric leach because I was running into so much silver... not that its a large amount of silver, but more that the silver chloride is so voluminous that it covers everything and will stop the reaction (i don't have a stirring hot plate so my solutions just sit overnight most of the time). I decant and wash and after i am convinced the silver is gone, then I use an AR leach for the gold.

 

[Tzoax]

mls26cwru, thank you for the tip with different sizes of sieves, i have not tried that. I will buy or make some sieves for that, i was using only one sieve for everything and it worked well. I collected some more of silicon dies - 71.6g, here is the picture.



I was separating this 71.6g of silicon dies from wires by hand for 2 days (2 hours per day).
I am intending to process today this dies and tomorrow when i drop the gold i will mix it with gold that i dropped from the first test (68.4g of silicon dies) so i will measure how much gold was in the total of 140g of material.

This 3 pictures are the look of gold dropped from first test (68.4g). It looks like it have much but i would still say something about 0.1g. The gold particles are so little that they need some time to settle and they are not clumped together when i try to concentrate them on one side. Possibly they have some impurities. When i process the other batch 71.6g, i will mix the gold and refine it again with AR, wash, and measure.

 

[Tzoax]

I dropped the gold from 71.6g of silicon dies and mixed with gold from previous dropping (68.4g). So, this result will be from 140g of silicon dies from mixed various IC chips and BGA.

Then i dissolved the gold powder with AR again to make sure that all contaminants are gone. But when gold dissolved there was milky color of solution and i knew that was is because of presence of silver chloride. I made a mistake because i filtered solution with (double) filter paper and some of silver chloride was going through it. I should wait at the first place that silver chloride settles at the bottom of the flask, and then i should decant AR solution prior gold dropping.

The first picture shows AR solution (of 120g of silicon dies) pictured with a flashlight, second picture is without flashlight, and the third picture shows AgCl starting to settle at the bottom.

I will wait the most of AgCl is settled at the bottom, and when AR solution becomes crystal clear i will drop the gold, wash, and post the result.

One thing confuses me...when i filtered the AR solution there was no visible AgCl, the solution was crystal clear, and now - after second AR dissolving it seems it have much of AgCl. Maybe it is because of the reduced volume of the solution at second AR dissolving.

 

[Topher_osAUrus]

According to 4metals, the solubility of silver chloride drops wayyyy off depending upon temperature.

If you initially filtered it while hot there could have been no apparent silver, but once it cools, it shows up.

Thats why alot of people add ice. Its cools it down, and dilutes it. Both things are beneficial. Removing silver chloride, and adding water to help keep SO2 gas in solution to precipitate gold.

Excellent thread!

 

[Tzoax]

Thank you very much Topher_osAUrus, i will have to start to use the ice when dealing with silver, i made a mistake because i filtered a warm solution, that explains why AgCl showed ostensibly suddenly in solution after cooling.

I finally finished the testing... here are some pictures of washed gold chloride - wet and dry, and microscope view. Conclusion is beneath the pictures.






The result is 0.1g of gold per 140g of mixed silicon dies.
The yield will be about 0.71 grams of gold per 1kg of mixed silicon dies.
In a way i am satisfied with result since it is good yield per kilogram, on the other side it takes too much of a chips and work to collect and separate 1kg of dies. Anyway, it all adds up. 8)

 

[Topher_osAUrus]

Looks good to me. I love me some gold though!

Only other thing I caught/saw is
Gold chloride is the salt of gold
The last pictures you sent/showed is of metallic gold
After gold chloride is reduced with whatever precipitation method you like, it's no longer gold chloride, but just gold.

Thats me just nit-picking

It's still beautiful, and you're right...every microgram adds up

 

[Tzoax]

Thank you again Topher_osAUrus, i learned a lot from you :shock: , and also feeling bit of shame not knowing such a basic things.
Now i see how much more i need to learn.

 

[Topher_osAUrus]

Thank you again Topher_osAUrus, i learned a lot from you :shock: , and also feeling bit of shame not knowing such a basic things.
Now i see how much more i need to learn.

Shame? Never should be felt when learning....ever.. For no one person knows it all. And those that claim to do, are surely full of it (knowledge isn't what they are full of..)

To me, it seems as if you know a great deal. And for you to share your knowledge and experiences with us on the forum (members and guests alike) speaks great things toward your character.

A great many just come to absorb the information contained in this library we call a forum, and then never show their progress or results for fear of judgement or constructive criticisms, (i myself am guilty of not posting up things that i have done...my rationalization is that "they have already been posted")..but, really it takes a big man[person] to take being corrected gracefully. You, are one of those graceful guys...even though it was just a couple of small oversights..

Thanks again for this thread. You have given me a great guideline of whats worth messing with next, and what can wait awhile.

Keep up the excellent work. I eagerly await your next contribution to the forum. You are very precise and methodical. And i love it.

-topher, the thankful

 

[Tzoax]

Topher, you have the right about everything, i will keep learning and trying to contribute, as long as here are a great people like you and many others who justifies the site's motto "Refiners helping one another". It is the way i comprehend this forum and that is why i feel pleasure to help someone and gratefulness when someone helps me. Thank you for all your kind words and for your "nit-picking". :lol:

 

[Topher_osAUrus]

Topher, you have the right about everything, i will keep learning and trying to contribute, as long as here are a great people like you and many others who justifies the site's motto "Refiners helping one another". It is the way i comprehend this forum and that is why i feel pleasure to help someone and gratefulness when someone helps me. Thank you for all your kind words and for your "nit-picking". :lol:

No worries! It wasnt any trouble at all. I like to help whenever i can. You have a great attitude and work ethic, and reading about your process is rewarding in its own right. There are alot of people that come here and want everything done for them, and there are alot of people like you, who take initiative and give back.

So thank you for that. Can't wait to see what you do next!
-topher
P.s. -i used to love playing hearthstone -(mtg really, but online too expensive)-but once i started my schooling for back yard refining, i had no time for it anymore...but it(they are)great game/s that require alot of forethought and strategy - similar to the work it takes to refine (feel free to message me about it/them, i used to LOVE to play strategy games/FPS games)

 

[goldsilverpro]

If I remember right, you said that your balance was only one decimal point. In that case. when you report a yield of 0.1g, it could be between .05 - .149 and a 0.2g yield from .15 to .249. Percentage-wise, those are big differences. Also, it can make a difference if you're not melting the powder. A melted BB will almost always weigh less than the powder.

 

[Tzoax]

If I remember right, you said that your balance was only one decimal point. In that case. when you report a yield of 0.1g, it could be between .05 - .149 and a 0.2g yield from .15 to .249. Percentage-wise, those are big differences. Also, it can make a difference if you're not melting the powder. A melted BB will almost always weigh less than the powder.

Yes indeed, in this case it may be between .05 - .149 grams of gold in these 140g of silicon dies. If i processed a larger amount it would be more precise but it was very slow for me to separate manually the dies from wires. It is time to buy a new scale with 2 decimals, and several sizes sieves. I will process the silicon dies again in larger quantity and measure the gold with 2 decimal points. In my case, i managed to make 997 purity of gold (tested with XRF), and about 3 percents of gold loss when melted in induction furnace. This is a look of one grain of it.

 

[Tzoax]

I am preparing a new type of material for testing - the BGA (green) fiber masks with BGA solder balls still attached on them. I will test the BGA solder balls one day separately, but now i would like to try to process them altogether. I removed the BGA chips (mostly N/S bridges, the rest was from the graphic cards, skazi drives etc.) with a sharp knife and hammer, so some of the solder balls stays on a motherboard, some dropped off. You can see in a picture how much of solder balls are still attached to the fiber. I removed the black tops (chips) with a heatgun (that's why gold is visible on the fiber) and there are 107 pieces, weight is 218.8g.

I am planning to process them on the next way:

1. Hot HCl bath (just below the boiling) for removing as much tin possible from the material (mostly from solder balls)
2. Filtering the remained HCl and collecting possible small particles of gold inside of filter
3. Fresh addition of HCl and if necessary repeating step 1 and 2
4. Processing the mamaterial (together with filter paper) with Aqua regia

There would be a lot of copper, maybe it would be better to process with A/P after HCl bath, prior AR...

If someone have experience with this material or have some advice, or how to process it more efficiently please give your opinion.

 

[Topher_osAUrus]

Salutations friend!

Are you incinerating them at all?

Or just doing a leech on the plastic and fiber?

I believe the gurus here pyrolize the blacks so they release the bonding wires in their entirety. There may be a miniscule amount of gold that is trapped in plastic if not?


I would be curious of numbers of recovery for pyro'd bga's vs. Non-pyro'd ones.

Edit (my 1 year old made me hit submit..) to add:

But, doing pyro vs non may be difficult, as to get equal lots of the exact same bga chips would be a tall order, unless it was a metric ton of rejects from the factory or something of the sort.

I know there are some members that get and recover/refine factory rejects, but i am not sure if it is an ongoing thing or just every now and then..

Thanks again for sharing your experiences with us!

 

[Tzoax]

Thank you Topher. I will not incinerate them (this time), i already begin to process them 2 days ago.
I started to boil the fiber masks in 16 percent HCl 2 days ago. I was adding portions of 400ml HCl and after several hours i replaced it with next fresh 400ml of HCl and so on.

The used HCl was stored and collected in a big beaker, where the stannous chloride crystals was forming. I diluted it with warm water to break the crystal form of tin. When that was done, there was white/gray powder at the bottom, when stirring it settles fast (few seconds). I believe it is mainly silver chloride, and maybe some trace of gold foils, so i filtered it and i am keeping the powder for later.

I added 5 portions of 400ml 16-percent HCl, totally 2 liters, and after many hours of boiling 15 hours totally i was start wondering is it possible that the tin needs so much acid to go to the chloride state, or maybe it is not so reachable inside the solder, or maybe it is slow because i didn't use concentrated acid, and similar thoughts... In a meanwhile, i noticed that all gold plated parts become covered with tin, it was tin plated .



I decided to stop boiling in HCl, i was thinking that after 15 hours and 2 liters of HCl the most of tin was gone, so i poured a fresh HCl, and added 10 grams of KNO3 to form AR. Reaction was very faster, the solder balls was rapidly dropping from the masks and dissolving..



But, on my surprise, the metastannic acid goo was starting to form, i thought that tin inside of AR solution should form soluble Stannic chloride, not metastannic (that is formed in a Nitric acid solution). So i poured it off and waited metastannic to settle. The color of AR solution is pale green. The gold plated parts are still tin plated. And thats the where i am now. I will add fresh AR, and continue to process.