question abaout IC's and their leggs

[frank-20011]

hello everybody,

i've stored mixed ic's and now i have almost 5kg.
the first time i made a mistake: i di not cut them with cutter knife or chisel, i de-soldered them and so they have their leggs, with a lot of solder.

after more studies i know any legg has to be removed before incineration but after trying it with a few hands of them it's almost impossible to cut off every legg from so much ic's.

I've read about etching them in HNO3 or better AR.

I think AR work's faster (HNO3 ist fast but i think AR is faster?) is it true?
Here it is impossible to buy HNO3 since 1 1/2 years (tanks to our great gouvernment) and so I will try HCL with NH4NO3....by rule of thump: how much AR i have to take (made of cheap HCL, 20%) for 1Kg of mixed ic's (flat packs, e-prom likes, BGA...small ones from cell phones and so on)?

The hole legg of an ic looks silvery, is it all tin or is it an other metall and only the tipps of the leggs are tin plated?
when the hole legg (out of the ic) of the ic is remove, is there any tin removed too or are there more tin on the inner metall parts, the inner ends of the leggs inside the ic under the plastic?

thanks a lot....regards!

 

[solar_plasma]

NH4NO3 ist no option as far as I remember.

Tin can easily be removed by HCl. Then the ICs can be incinerated (if you know what you are doing - cancerogene compounds may form under 800°C). Then it is possible to get the bondwires by mechanical means. BUT if you can't get HNO3 I am afraid you don't have an adequate laboratory either. You can easily sell the ICs to scheideanstalt.de or on ebay.

Further, you haven't learned that you can't use HNO3 to remove tin. This leads me to the assumption, you haven't read enough (not even the basics) or did not understand what you read.

Just wanted to mention.

 

[patnor1011]

Cutting legs away is no requirement. I simply do that as it save me bit on chemicals but there is a lot of IC I simply desolder. I would not even try to manually cut off legs off of desoldered IC, that will surely drive me to madhouse.

Simply toss them to AP and leave them there for as long as necessary. Or proceed with incineration. Some tiny legs may get melted and you will see small granules of metal when you will be sieving material. I do sieve material through multiple sieve and I am able to catch over 90-95% of legs in that process. Cutting legs is probably pointless task as what you see sticking out of the body of IC is probably less than 1/10th of their length anyway. Even AP or HNO3 leach will not dissolve all of it which is firmly bonded in resin.
While sieving I do last 2-3 rounds by gentle shaking small amounts of material on flat sieve so I am able to catch even small pins.

Whatever pins or legs you remove from material need to be processed as upon close inspection you will see many of pins with bonding wires still firmly attached on them. One cheap option is to use them in your stock pot, you can leave magnetic one's to rust away to collect values later. Even that some of them do have bonding wire attached I do not think that processing them for the sake of it is economical unless you do have a lot of time and free chemicals. I do prefer rusting on magnetic and stock pot on copper legs as chemicals here cost more than I can recover from this material.
I do recommend you to read through my post on processing IC, link is in my signature.

 

[frank-20011]

Hello to everyone,

in the past it's easy to buy HNO3 for everyone but at the moment here in germany you need a "Gewerbeerlaubnis" and an "Endverbleibserklärung" and with these papers it is possible to get a visit bey police...so i have the idea to use poor mans AR.

I know about metastannic but i thought if i soakt the whole ic's in AR or HNO3 the outer parts of the leggs dissolve, WITH the tin (is all of the whole tin of an ic outside of the plastic or is there tin inside of the ic too?) and after that the whole metal sollution, with the metastannic goes to the chemical waste in our puplic waste yard (for free)...after these process i can incinerate the ic's and process the ashes like written in well known books or the long sided thread by patnor without problems made by tin. by using AR there are no problems by metastannic.

I don't know if any tin is removed if i dissolve the outer parts of the leggs, these is my other question!

"Even AP or HNO3 leach will not dissolve all of it which is firmly bonded in resin. "

yes, no problem about that IF!!! all the tin is gone by one of these two ways:

1.) with the outer parts of the leggs by processing the whole un-incinerated chip in AP/AR/HNO3
2.) without the outer leggs by processing the whole chips in HCL for dissolving tin only

so i repeat my question: is there every tin gone by using one of the two processes named above or are there any tin trapped inside the resin/plastic body of the ic?

"Whatever pins or legs you remove from material need to be processed as upon close inspection you will see many of pins with bonding wires"

Well i know and so my idea is

-remove tin (with or without "base matels" =leggs outside the resin body)
-incinerate ic's
-crush them finely
-wash away the ash of the resin
-destroy base metals aka leggs inside the resin body (maybe in one ore maybe in two steps: first leaching them in HCL then incinerate again to destroy remaining HCl then leaching them again with HNO3, that's the two step way, one step ist leaching only by HNO3)
-wash all with water
- last AR

these process deals with magnetic and non magnetic leggs together, i'am not shure if it is okay...i know most of you will take out the magnetic pins but in my small scale with one of such a process in two years i will try to process these two kinds of base metalls together, if it's possible.

"that will surely drive me to madhouse."

yes...that's exactly the problem...or i will make it in one year, eyeryday only 20...30...50 Ic's and after that, i do not know if all of the tin is gone with the off cutted leggs?!

regards!

 

[Grelko]

Simply toss them to AP and leave them there for as long as necessary. Or proceed with incineration.

I do recommend you to read through my post on processing IC, link is in my signature.

Patnor's guide on processing IC chips is extremely good and very easy to use.

For the ashes, I use a gold pan, then AP (HCl+H2O2) to remove any tin or copper, filter/rinse, then dissolve the gold with HCl+NaClO.

For the rest of the material, I do the same thing, except for the gold pan. I don't use AR or HNO3.

Edit - I don't separate the magnetic pieces, I just dissolve everything I can.

 

[upcyclist]

in the past it's easy to buy HNO3 for everyone but at the moment here in germany you need a "Gewerbeerlaubnis" and an "Endverbleibserklärung" and with these papers it is possible to get a visit bey police...so i have the idea to use poor mans AR.

I know about metastannic but i thought if i soakt the whole ic's in AR or HNO3 the outer parts of the leggs dissolve, WITH the tin (is all of the whole tin of an ic outside of the plastic or is there tin inside of the ic too?) and after that the whole metal sollution, with the metastannic goes to the chemical waste in our puplic waste yard (for free)...after these process i can incinerate the ic's and process the ashes like written in well known books or the long sided thread by patnor without problems made by tin. by using AR there are no problems by metastannic.

Yes, there is tin throughout the IC, as Patnor said in the post just prior to your last one.

If you're using Poor Man's AR, then you have access to HCl. Why not go AP, or incinerate/sieve/pan and boil in HCl? Because if you just dunk everything in Poor Man's AR (or AR of any kind):

1) How do you know you haven't dissolved your gold, and you're throwing that out as well? If you test and find out that you have values, you'll still have to cement values on copper, which is another step.
2) Even if you know your values are not in solution, metastannic acid is the devil. If you have it in your solution, you won't be able to filter it easily, and it'll trap values and keep them from settling if you simply try to decant it.

 

[frank-20011]

Hello,

i will not use a pan, i never try it an with so small particles :|

i thought HCl/Chlorox isn't fine for bonding wires and maybe a few gold plated particles inside the chip, I thought it's only fine for much thinner platings like on glassware.

" Because if you just dunk everything in Poor Mens AR"

no no, these idea deals ONLY with leggs outside of the ic. i thought it's possible to remove any tin with the base metal underneath by soaking the whole ic in poor mens AR or HNO3 but if there is more tin inside the ic, under the resin that makes no sense, in deed!

"Why not go AP"

that's ok if you have time and only copper but i will process my small batch of mixed ic's together and so there are kovar, copper, iron...maybe brass and bronze leggs.

" How do you know you haven't dissolved your gold, and you're throwing that out as well"

read above, no AR if there are so MUCH base metals there!

"I don't separate the magnetic pieces, I just dissolve everything I can."

like my idea and to come to a conclusion:

-it's bull.... to soak the whole ic in HNO3/AR (to eliminate the tin) cause there are more tin trapped inside the resin
(i never consider to soak the ashes, the incinerated ic's with the whole leggs in AR/HNO3)

And so the following steps should be fine:

-incinerate my mixed ic's
-wash the ash away carefully
-soak the remaining residue in HCL to remove mainly tin but also magnetic parts
-incinerate the residue to destroy HCL and maybe remaining C from the resin
-then soak in HNO3 (maybe selfmade from H2SO4 and NH4NO3, it is the easiest nitrate salt to get for me) to eliminate remaining base metals
-wash carefully again to remove all the metal salts and finaly
-dissolve the gold by AR and refine it!


Regards!

 

[solar_plasma]

In fact panning has better effect than AR and it is faster - I would actually say it is easier. Best to try it in sunlight and save all solids until you are sure that you got it all.

The fine heavy powders are quite more resistant against AR than you will believe. Further any carbon will hold some gold and cause losses.

But don't listen to me. Do experience it yourself.

 

[frank-20011]

Hello,

warum sollte ich nicht auf dich hören?

why i shouldn't hear at your instructions? but why i shouldn't think about different sollutions (IF they work), don't forget i only read and collect, not processing at the moment.

MY other consider against panning only is the fact that removing all silicone and base metal parts by panning will also remove some parts which are gold plated...so i think if i remove ash at first by washing, then dissolve all base metals i will catch these 10% of the gold which are present not as bonding wires but rather in platings, as solder points of bonding wires and so on.

"The fine heavy powders are quite more resistant against AR than you will believe"

you mean gold powder?...in fact i never see AR in action.

" Further any carbon will hold some gold and cause losses"

Yep, as i've wrote:

"incinerate the residue again...maybe remaining C from the resin"

C means Carbon, it act's like activated carbon for dissolved gold.

are there any concerns about my idea to process the mixed ic's like written in the steps:

"-incinerate my mixed ic's
-wash the ash away carefully
-soak the remaining residue in HCL to remove mainly tin but also magnetic parts
-incinerate the residue to destroy HCL and maybe remaining C from the resin
-then soak in HNO3 (maybe selfmade from H2SO4 and NH4NO3, it is the easiest nitrate salt to get for me) to eliminate remaining base metals
-wash carefully again to remove all the metal salts and finaly
-dissolve the gold by AR and refine it!"


or do you suggest panning because it is much faster, deals not with acids and the waste of the processes, has an aceptable yield too?

thanks and regards.

 

[solar_plasma]

Read thisfrom start to end. Every detail has been covered here. All possible methods and submethods, I guess only smelting (obviously better called fluxing, in this case) is covered elsewhere.

No Imeant this heavy portland cement-like SiO2 powder that is left after incineration. It takes to long to leach and need several leachings, at least with modified AR (HCl and only as much nitric as needed.). As you can read in the thread above I have been there, too. It works, but it is a waste of time, chemicals and waste solution storage place. Further it would take really intensive incineration to oxidize all carbon, - have a look under a microscope or something else with strong magnification and you will see.

This is no good option to start with for a beginner. And I guess almost all more experienced folks would pan first, too.

There is no gold plating. The small amount that is attached to the solder points is said to be negligible. Well, you do not need to throw it away. You can save all solids for later inspection.

Btw. magnetic parts are to be removed by a magnet! Read Hoke more than one time - you will find out new details everytime. At this point you are asking a lot of unnecessary questions and you do not understand the answers.

 

[solar_plasma]

...and sort them IC's, cellphone kindred and north-bridge-like BGA's are better processed separate.

 

[frank-20011]

Hello again,

I've read hookes and the linked thread too, more than one time but as stated before: it's not my mothers language so i have enough problems by reading, understanding and at least by reminding everything.

I've read your contributions in these forum...and so i read you have a long way to learn with different trials and errors, different methods.

O.K. don't misunderstand me, i don't wan't to make a big chumbawumba, my idea was only incinerate the ic's, flushing the "fluffy" parts of the ash and then dissolve the base metals to reduce that stuff that goes to AR but after all, for me and for one bunch of ic's in maybe 2..3 years it's o.k. to incinerate the ic's, than pick out bigger heatsinks by hand...crush, sieve, crush, sieve (out leggs, save them)...flush away ash carefully with precautions of loosing small bonding wires and then AR...I agree with you that's enough stress for me.

The only thing i will change to your suggestion is to process all my IC's together.
i am not willing to understand.....until now why it is essential to process lower yield and hiegher yield ic's not mixed.
shure: some of them contain iron based leggs, others copper based ones but if i do not eleminate these leggs by a chemical way but rather by hand/magnet and so, what's the main argument for selecting them?

Thanks and regards!

 

[solar_plasma]

Those ICs from cell phones have green or brown epoxy at the bottom, the kind circuit boards are made of. Ugly stuff, you will not want to heat. Further they have tin solder on them.

BGAs (non flip-chips) do not contain any legs. You could process them with the other ICs, but if you have enough of them, why downgrade them...

The other black ones can be processed together, you get the kovar with a magnet and most of the copper together with the silicon dies with a sieve. Though I would think twice if I wanted to downgrade the good material with 0,1-0,01gAu/kg chips. In fact I think those lowgrade chips are not worth processing at all since you get the same price for them anyway if you sell them.

The guys who are doing this by the 20kg may have other priorities. I only tell you what makes most sense when doing small lots with a small setup and with high costs to get off toxical waste. Calculate with 400€ for 20 l waste.

 

[patnor1011]

I would do it differently. I mean why mix gold bonding wires with metal from inside IC and expose all of that to chemicals?
Bonding wires are as pure as they can be so I would try to get these separately from all bits of gold on metal legs.
Try to:
1 - incinerate
2 - break in smaller pieces
3 - remove sillicone waffers from middle of IC
4 - crush
5 - sieve
6 - repeat 4 and 5 using smaller and smaller sieve untill 95% of pins and metal from inside of IC are removed
7 - wash with water till 95% of powdered material is removed. (as you progress and will have less and less material you may occasionally dry it and crush/sieve again, use small mortar and pestle like one usually used for spices)
8 - HNO3 leach for every last grain of metal which may be present in concentrate
9 - AR
... rest is easy.

I do use big mayo buckets. That bucket full of incinerated IC is reduced to no more than 3-4 spoons of concentrate with bonding wires. Only then I do proceed with chemicals.

For wires and bits of metals you recovered while sieving they can be divided to 2 groups magnetic and non magnetic and treated as you desire but I see no reason to do it as you described and process them along with bonding wires. There will be very little of value there and they may be better used as stockpot feedstock instead of spending way too much of acid and time on them.

 

[patnor1011]

I do always separate IC in different categories as much as i can. That is mainly to have an idea of what I should expect when I do process them. Work with a mix of ic and you will never know if you got all of it. Work with uniformed batches and you know what to expect and if it is not there, you know you did mistake somewhere and you can start looking for missing values.

 

[solar_plasma]

frank wrote:

I've read your contributions in these forum...and so i read you have a long way to learn with different trials and errors, different methods.

And I can, because I have a safe, professional setup and because I am allowed to do what I do, since I have a minimum professional knowledge to legally buy, use and store any chemicals that didactically make a sense, further, because I use the best parts for my teaching after I have researched if it is save, understood the details and decided if it is useful for the teaching. Short: It is part of my job. Sure, I was able to enhance my work a lot by specializing and going into the deep of this subject. Compared to many of the professionals here, I am still digging at the surface of course, and that will never change.

Like anyone else I make mistakes and if this is relevant, others will most often join in and correct me. Nevertheless, it is your part to check any information. I can only try to be a help in some details, to get your focus on some points you do not see.

Any advice I give, I would have loved that I had got, listened to and/or understood myself - I do not need to do so and as soon, as I get the impression, that it is not welcome anymore I go my way.

 

[maynman1751]

Well said Bjorn!!!!! 8)

 

[nickvc]

frank wrote:

I've read your contributions in these forum...and so i read you have a long way to learn with different trials and errors, different methods.

And I can, because I have a safe, professional setup and because I am allowed to do what I do, since I have a minimum professional knowledge to legally buy, use and store any chemicals that didactically make a sense, further, because I use the best parts for my teaching after I have researched if it is save, understood the details and decided if it is useful for the teaching. Short: It is part of my job. Sure, I was able to enhance my work a lot by specializing and going into the deep of this subject. Compared to many of the professionals here, I am still digging at the surface of course, and that will never change.

Like anyone else I make mistakes and if this is relevant, others will most often join in and correct me. Nevertheless, it is your part to check any information. I can only try to be a help in some details, to get your focus on some points you do not see.

Any advice I give, I would have loved that I had got, listened to and/or understood myself - I do not need to do so and as soon, as I get the impression, that it is not welcome anymore I go my way.

We all learn in this particular field of science virtually everyday, no one knows it all and if they think they do they are fooling only themselves.
Bjorn has learnt a great deal and is a valued member of the forum freely giving of what he has learnt.
I would suggest a more polite way of addressing him if you wish him to bother with you any further, we expect good manners and politeness from all members and even more especially so when you are asking for help.
You may well have cut yourself off from help by that comment and not just from Bjorn!

 

[Anonymous]

Aye but let's bear in mind that we have a discussion here going on between two people talking in a second language to one another. The difference in nuances between two English speaking nations (GB and US) even causes issues, let alone trying to do it in a foreign language. 8) 8)

Frank does thank Bjorn later in his posts for his help so hopefully the misunderstanding is just the language thing and not meant as it first looks?

Just a friendly thought lads.

Jon

 

[solar_plasma]

Thank you guys, it is all okay. It was only this single sentence which I felt it required to be put into the right context. And in order to avoid further misunderstandings, such clarifications must be done right from the start in my opinion.