# ferric nitrate stripping solder



## hatemelborai (Oct 22, 2014)

I am very interest in removing motherboard components using chemical solution without affect on copper or components, I found 6 methods:

The 6 different chemistries for stripping Tin or Tin/Lead are:
1. Ammonium Bifluoride/Peroxide (the original, & still used for Tips)
2. Two step, Nitric followed by Ferric Chloride
3. Nitric/Ferric Nitrate
4. Nitric/HF
5- fluoroboric acid , hydrogen peroxide
6- methane sulfonic acid and the inorganic nitrate is ferric nitrate.

I have used fluoroboric acid , hydrogen peroxide, this method give me very good result, no any affect on components, connectors,.... but fluoroboric acid is difficult to obtained 
during search I found the next products:
https://www.youtube.com/watch?v=KR-_UKe71bQ
it use Nitric acid + ferric nitrate, 
I will use Nitric-ferric nitrate using the attached file.


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## kurtak (Oct 22, 2014)

hatemelborai said:


> I am very interest in removing motherboard components using chemical solution without affect on copper or components, I found 6
> I will use Nitric-ferric nitrate using the attached file.




Nitric acid dissolves copper --- it does not dissolve tin (solder) it simply brakes it down to stannic tin (the white stuff you see in the bottom of the tub at the end of the video)

so the nitric will dissolve copper from under gold plating & release the gold foils - but will also create stannic tin - gold foils will then be mixed in with stannic tin - this creates big problem in further refining steps

HCl dissolves tin but not copper - so HCl is used to remove tin solder --- HCL also dissolves aluminum so aluminum components should be hand striped from boards first

I see you have been a member here since 2012 --- you should really spend more time here for finding the methods "that work" --- instead of looking around on the net for what amounts to other peoples hair brained "experiments" & then posting them here (I did like the little tank/pump set up - but it really needs a fume scrubber set up to go along with it to deal with the fumes)

I don't mean to be rude but for someone that has been a member for more then 2 year - you should know that --------

HCl dissolves tin but not copper & therefore HCL is used to remove solder & -------

Nitric dissolves copper but not tin & therefore nitric is used to remove copper (or you can use the AP method if your nitric is hard to get &/or expensive)

All of which tells me you don't spend enough time here where we discuss tried, tested & proven methods that in fact work

Kurt


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## kurtak (Oct 22, 2014)

I should add that I did read the attached PDF --- that application is used for removing the tin plated on the copper traces - not the actual solder used to attach the components to the board

two different applications - & though the nitric thing (as described in the PDF) may work for component removal a well - why? when a bucket of HCl works for what we do here

Kurt

edit to correct spelling


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## hatemelborai (Oct 22, 2014)

kurtak said:


> hatemelborai said:
> 
> 
> > I am very interest in removing motherboard components using chemical solution without affect on copper or components, I found 6
> ...




Dear Kurt
I am working in small e-waste recycling company, we are recycling about 500- MB per day, we removing components desoldering machine, we use shredder and grinder to convert blanked PCB to powder (metals and non-metals) and static separate metals and non-metals. the metals are Copper and tin,lead, iron,....we use HCL to dissolve tin, lead, iron from copper.
I am trying to replace desoldering machine.
my first trial to remove components was using HCL, but it give me bad result, HCL react with PCI it convert it to mud, as you know HCL react with al, fe,....and removing al, fe parts is not easy
I read more about solder stripping I found HBF4 + H2O2 is very good, I used it many times but we import HBF4. I am trying to use local chemicals

I contacted the supplier and he sent me MSDS of the solution (attached) the solution use ferric nitrate and nitric acid, and I know we should add inhibitor 

I like the next procedure:

https://www.youtube.com/watch?v=XHSIcuSFULE

Hatem


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## MarcoP (Oct 22, 2014)

The only one that would dissolve tin and lead without attacking much copper and without creating stannic tin (using HNO3) or AgCl (using HCl) is fluoroboric acid and acid peroxide. If using Ti4 instead of acid peroxide no copper will be attacked and lead and tin could also be recovered by electrowinning stages. Fluoroboric acid costs about $2 per kilo when bought in tons, about the same of my 32% HCl that I get locally per Kg and I'm still looking for a local supply of 25-50Kg.

I recently read an article about salvaging electronic components and HBF4 with Ti4 as oxidizing agent was found not to damage any of them, acid peroxide will slightly attack copper. However I won't replace CuCl2 leach with fluoroboric acid for few good reasons like re-usability and availability.

HBF4 while dissolving lead and tin should deposit metallic silver power (or colloidal) from solders, say bye bye to silver chloride, stannic tin, metastannic acid, use of HSO4 to get rid of lead in AR...


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## hatemelborai (Oct 22, 2014)

MarcoP said:


> The only one that would dissolve tin and lead without attacking much copper and without creating stannic tin (using HNO3) or AgCl (using HCl) is fluoroboric acid and acid peroxide. If using Ti4 instead of acid peroxide no copper will be attacked and lead and tin could also be recovered by electrowinning stages. Fluoroboric acid costs about $2 per kilo when bought in tons, about the same of my 32% HCl that I get locally per Kg and I'm still looking for a local supply of 25-50Kg.
> 
> I recently read an article about salvaging electronic components and HBF4 with Ti4 as oxidizing agent was found not to damage any of them, acid peroxide will slightly attack copper. However I won't replace CuCl2 leach with fluoroboric acid for few good reasons like re-usability and availability.
> 
> HBF4 while dissolving lead and tin should deposit metallic silver power (or colloidal) from solders, say bye bye to silver chloride, stannic tin, metastannic acid, use of HSO4 to get rid of lead in AR...



You are Right , but it take some hours, I am looking for fast method.
hatem


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## MarcoP (Oct 22, 2014)

With my little, very little, knowledge I don't know a faster and cleaner way then using fluoroboric acid. Nitric would be faster but in this case read what kartak wrote in his posts as he stands great points or find a way to get rid of the troublesome products caused by nitric (more money, more time, etc).

Be aware that the above chart uses Ti4+, peroxide might be faster if used with higher concentration (thus oxidizing more copper).

Which steps are you taking to properly dispose of HBF4 wastes.


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## hatemelborai (Oct 22, 2014)

MarcoP said:


> With my little, very little, knowledge I don't know a faster and cleaner way then using fluoroboric acid. Nitric would be faster but in this case read what kartak wrote in his posts as he stands great points or find a way to get rid of the troublesome products caused by nitric (more money, more time, etc).
> 
> Be aware that the above chart uses Ti4+, peroxide might be faster if used with higher concentration (thus oxidizing more copper).
> 
> Which steps are you taking to properly dispose of HBF4 wastes.


MarcoP
thanks for your advise, HBF4 method time more than 4 hours, but if the video is true the time needed is 5 minutes
https://www.youtube.com/watch?v=KR-_UKe71bQ
https://www.youtube.com/watch?v=mnK8NxKVGok
Hatem


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## kurtak (Oct 23, 2014)

Hatem

First let me apologize - I thought you were posting a process for the average "back yard" guy that is working small scale --- but I see now that you are talking large scale production

So if I understand you correctly now - what you are looking for is a faster way to depopulate circuit boards then the de-soldering machine you are currently using

You are looking at a chemical method so I am guessing your current machine works with heat to melt the solder --- is that correct?

if so I don't think chemical stripping of the solder is going to be any faster as it takes time for the chemicals to do there work just as it takes time for heat to do its work --- in fact I can see chemicals taking more time depending on a number of conditions - plus with chemical striping you now end up with a chemical waste that has to be dealt with 

The only way I can see to depopulate boards faster then with heat or with chemicals would be to do it with a mechanical method with a machine something like this http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=60&t=10261

You could then set up a number of different methods to achieve sorting of the components including but not limited to screen sifting - salt water tank floatation - & magnetic

Kurt


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## hatemelborai (Oct 23, 2014)

kurtak said:


> Hatem
> 
> First let me apologize - I thought you were posting a process for the average "back yard" guy that is working small scale --- but I see now that you are talking large scale production
> 
> ...



Kurt
No problem, my explanation was not clear, yes our current machine works with heat to melt the solder. 
the advantage of using chemicals are: 1-reuse the chemical after retrieving solder, 2-retrieving solder 3- no smoke (we have fume scrubber for stripping station) 4- the motherboards is completely free from solder, we can get pure copper from it. For sorting we use screen sifting and manual, I will think how to use salt water tank
hatem


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