Tin etching solution

[massiwe]

Hello everybody

I'm trying to go from lab scale in small business scale with recycling / refining electronics from scrap.
Right now I'm stuck on depopulating boards. And I've found interesting process / solution:

https://www.youtube.com/watch?v=jQGT8X9zorI

It is russian but everything is there.
Here is the composition:

100ml H2O
9,6g urea nitrate CH5N3O4
6g citric acid C6H8O7
20ml HNO3

There is one more benzoic acid for passivation Fe but it can be used or not.
My question is, how is this solution working?
Where is Sn going?
This looks as nice process to get rid of Sn before AP or any nitric treatment.
For now I look at it theoretic, next weekend I'm going to do some experiments.

 

[Elektrikis]

Hello everybody

I'm trying to go from lab scale in small business scale with recycling / refining electronics from scrap.
Right now I'm stuck on depopulating boards. And I've found interesting process / solution:

https://www.youtube.com/watch?v=jQGT8X9zorI

It is russian but everything is there.
Here is the composition:

100ml H2O
9,6g urea nitrate CH5N3O4
6g citric acid C6H8O7
20ml HNO3

There is one more benzoic acid for passivation Fe but it can be used or not.
My question is, how is this solution working?
Where is Sn going?
This looks as nice process to get rid of Sn before AP or any nitric treatment.
For now I look at it theoretic, next weekend I'm going to do some experiments.

Hi! This is my old technology. Demo version. Its work but not selective and huge problems. I sell formula to russians and this is demomo. I have newest versions.
But not for free.
https://www.youtube.com/watch?v=_OnyJaHPVZw
https://www.youtube.com/watch?v=zlgZrxSmOAk

 

[goldsilverpro]

Fluoboric acid and peroxide work great on tin, lead, or tin-lead, probably with tin/silver too.

 

[arionbaron01]

Agree with the reply of goldsilverpro that Fluoboric acid and peroxide work great on tin, you can also use 100 ml ethanol and 2–10 ml hydrochloric acid. For pure tin and alloy. Immerse for 1–5 min.