SnCl2 turns yellow

[Traveller11]

I made stannous chloride by dissolving lead-free solder in muriatic acid 34%. I put a few drops of what I thought was dissolved gold in chlorine solution (amber coloured) onto paper towel and added a few drops of SnCl2 to test the solution. The solution and SnCl2 together turned a yellow colour and not the desired purple. Would this yellow be indicative of iron in solution? I was trying to keep the chlorine solution at a neutral pH but the HOCl, being unstable, gave off its O2 to atmosphere, making HCl, and lowered my solution pH to 4.8. As the material I was attempting to dissolve gold from had a great deal of magnetite (Fe3O4) in it, I greatly fear the acidic solution has put iron and not gold into solution and the amber coloured solution I ended up with is ferric chloride (FeCl3).

 

[kkmonte]

Hi Traveller, I'd say one problem is using the lead-free solder. The solder isn't just Tin, it contains other metals, some copper, I think and others. You need to use pure Tin powder or shot. Not sure about your other question.

Ken

 

[g_axelsson]

You should have some testing solution that you KNOW is gold in solution. If not you never know if your stannous is good or not.
Yes, lead free solder contains some other metals but that shouldn't be a problem. I have even tested to make stannous from solder dissolved directly from a circuit board and it worked. :mrgreen:

Göran

 

[Lino1406]

If I got you then darker solution
became brighter - meaning no
or negligible PM

 

[butcher]

Hoke's page 100 give's you the way to test for iron in solution.