Stannous Chloride Precipitant?

[nicknitro]

Hi all,

Newbie still surfing for all the right answers.

I recently did a test on an AR frankenstein from my very first attempt at PGM recovery. When I took a small sample of the AR solution 5-10 drops, then added some of my tested Stannous/Hcl mixture. I received an instant precipitation of what appears to be yellow/brown flakes. I picked one of the flakes out and tested it with a gold concentration solution from 10 karat "only nitric" all the way through to 22 karat "basically Aqua Regia" . Has anyone else experienced this? What is the precip? I can give any additional info if desired, like I say this is a frankenstein batch from a 50 cell phone board and plated pieces 1st attempt. I would like to continue this batch through to final smelting, but might also scrap it if someone wanted it for experiment purposes. Either way let me know.

Thanks in advance ,
Nick

 

[Oz]

You have me confused.

It seems you are testing for gold purity but are attempting to recover PGM (platinum group metals).

Greater detail about what you have done will help all in helping you.

 

[butcher]

We usually use a drop of the solution to be tested on paper,cotton swab, white paper,white dish,Etc. then add drop of stannous chloride, the color change to brown or violet indicates gold, you say you used more of each and got a precipitant of brown this is not how I use this test , but my answer would be your tin precipitated the metals higher in the electromotive series above tin, which would be whatever you had in your solution, my question did you eliminate base metals prior to aqua regia treatment? if not you could have pricipitated many metals, then you say you tested this brown precipitant with test solutions of different strength's, ( this sounds like the scratch test mthod, and I dont see how you could do that with a precipitant)?did you use a stone or slate?or with stannous again?
this question is confusing to me,
if you get brown indication with stannous you should have gold in solution, is this your question?
I would suggest studying the stannous chloride test and testing of metals some more.
also search forum for Pawnbrokers guide to testing metals, a good article on testing metals.
also look for Hokes book, also C.W. ammens is another good book,reading these will get you pointed in the right direction,thes are available on forum as downloads.
50 cell phone will get you some gold but it takes a whole lot of electronic scrap to get much, 50 cell phones is probably not gonna get much, I would get it to pure gold powder and save it up,
you say frenkienstien bath or batch, are you having trouble with it?
maybe explain what you have done and trouble your in with this, dont dump you solutions, you should be able to get your values from them and then treat the solutions to make them safe first.

 

[nicknitro]

Thank you Butcher,

To answer some easy questions, no I didn't eliminate the base metals on this first batch. That is why I called it the Frankenstien batch.

I have experienced the positive purple/brown color from a solution of the same boards I used a mix of phosphoric acid/nitric acid to dissolve the base metals, then collected the gold flakes, redissolved in HCl, after washing in water 5 times. The reaction was really cool, however left a very distinct purple stain in my test dish, so I haven't really usede it again, for fear of contamination.

However, when I retest this liquid solution with the stannous, It instantly puts a cemented yellow/ brown ppt , in this case , on the bottom of the white plastic cup. just used it cause it is white, I know it's hard to extract ppt's frrom plastic.

When I was talking about testing with different solutions of acids, yes you are correct, I was using the scratch method. Acid plate, and acid droppers, the standard Ebay Weekend Warrior outfit. LOL

But thats how big the precipitants were I picked out as pin-head sized piece and placed it on the spot plate. The only acid dropper I didn't try was the Platinum testing dropper. But I felt it was kinda over rated, as it must be the same as the 22k dropper right? Strong nitric, and muriatic. I thought it would only dissolve Plat in heat so why bother.

Frm what I've read here so far the most common chems found in these boards are Silver #1 from the solder I'm guessing, gold, and a lotta lesser base metals including lead. I don't put my hopes too high for Platinum or palladium, just cause of the way I went about this first batch would really surprise me if all the higher PGMs were even recovered, IE put into solution.

The dried on white paper of the test left very golden ring, unlike what I got from just the gold flake solution. Oh yeah I used HCl/Bleach to dissolve the flakes which I spoke about earlier.

My new favorite coulor is Purple. LOL