positive stannous test from nitric leeching?

[Tomd]

hi all. i have been leeching inquarted gold in a nitrc soloution and have had no problems woth this before but this time i had ahd got called away while running the leeching process and had no choice to leave it running overnite. i didnt think this would be an issue as i assumed when the nitric had been used up the reaction would stop and i would have no problems. upon return everything looked fine so i pour off the resulting soloution and tested with stannous just as i always do (dont know why) and this time got a positive test! i was under the impression that nitrtic alone would not dissolve the gold. what has happened? i m sure i wont have much problem recovering it from my soloution but was wondering if anyone could shed some light on this puzzel for me? will nitric dosolve gold if given enough time? this was also my last leech on this batch so prob some exess nitric left after leeching.

many thanks

Tom.

 

[butcher]

What type of water do you use, is it treated with Chlorine?
Dirty, or unclean glass with chloride salts from previous use?
Any bit of chlorine or chlorides in the mix will dissolve some gold.

 

[solar_plasma]

Oh, butcher has been faster than me...nevertheless:

Can you post a picture of the test? Look also for the purple stain if you do the test in a white drop plate.

Maybe you diluted with tap water, which contains chloride. Then you might have dissolved a little gold, enough to test positive.

Or you nitric has not been pure.

Or it is palladium (green/brown) or platinum (orange) that gave a positive test.

 

[g_axelsson]

Don't forget silver chloride. Silver from the inquarted material and chloride from stannous.

Given time and strong light silver chloride turns purple too.

Göran

 

[Tomd]

Thanks guys think you solved it!must have picked up the wrong beaker! And yes i do have platinum present but there is gold showing in the test also. and as for the acid that would be the other posibilty it hasnt caused a problem in any other soloutions. As usual human error :roll: Thanks again! Tom. ps: Glad i test every solotiun for gold now!