what is this grey powder?

[feby.ka]

hi all,

this is my 1st post in this forum. first of all, i am sorry with my bad english, because it is not my mother language, but i am trying my best

i did a smartphone leaching with HNo3 this afternoon. and the yields are clean PCB its self, swimming gold, blue solution ( i assume it is copper ii nitrate) and some grey powder. i dont really have any idea what is the grey powder actually, can anyone here give me information what that is? any information, would really help me and i thank for that

this is the pict with the grey powder.

 

[FrugalRefiner]

If you didn't dissolve the solder from the boards before the HNO₃ leach, it could be tin in the form of metastannic acid.

Your English is better than many who speak it as their first language.

Dave

 

[feby.ka]

thanks frugalrefiner,

i just searched the words metastannic acid, and someone ever posted bout it here http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?t=15324

so if i dont have to worry bout this metastannic, i just have to pour the AR into it (metastannic with gold foil), then i get dissolved gold and not dissolved metastannic, filter it and voila get the pregnant AR.

again thanks frugalrefiner and this forum

 

[FrugalRefiner]

Did you read the whole thread or just the first post? Go back and read the whole thread. You'll find a better way.

Dave

 

[feby.ka]

i've red it all the thread, i mean, from the thread i have at least lil bit clue to deal with it. my goal now is actually to dissolve the gold, then after that maybe work with this metastannic. i ask about this grey powder just because i don't want to make another mistake with my gold foil. but you do right, i still have to read another thread and in the end chose which methode is the best for me

 

[FrugalRefiner]

As you read, remember that we use stannous chloride to test our solutions for dissolved gold. It works well because the stannous chloride reduces dissolved gold to a metallic state, in the form of colloidal gold - that purple to black stain. It is best to keep dissolved gold away from tin except when testing.

You have to decide what works best for you in your particular situation, but tin can steal some of your gold.

Dave