MetaStannic Acid

[Bellien]

I have a quarter pound of pins soaking in 15% Nitric. I left the solder on so now I'm watching the massive amounts of tin paste pile up.

I found the formula for MetaStanic Acid, H2SnO3, but not the reaction of Tin with nitric acid. There are a number of sites with possible routes but all of the journals which seemed to have the full and agreed upon routes where unavailable to me.

The gist of my curiosity revolves around the observation that the nitric doesn't seem to be grossly consumed by the tin, it is still vigorously digesting the other metals despite the amount of paste. Does anyone know the reaction?

 

[butcher]

fun with gell?? are you just a glutton for punishment?

 

[patnor1011]

The only reaction I can comment on is me swearing when I see that happening. It is very hard and time consuming getting rid of tin and separate that mess from goodies. I still have about 0,1l of nice white-grayish tin gel with gold. I will have fun with that later. :mrgreen:

 

[Harold_V]

I still have about 0,1l of nice white-grayish tin gel with gold. I will have fun with that later. :mrgreen:

Incinerate, then grind in a mortar and pestle. Digest in HCl, then rinse well.

Harold

 

[patnor1011]

I still have about 0,1l of nice white-grayish tin gel with gold. I will have fun with that later. :mrgreen:

Incinerate, then grind in a mortar and pestle. Digest in HCl, then rinse well.

Harold

Thanks Harold, that is the plan. I need to start practicing art of incineration as my last attempt resulted in nice silverish button. Much heavier than tin will be - due to gold content. Say that I created white tingold. :mrgreen:

 

[Bellien]

I'd read through twice so now I was working working my way through the good book of Hoke and her familiarity experiments, not trying to extract the gold per say (not yet anyway). She doesn't go further then giving a name for the paste...

Harold I'm curious as to your method of removing the paste. While I can see that it would be very effective, why differ from the means given in Hoke? Is it just a better way?

 

[dtectr]

I'd read through twice so now I was working working my way through the good book of Hoke and her familiarity experiments, not trying to extract the gold per say (not yet anyway). She doesn't go further then giving a name for the paste...

Harold I'm curious as to your method of removing the paste. While I can see that it would be very effective, why differ from the means given in Hoke? Is it just a better way?

She was inaccurate in saying that it was "dissolved" by the concentrated acids. In reality, they merely "take it up" or hold it in suspension. As soon as you dilute the solution, down it drops.

Incineration converts metastannic acid to simple tin oxide, which is soluble in concentrated HCl & concentrated sulfuric.
http://books.google.com/books?id=cUcsAAAAYAAJ&pg=PA820&img=1&zoom=3&hl=en&sig=ACfU3U0jbYvLKniNgjoiYnWeRo-BAqLAsg&ci=142%2C349%2C804%2C298&edge=0
http://www.public.asu.edu/~jpbirk/qual/qualanal/tin.html

try this thread: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=8792

 

[Harold_V]

I'd read through twice so now I was working working my way through the good book of Hoke and her familiarity experiments, not trying to extract the gold per say (not yet anyway). She doesn't go further then giving a name for the paste...

Harold I'm curious as to your method of removing the paste. While I can see that it would be very effective, why differ from the means given in Hoke? Is it just a better way?

I learned that incineration and a boil in HCl prior to digestion yielded solutions that could be filtered. That was the result of an earlier experience where it took more than a day to filter a liter of gold chloride, thanks to the presence of tin.

Take note that I make the recommendation to incinerate and do an HCl wash on a pretty regular basis. It was one of the little things I discovered that made my life much easier.

Harold

 

[Bellien]

Thank, I have seen you make the same suggestion several times for several problems. This helps a lot, I've got the pins fully dissolved so I will try to filter and incinerate the waste later today.

 

[jonn]

:lol:

 

[Stowmaster]

Tin acid - this is bad, because it has a large adsorption capacity. Gold can be oxidized to NaAuCl4, and filtered through the parchment paper (very slowly!). But part of the gold salt is adsorbed tin acid, and get this gold later at home is almost impossible.

 

[miatakid99]

i have read the hoke book. not all the way i'm on chapter 8 but he dose say to soke your product in caustic soda to get rid of tin, lead,zinc, and aluminum. but i'm just a noob don't take my word on it.

 

[jeneje]

i have read the hoke book. not all the way i'm on chapter 8 but he dose say to soke your product in caustic soda to get rid of tin, lead,zinc, and aluminum. but i'm just a noob don't take my word on it.

A word of Caution be careful when using caustic soda, Caustic soda (NaOH) will heat up very quickly when mixed with water. When boiling caustic soda to clean material for processing do this inside a fume hood or outside, DO NOT BREATH THE FUMES posioning by this chemical can kill you several weeks or months later. Research the effects of caustic soda (lye) before using.

Ken

 

[AndrewSuperD]

Great thread, so I’ll add to it. I’m trying to understand exactly how to incinerate metastatic acid/gold mixtures. Should I evaporate solution in a beaker then transfer to melt dish? Then use propane torch? When I try to dry contents of the beaker, they just stick so hard to the beaker. Suggestions?

 

[Yggdrasil]

Great thread, so I’ll add to it. I’m trying to understand exactly how to incinerate metastatic acid/gold mixtures. Should I evaporate solution in a beaker then transfer to melt dish? Then use propane torch? When I try to dry contents of the beaker, they just stick so hard to the beaker. Suggestions?

Yes, dry it and then heat it to a dull red in a shallow container.

 

[Martijn]

Don't just evaporate. Rinse the tin paste free of acids and metal salts first.