I am a Mineral Processing Eng. Specialized in Gold Ores AMA

[Mick Tee]

Why do you want to boil it in Potassium Carbonate?
Do you hope to dissolve the Tin?

Yes, I have read that they use high alkaline solutions to dissolve quarts, and it can also apparently dissolve some of the tin oxides.
If this were the case, it would make separating the gold from the final heavy sands a pretty easy task.

 

[Yggdrasil]

Yes, I have read that they use high alkaline solutions to dissolve quarts, and it can also apparently dissolve some of the tin oxides.
If this were the case, it would make separating the gold from the final heavy sands a pretty easy task.

There are not much dissolving quartz.
All that do, is slow and exeedingly dangerous.
I'm not sure about this species of Tin Oxide , but I think plain old HCl will be sufficient for that.
Have you crushed and roasted it?
That should always be the first step.