Everyone wants it to be happened, but it just won't happen.
In 2013, snk said "Guns will be able to be turned into minerals as refund" in Q&A last time, and after that he forgets about it.
I know right, I remember that, it will never happen, also it's a bad idea.
This most likely won't happen, as said on other threads. Though I was excited when snk said they could be refunded for minerals, though it depends on how much you would get.