The Dusts page states that BREL cannot be melted and cooled back into it's original form, but the page for ELEMENT:BREL states that it can.
Strangely, the answer seems to be "Both"
BREL that comes from something being destroyed by an EMP can be melted down and will cool into what it came from even if it doesn't have a ctype.
BREL that comes from the dusts menu won't melt at any temperature - At least, not at any temperature I can generate - even if it does have a ctype.
I suppose it's possible there were contaminents already present in the BREL, though could have been sure I saw BREL (NSCN) turn into molten NSCN.
But the vast majority of it doesn't melt even at 4k + degrees. It's not as if it makes sense to have the option anyway, since the things BREL comes from are solids and there's no way to separate liquids. Perhaps if you could melt the BREL and then electrolyse it, but it's still pretty useless.