When molten SLCN is treated with OXYG, it turns into either molten STNE, molten SAND, or--depending on temperature--molten CLST or molten PQRT.  STNE, CLST, and PQRT have ways of turning back into SLCN; SAND and GLAS don't.  SAND can only turn into GLAS, while GLAS can only turn into BGLA and back again. One of the benfits of SLCN is that it allows TPT to have a rock cycle, but it comes up short because when SLCN turns into SAND, it's not a cycle, it's a one-way street.  Here are some mechanics that would fix that:

Molten SAND when mixed with COAL or BCOL can turn into 2 possible things depending on temperature.  If colder than 13435.34F (or 7446.3C) it'll turn into molten SLCN when mixed with COAL or BCOL, otherwise it'll turn turn into molten PQRT when mixed with COAL or BCOL.

EDIT:  I had just remembered that the only way to produce molten SAND without console or property tool is to oxegenate molten SLCN, so molten GLAS (FYI, BGLA turns into molten GLAS when melted) should also turn into these things when mixed with COAL or BCOL; this would allow complex CRMC factories that don't have to also be GLAS factories.