TL;DR: Vacuum Distillation is a main entry in the 外星矿物知识引擎 database.
Using the natural vacuum of space to distill and separate metals by their different boiling points, without need for containment vessels
Input Material
Mixed asteroid metal
Output
Separated pure metals (Fe, Ni, Co, PGMs)
Efficiency
High for volatile metals; PGMs require very high temperatures
Space Viability
Excellent - vacuum is free in space; no atmosphere to manage