From Wiki and interpolating:
K for K for K for K for K for K for
1Pa 10Pa 100Pa 1kPa 10kPa 100kPa
610 670 750 852 990 1185 Zn
882 997 1097 1412 1660 2027 Pb
1283 1413 1575 1782 2055 Ag
1509 1661 1850 2089 2404 Cu
1497 1657 1855 2107 2438 Sn
1783 1950 2154 2410 2741 Ni
Zn is easily evaporated from brass CuZn. At 1356K to melt Cu, Zn has roughly 750kPa and Cu 0.1Pa, clear case with one crucible. Even a few per-cent Pb in brass (664Pa) separate easily from both, optionally in two steps for Pb-Cu.
Pb is easily evaporated from Sn63 Pb37. At 1660K for 10kPa Pb, Sn has 10Pa. Leaving a bit over 0.1% impurity in each takes two steps, so crucibles suffice.
Ag could be recovered from Sn95.9 Ag3.8 Cu0.7 solder where it makes half the value. At 1782K that give 1kPa Ag vapour pressure, Sn has 43Pa and Cu 44Pa. The pressure ratio 4/100 is also the initial composition ratio, making few steps inefficient. A distillation column is better.
Ag could be recovered from Sn61 Pb37 Ag2 solder. At 1660K for 10kPa Pb, Ag has 257Pa so Pb would separate first with very few stages, but then the separation of Ag from Sn needs a distillation column anyway.
Cu and Ni can be separated by a distillation column or several crucible steps. This needs high temperatures.
Cu and Sn shouldn't be separated that way.
With Pb, Ag, Cu, Sn, Ni more noble than Mg and Al, the ceramics MgO and Al2O3 have chances to resist the molten alloys and possibly molten Zn. Suggested operating temperatures in air are 2500K for MgO, 1800-2100K for Al2O3, with big variations.
Marc Schaefer, aka Enthalpy