Vacuum refining furnace

A vacuum refining furnace, comprising:

• a) a furnace body, the furnace body comprising:
• an evaporation laminate, a plurality of graphite condensing casings, and a graphite insulating casing, and the evaporation laminate comprising a plurality of evaporators;
• b) a graphite heater comprising a heating pin;
• c) an electrode;
• d) a sealed furnace housing;
• e) a positioning member;
• and
• f) a connecting base;
• wherein
• the evaporation laminate is nested within the graphite insulating casing, and the graphite insulating casing comprises a plurality of through holes;
• each of the plurality of graphite condensing casings has a different diameter from another one of the plurality of graphite condensing casings;
• the graphite insulating casing is nested within the graphite condensing casing having a smallest diameter;
• each graphite condensing casing except for the graphite condensing casing having the largest diameter is nested within one of the graphite condensing casings;
• and each graphite condensing casing that is nested within one of the graphite condensing casings has a smaller diameter than the one of the graphite condensing casings it is nested within;
• all the graphite condensing casings except for the graphite condensing casing having the largest diameter comprise a plurality of through holes;
• the heating pin and the connecting base are connected to each other via a graphite bolt;
• the positioning member is disposed on the connecting base;
• each of the heating pin, the graphite bolt, and the electrode comprises a side surface;
• the positioning member comprises a first side surface and a second side surface;
• the connecting base comprises a third side surface and a fourth side surface;
• an area of the third side surface is substantially the same as an area of the fourth side surface;
• the second side surface, the third side surface, and the fourth side surface are substantially parallel to one another;
• the first side surface is disposed between the second side surface and the third side surface and is oblique with respect to the second side surface and the third side surface;
• and
• the side surface of the heating pin is in contact with the second side surface of the positioning member, the side surface of the electrode is in contact with the third side surface of the connecting base, and the side surface of the graphite bolt is in contact with the fourth side surface of the connecting base.