Variants of zone refining

Characteristics

Advantages

Disadvantages

Application

Horizontal

zone refining

Crucible is positioned horizontally; Heating elements move horizontally

Easy to load and unload materials; easily distinguish the interface

Bulk transport phenomenon; equipment occupies more spaces

Most metals, except for some reactive materials

Vertical

zone refining

Crucible is positioned vertically and heating elements move vertically

Less place occupation

Not easy to load and unload materials; more risk on cracking crucible

Most metals, except for some reactive materials

Floating

zone refining

Without crucible; The material is positioned vertically; The molten zone is held by liquid surface tension

Less contamination resources; less place occupation; good heat transfer

Limited charging material with high surface tension; Less production due to small size of material

Reactive metals, such as silicon, tungsten, zirconium, iron, etc.

Continuous

zone refining

Having feeding inlet and product and waste outlet; Feed Materials and get product and waste continuously

High production; High refining efficiency

Complicated design; High cost; Difficulty in operation

Theoretically most metals, but the development is in the experimental stage; no practical results or commercial use at present