Editing Zone melting (section)

===Heaters===
A variety of heaters can be used for zone melting, with their most important characteristic being the ability to form short molten zones that move slowly and uniformly through the ingot. [[Induction coil]]s, ring-wound [[resistance heater]]s, or gas flames are common methods. Another method is to pass an electric current directly through the ingot while it is in a [[magnetic field]], with the resulting [[magnetomotive force]] carefully set to be just equal to the weight in order to hold the liquid suspended. Optical heaters using high-powered [[halogen lamp|halogen]] or [[xenon arc lamp|xenon lamps]] are used extensively in research facilities particularly for the production of insulators, but their use in industry is limited by the relatively low power of the lamps, which limits the size of crystals produced by this method. Zone melting can be done as a [[batch production|batch process]], or it can be done continuously, with fresh impure material being continually added at one end and purer material being removed from the other, with impure zone melt being removed at whatever rate is dictated by the impurity of the feed stock.{{Citation needed|date=February 2021}}

''Indirect-heating floating zone'' methods use an induction-heated tungsten ring to heat the ingot radiatively, and are useful when the ingot is of a high-resistivity semiconductor on which classical induction heating is ineffective.{{Citation needed|date=February 2021}}