|This article has not been revised for the current version (U35-479045). It was last updated for AP-398142. It may contain inaccuracies.|
Heating Rust over its melting point will turn it into liquid iron with a 1:1 ratio, which can then be cooled into refined iron. The conversion is 87.5% more efficient than what can be achieved with a using Rust Deoxidizer, but doesn't produce Oxygen or Chlorine.
Magma spawns from Volcanoes with a high enough temperature to melt rust. That temperature can also be reached by using Liquid Steel as "coolant" in a Metal Refinery. In both cases, reusing the heat from the resulting iron to preheat more rust will make the process much more heat-efficient. A properly designed rust melter may later be used to refine most other Metal Ores faster than with a metal refinery or it can be converted into a Regolith melter.