Electrolytic action has long been applied to electro-plating, and in recent years to the refining of copper. The combined electrolytic and heat actions of current are used in producing aluminum, and very recently the heat of the electric arc has been made commercially successful in refining steel from a lower quality to a higher quality.

The advantages of the higher heat of the electric furnace, and its easy control, make the application of electric heat to the smelting of metals highly desirable, at least to the extent of (1) assisting the fuel at the point of ore fusion, (2) of making the extracted metal more fluid, and (3) of improving its quality by producing a neutral atmosphere due to electric heating as compared with the oxidizing atmosphere of fuel heating. Also, as some impurities come from the fuel used, the reduction in fuel reduces the per cent of these, particularly so of phosphorus.

Recent experiments in Sweden have shown that an improved grade of iron can be made in a combined electric and fuel furnace, but as yet this is not economical enough for commercial requirements in general.