Another method of improving the quality of steel, recently perfected, is that of electric refining. This method seems destined for a wide range of usefulness in steel making, as it does more than the Bessemer or open-hearth methods can do in eliminating initial impurities and in turning out a product freer from slag, oxides and gases. In fact the electric furnace promises to rival the crucible furnace in quality of product at lower cost.

The ability of the electric furnace to eliminate sulphur and phosphorus brings into the range of practical usefulness the enormous deposits of iron ores which have heretofore been excluded because none of the iron or steel-making processes could eliminate these impurities without undue cost. The success of this furnace is due (1) to the higher temperature which can be maintained and regulated as compared with the open-hearth furnace, and (2) to the control of the chemical reactions exclusively through the action of the slag which can be made of the right chemical composition for the reactions desired, and which forms over the metal a covering protecting it from the oxidizing or reducing action of atmospheric oxygen.

In the high temperature of the electric furnace, the chemical affinities of sulphur and phosphorus for iron can be overcome by certain elements placed in the slag, and by this means these impurities are reduced to within safe limits.

These furnaces will melt and refine the poorest grade of steel and iron scrap, but it is more economical to refine the steel preliminarily in the Bessemer converter or the open-hearth furnace and transfer it to the electric furnace for further purification.