SMELTING ORES BY RLE<;TRICITV 



electrodes pass vertically downward through the roof of the 

 furnace. These are sometims'i water-jacketed above and 

 below their passage through the iron casing. The elec- 

 trodes can be raised or lowered by hand or by an automatic 

 regulator. In this way the intensity of the current can be 

 closely regulated as the air-gap is increased or decreased. 

 The current passes through one electrode, through the 

 narrow air-gap, into and through the slag to the molten 

 metal ; thence along the metal to the slag and air-gap to 

 the other electrode. The energy contained in this furnace 

 in an ordinary operation is about 4,000 amperes at no 

 volts A.C. The electrodes used are square prisms 14.5 

 inches to a side by about 68 inches long. The estimated 

 cost of converting scrap into steel by this process, exclusive 

 of the cost of the scrap and metal, is about $14.50 per ton 

 of product. 



Steel of a very superior qualit}^ can be made by smelting 

 together charcoal, pig and scrap in the Kjellin Induction 

 Furnace. As the name of the furnace implies, it operates 

 on the principle of magnetic induction— no electrodes being 

 required. Unlike the Heroult process of steel making, this 

 does not permit the purification of the materials wliicli go 

 to make the steel, and the quality of the steel depends alto- 

 gether upon the purity of the component materials. In 

 this respect it is like the crucible steel process, but differs 

 from it in that no gasses are present to impair the quality 

 of the steel. Since there are no electrodes, there are no 

 impurities from this source. 



The Kjellin furnace is simply a step-down transformer, 

 the primary of which consists of an insulated wire wound 

 around one leg of a laminated iron magnetic circuit. The 

 secondary consists of a single, continuous circular trough 

 (which contains the charge) outside of and separated from 

 the primary, but concentric with it. This annular groove is 

 lined with magnesite or silicia brick, according as a basic 

 or acid lining is required for the groove which forms the 



