ABSTRACT
Methods have been developed, therefore, to produce iron in furnaces other than the blast furnace; such methods are called direct reduction. The purpose of such method would be mainly the production of a raw material for making steel by existing processes, that is, the production of a substitute for pig iron or scrap. A multiple hearth furnace was tried but found to be difficult to operate due to the sticking of the reduced iron and its interference with the action of the rabbles. In these processes lump ore or agglomerated concentrate is continuously fed to the top of a low shaft furnace and the reducing agent is a hot mixture of CO and hydrogen is passed upward through the furnace. Electric furnace processes yield pig iron. These processes were popular at the begining of the Twentieth Century especially in Sweden and Norway where hydroelectric power is cheap.
