GB926334A - Process and apparatus for the production of metals or ferroalloys - Google Patents

Abstract

In a process for the reduction of metals and alloys from oxidic materials, the latter and solid reducing agent are continuously charged to a refractory-lined arc furnace in such proportions that the slag formed always contains a proportion of the reducible oxide, whereby a layer of carbon-free metal or alloy is caused to form at the bottom of the furnace. The reduction of complex ores may be so controlled that only the desired metals are reduced, e.g. iron and nickel may be reduced while chromium is retained in the slag. The furnace is so constructed that certain minimum depths of metal and of slag are always retained therein; tapping is carried out intermittently from two vertically spaced tapping holes. The electrodes are adjustable to be either slightly immersed or slightly above the level of the slag, so that heat is generated in the upper part of the slag layer, the depth of the latter being such that the metal is maintained at a temperature slightly above its melting point by conducted heat. Pre-reduction of the charge may be carried out in a rotary furnace or fluidized bed, and may be carried on to such an extent that no further reducing agent need be added at the electric furnace smelting stage. The direct production of low carbon steel is exemplified.