GB1476104A - Production of iron by electrolytic reduction - Google Patents

Abstract

1476104 Electrowinning iron INST DE RECHERCHES DE LA SIDERURGIE FRANCAISE 10 Oct 1975 [11 Oct 1974] 41588/75 Heading C7B A hot concentrated alkaline pulp of ferriferous material. e.g. iron ore or steel works fume, is continuously electrolytically reduced while simultaneously (a) recycling a portion of the pulp without any external treatment preferably so as to maintain unidirectional pulp flow perpendicular to the cathode, (b) treating the remaining portion mechanically, physically and chemically to remove impurities, recover unreduced iron oxides and regenerate the alkali and recycling the unreduced oxides and alkali to electrolysis and (c) adding sufficient water, alkali and ferriferous material to the electrolytic bath to maintain a constant composition thereof. Electrolysis may be under pressure, e.g. generated autogenously by H 2 and O 2 from the water and may involve a series of electrolysis baths. The H 2 and O 2 outlets may have pressure relief valves with a baffle separating the space above and between anode and cathode. The recycled untreated pulp may be a large excess relative to the other portion and all the recycled and added components may be mixed for homogeneity before entering the electrolysis region. This latter may have a heating jacket and the bath temperature by monitored. The recycling streams are analyzed/monitored for composition and adjustments made accordingly. When iron ore is used with NaOH, unreduced oxide may be magnetically flocculated for recycling, while NaOH remaining is diluted, treated with lime to remove Si and Al as Ca salts, reconcentrated and recycled.