GB454165A - Improvements in and relating to processes for the production of ferro-manganese - Google Patents

Abstract

Manganese ores or slags containing too large a proportion of iron to permit of being worked up to ferro-manganese in one stage are melted, after the addition if necessary of fluxes, e.g. limestone, fluorspar, or sand, to form a neutral or slightly acid and low-melting manganous oxide slag, and so much iron is reduced, as by means of charcoal, at a temperature below the reduction temperature of the manganese, as to form an intermediate product possessing an iron-manganese ratio required for producing the ferro-manganese desired. The basicity of this product is then increased by the addition of lime and on increase of temperature it is reduced to ferro-manganese. The two stages may be effected in one or separate furnaces. The iron reduced from the manganous oxide slag may be continuously or intermittently removed. In an example an ore containing 31,1 per cent of iron and 17,8 per cent of manganese are melted with a flux and by the addition of reducing charcoal so much iron is reduced at 1300-1400 DEG C. as to leave a manganous oxide slag containing 5,2 per cent of iron and 25,9 per cent of manganese. Lime and reducing charcoal are added to this slag which is reduced at about 1600 DEG C. to ferromanganese containing 11,4 per cent of iron and 79,1 per cent of manganese.