GB1158547A - Process and Cell for the Production of Manganese of Low Carbon Content by Means of a Fused Electrolytic Bath - Google Patents

Abstract

1,158,547. Electrolytically producing manganese or manganese alloy. UNIVERSITE LIBRE DE BRUXELLES. July 14, 1966 [July 16, 1965; July 5, 1966], No. 31730/66. Heading C7B. Mn or Mn alloy having a carbon content less than or equal to 2À8% by weight is produced by electrolysis of a fused bath in the substantial absence of fluorides, the bath comprising either a ternary system selected from MnO-SiO 2 -CaO, MnO-SiO 2 -MgO, MnO-CaO-MgO, MnO-CaO-Al 2 O 3 and MnO-MgO-Al 2 O 3 , or a system containing at least four components of said ternary systems, one of the components being MnO, the cathode being formed of the metal to be produced, this metal being in the liquid state, and the anode being formed of carbon (e.g. an anode of amorphous carbon, graphite or of the soderberg type). The MnO to be used in the bath may be produced from carbonate ores or from MnO 2 . The bath may be purified from Fe and other metals by a pre-electrolysis. For example, in a two-stage electrolysis process, Fe/Mn is produced in the first stage and Mn in the second. The electrolyte can contain minute additions of BaO, B 2 O 3 , NaF or CaF 2 to reduce the melting temperature or increase the electrical conductivity. The electrolytic production of Mn may be accomplished in three ways (1) by an arc system using 35-60V, (2) by an anode effect system using 20V wherein the anode is dipped in but not moistened by the electrolyte and (3) by a system in which the anode is moistened by the electrolyte using 10V. In producing a Mn based alloy, a metal having an affinity for oxygen less than, equal to, or slightly in excess of that of Mn may be introduced into the electrolytic bath in the form of an oxide so that the metal is co-deposited with the Mn. Metal having a melting point lower than the temperature of the bath may be added directly to the bath to alloy with the electrolytically produced Mn. By the electrolysis it is possible to obtain metal with a C content less than 0À1% and Si content less than 2%. It is possible to produce 99% or more pure Mn. Fig. 4 shows an electrolysis cell comprising a graphite anode 9, a water-cooled Cu tube 10 supplying current to a liquid Mn cathode 13 via a stainless-steel component 18, a carbon free magnesia lining 7', refractory bricks 7, steel outer casing 6, steel lid 19 and stainless steel thermal shield 22. The lid maintains a reducing atmosphere in the cell. Figs. 1 to 3 (not shown) illustrate cells which may be heated by induction coils 1 cooled by water circulation. Fig. 5 (not shown) illustrates a cell which could be used on an industrial scale.