[Oxygen applications for sustainable steelmaking/steel melting] Reduction behavior of composite manganese ore-carbon: an analysis Reduction behavior of composite manganese ore-carbon: an analysis Cyro Takano1; Jose Dabreu2; Ricardo Braga1; Ferry S Belisario Benique3; Flavio Beneduce4; 1UNIVERSITY OF SAO PAULO, Sao Paulo, Brazil; 2PUC-RIO UNIVERSITY, Rio de Janeiro, Brazil; 3CATHOLIC UNIVERSITY OF RIO DE JANEIRO, Rio de Janeiro, Brazil; 4USP, Sao Paulo, Brazil; PAPER: 401/Iron/Plenary (Oral) SCHEDULED: 14:25/Mon./Mar Azul (50/1st) ABSTRACT: There is a great diversity of minerals containing manganese. The important ones are psilomelane (Ba,H<sub>2</sub>O)<sub>2</sub>Mn<sub>5</sub>O<sub>10</sub>) pyrolusite (MnO<sub>2</sub>), criptomelane (K(Mn<sup>++++</sup>,Mn<sup>++</sup>)<sub>8</sub>O<sub>16</sub>), rhodochrosite (MnCO<sub>3</sub>) and some ore with high content of iron oxides. For ferro-manganese production, the accepted reduction steps are gas/solid reaction to reduce higher oxides to lower ones (MnO<sub>2</sub>> MnO and Fe<sub>2</sub>O3>FeO) and at temperatures higher than around 1000°C gas/solid, solid/solid, liquid/solid and liquid/liquid reactions. The liquid/liquid and metal/slag reactions are the predominant ones at conventional Smelting Electric Furnace, for effective reduction of MnO>Mn at temperatures (~>1300°C) and it involves slag formation, dissolution of MnO in the slag, reduction of Mn++ in slag by carbon embebeded by slag or by slag/metal reaction by carbon dissolved in liquid Fe-Mn(MnxCy). The result is low production rate due to slow reactions. This paper analyzes some important effects from the characteristics of the manganese ores for ferromanganese production, such as: gangue and mineral compositions regarding the components that may form liquid phase during high temperature processing, impairing the rate of reduction of manganese ore-carbon composite. It may conclude that ores with high manganese content and low content of silica, iron oxide, (and others which may form liquid phase-slag at temperatures around 1350/1400°C) are prone to having better reduction behavior and consequently higher productivity and lower energy consumption. References: 1 Braga, R.S., Takano, C., Mourao, M.B. Prereduction of self-reducing pellets of manganese ore. Ironmaking & Steelmaking. London. The Institute of Materials, Minerals and Mining. 2007, v.34, no. 4, pp. 279-284. ISSN: 0301-9233.<br />2 Benique, F.B., DAbreu, J.C., Kohler, H.M., Rodrigues, R.N. Auto-reducao carbotermica de aglomerados de oxidos de manganes. Proc. 7th Japan-Brazil Symposium on Dust Processing-Energy-Environment in Metallurgical Industries. ABM-Sao Paulo- Brazil Sept 2008. pp 1-10 |