ORALS

SESSION: IronMonPM1-R1	Afonso International Symposium on Advanced Sustainable Iron and Steel Making(6th Intl. Symp. on Advanced Sustainable Iron and Steel Making)
Mon Nov, 5 2018 / Room: Mar Azul (50/1st)
Session Chairs: Tateo Usui; Jose Carlos D Abreu; Session Monitor: TBA

14:25: [IronMonPM106] Plenary
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 Id: 401 [Abstract]

There is a great diversity of minerals containing manganese. The important ones are psilomelane (Ba,H₂O)₂Mn₅O₁₀) pyrolusite (MnO₂), criptomelane (K(Mn⁺⁺⁺⁺,Mn⁺⁺)₈O₁₆), rhodochrosite (MnCO₃) 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 (MnO₂> MnO and Fe₂O3>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.\n2 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