Chemical, Physical and Typological Characterization of
Main Brazilian Manganese Lump Ores
G. L. Faria1, E. L. Reis1, C. B. Vieira1,2, N. Jannotti Jr.3, F. G. da Silva Araújo1,2
1
Rede Temática em Engenharia de Materiais – REDEMAT, MG, Brazil
2
Universidade Federal de Ouro Preto – UFOP, MG, Brazil
3
VALE – Manganês, Brazil
In Brazil, the manganese lump ores are yet the main raw material for manganese ferro-alloys
production. In Brazilian companies the choice of ores to compose the furnace charge are
based just on grain size and chemical composition, but the manganese ores present many
other important characteristics that must be better understood by the researchers and alloys
producers. This work presents a physical, chemical and typological characterization of
manganese lump ores from the three main Brazilian mines, Azul, Morro da Mina and
Urucum. The chemical analyses were made by AES-ICP and titration. The typological
characterization was obtained by optical microscopy and X-ray diffraction. The physical
properties studied included density, surface area and porosity measurements. The contents of
Mn for Azul, Urucum and Morro da Mina are, respectively, 47.68, 42.69 and 28.44%. The
Urucum lump ore presents the highest structural density (4.29g/cm3), followed by the Azul
lump ore (3.98g/cm3) and by Morro da Mina (3.56g/cm3). The Urucum, Morro da Mina and
Azul ores bulk porosity are 22.68; 10.79 and 29.40cm3/kg, respectively. The typological
classifications of the ores are: anhydrous-oxide for Urucum, hydrated-oxide for Azul and
silicate-carbonate for Morro da Mina. The thermogravimetrical analyses showed the behavior
of the ores at high temperature in air. The mass losses could be associated to different
phenomena, depending on the type of ore. The thermal decompositions of oxides
(cryptomelane, pyrolusite and braunnite), carbonates (rhodochrosite) and of the hydrated
constituents (mainly todorokite and anphibolites) was identified.
Keywords: Manganese, Lump Ores, Brazilian Deposits, Typological Characterization.
Work supported by CNPq, Fundação Gorceix and VALE Manganese.
[1] J. R. Amaral, J. D. T. Capocchi, M. A. B. Marcial, A Produção de Ferro-Ligas de
Manganês e Perspectivas para o Uso de Ferro-Ligas. In: Conferência Internacional de
Tecnologia Siderúrgica – ABM, vol 1. p.551-582. 1986.
[2] S. E. Olsen, M. Tangstad, T. Lindstad, Production of Ferromanganese Alloys in the
Submerged Arc Furnace. Trondheim, Norway. 247p. 2007.
[3] M. Tangstad and S. E. Olsen, The Ferromanganese Process – Material and Energy
Balance. INFACON7, 621-630, 1995.
[4] C. Schobbenhaus and C. E. S. Coelho, Principais Depósitos Minerais do Brasil –
Volume II – Ferro e Metais da Industria do Aço. Departamento Nacional da Produção
Mineral. Companhia Vale do Rio Doce.