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D'Abreu J.C.,Pontifical Catholic University of Rio de Janeiro | Kohier H.M.,State University of Rio de Janeiro | Falero E.E.T.,Pontifical Catholic University of Rio de Janeiro | Otaviano M.M.,SAMARCO
TMS Annual Meeting | Year: 2015

Nowadays the most important Direct Reduction - DR processes in shaft furnaces has to deal with carbon fines precipitation and DRI carburization issues. Based in a cooperative research program joining Catholic University (PUC-Rio) and SAMARCO Mining Co, a project dealing with pellets reduction and those two phenomena was established. This work analyzes kinetically the three reactions mentioned before, considering typical values for the operational variables temperature, flowrate, pressure and gas composition, parameters commonly used to control the DRI formation in the Reduction Zone - RZ of the shaft furnaces. From laboratories experimental results, the kinetic equations for those reactions were established and, using the superposition principle, generated a specific global kinetic model for the iron oxide reduction and the soot formation. Finally, using those experimental results and applying a planned statistical factorial analysis for the experiments, the numerical coefficients for each equation were calculated and the correlation factor determined for the proposed global kinetic equation.

Loeffler C.F.,Federal University of Espirito Santo | Peixoto R.G.,SAMARCO
CMES - Computer Modeling in Engineering and Sciences | Year: 2013

Here is presented a formal deduction for the Dual Reciprocity hypersingular boundary integral equation for application to two dimensional potential problems. The theoretical and numerical derivations are presented in detail, and some simple test problems are included to verify the accuracy of the proposed formulation. Due to its simplicity, Poisson's Equation is used as a basis for the mathematical formulations and operational procedures related to the body force term, but the methodology can easily be extended to other more elaborate classes of potential problems. Poles are inserted internally to improve the interpolation within the domain, resulting in a hybrid singular and hyper-singular matrix system and global polynomial functions are also implemented for the same purpose. Problems belonging to scalar field theory that have known analytical solutions are solved, in order to obtain a preliminarily assessment of the efficiency and capability of the technique for more elaborate applications.

Castro E.F.,Samarco | Peres A.E.C.,Federal University of Minas Gerais
Revista Escola de Minas | Year: 2013

The recovery of iron bearing minerals from the reject products of the beneficiation of iron ores is a challenge concerning the sustainability of the preliminary stage of iron and steel making. This investigation addressed the production of iron ore concentrate within the specifications of Samarco's pellet feed from a representative sample of the concentrator I desliming cyclone's (101.6 mm, 4") overflow. The experiments included stages of microdesliming and flotation. The developed microdesliming method was efficient and the concentrate produced via cationic reverse flotation presented silica content compatible with pellet feed requirements.

De Carvalho R.L.N.,Samarco | Peres A.E.C.,Federal University of Minas Gerais | Rangel E.P.,Samarco | Gaggiato V.C.,Samarco
6th Int. Congress on the Science and Technology of Ironmaking 2012, ICSTI 2012 - Including Proceedings from the 42nd Ironmaking and Raw Materials Seminar, and the 13th Brazilian Symp. on Iron Ore | Year: 2012

This paper targeted the creation of guidelines for the teams connected to the Commercial Director of Samarco Mineração upon the new trends of the iron ore and steel market. Having as the analysis focus the impact of the entrance of lower Fe content ores into the market, the internal papers, and academic studies prepared by the organization technical staff and the marketing tools available to the teams in direct contact with the market and customers. As outcomes, cyclical behaviors by the steel industry have been noticed, leading to the recurrence of strategies already applied throughout the relationship with the mining industry. However, some new factors have come into the scene and increased the uncertainty over the future developments to the sector. Thus, it was created an internal need to adequate some organizational procedures as a reply to the behaviors already mapped in the past, as well as a deepening into the knowledge of these new factors not yet noticed and that have been changing the sector characteristics. As a conclusion, further to the definition of the lines for work and research, becomes mandatory and shall be implemented following this study, facing this higher pricing systems complexity, the available products and the new competitors.

Vieira M.G.,Samarco | Peres A.E.C.,Federal University of Minas Gerais
Journal of Materials Research and Technology | Year: 2013

This investigation addressed the study of the effects of the slurry's rheological behavior and the state of aggregation and dispersion on wet ultrafine grinding of an iron ore concentrate. Regrinding tests were conducted under different conditions of dispersion (pH 7.3, 8.5 and 10.0) and with the addition of 300 g/t of lime. The increase of pH from 7.3 to 10.0 increased the slurry dispersion degree, providing lower values of yield stress and apparent viscosity, and a reduction in specific energy consumption of 17.4%. So, sodium hydroxide, added at previous processing steps, has acted as a grinding aid. The addition of 300 g/t of lime caused an increase of 27% in specific energy consumption, with significant increase in yield stress and consistency index of the fluid, especially for the condition of 18 kWh/t. © 2013 Brazilian Metallurgical, Materials and Mining Association.

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