PARÂMETROS TERMODINÂMICOS E CINÉTICOS DE MISTURAS DESSULFURANTES À BASE DE CaO, MgO, SiO2 E CaF2
THERMODYNAMIC AND KINETIC PARAMETERS OF MIXTURES DESULFURIZING THE MADE WITH CaO, MgO, SiO2 AND CaF2
Aguiar, Felipe Nylo de; Oliveira, Heitor Cristo C. de; Nascimento, Ramiro da Conceição; Oliveira, José Roberto de
http://dx.doi.org/10.4322/tmm.2012.034
Tecnol. Metal. Mater. Min., vol.9, n3, p.242-249, 2012
Resumo
Este trabalho apresenta uma análise cinética e termodinâmica da utilização de misturas à base de resíduo de mármore na dessulfuração de ferro-gusa. Para a realização da dessulfuração foram utilizados: cal, resíduo de mármore, fluorita e ferro-gusa. Diferentes misturas destes materiais foram adicionadas em um banho de ferro-gusa a 1.450°C. Amostras do metal foram retiradas através de amostradores a vácuo nos tempos de 5, 10, 15, 20 e 30 minutos e feitas suas análises para checar a variação de enxofre. Com base nos resultados das análises químicas do metal e da mistura dessulfurante utilizadas, são calculados a capacidade de sulfeto das misturas, o coeficiente de partição de enxofre e os valores do coeficiente de transporte de massa do enxofre. Os resultados obtidos mostram a viabilidade técnica da utilização do resíduo como agente dessulfurante.
Palavras-chave
Resíduo de mármore, Fluorita, Dessulfuração de ferro-gusa
Abstract
This paper presents an analysis of the kinetics and thermodynamics of marble residue mixtures utilisation on desulfurization of pig iron. The desulfurization was carried out using lime, marble residue, fluorite and pig iron. Different mixtures of these materials were added into a bath of pig iron at 1,450°C. Metal samples were collected via vacuum samplers at times of 5, 10, 15, 20 and 30 minutes, in order to check the variation of sulfur content. Based on the results of chemical analysis of the metal and the desulfurizer mixture, the sulfide capacity of mixtures, the sulfur partition coefficient and the sulfur mass transport coefficient values were calculated.The results show the technical feasibility of using marble waste as desulfurizer agent.
Keywords
Marble waste, Fluospar, Hot metal desulphurization
Referências
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2 YOUNG, R. et al. Use of optical basicity concept for determining phosporus and sulphur slag-metal partitions. Ironmaking and Steelmaking, v. 19, n. 3, p. 201-19, 1992.
3 SHEVCHENKO, A.; KIYASHKO, A.; MAL’KOV, A. Influence of particle size of lime on effectiveness of pig iron desulphurization. Steel in the USSR, v. 14, n.3, p. 116-117, 1984.
4 GHOSH, A. Secondary steelmaking: principles and applications. Boca Raton: CRC, 2001. p. 180, 184, 198.
5 NITA, P. Evaluation of some self-sustained capillary effects taking place in slag at the interface during desulphurization process. Materials Science and Engineering A, v. 495, n. 1-2, p. 320-25, Nov. 2008. http://dx.doi. org/10.1016/j.msea.2007.12.048
6 CHUSHAO, X.; XIN, T. The kinetics of desulfurization of hot metal by CaO-CaF2 based fluxes. ISIJ International, v. 32, n. 10, p. 1081-3, 1992.
7 OHYA, T. Desulfurization of hot metal with burnt lime. Steelmaking Proceedings. v. 60, p. 345-55, 1977.
8 NIEDRINGHAUS, J. C.; FRUEHAN, R. J. Reaction mechanism for the CaO-Al and CaO-CaF2 desulfurization of carbon-saturated iron. Metallurgical Transactions B, v. 19, n.2, 261-8, Apr. 1988. http://dx.doi.org/10.1007/ BF02654211
9 MITSUO, T. et al. Improvement of desulfurization by addition of aluminum to hot metal in the lime injection process. Transactions of the Japan Institute of Metals, v. 23, n. 12, p. 768-79, 1982.
10 RIBEIRO, D. B.; QUINTÃO, H. A.; CRUZ, C. A. Refino secundário dos aços. São Paulo: Associação Brasileira de Metalurgia e Materiais, 2008.