Tecnologia em Metalurgia, Materiais e Mineração
https://www.tecnologiammm.com.br/article/doi/10.4322/tmm.2012.024
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

INFLUÊNCIA DAS COMPOSIÇÕES QUÍMICA E MINERALÓGICA DE CINZAS DE MISTURAS DE CARVÕES PARA PCI NO COMPORTAMENTO DE FUSIBILIDADE E VISCOSIDADE A ALTAS TEMPERATURAS

INFLUENCE OF THE CHEMICAL AND MINERALOGYCAL ASH COMPOSITION OF COAL BLENDS FOR PCI IN THE BEHAVIOR OF FUSIBILITY AND VISCOSITY AT HIGH TEMPERATURES

Ghiggi, Maria Luisa F.; Osório, Eduardo; Vilela, Antônio Cezar F.; Barros, Ricardo José T.; Cruz Junior, Roberto da

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Resumo

As causas da deterioração da permeabilidade da carga no alto-forno sob taxas altas de injeção de carvão pulverizado ainda não são bem conhecidas. Sabe-se na prática operacional que variações na qualidade das cinzas dos carvões injetados podem afetar a estabilidade do forno. Trabalho anterior analisou o comportamento de cinzas de carvões a altas temperaturas em relação às suas composições químicas e mineralógicas. O objetivo deste trabalho foi avaliar o mesmo comportamento em misturas de carvões. Amostras de quatro carvões e sete misturas foram queimadas entre 800-850°C e suas cinzas analisadas por fluorescência e difração de raios X e por testes de fusibilidade e viscosidade. Cinzas com teores mais altos de Si e Al apresentaram alta temperatura de fluidez e maior viscosidade a 1.500°C, devido à grande proporção de mulita e à baixa basicidade. Cinzas com teores significativos de Fe, Ca e S apresentaram temperaturas de fluidez e viscosidade mais baixas, em função da transformação de mulita em anortita e/ou da mais alta basicidade.

Palavras-chave

Injeção de carvão pulverizado, Cinzas, Carvão, Fusibilidade, Viscosidade

Abstract

Some aspects of permeability deterioration in blast furnace process at high rates of pulverized coal injection are not well known yet. At operational practice variations in the ash quality of injected coals can affect the furnace performance. Previous work has investigated the behavior of individual coals ash at high temperatures in relation to the chemical and mineralogical compositions. This work aimed to assess this behavior for coal blends. Four coals and seven blends were selected and ashed at 800-850°C. The samples were analyzed by X-ray fluorescence and X-ray diffraction techniques and ASTM ash fusion (AFT) and viscosity tests were performed. Ash containing high contents of Si and Al showed higher fusion temperatures and higher viscosity at 1500°C, due mainly to the higher content of Mullite and to the low basicity, while those presenting significant contents of Fe, Ca and S had lower fusion temperatures and lower viscosity, due to the higher content of Anorthite and/or to the higher basicity

Keywords

Pulverized coal injection, Ash, Coal, Fusibility, Viscosity

Referências

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