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

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.