ISSN 2594-357X
5º Simpósio Brasileiro de Minério de Ferro — Vol. 01 , num. 5 (2004)
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Abstract
Coking coal plasticity decreases during transport and stockpiling due to ageing. The effects of ageing are estimated using a range of plasticity measures and changes in these plasticity measures are commonly used to indicate that the coal will produce a coke of poorer quality. Commercial contracts may include penalties if the plasticity of a coal decreases below a specified limit. This study identified which coal plasticity measures best assess the change in coke quality due to ageing at room temperature of an Australian, high volatile coal. The influence of an aged coal, in a blend with fresh coals, was also assessed. Coal and coke properties were measured at various intervals, over a period of one year, as the coal aged. The aged coal was also blended with fresh coal, at the same intervals, to assess its effect on the coke properties of the blend. The cold strength of the cokes, produced from both the aged coal and the blend, as measured by various standard tests, remained constant over the duration of the study. This is despite a significant decrease in the plasticity measures; Gieseler plastometry and Ruhr dilatation, and the more recently developed, Proton Resonance Thermal Analysis (PMRTA). Gieseler fluidity and Ruhr dilatation decreased significantly before any change was observed in the hot strength of coke, produced from the aged coal, as measured by the Coke Strength after Reaction (CSR) test. The PMRTA results showed a correlation with the CSR of the coke produced from the aged coal. The effect of the progressive decrease in plasticity of the aged coal, on the CSR of the coke produced from the blend, was negligible. This study has shown that while there is a measurable and rapid decrease in fluidity and dilatation with both aged and blended coal there is not a corresponding decrease in the cold strength of the resulting coke.
Coking coal plasticity decreases during transport and stockpiling due to ageing. The effects of ageing are estimated using a range of plasticity measures and changes in these plasticity measures are commonly used to indicate that the coal will produce a coke of poorer quality. Commercial contracts may include penalties if the plasticity of a coal decreases below a specified limit. This study identified which coal plasticity measures best assess the change in coke quality due to ageing at room temperature of an Australian, high volatile coal. The influence of an aged coal, in a blend with fresh coals, was also assessed. Coal and coke properties were measured at various intervals, over a period of one year, as the coal aged. The aged coal was also blended with fresh coal, at the same intervals, to assess its effect on the coke properties of the blend. The cold strength of the cokes, produced from both the aged coal and the blend, as measured by various standard tests, remained constant over the duration of the study. This is despite a significant decrease in the plasticity measures; Gieseler plastometry and Ruhr dilatation, and the more recently developed, Proton Resonance Thermal Analysis (PMRTA). Gieseler fluidity and Ruhr dilatation decreased significantly before any change was observed in the hot strength of coke, produced from the aged coal, as measured by the Coke Strength after Reaction (CSR) test. The PMRTA results showed a correlation with the CSR of the coke produced from the aged coal. The effect of the progressive decrease in plasticity of the aged coal, on the CSR of the coke produced from the blend, was negligible. This study has shown that while there is a measurable and rapid decrease in fluidity and dilatation with both aged and blended coal there is not a corresponding decrease in the cold strength of the resulting coke.
Keywords
coal, ageing, coke
coal, ageing, coke
How to cite
Keating, Jeff; Mahoney, Merrick; Bas, Tony Le; Wilson, Belinda; McGuire, Sid; Sakurovs, Richard.
COAL FLUIDITY, STOCKPILING AND COKE QUALITY,
p. 761-770.
In: 5º Simpósio Brasileiro de Minério de Ferro,
None,
2004.
ISSN: 2594-357X, DOI 10.5151/2594-357x-5MinFe-761-770
