Title

A PROPOSED PROCEDURE FOR COAL EVALUATION ACCORDING TO RANK AND RHEOLOGICAL PROPERTIES

A PROPOSED PROCEDURE FOR COAL EVALUATION ACCORDING TO RANK AND RHEOLOGICAL PROPERTIES

Authorship

ULHÔA, MURILO BOTELHO

ULHÔA, MURILO BOTELHO

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DOI

10.5151/2594-357x-5MinFe-1031-1050

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Abstract

All types of coals inserted on the coking coals range, having or not adequate chemical characteristics, may be used as elements of the multi-component coal blends nowadays used for blast furnace coke making. The rank of coal and its caking ability are the dominant factors governing its amount in the coal blend. Coals can be ranked more properly by the reflectance. Broadly speaking is possible to say that mean rank coking coals - coals with mean random reflectance near the limits nowadays defined for coal blends reflectance (1.25% to 1.35%) - can be used to produce the best coke (since that sufficient plastic mass is provided) and the further way the coal vitrinite types are from these limits mainly if the coal mean reflectance is lower than 0.90% or higher than 1.70%, the less suitable it is. The use of an individual coal is more difficult if it has low caking ability for any given rank. Considering that: i) the volatile matter is not an accurate parameter for the evaluation of rank of coal mainly when we consider coking coals from different sources and ii) to measure the caking ability the methods adopted should assess as simply as possible the behaviour of coal during the coking process, a procedure for individual coal evaluation, based mainly on the measurement of rank of coal by mean random reflectance and caking ability by Gieseler plastometry, is suggested.

All types of coals inserted on the coking coals range, having or not adequate chemical characteristics, may be used as elements of the multi-component coal blends nowadays used for blast furnace coke making. The rank of coal and its caking ability are the dominant factors governing its amount in the coal blend. Coals can be ranked more properly by the reflectance. Broadly speaking is possible to say that mean rank coking coals - coals with mean random reflectance near the limits nowadays defined for coal blends reflectance (1.25% to 1.35%) - can be used to produce the best coke (since that sufficient plastic mass is provided) and the further way the coal vitrinite types are from these limits mainly if the coal mean reflectance is lower than 0.90% or higher than 1.70%, the less suitable it is. The use of an individual coal is more difficult if it has low caking ability for any given rank. Considering that: i) the volatile matter is not an accurate parameter for the evaluation of rank of coal mainly when we consider coking coals from different sources and ii) to measure the caking ability the methods adopted should assess as simply as possible the behaviour of coal during the coking process, a procedure for individual coal evaluation, based mainly on the measurement of rank of coal by mean random reflectance and caking ability by Gieseler plastometry, is suggested.

Keywords

blast furnace coke, rank of coal, Gieseler fluidity coke texture, coke strength, coke strength after reaction

blast furnace coke, rank of coal, Gieseler fluidity coke texture, coke strength, coke strength after reaction