Method for evaluating thermal plasticity of coals and caking additives, and method for producing coke

A method for evaluating thermal plasticity of coals and caking additives, comprising:

• packing a coal or a caking additive into a vessel to prepare a sample,
• arranging a through-hole material having through-holes from top to bottom surfaces, onto the sample,
• heating the sample while maintaining the sample and the through-hole material in a constant volume,
• measuring the pressure of the sample that is transmitted via the through-hole material, and
• evaluating thermal plasticity of the sample using the measured value.

A method for evaluating thermal plasticity of coals and caking additives, comprising:

• packing a coal or a caking additive into a vessel to prepare a sample,
• arranging a through-hole material having through-holes from top to bottom surfaces, onto the sample,
• heating the sample while applying a constant load onto the through-hole material,
• measuring the permeation distance with which the molten sample has permeated into the through-holes, and
• evaluating thermal plasticity of the sample using the measured value.

A method for evaluating thermal plasticity of coals and caking additives, comprising:

• packing a coal or a caking additive into a vessel to prepare a sample,
• arranging a through-hole material having through-holes from top to bottom surfaces, onto the sample,
• heating the sample while applying a constant load onto the through-hole material,
• measuring the swelling coefficient of the sample, and
• evaluating thermal plasticity of the sample using the measured value.

A method for producing coke, comprising:

• measuring the permeation distance, which is a thermal plasticity of coal, with respect to a coal or coals to be added to a coking coal blend that have a logarithmic value of Gieseler maximum fluidity, log MF, of not less than 3.0;
• wherein the step of measuring the permeation distance includes,
• packing the coal or coals to be added into a vessel to prepare a sample,
• arranging a through-hole material having through-holes from top to bottom surfaces, onto the sample,
• heating the sample while maintaining the sample and the through-hole material in a constant volume or while applying a constant load onto the through-hole material, and
• measuring the permeation distance with which the molten sample has permeated into the through-holes;
• based on a weighted-average value of the measured permeation distance(s), determining the blend ratio of the coal(s) having a logarithmic value of Gieseler maximum fluidity, log MF, of not less than 3.0;
• and
• carbonizing coals that have been blended according to the determined blend ratio.

A method for producing coke, comprising:

• determining beforehand brands of coals or caking additives to be added to a coking coal blend, as well as the total blend ratio of a coal or coals with log MF of less than 3.0 relative to the coal blend,
• measuring the permeation distance with respect to a coal or coals having a logarithmic value of Gieseler maximum fluidity, log MF, of not less than 3.0, among the coals to be added to the coking coal blend;
• wherein the step of measuring the permeation distance includes,
• packing the coal or coals to be added into a vessel to prepare a sample,
• arranging a through-hole material having through-holes from top to bottom surfaces, onto the sample,
• heating the sample while maintaining the sample and the through-hole material in a constant volume or while applying a constant load onto the through-hole material, and
• measuring the permeation distance with which the molten sample has permeated into the through-holes;
• determining a relationship between the weighted-average permeation distance of the coals or caking additives with log MF of not less than 3.0 that are to be added to the coal blends, and
• the coke strength obtained with the coal blends prepared while changing the proportions of the individual brands of coals, the relationship being obtained by changing the proportions of the individual brands of coals or caking additives with the total blend ratio of the coal or coals with log MF of less than 3.0 being kept constant relative to the coal blend;
• and
• adjusting the weighted-average permeation distance by controlling the brand and the proportion of the coal(s) with log MF of not less than 3.0 so as to achieve coke strength that is not less than a desired value.