Mean Coke Size – the arithmetic mean size of the coke, determined by hand sizing the coke over a specified series of screens. Generally, the larger the coke the better. A narrow size distribution is also desirable.

Japanese Drum Test – a 10kg representative sample of the +50mm square hole coke is placed in the specified tumble drum and rotated for 30 revolutions, removed, screened and replaced in the drum and subjected to a further 150 revolutions. The drum contains lifters that raise the coke and allow it fall so that it undergoes a large number of impacts with the drum walls. The test is based on the Japanese Industrial Standard JIS K2151. A number of indices can be measured. The two reported in this study are

For these indices, the larger the number, the stronger the coke. This test is commonly used in Japan to evaluate coke strength.

Combined Half Micum / Irsid Test – a 25kg representative sample of the +20mm round hole coke is placed in the specified tumble drum and rotated for 100 revolutions. The coke is removed, screened and replaced in the drum and subjected to a further 400 revolutions in the drum. The test is based on the ISO 556 standard.

Larger values of M40 and I20 and smaller values of M10 and I10 generally indicate strong coke. This test is commonly used in Europe to evaluate coke strength.

ASTM Tumbler Test – a 10kg representative sample of the –75mm +50mm square hole coke is placed in the specified tumble drum and rotated for 1400 revolutions. The test is based on the American standard ASTM D 3402.

Generally the higher both indices the stronger the coke. The test is commonly used in North America to evaluate coke strength.