ISO 502:1982

Coal — Determination of caking power — Gray-King coke test

The sample is heated under standard conditions to a final temperature of 600 C. The coke residue obtained is classified by reference to a series of standard residues. If the coke residue produced is so swollen that it fills the crosssection of the retort tube, the determination is repeated with the coal admixed with a suitable quantity of electrode carbon or equivalent material.