The HGI is used to predict the ranking of raw petroleum cokes or calcined petroleum cokes in industrial size mills used for crushing operations. The rankings are based on energy required and feed rate or both.

The HGI is also used to select raw petroleum cokes and coals that are compatible with each other when milled together in a blend so that segregation of the blend does not occur during particle size reduction.

1.1 This test method covers the determination of the hardgrove grindability index (HGI) of those petroleum cokes that contain no dedusting additive. The procedure for this test method is the same as in Test Method D409. Sections of this test method contain the significance and use of the HGI of petroleum coke, preliminary sample preparation procedures, and procedure and precision and bias data specific to petroleum coke.

Note 1—The size consistency (particle size distribution) of fluid petroleum coke is generally 100 % passing a 6.73 mm (No. 3) sieve and greater than 80 % passing a 2.00 mm (No. 10) sieve. Much of fluid cokes will pass a 0.59 mm (No. 30) sieve. Because of this fineness the HGI value is related to the coarser particles in fluid coke and large samples are required to prepare sufficient material of the correct particle size for Test Method D409.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.2.1 Exception—Hardgrove grindability index is unitless.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.