hargrove grindability index

abbr. HGI

A measure of the relative hardness of the coke in terms of resistance to grinding. An HGI below 35 usually means a very hard coke requiring considerable grinding before it can be properly sized to meet burner nozzle specifications for the pulverized feed to the furnace where the coke will be burned. An HGI above 65 is usually recognized as a soft coke that will grind very easily.