The quality of interfaces between reactive and inert textural componen
ts in cokes produced from three single coals with added petroleum coke
and calcined anthracite were quantified by microscopy and expressed a
s an interface quality index, IQI. For interfaces involving the three
inert components studied, the IQI decreased in the order: inherent ine
rts > petroleum coke > calcined anthracite. The IQI of interfaces invo
lving inherent inerts decreased in the presence of added inerts in the
coke, implying that the ability of a coal to bind inerts into the cok
e structure was shared between the two types of inerts.