Observations on the coke air reactivity test

Abstract

The ISO Coke Air Reactivity test has been used by the smelting industry for many years but its use as a calcined coke specification is decreasing. This paper presents a review of previous work published on this test and presents experimental data on a wide range of cokes currently being used for anode production. Coke air reactivities are strongly dependent on coke calcination levels and it is possible to drive air reactivities lower by increasing calcining temperatures. With the general increase in sulfur level of high sulfur cokes used in anode coke blends, higher calcining levels are not desirable due to their negative influence on coke porosity as a result of thermal desulfurization. Many smelters are now adopting lower real density specifications, which runs counter to achieving the low coke air reactivities required to meet coke air reactivity specifications.