Effects of Simple and Complex Minerals in the Alumina-Silica-Magnetite Ternary System on Coke Analogue Reactivity

Abstract

The effect of combinations of minerals in the alumina-silica-magnetite ternary system on the reactivity of coke analogues with CO₂ at 1100°C in a pseudo-CRI test. The reactivity of coke analogue was found to be largely linearly related to the proportions of each mineral in the alumina-quartz-magnetite ternary system. It was found that quartz decreased the reactivity of the coke analogue, alumina had little effect, while magnetite increased the reactivity. The effect of minerals in the pseudo-binary combinations of mullite-magnetite and kaolinite-magnetite was found to be similar to the effect of the simple alumina-quartz-magnetite ternary combination with the equivalent composition, i.e. the minerals of different phases but the same composition had the same effect on the reactivity of the coke analogue. Pre- and post-experimental characterisation confirmed the mineral (aluminosilicates, quartz and alumina) phase did not change and that they remained as separate particles. It was also shown the effect on minerals with compositions in the alumina-silica-magnetite system on coke reactivity can be considered to be linearly related to the composition of the coke mineral. As such, the reactivity of coke under CRI conditions may be predicted based on a simple ash composition analysis for the alumina-silica-magnetite ternary system. This supports the often used practice of using relations between reactivity and coke ash composition for the prediction of measures of coke performance such as CRI, for minerals in the alumina-silica-magnetite system.