Influence of Mineral Matter on Coke Reactivity with Carbon Dioxide

Abstract

A method to improve blast furnace efficiency and make it sustainable is to lower the temperature of the iron oxide reduction using a highly reactive coke. Understanding the role of coal rank, maceral composition and mineral matter in coke in the gasification reaction under these new conditions is of major importance. Four cokes prepared from Australian coals of varying rank, maceral composition and ash composition were gasified with carbon dioxide. The rank and maceral composition of the parent coals did not appear to be related to the reactivity of the cokes. However, coke reactivity increased with increasing total amount of catalytic minerals in crystalline phases such as metallic iron, iron sulfides. Calcium sulfide could be a potential catalyst for the gasification reaction. Iron, potassium and sodium present in the amorphous phase did not appear to have any effect on coke reactivity. Calcium was present only in the crystalline phases. Knowing the form and amount of the mineral phases that catalyse the gasification reaction in coke would improve the ability to predict coke reactivity. This knowledge would contribute to more efficiently matching cokes to blast furnace requirements.