The Effects of Ash Minerals on Coke Reactivity at High Temperatures

An investigation into how coke mineralogy affects coke reactivity has been carried out with a view to better understand the use of CRI data in predicting coke performance in a blast furnace. This was carried out by reacting coke and coke analogue samples under pseudo-CRI conditions and at higher temperatures and gas compositions more representative of the lower zone of a blast furnace.

Two cokes from the ACARP coal bank were studied, a high iron coke 131-K-001 and a high silica coke 114-K-001, along with coke analogue samples that had a mineral component derived from ashing the ACARP coal bank cokes or specific minerals (quartz, magnetite alumina and troilite). Three temperature and gas compositions were used that represented different parts of the blast furnace. 1100°C, 100% CO2 replicated the conditions of the CSR/CRI test, and can be considered representative of the blast furnace stack, while 1350°C, 39% CO-2% CO2-59% Ar and 1600°C, 40%CO-60% Ar were representative of the cohesive zone and hearth respectively in the blast furnace.

The primary output of this study was the characterisation of effects of minerals on coke reactivity and changes in coke carbon structure under blast furnace like conditions, relative to what the coke undergoes in a CRI test.  The main findings are described in the project report.

Further work currently being undertaken in an extension to this project which is due to be completed mid-2022.