Abstract
Due to enlargement, stabilized and efficient operation of blast furnaces (BF), cokes with high strength have been required in BF in recent years. Recently, on the coke reactivity with carbon dioxide, it is reported that high reactive cokes can improve the reduction of iron ore in BF and reduce carbon dioxide emissions from BF. These coke strength (DI) and coke reactivity (CRI) have been primarily controlled by the blending operation of coals in coke production. However, it is difficult to get the cokes which possess both high DI and high CRI, because the blending operation for increasing DI usually results in the decrease of CRI. To get high DI, we investigated the effect of coating on coke with polyvinyl alcohol (PVA) on coke strength. Coke particles were dipped into the PVA aqueous solution and dried out. DI and CRI/CSR of the PVA coated coke prepared by the above method were measured. Those results showed that 0.011 g/g-coke PVA coating on the surface of the coke resulted in the increase of the DI by 4.2 points and no change in the CRI/CSR values. It may be possible to control the coke strength (DI) and the coke reactivity (CRI) independently without any change of coal blending by using our new method.
