Attempts to produce blast furnace coke from Victorian brown coal. 4. Low surface area char from alkali treated brown coal

•Alkali treated coal became plastic during carbonization.•The treatment could give a low surface area product.•Product reactivity was relatively low, but higher than for a blast furnace coke.•Product reactivity decreased with increase in the amount of graphitic structure.•The product had a small macropore volume and a smooth surface.

A Victorian brown coal (VBC) has been heated with strong aqueous KOH under severe conditions, neutralized with dilute H2SO4 and then hot-briquetted with or without coking coal tar pitch as a binder, optionally air cured and finally carbonized. The final products were evaluated as a blast furnace (BF) coke substitute. The least reactive final product had a much lower reactivity than the product obtained by carbonizing a hot-briquetted VBC-VBC tar mixture. Furthermore, the final product obtained from alkali treated coal had a surface area as low as that of a BF coke. However, the reactivity remained higher and the amount of graphitic structure lower than those of a BF coke. In addition, although the coal/coal-binder mixture, like coking coal, appeared to have fused during carbonization, the final products had virtually no meso + macropore volume, in contrast to a typical BF coke.