Partial briquetting vs direct addition of biomass in coking blends

• Briquettes containing sawdust were used for metallurgical coke preparation.
• Partial briquetting compensates for lower sawdust bulk density.
• Inclusion of coking coal in briquettes helps to integrate sawdust in the coke matrix.
• Additions of 10–15 wt.% of briquettes can be used depending on the base coal.

In this work partial briquetting is employed as a means of biomass densification to allow for biomass inclusion in coking coal blends. The effect of increasing the bulk density was evaluated by comparison with direct addition. Two briquettes of different composition were studied. The influence of the briquettes on the Gieseler plasticity of the coals was determined. It was found that the effect of the binder was not enough to compensate for the decrease in plasticity produced by the inert components of the briquettes. Carbonizations were carried out in a movable wall oven of 17 kg capacity and the quality of the cokes produced was tested by evaluating their mechanical strength, coke reactivity to CO2 and post-reaction strength. In addition, the porosity and ash chemistry of the cokes was determined and an attempt was made to establish a relation between these results and the quality of the cokes. Coke quality results suggest that 10–15 wt.% of briquettes containing biomass can be included in coking blends.