Quality of some Nigerian coals as a blending stock in metallurgical coke production.
Two Nigerian coals, Lafia-Obi and Chikila were blended in the mass ratio of 70:30 with imported American and Polish coking coals. Proximate analysis, free swelling index, Ruhr dilatometer and Gieseler plastometer were used in accessing the coking qualities of both the single coals and the blends. The results showed that the blends are lower in moisture and ash contents; higher in volatile matter and fixed carbon than the single Nigerian coals. The rheological parameters revealed superiority in thermo-plastic properties of the blends over the unblended local coals. Lafia- Obi/foreign coals blends possess lower ash and better rheological properties compared to Chikila/foreign coal composites which have high ash and poor rheological properties. These together suggest that amongst the two Nigerian coals, Lafia-Obi is superior for blending with the foreign ones in metallurgical coke making.