Assessment of Some Nigerian Coals for Metallurgical Application

In the quest for a search of a suitable coal deposit of metallurgical importance, the qualities of three Nigerian coal samples, Lafia-Obi, Doho and Lamja, were assessed for possible utilization in metallurgical coke production. Several parameters that determine coking quality, such as moisture content, ash, volatile matter, free swelling index, sulphur content, Gray-King coke test, dilatation and plasticity (fluidity), were investigated. Lafia-Obi has the lowest moisture and volatile matter and the highest fixed carbon content. Its ash and sulphur contents are greater than that required by a coking but washing prior to use is expected to improve it. The volatile matter places Lafia-Obi in the medium-volatile bituminous rank, while Lamja and Doho are of medium-volatile bituminous rank. The rheological properties show that Lafia-Obi is the only caking coal. This put together single out Lafia-Obi as a potential candidate for coke making. Doho and Lamja coals may be useful for steam raising, liquefaction or chemicals manufacture.