Feasibility of Producing Char for Metallurgical Applications from the Pyrolysis of Collie Coal Briquettes
Rapid depletion in coking coal reserve has been driving considerable R&D efforts to develop new technology of utilising non-coking coals for the production of metallurgical reductant. Collie coal is the only coal currently being mined in Western Australia (WA) and has a great potential to widen its applications in metallurgical industries. However, such applications are currently limited because Collie coal is a high moisture sub-bituminous coal of a non-coking nature. This study investigates the feasibility to use char produced from Collie coal briquettes for metallurgical applications. Pyrolysis of Collie coal briquettes was carried out in a laboratory furnace at temperatures of 500-1000oC and a slow heating rate (10 K/min). The briquette char yield and reactivity decreases with increasing pyrolysis temperature. The strength of briquette char also increases with pyrolysis temperature. Depending on pyrolysis temperature, the char produced from Collie coal briquette has a low ash content (<12.5 %), a low sulphur content (<1.0 %), a mechanical strength of 14-17MPa, and reactivity of 28-40% (ECE-INCAR reactivity test). Therefore, char produced from Collie coal briquette has the potential to be a good metallurgical reductant as it broadly meets the general requirements of a good metallurgical reductant, which should have a low ash content (<15%), a low sulphur content (<1.5%), a high mechanical strength (15-30MPa), a reactivity towards CO2 of 10-28%.