<![CDATA[Corn cob is an abundant agricultural residue in Indonesia that is still underused, and binderless densification offers a route to convert it into a solid fuel. This study examined the physical quality of binderless corn cob briquettes and its relationship with calorific value. Corn cobs were chopped, sieved through a 30-mesh sieve (about 0.595 mm), oven-dried, and hot-pressed (15 g per briquette, 15 min holding time) at 250 and 270 °C under 3, 5, and 10 MPa, producing six briquettes. Appearance, mass yield, density, moisture content, and surface morphology (SEM) were evaluated, while elemental composition (EDS) and calorific value (bomb calorimeter) were determined for the 250 and 270 °C conditions. Briquettes pressed at 5 MPa were sturdy, those at 3 MPa were brittle, and those at 10 MPa showed cracks. Mass yield ranged from 76.53% (250 °C, 3 MPa) to 36.60% (270 °C, 10 MPa), density from 0.855 to 1.202 g/cm³, and moisture content from 3.36 to 3.64%. Calorific value increased from 18,286 J/g at 250 °C to 20,746 J/g at 270 °C (+13.45%), accompanied by an increase in surface carbon from 48.48% to 51.47% and a decrease in oxygen from 44.68% to 42.23%. The higher calorific value was not accompanied by higher density or lower moisture content. Because each condition was represented by a single briquette and calorific value was measured at two temperatures only, these results indicate trends rather than statistically tested relationships; replicated tests are recommended.]]>
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