Manufacturing and testing of briquettes from inertinite-rich low-grade coal fines using various binders

Inertinite-rich, low-grade coal was used with 12 binders: clays (attapulgite and bentonite), biochar, cow dung, crystallized medium-tar pitch, coal tar sludge, flocculant, fly ash, lignosulphonates, polyester resin, and two South African coal tar pitches in order to produce mechanically strong and water-resistant briquettes. The binders were added in concentrations of 2.5, 5, 7.5, and 10 mass%, and the compressive strength, cohesiveness, and water resistance of the resultant briquettes were determined. The briquettes manufactured using lignosulphonate and resin as binders were the strongest, with compressive strengths of 16 and 12 MPa respectively at a 7.5 mass% binder. Cured and uncured, with and without binder addition, the briquettes all retained their shape and size during drop tests, but none proved to be water-resistant. Paraffin and wax were therefore used as waterproofing agents after pressing and curing. These briquettes showed sufficient strength, cohesiveness, and water resistance to be considered for industrial application.