The explosion suppression effects of added limestone dust on minimizing the risk of dust explosions in the printer cartridge recycling installation

Experimental investigations of explosive properties have confirmed that toner powder presents a significant explosion hazard. Existing explosion protection systems are mainly based on complex detection mechanisms and mitigation of the consequences of an explosion event. This study presents an explosion suppression approach employing inert dust, demonstrated using a small-scale recycling facility for spent laser printer cartridges as a case study. The scope of work encompassed a detailed operational analysis of the facility, identification of explosion hazard areas and zones, followed by laboratory-scale experiments and full-scale on-site tests. The aim of this study is to assess the possibility of using inert material to neutralize the explosive properties of toner powder. In this case, calcium carbonate dust was chosen as an inert material. Furthermore, the mechanism of explosion suppression by inert dust was examined using TGA/DSC analyses. The results demonstrated that explosions in the recycling installation can be eliminated by continuous dosing of inert material. The explosion inhibition effect achieved exceeded 90 %, confirming the effectiveness of inert dust as a suppression medium. Analysis of the suppression mechanism revealed that the calcination of calcium carbonate generates products that enhance the suppression effect and significantly limit explosion propagation. • Minimizing the risk of toner powder explosions in the recycling installation. • Neutralization of the explosive dust properties by adding inert CaCO 3 . • Explosion parameters of toner powder and toner powder-inert material blends. • Possibility of complete neutralizing the explosive properties of the toner powder. • Explosion suppression mechanism using inert materials.