Experimental study on explosion characteristics of epoxy electrostatic coating powder mixed with different proportions of calcium carbonate

Epoxy (EP) powder is widely used in the industrial field of electrostatic coating due to its excellent physicochemical properties. However, the dust explosion risk caused by its flammability cannot be ignored. Calcium carbonate (CaCO₃) is often added into EP as an inorganic fillers because of its low cost and wide availability. This study explores the effects of different proportions of CaCO₃ on the explosion characteristics and pyrolysis behavior of EP powder. The results show that the maximum explosion pressure (P_max), the minimum ignition energy (MIE), and the minimum ignition temperature (MIT) of EP are 6.82 bar, 6 mJ, and 460 °C, respectively. The addition of CaCO₃ reduces the explosion sensitivity and severity of EP dust to a certain extent. The thermal decomposition of CaCO₃ absorbs heat and produces CaO and CO₂. This process hinders the oxygen transfer, and dilutes the flammable volatiles, thereby reducing the explosion hazard of EP dust.