Preparation and characterization of NaAl(OH)2CO3 dry powder extinguishing agent with environmentally friendly and extinguishing efficiency

A novel type of ABC dry powder fire-extinguishing agent, alkaline sodium aluminum carbonate (NaAl(OH) 2 CO 3 ) dry powder fire-extinguishing agent, which is phosphorus-free and halogen-free, was investigated. In Class A and B fire tests, NaAl(OH) 2 CO 3 extinguishing agent (Na-DW) is able to extinguish Class A and B fires within 3.2 s and 0.34 s, respectively, and is 25.6% and 30.6% faster than common ABC extinguishing agent at 0.4 MPa, respectively. To explore its firefighting mechanism, the thermal decomposition of NaAl(OH) 2 CO 3 was analyzed. The pyrolysis of NaAl(OH) 2 CO 3 can be divided into two stages and stage 1 ( E = 309.5 kJ mol −1 ) can be characterized by the diffusion model g ( α ) = (1 − α ) −3 –1. Throughout the pyrolysis, the products CO 2 and H 2 O in the gas phase are generated, which play a crucial role during fire extinguishing. In addition, consistent with common ABC extinguishing agents, the presence of NaAlO 2 and oxides of Al in the condensed phase in the char layer of Class A fires confirms that Na-DW can also form an insulating layer, which can act as a barrier to barrier flame retardant and firefighting. Graphical abstract