Three kinds of superfine sodium bicarbonate explosion suppression powder were prepared from commercial BC dry powder with different process and surface modification. Scanning electron microscopy and laser particle analyzer were used to investigate the surface properties and particle size distributions. Preliminary suppression experiments on methane-air mixture explosion at chemical equivalent ratio were carried out with the prepared superfine sodium bicarbonate powder in 200 L chamber. The key physical parameters of the suppression powder such as particle size and distribution

surface area

and surface properties are improved significantly with two of the preparation processes. For the designed explosion suppressor with optimized parameters

the total spray time of the suppression powder is in the range of 12 ms and the maximum jet velocity can reach 5-15 m·s-1 at the opening pressure of diaphragm of 8 MPa. The efficiency of explosion suppression is not only related to the average particle size

the particle size distribution is also important

and powder with irregular surface shape can suppress the explosion more effectively. Compared to the normally commercially available BC powder

the ability of explosion suppression is improved eight to ten times when the powder is refined to the order of magnitude of ten micrometers.