Frequent dust explosion incidents have gradually drawn attention to the study of dust explosions. Dust explosion refers to the ignition of combustible dust when the dust cloud concentration reaches a certain level, encountering an ignition source. The flame rapidly propagates throughout the mixed dust space, simultaneously releasing a large amount of heat, generating high temperature, high pressure, and converting the system's energy into mechanical energy, as well as radiation of light and heat. This process is highly destructive, and the explosion is accompanied by the release of toxic and harmful gases.

The basic principles of dust explosion are as follows: 1) Dust particles on the surface, through heat conduction and thermal radiation, acquire ignition energy from an ignition source, causing a rapid increase in surface temperature. This temperature rise reaches the accelerating decomposition temperature or evaporation temperature of the dust particles, leading to the formation of dust vapor or decomposition gases. 2) The dust vapor or gases produced by dust decomposition mix with air, forming an explosive mixture that can be ignited. 3) Dust particles themselves, from the surface to the interior (until the particle's center), undergo successive melting and vaporization. Tiny sparks erupt, serving as ignition sources for the surrounding unburned dust, causing the dust to ignite and thereby expanding the range of the explosion flame.

Particle size is one of the significant influencing factors on the sensitivity and severity of dust explosions. Because the majority of dust particles are not spherical and have non-smooth surfaces, a simple particle size distribution test is insufficient to explain their impact on the characteristic parameters of dust explosions. Therefore, characterizing the physical properties of dust surfaces by testing specific surface area holds great significance in the field of dust explosion research.

In a study on the characteristics of coal dust explosions and corresponding explosion suppression techniques, the specific surface area and pore size of coal samples from the researched mine were characterized. The research indicates that as the dust specific surface area increases, the rates of heat conduction and thermal radiation accelerate, making it easier to generate volatile fractions and form explosive gas sources. Additionally, a larger specific surface area implies a greater contact area between the dust material and air, speeding up the reaction between the dust surface and oxygen. This increases the chemical reactivity of the dust, resulting in faster combustion and higher explosiveness after ignition.

Our laboratory conducted specific surface area measurements on several explosive dust types, as shown in Table 1. It is evident that, for the same type of dust, factors such as origin, type, production batch, and particle size are important influencing factors for specific surface area. Since a simple particle size distribution test cannot accurately characterize dust surface properties, specific surface area testing has become an indispensable tool in the field of dust explosion research to more accurately characterize the surface physical properties of the dust under study.

Table 1: Results of Specific Surface Area Measurements for Some Combustible Dusts

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