Investigation of sulfur powders self-ignition

During railway transportation of coma sulfur (GOST 127.1-93) cases of its spontaneous self-ignition and combustion take place. By long-lived statistical observation is established, that the spontaneous combustion happens irrespective of season, time of day and velocity of coaches. The fixed factor influencing frequency of fire of sulfur in coaches is its "dusting": formation of aerosols of sulfur. Probably, the ignition begins with the most small-sized fraction of a powder, then is spread to more coarse-dispersion part and on a massive part. Samples of sulfur powder were tested. As a result, it is found that the spontaneous combustion of powdery sulfur in air demands the presence of exothermic reactions-initiators of combustion. In the case of "pure" sulfur such responses are not revealed. It is probable, that the ignition happens due to participation of attendant reactants-junctions of iron.