One of the main questions asked about nanopowders, when it comes to explosivity and flammability, is: Do nanopowders behave like other powders and, as such, can they more readily ignite and explode? During this study, carried out in the frame of the European Nanosafe2 project, safety parameters of nanopowders and their associated techniques and practices have been characterised for a representative set of particles of industrial relevance.
Main results
New confined stainless steel Hartmann tube and falling hammer equipment help bring experiments to a higher degree of safety and efficiency
- Lesson: Studied carbon nanotubes exhibit explosion severities and sensitivities of the same order as those found for various coals, food flours and other nanostructured carbon blacks.
- Lesson: For metallic aluminum nanopowders, the small oxyde layer wrapping passivated nanoparticles may make them less explosible than micropowders.
- Lesson: Nanopowders which tend to agglomerate show explosion violence characteristics of the same order as those observed with micropowders of the same substance.
- Lesson: Onset temperature of carbon materials strongly depends on the specific surface area of those materials.
- Warning: For aluminum, combustion mechanisms of nanosized particles are different from those observed with microsized particles. This may lead to potential problems of large scale industrial storage of such particles.
- Advice: Specific prevention and protection measures should then be taken.