With
expanded industrial-scale production of nanomaterials fast approaching,
scientists are reporting indications that dust generated during
processing of nanomaterials may explode more easily than dust from wheat
flour, cornstarch and most other common dust explosion hazards. Their
article in ACS’ journal Industrial & Engineering Chemistry Research
indicates that nanomaterial dust could explode due to a spark with only
1/30th the energy needed to ignite sugar dust—the cause of the 2008
Portwentworth, Georgia, explosion that killed 13 people, injured 42
people and destroyed a factory.
Paul
Amyotte and colleagues explain that dust explosions are among the
earliest recorded causes of industrial accidents—dating back to a 1785
flour warehouse disaster—and are still a constant threat at facilities
that process fine particles of various materials. Despite significant
research, there is still much for scientists to learn about the risks of
dust explosions in industry, especially of so-called “nontraditional”
dusts (such as those made of nanomaterials), and a constant threat
exists. That’s why the researchers decided to probe the explosibility of
three types of nontraditional dusts: nanomaterials; flocculent (fibrous
or fuzzy) materials used in various products, such as floor coverings;
and hybrid mixtures of a dust and a flammable gas or vapor.
After
reviewing results of studies that exist on the topic, the researchers
concluded that the energy needed to ignite nanomaterials made of metals,
such as aluminum, is less than 1 mJ, which is less than 1/30th the
energy required to ignite sugar dust or less than 1/60th the energy
required to set wheat dust aflame. Flocking is often made with a process
that generates static electricity, which could set off an explosion of
flocculent dust, they point out. And the addition of a flammable gas or
vapor to a dust as a hybrid mixture increases the chance that the dust
will explode. The researchers warn that precautions should be taken to
prevent these materials from exposure to sparks, collisions or friction,
which could fuel an explosion.
The authors acknowledge funding from the Natural Sciences and Engineering Research Council of Canada.
