Pyrophoricity

Source: Wikipedia, the free encyclopedia.

A substance is pyrophoric (from

Class D fire extinguishers are designated for use in fires involving pyrophoric materials. A related concept is hypergolicity
, in which two compounds spontaneously ignite when mixed.

Uses

The creation of

firesteel; the flintlock mechanism in firearms; and spark testing
ferrous metals.

Handling

Small amounts of pyrophoric liquids are often supplied in a glass bottle with a

polytetrafluoroethylene-lined septum. Larger amounts are supplied in metal tanks similar to gas cylinders, designed so a needle can fit through the valve opening. A syringe, carefully dried and flushed of air with an inert gas
, is used to extract the liquid from its container.

When working with pyrophoric solids, researchers often employ a sealed glove box flushed with inert gas. Since these specialized glove boxes are expensive and require specialized and frequent maintenance, many pyrophoric solids are sold as solutions, or dispersions in mineral oil or lighter hydrocarbon solvents, so they can be handled in the atmosphere of the laboratory, while still maintaining an oxygen- and moisture-free environment. Mildly pyrophoric solids such as lithium aluminium hydride and sodium hydride can be handled in the air for brief periods of time, but the containers must be flushed with inert gas before the material is returned to the container for storage.

Pyrophoric materials

Solids

Liquids

hypergolic with oxidants like dinitrogen tetroxide or hydrogen peroxide
, but not truly pyrophoric.

Gases

Explanatory notes

  1. ^ Phosphine, PH3 is only pyrophoric if impure, with P2H4 present.

References

  1. ^ GHS, seventh revised version. https://www.unece.org/fileadmin/DAM/trans/danger/publi/ghs/ghs_rev07/English/ST_SG_AC10_30_Rev7e.pdf
  2. ^ a b c Angelo & Subramanian (2008), Powder metallurgy: science, technology and applications, p. 48, Powders of aluminium, iron and magnesium are highly pyrophoric in nature
  3. ^ C.W. Corti et al. / Applied Catalysis A: General 291 (2005) 257
  4. ^ Pyrophoric lead composition and method of making it
  5. .
  6. ^ DOE | Office of Health, Safety and Security | Nuclear Safety and Environment | Uranium Archived 2015-02-21 at the Wayback Machine, retrieved 3 September 2013; archived on 24 August 2010.
  7. ^ DOE | Office of Health, Safety and Security | Nuclear Safety and Environment | Plutonium Archived 2015-02-21 at the Wayback Machine, retrieved 3 September 2013; archived on 28 September 2010.

External links