Sprengel explosives are a generic class of materials invented by

Hermann Sprengel Hermann Sprengel FRS (29 August 1834 – 14 January 1906) was a German-British chemist who discovered the explosive nature of picric acid in 1873, patented safety explosives and invented the mercurial air pump. Life He was born at Schille ...

in the 1870s. They consist of stoichiometric mixtures of strong oxidisers and reactive

fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but ...

s, mixed just prior to use in order to enhance safety. Either the oxidiser or the fuel, or both, should be a liquid to facilitate mixing, and intimate contact between the materials for a fast

reaction rate The reaction rate or rate of reaction is the speed at which a chemical reaction takes place, defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit ...

. Sprengel suggested

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...

nitrate Nitrate is a polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zer ...

s and

chlorate The chlorate anion has the formula ClO3-. In this case, the chlorine atom is in the +5 oxidation state. "Chlorate" can also refer to chemical compounds containing this anion; chlorates are the salts of chloric acid. "Chlorate", when followed by ...

s as oxidisers, and

nitro Nitro may refer to: Chemistry *Nitrogen, a chemical element and a gas except at very low temperatures, with which many compounds are formed: **Nitro compound, an organic compound containing one or more nitro functional groups, -NO2 **Nitroalkene, ...

aromatic In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to satur ...

s (e.g.

nitrobenzene Nitrobenzene is an organic compound with the chemical formula C6H5 NO2. It is a water-insoluble pale yellow oil with an almond-like odor. It freezes to give greenish-yellow crystals. It is produced on a large scale from benzene as a precursor t ...

) as fuels. Other Sprengel explosives used at various times include

charcoal Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, cal ...

with

liquid oxygen Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is the liquid form of molecular oxygen. It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an applica ...

(an

oxyliquit An Oxyliquit, also called liquid air explosive or liquid oxygen explosive, is an explosive material which is a mixture of liquid oxygen (LOX) with a suitable fuel, such as carbon (as lampblack), or an organic chemical (e.g. a mixture of soot and n ...

), "Rackarock", and ANFO ammonium nitrate (oxidiser) mixed with a fuel oil (fuel), normally diesel, kerosene, or nitromethane. Eventually ANFO supplanted all others because its oxidiser was the safest, and - due to its widespread use as a fertiliser in

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...

- also the cheapest. "Rackarock" consisted of

potassium chlorate Potassium chlorate is a compound containing potassium, chlorine and oxygen, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. After sodium chlorate, it is the second most common chlorate in industrial use. It ...

and

. It was provided in the form of permeable cartridges of the chlorate, which were placed in wire baskets and dipped in the nitrobenzene for a few seconds before use. For underwater use, it could be provided in cans instead. It was famously used in the massive submarine demolition of Flood Rock, a navigational hazard in

Long Island Sound Long Island Sound is a marine sound and tidal estuary of the Atlantic Ocean. It lies predominantly between the U.S. state of Connecticut to the north and Long Island in New York to the south. From west to east, the sound stretches from the Eas ...

in 1885. The charge of over a hundred

tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...

s of explosive (laid in tunnels 20 metres below sea level) destroyed approximately 600,000 tonnes of rock.

References

{{Reflist Explosives

See also

References