Sprengel explosives are a generic class of materials invented by Hermann Sprengel in the 1870s. They consist of

stoichiometric Stoichiometry () is the relationships between the masses of reactants and products before, during, and following chemical reactions. Stoichiometry is based on the law of conservation of mass; the total mass of reactants must equal the total m ...

mixtures of strong

oxidiser An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ''electron donor''). In ot ...

s 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 (physics), work. The concept was originally applied solely to those materials capable of releasing chem ...

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 u ...

. Sprengel suggested

nitric acid Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...

nitrate Nitrate is a polyatomic ion with the chemical formula . salt (chemistry), Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are solubility, soluble in wa ...

s and

chlorate Chlorate is the common name of the anion, whose chlorine atom is in the +5 oxidation state. The term can also refer to chemical compounds containing this anion, with Chlorate#Compounds (salts), chlorates being the salt (chemistry), salts of chlo ...

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 **Nitro ligand ...

aromatic In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated system, conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected from conjugati ...

s (e.g.

nitrobenzene Nitrobenzene is an aromatic nitro compound and the simplest of the nitrobenzenes, 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 ...

) 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, ca ...

with

liquid oxygen Liquid oxygen, sometimes abbreviated as LOX or LOXygen, is a clear cyan liquid form of dioxygen . It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an application which is ongoing. Physical ...

(an oxyliquit), "Rackarock", and

ANFO ANFO ( ) (or AN/FO, for ammonium nitrate/fuel oil) is a widely used bulk industrial high explosive. It consists of 94% porous prilled ammonium nitrate (NH4NO3) (AN), which acts as the oxidizing agent and absorbent for the fuel, and 6% number ...

ammonium nitrate Ammonium nitrate is a chemical compound with the formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, but does not form hydrates. It is predominantly us ...

(oxidiser) mixed with a fuel oil (fuel), normally diesel, kerosene, or

nitromethane Nitromethane, sometimes shortened to simply "nitro", is an organic compound with the chemical formula . It is the simplest organic nitro compound. It is a polar liquid commonly used as a solvent in a variety of industrial applications such as in ...

. Eventually ANFO supplanted all others because its oxidiser was the safest, and - due to its widespread use as a

fertiliser A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrition, plant nutrients. Fertilizers may be distinct from Liming (soil), liming materials or other non- ...

agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...

- also the cheapest. "Rackarock" consisted of

potassium chlorate Potassium chlorate is the inorganic compound with the molecular formula KClO3. In its pure form, it is a white solid. After sodium chlorate, it is the second most common chlorate in industrial use. It is a strong oxidizing agent and its most impor ...

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 sound (geography), 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 (state), New York to the south. From west to east, ...

in 1885. The charge of over a hundred

tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1,000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the s ...

s of explosive (laid in

tunnel A tunnel is an underground or undersea passageway. It is dug through surrounding soil, earth or rock, or laid under water, and is usually completely enclosed except for the two portals common at each end, though there may be access and ve ...

s 20 metres below sea level) destroyed approximately 600,000 tonnes of rock.

References

Explosives {{explosive-stub

See also

References