Sprengel explosive
Encyclopedia
Sprengel explosives are a generic class of materials invented by Hermann Sprengel
in the 1870s. They consist of stoichiometric mixtures of strong oxidisers and reactive fuel
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
.
Sprengel suggested nitric acid
, nitrate
s and chlorate
s as oxidisers, and nitroaromatics (e.g. nitrobenzene
) as fuels. Other Sprengel explosives used at various times include charcoal
with liquid oxygen
(an oxyliquit
), "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
- also the cheapest.
"Rackarock" consisted of potassium chlorate
and nitrobenzene
. 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 a navigational hazard in Long Island Sound
in 1885. The charge of over a hundred tonne
s of explosive (laid in tunnel
s 20 metres below sea level) destroyed approximately 600,000 tonnes of rock, and created a wave 30 m high.
Hermann Sprengel
Hermann Sprengel FRS was a German chemist who discovered the explosive nature of picric acid in 1873. He also invented a generic class of materials called Sprengel explosives...
in the 1870s. They consist of stoichiometric mixtures of strong oxidisers and reactive fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
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
Reaction rate
The reaction rate or speed of reaction for a reactant or product in a particular reaction is intuitively defined as how fast or slow a reaction takes place...
.
Sprengel suggested nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
, nitrate
Nitrate
The nitrate ion is a polyatomic ion with the molecular formula NO and a molecular mass of 62.0049 g/mol. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a...
s and chlorate
Chlorate
The chlorate anion has the formula ClO. 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 a roman numeral in parentheses, e.g...
s as oxidisers, and nitroaromatics (e.g. nitrobenzene
Nitrobenzene
Nitrobenzene is an organic compound with the chemical formula C6H5NO2. 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 as a precursor to aniline. Although occasionally used as a flavoring or perfume...
) as fuels. Other Sprengel explosives used at various times include charcoal
Charcoal
Charcoal is the dark grey residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen...
with liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
(an oxyliquit
Oxyliquit
An oxyliquit, also called liquid air explosive or liquid oxygen explosive, is an explosive material made of a mixture of liquid air or liquid oxygen with a suitable fuel, usually carbon or some organic chemical An oxyliquit, also called liquid air explosive or liquid oxygen explosive, is an...
), "Rackarock", and ANFO
ANFO
ANFO is a widely used bulk industrial explosive mixture. It consists of 94 percent porous prilled ammonium nitrate , that acts as the oxidizing agent and absorbent for the fuel — six percent Number 2 Fuel Oil...
ammonium nitrate (oxidiser) mixed with a fuel oil (fuel), normally diesel kerosene or nitromethane
Nitromethane
Nitromethane is an organic compound with the chemical formula . It is the simplest organic nitro compound. It is a slightly viscous, highly polar liquid commonly used as a solvent in a variety of industrial applications such as in extractions, as a reaction medium, and as a cleaning solvent...
. Eventually ANFO supplanted all others because its oxidiser was the safest, and - due to its widespread use as a fertiliser in agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
- also the cheapest.
"Rackarock" consisted of potassium chlorate
Potassium chlorate
Potassium chlorate is a compound containing potassium, chlorine and oxygen atoms, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. It is the most common chlorate in industrial use...
and nitrobenzene
Nitrobenzene
Nitrobenzene is an organic compound with the chemical formula C6H5NO2. 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 as a precursor to aniline. Although occasionally used as a flavoring or perfume...
. 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
Demolition
Demolition is the tearing-down of buildings and other structures, the opposite of construction. Demolition contrasts with deconstruction, which involves taking a building apart while carefully preserving valuable elements for re-use....
of a navigational hazard in Long Island Sound
Long Island Sound
Long Island Sound is an estuary of the Atlantic Ocean, located in the United States between Connecticut to the north and Long Island, New York to the south. The mouth of the Connecticut River at Old Saybrook, Connecticut, empties into the sound. On its western end the sound is bounded by the Bronx...
in 1885. The charge of over a hundred tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s of explosive (laid in tunnel
Tunnel
A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...
s 20 metres below sea level) destroyed approximately 600,000 tonnes of rock, and created a wave 30 m high.