Explosive

Explosive euro symbol according to Directive 67/548/EEC

Preparation of an explosive C-4.

An explosive is a substance that due to some external cause (rubbing, heat, percussion, etc.) is transformed into gases; releasing heat, pressure or radiation in a very short time.

History

Thermal weapons, like Greek fire, have been around since ancient times. At its roots, the history of chemical explosives lies in the history of gunpowder. During the Tang dynasty in the IX< century, Taoist Chinese alchemists were eagerly trying to find the elixir of immortality. In the process, they stumbled upon the explosive invention of black powder made of coal, saltpeter, and sulfur in 1044. Gunpowder was the first form of explosives chemicals and by 1161, the Chinese were using explosives for the first time in warfare. The Chinese would incorporate explosives fired from bamboo or bronze tubes known as bamboo firecrackers. The Chinese also inserted live rats into bamboo firecrackers; when fired at the enemy, the flaming rats created great psychological ramifications: they scared away enemy soldiers and caused cavalry units to go berserk.

The first useful explosive stronger than black powder was nitroglycerin, developed in 1847. Since nitroglycerin is a highly unstable liquid, it was replaced by nitrocellulose, trinitrotoluene (TNT) in 1863, smokeless gunpowder, dynamite in 1867 and gelignite (the latter two are sophisticated, stabilized preparations of nitroglycerin rather than chemical alternatives, both invented by Alfred Nobel). World War I saw the adoption of TNT in artillery shells. World War II saw extensive use of new explosives, Grenades (see Annex: Explosives used in World War II).

In turn, these have largely been superseded by more powerful explosives like C-4 and PETN. However, C-4 and PETN react with metal and easily catch fire; however, unlike TNT, C-4 and PETN are impermeable and malleable.

Classification of explosive substances

The classification of explosive substances of different types can be carried out in multiple ways, however, there are three main widely accepted ways: by nature, by sensitivity and by use. Furthermore, in the classification that is given, it is very difficult and it is common to find typologies based on a functional chemical group and trade names when it comes to mixtures of explosive substances.

The practical characteristics that are basic to an explosive are the following:

• Explosive power.
• Breaking power.
• Detonation speed.
• Dust density.
• Water resistance.
• Smoke quality
• Sensitivity.
• Chemistry stability.

Explosive substances by explosive nature

Exploding

They are the explosives in which the reaction starts by thermokinetic activation (heat). Their speed does not exceed the speed of sound (measured in the explosive medium, which, being solid or liquid, is much higher than air -343m/s). The sound barrier tempers the energy released by it, so they are not very powerful.

pyrotechnia and some applications where low energy is required.

In this line, propellants are considered a subgroup of explosive explosives.

Triggers

The reaction in this group is self-sufficient by a supersonic shock wave (in the medium it travels), which starts the explosive as it passes. Given the high speed of the reaction, they are very powerful explosives. Within this class can be included all the explosive substances mentioned below.

• Black gunpowder
• Other powders or explosives that use potassium nitrate and potassium chlorate from oxidant are usually deflagrating.

Explosive substances by sensitivity

Primaries

Substances that require minute amounts of energy to activate. They are highly dangerous and are generally used phlegmatized (numbed). Its potency is modest compared to the other groups.

The energy released by primary explosives upon detonation is generally small; in the most common cases, their explosion heats are around 400 kcal/kg (1700 kJ/kg), as opposed to values of 1000 kcal/kg and above typical of secondary explosives.

• Nitrogen Triyodide
• Mercury Fulminate
• Silver Fulminate
• Lead ace or lead nitride.
• Silver Azida
• Lead stifate or lead trinitroresorcinto.
• Hexanitrate of manitol
• Silver acetylide
• Acetone peroxide
• 1-diazidocarbamoil-5-azidotetrazol

Secondaries

They need a primary explosive to start. They respond with intermediate activation energies, although not strictly homogeneous. The powers are very high, being in the order of GW, depending on their speed, chemical composition or their use.

• Nitroglycerin. Very sensitive. A desensitizer is usually applied.
• Trilita or TNT
• Hexgen, RDX Cyclonite (trinitropheylmethylnitramine)
• Pentrita, PT, PETN Tetranitrate Pentaeritrita
• Pucritical acid or NPT (Trinitrophenol)
• Ammonium Picrato
• Tetranitrometano
• Octogen or HMX (Ciclotetramethylentetranitramine)
• Nitrocellulose
• Cloratita

Tertiaries

Family constituted almost unanimously by NAFOS (ammonium nitrate/fuel oil) known for its enormous insensitivity.

• ANFO or NAFO in Spanish.

Explosive substances by use

Launcher

Energetic material, with a relatively low activation energy, used to initiate a secondary explosive. They are usually high sensitivity (primary) explosives in combination, according to the impulse required: impact, electrical or thermal. They are usually called detonators as they are commercially cartridged.

Load

It is the base mass that will explode and is the object of the blast design. The initiator is responsible for starting the upload. Some substances may not require an initiator: gunpowder, nitroglycerin, or pentrite ignite relatively easily under flame.

Multiplier

Sometimes the charge does not detonate with the initiator, so an intermediate explosive is required that is sensitive to the initiator and at the same time initiates the charge. Very frequently the anfos require this type of load.

Mixed explosive substances

Substances often lack all the properties requested for a function; for example: nitroglycerin is very unstable, ammonium nitrate very mediocre or lead styphnate should be more sensitive to flame. To circumvent these problems, mixtures of these are used to enhance them. Commercially they are known:

Dynamite

Dynamites are generally two-component explosives: nitroglycerin or nitroglycol with nitrocellulose, forming a paste with greater stability than each explosive separately.

Traditionally, dynamite has been a mixture of nitroglycerin with clay - originally diatomaceous earth; Nobel's own recipe. The technical evolution of this, led to the production of gums: nitroglycerin plus nitrocellulose. Currently, dynamites have favored mixtures of nitroglycol, with greater stability, together with nitrocellulose. In addition, they include other ingredients such as aluminum (increases heat and power), which gives it a grayish and oily appearance to the touch.

In general terms they are considered very powerful explosives (compared to gunpowder, mercuric fulminate and other weak explosives.

Rubbers

La Goma-2 is a dynamite-type explosive manufactured in Spain for industrial use (especially in mining) by the Unión Española de Explosivos, S.A. (currently MAXAM). It is marketed in at least two variants, the Goma-2 EC and the Goma-2 ECO.

Powdery

Pulverulent explosives are composed of ammonium nitrate, waterproofing agents, stabilizers, and combustible and oxidizing substances. These have a powdery consistency, presenting poor resistance to water.

Its power, density and detonation velocity is lower than that of gelatinous explosives, producing very few toxic gases. Powdered explosives are not very sensitive to shock and friction.

ANFO

ANFO, from English: Ammonium Nitrate - Fuel Oil, is a high-order explosive. It consists of a mixture of ammonium nitrate and a fuel derived from petroleum, from gasoline to motor oils. These mixtures are widely used mainly by mining and demolition companies, because they are very safe, cheap and their components can be purchased very easily. The amounts of ammonium nitrate and fuel vary depending on the hydrocarbon chain length of the fuel used. The percentages range from 90% to 97% ammonium nitrate and 3% to 10% fuel, for example: 95% ammonium nitrate and 5% kerosene. The use of a water-insoluble fuel eliminates the main problem with ammonium nitrate: its tendency to absorb water (hygroscopy). If aluminum powder is also added, ANFO becomes an even more powerful variety called ALANFO. It is widely used in medium to soft rock blasting, either by introducing the granules into the holes with compressed air or in its other form of presentation, which is cartridged. It is necessary to strongly prime the hole with a detonator and a rubber cartridge to the bottom, to produce its correct operation, in addition its use is contraindicated in holes with the presence of water, unless a cartridge is used. ANFO is also often mixed with other explosives such as hydrogels or emulsions to form, depending on the percentage of ANFO or ANFO Heavy (approximately 70% emulsion or hydrogel and 30% ANFO).

Hydrogels

Hydrogels are explosive agents made up of saturated aqueous solutions of NA, often with other oxidants such as sodium and/or calcium nitrate, in which are dispersed fuels, sensitizers, thickening agents, and gelatinizers that prevent segregation of solid products. With respect to emulsions, they have the advantage of cross-linking or gelatinization, a property that allows them to be resistant to water by becoming a gelatinous semi-solid substance. Its relative potency with respect to ANFO in kJ/kg is higher than that of the emulsions, as can be verified in the technical sheets of their manufacturers.

Emulsions

Explosive emulsions are of the type called <water in oil> in which the aqueous phase is composed of oxidizing inorganic salts dissolved in water and the oily phase by a liquid fuel immiscible with water of the hydrocarbon type.

Trilite base

Plastic binder

Properties

Detonation speed

The speed with which the reaction process propagates in the mass of the explosive. Most commercial mining explosives have detonation velocities ranging from 1,800 m/s to 8,000 m/s. Today, the detonation velocity can be accurately measured. Along with density, it is an important element influencing the performance of the transmitted energy for both atmospheric overpressure and ground acceleration. By definition, a "low explosive", such as black powder or smokeless powder, has a burn velocity of 171 to 631 m/s. In contrast, a "high explosive", either primary, such as detonating cord, or secondary, such as TNT or C-4, has a significantly higher burn rate.

Volume of explosion products

The most commonly used explosives are condensed liquids or solids converted to gaseous products by explosive chemical reactions and the energy released by those reactions. The gaseous products of the reactions are typically carbon dioxide, steam, and nitrogen. The gaseous volumes calculated by the ideal gas law tend to be too large at the high pressures characteristic of explosions. Explosives with an oxygen deficit will generate soot or gases such as carbon monoxide and hydrogen, which can react with surrounding materials such as atmospheric oxygen. Attempts to obtain more accurate volume estimates must consider the possibility of such side reactions, vapor condensation, and aqueous solubility of gases such as carbon dioxide.

In comparison, the detonation of CDP relies on the rapid reduction of carbon dioxide to carbon with the abundant release of energy. Instead of producing typical waste gases like carbon dioxide, carbon monoxide, nitrogen, and nitric oxides, CDP is different. Instead, the highly energetic reduction of carbon dioxide to carbon vaporizes and pressurizes excess dry ice at the wavefront, which is the only gas released by detonation. Therefore, the detonation rate of CDP formulations can be customized by adjusting the weight percentage of reducing agent and dry ice. CDP blasting produces a large amount of solid materials that can have great commercial value as an abrasive:

Example: detonation reaction of CDP with magnesium: XCO2 + 2Mg → 2MgO + C + (X-1)CO2

The products of detonation in this example are magnesium oxide, carbon in various phases, including diamond, and excess carbon dioxide vaporized that was not consumed by the amount of magnesium in the explosive formulation.

Oxygen balance (OB% or Ω)

Oxygen balance is an expression used to indicate the degree to which an explosive can oxidize. If an explosive molecule contains enough oxygen to convert all of its carbon to carbon dioxide, all of its hydrogen to water, and all of its metal to metal oxide without excess, the molecule is said to have zero oxygen balance. The molecule is said to have a positive oxygen balance if it contains more oxygen than necessary, and a negative oxygen balance if it contains less oxygen than necessary.

The oxygen balance is applied to traditional explosives mechanics with the assumption that carbon is oxidized to carbon monoxide and carbon dioxide during detonation. In what seems like a paradox to an explosives expert, Cold Detonation Physics uses carbon in its most oxidized state as a source of oxygen in the form of carbon dioxide. Therefore, the oxygen balance does not apply to a CDP formulation or must be calculated without including carbon in carbon dioxide.

Nuclear Reactions

Extremely powerful, they are prohibited for commercial use, they are only produced and used by the armies of technologically developed countries.

The basic operation of these bombs consists of the fission or fusion of atoms. There are essentially two types: those that work with Uranium and those that work with Plutonium, which with the help of a detonator or initiator splits its atoms, generating other smaller unstable atoms and a chain reaction and lots of heat and energy.

Another class is the Hydrogen fusion bomb (known as an H bomb), which consists of the fusion of the atoms of said substance. This kind of bomb generates much more energy than the previous one, and has not yet been tested in actual combat, unlike the Uranium and Plutonium bombs, dropped on Hiroshima and Nagasaki (respectively) at the end of World War II..

Grouping of explosives for compatibility

Signal of "Procaution Explosives".

These signs are used in Transportation, Shipping, Storage; includes A & US DOT, Hazardous Material Classes with Compliant Signage. Wikipedia provides this information, but it should never be a primary source for handling explosives.

• 1.1 Explosion danger
• 1.2 Non-Massive Explosion produces fragments
• 1.3 Fire in Masa, lower risk of fragmentation
• 1.4 Moderate fire, there is no risk of expansion or fragmentation: pyrotechnia and devices for controlled rock fragmentation are 1.4G or 1.4S
• 1.5 Explosive substance, very insensitive (at risk of mass explosion)
• 1.6 Explosive Article, Extremely Insensitive

A Primary explosive substance (1.1A, 1.2A)

B An article with a primary explosive, without two or more effective protective devices. Included are some items, detonator assemblies for blasting and primers, capsule-type. (1.1B, 1.2B, 1.4B)

C Propellant or other explosive explosive substances or articles containing such explosive substances (1.1C, 1.2C, 1.3C, 1.4C)

D Detonating secondary explosive substances or black powder or article with detonating secondary explosive substance, in each case without means of initiation or propellant charge, or article with primary explosive substance with two or more devices effective protectors. (1.1D, 1.2D, 1.4D, 1.5D)

E Article with a detonating secondary explosive substance without means of initiation, with propellant charge (with more than one flammable liquid, gel or hypergolic liquid) (1.1E, 1.2E, 1.4E)

F Article with a detonating secondary explosive substance with its means of initiation, with a propellant charge (with more than one flammable liquid, gel or hypergolic liquid) or without a propellant charge (1.1F, 1.2F, 1.3F, 1.4F)

G Pyrotechnic substance or article containing a pyrotechnic substance, or article containing an explosive substance and a lighting, incendiary, tear-producing, or smoke-producing substance (with an article activated by water or containing white phosphorus, phosphate, or flammable liquid or gel or hypergolic liquid) (1.1G, 1.2G, 1.3G, 1.4G)

H Article with an explosive substance and white phosphorus (1.3H, 1.8H)

H a Article with only one of the two explosives without white phosphorus (1.3H, 1.8H)

J Item with both explosive substances and flammable liquid or gel (1.1J, 1.2J, 1.3J)

K Article with both explosive substances and a toxic chemical agent (1.2K, 1.3K)

L Explosive substance or article with an explosive substance with special risk (for example, activatable with water or presence of hypergolic liquids, phosphates or pyrogenic substances) requiring insulation in each type (1.1L, 1.2 L, 1.3L)

N Article with only extremely insensitive detonating substances (1.6N)

S Substance or article packaged or designed such that any hazardous effect from accidental handling is limited to the package itself and does not significantly extend to the environment; not affected by nearby fire, or other emergency in the immediate vicinity of the package (1.4S)

Regulation

The legality of possessing or using explosives varies by jurisdiction. Various countries around the world have enacted laws and require licenses to manufacture, distribute, store, use, possess explosives or ingredients.

Netherlands

In the Netherlands, the civil and commercial use of explosives is covered by the Wet explosieven voor civiel gebruik (Civilian Explosives Act), in accordance with EU directive no. 93/15/EEG. Illegal use of explosives is covered by the Wet Wapens en Munitie (Weapons and Ammunition Act).

United Kingdom

The New Explosives Regulations 2014 (ER 2014) came into effect on October 1, 2014 and defines "explosive" as:

(a) Any explosive or explosive article that:

(i) if they are packed for transportation, be classified according to the United Nations Recommendations as belonging to Class 1; or

(ii) be classified according to the United Nations Recommendations as:

aa) be excessively sensitive or as reagent to be subject to a spontaneous reaction and therefore too dangerous for transportation, and

(bb) belong to class 1; or

(b) Insensitized explosive,

but does not include an explosive substance produced as part of a manufacturing process that subsequently reprocesses it to produce a substance or preparation that is not an explosive substance.

Anyone wishing to acquire or retain relevant explosives should contact their local police explosives liaison officer. All explosives are relevant explosives, except those listed in Annex 2 of the Explosive Regulations of 2014.

United States

During World War I, numerous laws were created to regulate war-related industries and increase security within the United States. In 1917, the 65th United States Congress created many laws, including the Espionage Act of 1917 and the Explosives Act of 1917.

The Explosives Act of 1917 (Session 1, Chapter 83, 40 Stat. 385) was signed into law on October 6, 1917, and took effect on November 16 of the same year. The legal summary is "An act to prohibit the manufacture, distribution, storage, use, and possession in wartime of explosives, establishing regulations for the safe manufacture, distribution, storage, use, and possession of the same and for other purposes." This was the first federal licensing regulation for the purchase of explosives. The law was deactivated after World War I ended.

After the United States entered World War II, the Explosives Act of 1917 was reactivated. In 1947, the law was deactivated by President Truman.

The Organized Crime Control Act of 1970 (Pub. L. 91–452) transferred many explosives regulations to the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) of the Treasury Department. The bill came into force in 1971.

Currently, regulations are governed by Title 18 of the United States Code and Title 27 of the Code of Federal Regulations:

• "Importation, Manufacturing, Distribution and Storage of Explosive Materials" (18 U.S.C. Chapter 40).
• "Explosions trading" (27 C.F.R. Chapter II, Part 555).