Explosives and its classification

1Hritik Kumar & Easha Das (DHGSU)

CONTENTS
 INTRODUCTION
 HISTORY OF EXPLOSIVE
 CHARACTERISTICS OF EXPLOSIVE
 PROPERTIES OF EXPLOSIVE
 INGREDIENT OF EXPLOSIVE
 CLASSIFICATION OF EXPLOSIVE
- Low Explosives
 - High Explosives
 MISCELLANEOUS
 CASES
 REFERENCES

INTRODUCTION
Explosive Meaning :-
likely to shatter violently or burst apart.

 An explosive material, also called explosive, is a reactive substance
that contains a great amount of potential energy that can produce an
explosion if released suddenly, usually accompanied by the production
of light, heat, sound, and pressure.
(This potential energy stored in an explosive material may be chemical
energy , pressurized gas or nuclear energy.)
Or, Refers to a chemical compound, mixture, device etc. that is
capable of exploding. “Gasoline forms an explosive mixture with air”.
5
Hritik Kumar & Easha Das (DHGSU)

 An explosive is a compound or mixture
susceptible (by heat, shock, friction or other
impulse)to a rapid chemical reaction,
decomposition or combustion with the rapid
generation of heat and gases with a combined
volume much larger than the original substance.
 The explosive material consists of chemical
compound or mixture , which when subjected to
sudden shock (mechanical or thermal) get
oxidized and releases huge amount of energy in
an extremely brief period which is observed in
the form of an explosion.

HISTORY
The most primitive explosive
known to mankind is
supposed to be gun powder.
The Chinese invented it
around A.D. 1250 and also
Arab and Hindus had its
knowledge. The earliest
explosive consisted of
charcoal, sulphur , and nitrate
of either sodium or
potassium.

Some important dates related to explosive are
A.D. 1230-1250 Gunpowder known and used by Chinese Arabs
and Hindus.
1267 Black powder described by Roger Bacon.
1425 Granulated gunpowder
1604 Development of ordnance and firearms,
fulminate of gold.
1605 The Gunpowder plot.
1771 Picric acid used as dye, but its explosive
properties not discovered until 1805 and
not used until 1885.

1788 Discovery of fulminate of silver by Berthollet.
1800 Preparation of Hg(CN)2 by Howard, who describe its
detonation by an electric spark, by impact, by conc. HCL
1831 ‘Safety fuse’ with waterproof cover introduced.
1836 Percussion cap and firing pin gun invented.
1845 Discovery of nitrocellulose by Schoenbein.
1846 Preparation of nitroglycerine by Sobrero.
1865 Nobel’s dynamite, nitroglycerine, in diatomaceous earth.
1865 Smokeless powder from nitrated wood (Ba(NO3), and KNO3
1869 Improved Dynamite , nitroglycerine with wood flour, nitrate
and wax
1879 Novel patented special dynamite containing nitrocellulose and
ammonium nitrate preparation of tetryl.
1920 RDX or cyclonite first prepared as a medicine in 1899, was
as an explosive.
1925 Pentryl, a high explosive.

1935 Biazzi continuous process for the manufacture of
nitroglycerine
1940 Canadian and American chemical team perfected new
and continuous process
Alfred Nobel (invented RDX)

(1) It is a chemical compound or mixture ignited by heat,
shock, impact, friction, or a combination of these
conditions;
(2) Upon ignition, it decomposes rapidly in a detonation;
(3) There is a rapid release of heat and large quantities of
high-pressure gases that expand rapidly with sufficient
force to overcome confining forces; and
(4) The energy released by the detonation of explosives
produces four basic effects;
(a) rock fragmentation;
(b) rock displacement;
(c) ground vibration; and
(d) air blast

Density :-
The density of an explosive may be expressed in terms of
specific gravity. Specific gravity is the ratio of the density of
the explosive to the density of water under standard conditions.
Density is an important consideration when choosing an
explosive. For difficult blasting conditions or where fine
fragmentation is required, a dense explosive is usually
necessary. In easily fragmented rock or where fine
fragmentation is not needed, a low-density explosive will often
suffice. Low-density explosives are particularly useful in the
production of riprap or other coarse products .
12

Water Resistance :-
An explosive's water resistance is a measure of its ability to
with stand exposure to water without deteriorating or losing
sensitivity. Sensitivity is the ease with which an explosive
detonates.
Gelatins and emulsions offer the best water resistance.
Detonation and Borehole Pressure :-
Detonation pressure is a function of the detonation velocity
and density of an explosive , the detonation pressure is more
dependent on detonation velocity than specific gravity. A
high detonation pressure is necessary when blasting hard,
dense rock. In softer rock, a lower pressure is sufficient.
13

The ingredients in
explosives
 Explosive bases :
An explosive base is a solid or a liquid which, upon
application or heat or shock, breaks down very rapidly
into gaseous products, with an accompanying release of
heat energy. Nitroglycerine is
an example.
 Combustibles:
A combustible combines with excess oxygen in an
explosive to achieve oxygen balance, to
prevent the formation of nitrous oxides (toxic fumes),
and to lower the heat of the explosion.

 Oxygen carriers:
Oxygen carriers assure complete oxidation of the carbon in
the explosive mixture, which inhibits the formation of carbon
monoxide. The oxygen carriers assist in preventing a lowering
of the exploding temperature. A lower heat of explosion
means a lower energy output and thereby less efficient
blasting.
 Antacids:
Antacids are added to an explosive compound to increase its
long term storage life, and to reduce the acidic value of the
explosive base, particularly nitroglycerin (NG).

 Absorbents:
Absorbents are used in dynamite to hold the explosive base
from exudation, seepage, and settlement to the bottom of the
cartridge or container. Sawdust, rice hulls, nut shells, and
wood meal are often used as absorbents.
 Antifreeze:
Antifreeze is used to lower the freezing point of the explosive.
 Air gap sensitivity:
Air gap sensitivity is a measure of an explosive’s cartridge-to-
cartridge sensitivity to detonation under test conditions,
expressed as the distance through air at which a primed half-
cartridge (donor) will reliably detonate an unprimed half-
cartridge (receptor). 16Hritik Kumar & Easha Das (DHGSU)

 Cap Sensitivity:
Cap sensitivity is a measure of the minimum energy, pressure,
or power required for initiation of a detonation; i.e., “cannot
be detonated by means of a No. 8 test blasting cap when
unconfined.”
 Detonation Pressure :
It is a measure of the product's shock wave energy, influenced
by the product's density(latent energy) and detonation velocity
(rate of energy release).
 Pressure Magnitude or Gas Pressure:
It is a measure of the potential expanding-gas energy,
influenced by the product's density (latent gas volume) and
the heat and velocity of detonation (rate of gas production
and expansion). 17Hritik Kumar & Easha Das (DHGSU)

cLASSIFICATION OF EXPLOSIVES
HIGH
EXPLOSIVES
LOW
EXPLOSIVES

These explosives are known as
deflagrating explosives . These
are mild explosive, which do not
explode suddenly but burn with
flame speed less than 100m/sec.
The liberated gas shattering
disperses readly without building
high pressure and can be
controlled . The action of low
explosive is less shattering and
they produce larger volume of
gas on combustion in controlled
manner .
Low explosives are used in
propellants ( missiles) and in the
pyrotechniques ( fire works )

 They simply burn and do not explode suddenly.
 The chemical reactions taking place in such explosives are
comparatively slow and their burning proceeds from the
surface inward in layers at an approximate rate of 20 cm per
second.

1. BLACK POWDER OR GUN POWDER
Gunpowder and gunpowder weapons were transmitted to
India through the Mongol invasions of India .
 It is a mixture of 75 % potassium
nitrate,
15% charcoal and 10% sulphur.
It is cheap and excellent explosive ,
still it is used to considerable extent ,
in spite of number of new explosives
are available .
A small spark is sufficient to explode
the whole mass . It as some desirable
properties . It is not good for coal
mines because it produces flame
which can ignite gas and coal , dust
particles and it also prodce CO gas .
( it is harmful for human beings )
Uses : for blasting, in shells, igniters
for propellants, practice bombs.

A simple, commonly cited, chemical equation for the
combustion of black powder is:
2 KNO3 + S + 3 C → K2S + N2 + 3 CO2
A more accurate, but still simplified, equation is
10 KNO3 + 3 S + 8 C → 2 K2CO3 + 3 K2SO4 + 6 CO2 + 5 N2
The products of burning do not follow any simple equation.
One study's results showed that it produced (in order of
descending quantities): 55.91% solid products: potassium
carbonate, potassium sulfate, potassium sulfide, sulfur,
potassium nitrate, potassium thiocyanate, carbon, ammonium
carbonate. 42.98% gaseous products: carbon dioxide,
nitrogen, carbon monoxide, hydrogen sulfide, hydrogen,
methane, 1.11% water.

Smokeless powders was introduced as a black powder
replacement in the 1880's.
Besides generating a lot less smoke, smokeless powder burns
much cleaner and more efficiently than black powder, greatly
reducing powder fouling and increasing the performance of the
shotgun, handgun, and rifle cartridges in which it is used.
It is also much safer to produce than black powder, which has
saved many lives over the years.
 It is prepared by treating cellulose with nitric and sulphuric
acids.
 It is called smokeless powder because it produces carbon
dioxide, carbon monoxide,nitrogen, water vapour and almost
no smoke.
24

 Smokeless powder consists of :
* Nitocellulose (single-base powders)
* Nitocellulose + Nitroglycerin (double-base powders)
* Nitocellulose + Nitroglycerin + Nitroguanidine (triple-base
powders),
corned into small spherical balls or extruded into cylinders or
flakes using solvents such as ether.
Other minor ingredients, such as stabilizers and ballistic
modifiers, are also added. Double-base propellants are
common in handgun and rifle ammunition.
The combination of NITROCELLULOSE AND
NITROGLYCERIN produce very less amount of smoke ,
hence it is called SEMI-SMOKLESS POWDERS.

HIGH EXPLOSIVES
 They have higher energy content than low explosives.
 They are stable and quite insensitive to fire and mechanical
shocks.
TYPES :-
Primary
Explosives
Secondary
Explosives
26
Hritik Kumar & Easha Das
(DHGSU)

 Initiating Explosives or detonators.
 They are highly sensitive explosives which
explode on receiving a slight shock or by
fire.
 And are extremely sensitive to mechanical
shock, friction, and heat, to which they will
respond by burning rapidly or detonating.
They are used comparatively in small
quantities in cartridge , shells etc and have to
be handled carefully because they are
dangerous .
* The detonation is an uncontrolled combustion,
propagated by compression wave that heats
the explosive mass to its decomposition
temperature , as the wave proceeds with
approximately the speed of sound , through
the explosive. 27Hritik Kumar & Easha Das (DHGSU)

 By the time the first shock wave reaches the end of the
explosive , opposite the initiating point , the entire explosive
would have decomposed . The detonators are employed for
shattering , making holes in mountain rocks etc .
1. LEAD AZIDE (Pb(N3)2
IUPAC NAME: lead (II) azide
MOLECULAR FORMULA: Pb(N3)2
MOLAR MASS: 291.2402 g/mol
SHOCK SENSITIVITY: High
FRICTION SENSITIVITY: High
EXPLOSIVE VELOCITY: 5180 m/s <

 Lead azide is an explosive and toxic crystalline compound
frequently used in primers, blasting caps, and fuses. Lead azide is
sensitive to heat, shock and friction. The velocity of detonation is
approximately 17,500 feet /second. Its color varies from white to
buff. It is not very hygroscopic, but when properly protected from
moisture it will not suffer a decrease in performance and can be
stored for long periods of time. Water does not reduce its impact
sensitivity. When protected from humidity, is completely stable in
storage.
 NaNH2+N2O  NaN3+H2O
( Sodium azide )
2NaN3+Pb(OAc)2  Pb(N3)2+2NaOAc
( Lead azide )
Lead azide decomposes exothermically
Pb(N3)2  Pb+3N2

2. MERCURY FULMINATE Hg(ONC)2
IUPAC NAME: mercury (II) oxidoazaniumylidynemethane
MOLECULAR FORMULA: Hg(CNO)2
SHOCK SENSITIVITY: High
FRICTION SENSITIVITY: High
EXPLOSIVE VELOCITY: 4250 m/s
Mercury(II) fulminate is highly sensitive to friction and shock and sparks.
It is mainly used as a trigger for other explosives in percussion caps and
blasting caps .
It explosively decomposes to form mercury, carbon monoxide, and
nitrogen .

 Alfred Nobel put mercury fulminate into blasting caps for
detonating dynamite. This relatively safe new detonator was
what allowed for the huge success of dynamite. In Germany
alone, the annual production of mercury fulminate in the early
20th century reached about 100,000 Kg.
Mercury fulminate is toxic and is practically insoluble in
water. When dry, it is highly sensitive to shock, impact, and
friction, and is easily detonated by sparks and flames. It can
be phlegmatized by the addition of oils, fats, or paraffin, and
also by press-molding under very high pressure .
 Mercury fulminate decomposed exothermically ,
Hg(ONC)2  Hg+N2+2CO+117Kcal

3.TETRACENE
IUPAC NAME: 1(5-tetrazolyl)-4-guanyl tetrazene hydrate
OTHER NAME: tetrazolyl guanyltetrazene hydrate; tetrazen; tétrazéne
MOLECULAR FORMULA: C2H6N10·H2O
SHOCK SENSITIVITY: high
FRICTION SENSITIVITY: high
EXPLOSIVE VELOCITY: ~4000 m/s
It is formed by the action of nitrous acid on aminoguanidine,
or, more exactly, by the interaction of an aminoguanidine salt
with sodium nitrite in the absence of free mineral acid.

 Tetracene is a colorless or pale yellow, fluffy material which is
practical1y insoluble in water, alcohol, ether, benzene, and
carbon tetrachloride.
 Tetracene forms explosive salts, among which the perchlorate is
especial1y interesting. It is soluble in strong hydrochloric acid;
ether precipitates the hydrochloride from the solution, and this
on treatment with sodium acetate or with ammonia gives
tetracene again.
 Tetracene is only slightly hygroscopic. It is stable at ordinary
temperatures both wet and dry, but is decomposed by boiling
water with the evolution of 2N2 per molecule.
Tetracene explodes readily from flame without appreciable
noise but with the production of much black smoke.

SOME OTHER PRIMARY HIGH EXPLOSIVES :
LEAD STYPHNATE :
 Lead styphnate is particularly sensitive to fire and the
discharge of static electricity.When the styphnate is dry, it
can readily ignite by static discharges from
the human body.The longer and narrower the crystals, the
more susceptible the material is to static electricity. Lead
styphnate does not react with metals. It is less sensitive to
shock and fiction than lead azide
 Lead styphnate is slightly soluble in water and methyl
alcohol and may be neutralized by a solution of sodium
carbonate. The velocity of detonation is
approximately 17,000 fps. The color of lead styphnate
varies from yellow to brown. Lead styphnate is used as an
initiating explosive in propellant primer and high-explosive
detonator devices.


Hritik Kumar & Easha Das (DHGSU) 35
LEAD STYPHNATE

Diazodinitrophenol (DDNP)
DDNP is a yellowish brown powder. It is soluble
in acetic acid, acetone, strong hydrochloric acid, and most of
the solvents, but is insoluble in water. A cold sodium
hydroxide solution may be used to destroy it. DDNP is
desensitized by immersion in water and does not react with it
at normal temperatures. It is less sensitive to impact but more
powerful than lead tide. The sensitivity of DDNPto friction
is approximately the same as that of lead tide. DDNP is often
used as an initiating explosive in propellant primer devices.

SECONDARY HIGH EXPLOSIVES
They are generally classified into four groups :
SINGLE
COMPOUND
EXPLOSIVES
BINARY
EXPLOSIVES
PLASTIC
EXPLOSIVES DYNAMITES

1. SINGLE COMPOUND EXPLOSIVES
- Contains only one chemical compound .
i.)AMMONIUM NITRATE
It is cheap , stable , low brisance value , insensitive and non
toxic. It is a high explosive, though about half powerful as
TNT and used along with another explosive in making binary
explosive . It is dangerous to store near any inflammable
material . It cannot be used in contact with the alloy of copper
as it forms tetramino cupric nitrate which detonates easily . It
has positive oxygen balance and is therefore , used to supply
oxygen for other explosives having negative oxygen balance .
It can be obtained by passing through Ammonia gas through
HNO3 (40-60%). It decomposes on heating to give N20 ,
NO2 and N2.

AMMONIUM NITRATE

ii.) TRINITROTOLUENE (TNT)
It is prepared by nitration of toluene , using nitrating mixture of
conc. HNO3 and H2SO4 in 1:1 ratio , in a tank reactor , in which
reactant are vigorously stirred . The liquid product is washed with
ammonical solution of Na2SO3 and then cold water .
TNT will crystallize out . TNT crystals are purified by melting .
It differs from many other explosive containing nitrates . In this
class of explosives , NO2 group are attached to the carbon atoms .
TNT is a true nitro compound and is a powerful explosive . It is not
sensitive to impact or friction and its ignition temperature is 250*C.
So it is safe explosive in transportations , storage and manufacture .
It is explosive of its own but forms a part of many commercial /
military explosives i.e amatol and ammonal .

TRINITROTOLUENE

iii.) PENTAERYTHRITOL TETRANITRATE (PETN)
It is and extremely sensitive , powerful and standard military
explosive . It is so sensitive , that it can be detonated even by
the impact of the rifle bullet .
It is formed from formaldehyde and acetaldehyde by the
cannizaro reaction
H3C-CHO+3CH2O C(CH2ONO2)4
PETN
On decomposition it give the following gases
C(CH2ONO2)4 4H20(g)+2CO+2N2+180Kcal

PENTAERYTHRITOL TETRANITRATE

iv.) RDX CYCLONITE
( CYLOMETHYLENE TRINITROAMINE)
This is another explosive of the class having NO2 group .
However , in this compound it is attached to nitrogen of the
ring structure . Cyclonite was prepared in 1899 to be used as
drug . However, its explosive properties were discovered and
the patented in 1920 . The process was established in Britain
before second world war . It was prepare form the reaction of
hexa-methylene tetra amine , (CH2)6N4 , and nitric acid
resulting RDX and formaldehyde as following :
(CH2)6N4+4HNO3 (CH2NNO2)3+NH4NO3+3CH2O
Cyclonite

RDX

In the improved process, reacting constituents are dissolved in
glacial acetic acid or anhydride and the reaction takes place in
a large glass coil which continuously produce RDX in
crystalline form with a byproduct explosive known as HMX .
RDX is 35% more powerful than TNT as strength and in
brisance it is placed above PETN , where as its impact
sensitivity lies in between PETN and tetryl , less toxic than
TNT .
The RDX melts at 204*C and detonates at 360*C. However ,
it starts decomposing at melting point .
This is also used in combination with other explosives. A
mixture of RDX,TNT and aluminum powder makes an
accepted combination for torpedo warheads.
Its VOD is 8500 m/ sec .

2.)BINARY EXPLOSIVES
These explosives consist of mixture of various explosives
particularly of TNT with other explosive .
For certain application, they are superior to single compound
explosives and is convenient to prepare .
TNT is an important ingredient of these explosives because it has a
low melting temperature .
The widely used combination are :
• AMATOL ( ammonium nitrate 50% and TNT 50%)
• PENTOLITE ( PETN 50% and TNT 50%)
• TETRYTOL (Tetryl70% and TNT 30%)
• TROPEX (RDX 40% and TNT 40% and 20%Aluminum powder)
• TITRONAL( TNT 80%, Aluminum flakes 20%)
The chief advantages are higher energy output and low cost of
making of the ammunition because they can be melted and
powdered.

BINARY
EXPLOSIVE

3. PLASTIC EXPLOSIVES
These are combination of explosives because they contain
high explosive admixed with wax or oil to render them less
sensitive .
They are in plastic state and can be hand moulded or pressed
and made into different configurations .
The plastic sheet explosive is usually prepared using 90-95%
RDX ,HMX or PETN and are much more sensitive to heat ,
friction, shock and impact than pure RDX , HMX , AND
PETN .

SEMETEX
( PLASTIC
EXPLOSIVE)
C4 ( PLASTIC
EXPLOSIVE)

4. DYNAMITES
Alfred Nobel was the first engineer who utilized N.G for
engineering purpose. Since his younger brother met death due to
nitroglycerine explosion, Alfred noble carried out effort to find
out safer means to handle this sensitive substance.
And he found that nitroglycerine when absorbed on Keisel guhr, a
porous material , sensitivity to shock was greatly reduced, this
dynamite could be only exploded only with the help of primer or
initiator, i.e., Hg(CN2) . Alfred further replaced keiser guhr with
combustible absorbent fillers such as wood flour or charcoal.
4C3H5(NO3)  10H2O + 6N2 + 12CO2 + O2

DYNAMITE

MISCELLANEOUS
 Blasting gelatin
This is the strongest commercially used dynamites. This is a
rubbery mixture of 91.5% N.G and 8% guncotton and 0.5%
CaCO3. it is highly water resistant and is recommended for
making shaft in hard rock, shooting oil wells, submarine blastings
,etc. its fumes are objectionable for underground mining.
It is gel like and highly water resistant. It doesn't flow but stick
well in to holes in which it is loaded.
It can be used in wet condition and thus, meets the demand for
non freezing dynamite use in weather.
Their chief use are submarine blasting , tunnel driving, deep well
shooting at place where the maximum shattering effects are
desired.

BLASTING
GELATIN

 CORDITE
It is a mixture of glyceryl trinitrite (GTM) cellulose nitrate and
petroleum jelly in acetone. It is used as a smokeless powder . The
petroleum jelly serves as stabilizer. It has tendency to reduce the
temperature of explosions. The cordite is an excellent propellant
for large naval guns.
A cordite unit in located in Tamilnadu.

GLOSSARY
 Brisance : It is shattering power of an explosive .
 Black Powder : It is low explosive . It is a mixture of It is
a mixture of 75 % potassium nitrate, 15% charcoal and
10% sulphur.
 Dynamite: It is a high explosive , glyceryl trinitrate
absorb kiselguhr .
 Explosive: It is a mixture of compound, when subjected
to sudden shock and get oxidized and release large
amount of energy instantaneously .
 Fuses: It is device for setting off the charges of
explosives .
 Cordite: It is a secondary explosive , prepared by
dissolving 65 parts of gun cotton, 30 parts of
nitroglycerin, 5 percent of petroleum jelly in acetone .
57
HritikKumar&EashaDas(DHGSU)

 Oxygen Balance: It is a difference between the oxygen
content in the molecule of the explosive and the oxygen
required to oxidize the carbon and hydrogen contained in
it .
 RDX: It is CYLOMETHYLENE TRINITROAMINE
and is a powerful high explosive .
 TNT: It is produced by nitration of toluene and is a
powerful high explosive.
58
HritikKumar&EashaDas(DHGSU)

CASES:-
Some famous bomb blast cases in India:-
 Bombay bomb blast case,1993 (Explosive-RDX filled vehicle bomb
and suitcase bomb,hand grenade)
 Indian Parliament attack,2001 (Explosive-Grenade and AK 47 rifle)
 J&K legislative Assembly attack,2001 (Explosive-IEDs Suicide
bomb)
 Akshardham temple attack,2002(Explosive-Grenade and AK47)
 Mumbai train blast,2006 (Explosive-pressure cooker bomb)
 Hyderabad Twin bomb blast case,2007 (Explosive IED made with
Ammonium nitrate, Neogel 90
 Delhi serial blast,2008(Explosive-Ammonium nitrate based bomb
tied to Integrated circuit with timer)
 Assam serial blast.2008(Explosive-RDX,TNT,PETN)
 Jaipur bombing, 2008 (Explosive- bicycle bomb, Ammonium nitrate,
RDX)
 Pune bomb blast,2010 (Explosive -IED )
 26/11 Terror attack Mumbai,2008(weapon AK-47, Explosive- RDX
,IED, Grenade)
 The Pulwama attack, 2019 (Explosive-high grade RDX) etc.

REFERENCES:
 http://web.mst.edu/~dludlow/classes/che258/Reactive%2
0and%20Explosive%20Materials.ppt
 https://www.ibanet.org/Document/Default.aspx?Documen
tUid=E1C79314-3A7B-404B-8420-57574B852DD2
 https://www.nps.gov/parkhistory/online_books/npsg/explo
sives/Chapter2.pdf
 blob:https://web.whatsapp.com/08566c55-3f39-46a6-
8170-de2857e92d88
 blob:https://web.whatsapp.com/d8ae96e2-06eb-4e88-
aff4-b76aebe97152

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