PARTⅠ PYROLYSISENERGY REUSE OF OBSOLETE PROPELLANT
Yanling Lu*, Li Zhang, Shiguo Du, Dongmei Shi, Yi Guo
The Third Department, Shijiazhuang Mechanical College, Shijiazhuang 050000,China.
E-mail:luylrp01@yahoo.com.cn
Abstract: Obsolete Propellant is also high macromolecule material with high volume energy
density. To reuse the energy, converting obsolete propellant to civilian explosive was studied
in this paper,and a kind of perfusion gel explosive was got. In the explosive, obsolete
propellant, unnecessary to be crashed, served as reducing agent, ammonium nitrate andsodium nitrate served as oxidant, polyacry lamide served as gelatinizer, little amount ofchromium nitrate served as cross linker. In the process, the oxidant water solution, gelatinizer,
cross linker were mixed at a certain temperature, then poured into the obsolete propellant toform perfusion gel explosive after gelling, and there are no second pollution. The perfusion
gel explosive was tested for its power, brisance, thermal consistency, vibration consistency.
Keywords: obsolete propellant; perfusion explosiveAfter World War II, because of political and military need, the countries all over theworld had stored a large number of weapons and ammunitions. The ammunitions stored
would be turned into obsolete after certain storage period. The explosives filled in projectile
are the mixture of TNT and RDX or TNT and HMX or explosives and non-explosives. The
disposal of this part of explosives at present is that TNT would be reclaimed and the otherexplosive would be demolished directly. The quantity of the propellant out of date is much
more than that of explosives. The propellant, a kind of energy material, contain a large
amount of chemical groups as C-NO2,N-NO2,O-NO2, whose fracture energy are more than
240kJ/mol, so the reuse of obsolete propellant is very important under current situation lackof energy.
1. Introduction
There are three kinds of traditional methods to dispose obsolete propellant in big
batch:①dumping in international waters;②burying in deep land;③burning in open area.
Burning in open area would produce a large amount of high density polluted gas and ignition
residue, which can flow with air, rainwater, etc, encroaching on mankind and ecologicalenvironment. Developed countries began to ban burning in open area gradually from themiddle of the seventies [1]. Some developed countries began to adopt burning in destructor,- 41 -

The 5th ISFR (October 11-14, 2009, Chengdu, China)that is, burning under the terms of adjusting and controlling, making obsolete propellant fully
decomposed and then oxidized fully again. But this approach need a lot of maintenancecharge, and will consume certain fuel and electricity energy. In order to make the best use ofobsolete propellant without polluting environment, some countries have begun to study on
recycling discarded material containing energy, and research on obsolete propellant is themost active. The nitrocellulose retrieved from single-based propellant can serve as raw
material of nitro-cotton coatings; the overdue propellant can be used to make highhydroscopicity resin, or serve as assisting fuel of boiler. Regarding the characteristic ofburning or exploding rapidly of propellant, it can be turned to special energy sources, ofwhich industry explosive is the best. In China, research of obsolete propellant reused as
explosive began in 1986, and had already made great progress now, and make the leading
position in the world. Some technique has realized industrialization production.
Militarily propellant has certain shape and size, such as single-hole or porous or floriatedgranular propellant, single-hole or porous tubular propellant with different length, cricoid
propellant and other special shape propellant. Under normal conditions, propellant only canburn, not explode, but, can explode under strong constraint condition (powder grain filled insteel tube) or detonated with strong strength (such as detonated by RDX). So the obsolete
propellant can't be used as explosive alone directly. When made to industry explosive, such as
water-glue and emulsification-explosive,powdered industry explosive,pappy industry
explosive [2,3], propellant is mainly used as sensitizer. In the above technique process,comminuting propellant into powder of certain granularity is very dangerous, and the storage,transportation of the explosive powder is very dangerous, too. In September of 2005, anaccident of deflagrating happened when ex-service gunpowder was made to emulsification
explosive in the Northeast, causing 3 deaths. The Nanjing university research institute ofcharge technology has explored a method, perfusion technique, without comminution, ofmaking obsolete propellant into civil explosive, but it is still at experiment explore stage. In
this paper, the research of making obsolete 14/7 and 22/1 single-based propellant into
perfusion explosive were carried out.
2. Experiment
2.1 Material
14/7, 22/1 single-based propellant; UPVC tube, Inner diameter: 30mm, 50mm, 75mm,length:13cm; nitrate ammonia and cubic niter, weigh ratio of NH4NO3:NaNO3:H2O is 4:1:1(according to the ternary phase diagrams of NH4NO3-NaNO3-H2O); polyacrylamide
macromolecule, serve as absorbent material; cross linker.
Fig. 1 shows the experiment process of making perfusion explosive from single-based
propellant:- 42 -PARTⅠ PYROLYSIS

oxidant

assistansolutionwatehigh polymer

cross linker

low viscous miscible liquids

powder grain
perfusion explosiveFig. 1 flowchart of making perfusion explosive
At room temperature, the bottom of UPVC tube was sealed with PVC board. The
propellant was filled in UPVC tube in natural state, and the effective porosity of the volumeof the UPVC tube is measured with method of filling water. A certain amount of highpolymer polyacrylamide and firming agent were added to water solution of solid oxida
including ammonia nitrate and cubic niter. Then, mixed high polymer-saline solution waspoured slowly into UPVC tube filled with propellant, and the space for detonating charge
shoud be left with emplacing a mould at one end of the tube. about an hour later, the mouldfor detonating charge can be removed, the UPVC tube with perfusion gel explosive can besealed with PVC board for use.
3. Results and discussion
The compositions of single-based propellant are basically same except for the shape andthe size,such as 7/7,9/7,11/7,12/7,13/7,14/7,16/7 and 8/4 single-based propellant, whose main
ingredient, about 94×10-2～98×10-2, is the same batch of nitrocellulose with nitrogen content
between 12.75%～12.97%. As can be seen, single-based propellant has high content ofnitrocellulose with high content of nitrogen and comparatively single composition. So, 14/7
and 22/1 single-based propellant were chosen to be made into perfusion civil explosive firstly.
3.1 Test for power and brizance
Making 14/7 and 22/1 single-based propellant into perfusion explosive according to Fig.
1 .The ready-made perfusion gel explosive was detonated with 1# and 2# detonating charge
made with a certain of pressure in laboratory, while the detonating ability of 2# is greater thanthat of 1 #. The explosion ability was tested by lead plate . Tab.1 and Tab.2 show theexplosion ability of the perfusion explosive made from 14/7 and 22/1 single-based propellant.

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The 5th ISFR (October 11-14, 2009, Chengdu, China)
Tab. 1 explosion ability of perfusion explosive from 14/7 single-based propellant
Serialnumber

UPVC tube
inradius/
mm

130

35

230

3

Porosity/ Solidifying％
time/hExploding
speed/

Detonating
chargeDetonating
ability48

1＃penetrated

5210

33

48

1＃

penetrated

5137

30

34

48

2＃

penetrated

5312

43033

48

2＃

penetrated

5426

550

28

48

1＃

deep dint

650

28

48

1＃

deep dint

750

26

48

2＃

penetrated

5408

850

26

48

2＃

penetrated

5411

975

23

48

1＃

undetonated

1075

24

48

1＃

undetonated

1175

24

48

2#

penetrated

5189

1275

23

48

2#

penetrated

5213(m﹒s-1)

Tab. 2 explosion ability of perfusion explosive from 22/1 single-based propellant
Seria
lnum
ber

UPVC tube
inradius/mm

porosity/

130

2

Exploding
speedtime ofsolidifying/hdetonati
ngcharge

Detonating
ability

38

48

1＃

undetonated3037

48

1＃

undetonated

330

38

48

2＃

penetrated

5245

430

38

48

2＃

penetrated

5107

550

35

48

1＃

undetonated

650

34

48

1#

undetonated

33

48

2#

deep dint

750％

850

34

48

2#

deep dint

975

32

48

1#

undetonated

1075

31

48

1#

undetonated

1175

31

48

2#

deep dint

1275

30

48

2#

deep dint- 44 -(/m﹒s-1)

PARTⅠ PYROLYSIS
Through the test data in Tab.1 and Tab.2, it can be seen , the perfusion gel explosive
made from 14/7 single-based propellant can explode steadily when detonted by 2# detonating
charge, and the explosion speed tested is relatively identical, from the date of Tab.1, thecharge critical diameter should be smaller than 30mm and its terminal diameter should begreater than 75mm. 1# detonating charge can only detonate perfusion explosive with adiameter smaller than 30mm completely. The detonating ability of 1# detonating charge
suppressed in laboratory is greater than that of the detonator, it can be seen that the perfusion
explosive made from 14/7 single-based propellant is not sensitive to detonator and it iscomparatively safe. The nature of the perfusion explosive made from 22/1 single-based
propellant is similar to that made from 14/7 single-based propellant. However, it can be seenfrom the data in Tab.1 and Tab.2 that the perfusion gel explosive made from 22/1
single-based propellant is less sensitive, because 2# detonating charge can only detonate theperfusion explosive completely with a diameter smaller than 30mm. When the diameter is50mm or 75mm, 2 # detonating charge can not detonate perfusion explosive. So the perfusion
explosive made from 22/1 single-based propellant is safer, and even more difficult to bedetonated.
3.2 Test for thermal consistency and vibration consistency
There are much of water astricted by polyacry lamide in the perfusion gel explosive
made from obsolete propellant. So the thermal consistency and vibration consistency weretested.
When the perfusion gel explosive were put in 80℃, there are no water lost, when put in100℃,there are some little lost. As can be guessed that under nomal environment temperature,also the perfusion explosive storage temperature, the thermal consistency is good.
When the perfusion gel explosive were put in tractor traveling about 100km, there are nowater lost. And the state of the perfusion explosive is good.
When perfusion explosive explodes, chemical reaction in detonating wave is very fast.
The explosion mechanism can be explained by mix reaction mechanism because ofcomplicated components . The perfusion explosive is composed of oxidant, incendiary agent
and non- explosive composition, the detonating reaction is not carrying on in the wholechemical reaction area but in some boundaries. While exploding, the gas produced by oxidant
decompound permeates or spreads to the surface of other particles to react at first, and the
producer of different components react with each other once again. The explosion process ofthe perfusion explosive researched in this paper is great impacted by the granularity. The
littler the granularity is, the more easily the reaction is; while the larger the granularity is, themore unfavorable the reaction is, and the exploding speed may drop even .

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The 5th ISFR (October 11-14, 2009, Chengdu, China)
4. Conclusions
The perfusion explosive composed of oxidant including ammonium nitrate and cubicniter, polyacrylamideit and obsolete 14/7, 22/1 single-based propellant without comminuting
is not sensitive to detonator, but can be detonated by detonate charge of certain ignition ability,
and the exploding speed is more than 5000m/s. That means it is possible to use obsolete
single-based and double-based propellant to make perfusion explosive without any dangerous
and any pollution. The work in this paper is only preliminary experiments. The experiments
on others have not been carried out, and stability, compatibility and long storing performanceof theperfusion explosive made from14/7, 22/1 single-based propellant need further
discussion and research.
Reference:[1] J. L. Gu. , Z. S. Wang. The research of obsolete material containing energy Expolosive
equipment,2004,33(4),4~7.
[2] X. A .Wei, Z. S. Wang. The study of obsolete propellant made to perfusion explosive,Expolosive equipment ,2001,30(3) ,6~10.
[3] S. Cai, Z. S. Wang. A kind of perfusion containing obsolete propellant , Expolosive
equipment,2004,33(1),12~15.

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