Nitro-Explosives: A Practical Treatise

cerine-Manufacture of N

aration-Filtering and W

Acid from the Manufactu

-Co

oluble in water, crystallises at 10.5° C., but different commercial samples behave very differently in this respect, and minute impurities prevent or delay crystallisation. Solid nitro-glycerol[A] melts at about 12° C., but requires to be exposed to this temperature for some tim

hen added to nitro-glycerine up to 20 per

, Chem. Tech., 22

heir showing signs of decomposition; but if it should contain the smallest trace of free acid, decomposition is certain to be started before long. This will generally show itself by the formation of little green spots in the gelatine compounds, or a green ring upon the surface of liquid nitro-glycerine. Sunlight will often cause it to explode; in fact, a bucket containing some water that had been used to wash nitro-glycerine, and had been left standing in the sun, has in our experience been known to explode with

for C_{3}H_{

.62 15.86

en 2.4

n 17.90

... 6

umas' method; but I have never found any difficulty in obtaining percentages as high as 18.46 by the u

}){3} = 6CO{2} +

t. of oxygen above that required for complete

d (CO_{2}) 5

r 19

3.52 pe

gen 1

o-glycerine is decomposed differently if it is ignited as dynamite (i.e., kieselguhr dynamite), and if the gases are allowed to escape fr

.2 pe

35.

2} 1

per

1.

4} 0

ss fire). In a recent communication, P.F. Chalon (Engineering and Mining Journal, 1892) says, that in practice nitro-glycerine vapour, carbon mo

t of combustion by M. Longuinine, is 432 calories for 1 grm.; and the heat of combustion equals 1,576 cals. for 1 grm. In the case of nitro-glycerine the heat of total combustion and the heat of complete decomposition are interchangeable terms, since it contains an excess of oxygen. According to Dr W.H. Perkin, F.R.S.,[B] the magnetic rotation of nitro

Soc. Chem. Ind.,

Chem. Soc., W.H. Pe

solvents has been investigated by A.H. Elli

| " | " Nitric acid (1.400) | Slowly soluble | " Hydrochloric acid (1.200) | Insoluble, decomposed| Slowly soluble Acetic acid, glacial | Soluble | Soluble Carbolic acid | " | " Astral oil | Insoluble | Insoluble Olive " | Soluble | Soluble Stearine oil | " | " Mineral jelly | Insoluble | Insoluble Glycerine | " | " Benzene | Soluble | Soluble Nitro-benzene | " | " Toluene | " | " Carbon bi-sulphide | Insoluble | Slightly affected Turpentine | " | Soluble Petroleum naphtha,

. The true freezing point of pure nitro- glycerine was found to be 12.3°C. The technical product, owing to the presence of di-nitro-glycerine, freezes at 10.5° C. According to Raoult's law, the lowering of the freezing point caused by m grms. of a substance with the molecular weight M, when dissolved in 100 grms. of the solvent, is expressed by the formula: [Delta] = E(m/M), where E is a constant characteristic for the solvent in question. The value of E for nitro- glycerine was found to be 70.5 when calculated, according to Van't Hoff's formula, from the melting point and the latent heat of fusion of the substance. Determinations of the lowering of the freezing point of nitro- glycerine by additions of benzene, nitro-benzene, di-nitro-benzene, tri- nitro-benzene, p.-nitro-toluene, o.-nitro-toluene, di-nitro-toluene, naphthalene, nitro-naphthalene, di-nitro-naphthalene, ethyl acetate, ethyl nitrate, and methyl alcohol, gave results agree

g. Pat. 25,797,

gew. Chem., 1905,

are contained in a lead vessel, which is kept cool by a stream of water continually passing through worms in the interior of the nitrating vessel, and the glycerine is gradually added in the form of

about 97 per cent. of mono- hydrate. It is of the very greatest importance that the nitric acid should be as strong as possible. Nothing under a gravity of 1.52 should ever be used even to mix with stronger acid, and the nitration will be proportional to the strength of the acid used, provided the sulphuric acid is also strong enough. It is also of great importance that the oxides of nitro

give very poor nitration results. A tenth normal solution of sodium hydroxide (NaOH), with phenol-phthalein as indicator, will be found the most convenient method of determining the total acid present. The following method will be found to be very rapid and reliable:-Weigh a 100 c.c. flask, containing a few cubic centimetres of distilled wat

aining about 10 c.c. of water, and add from a burette 10 to 16 c.c. of the permanganate solution; then add 2 c.c. of the acid to be test

ken for analysis. Took 20 c.c. permanganate solution, O.0046 x 20 =.092 grm. N_{2}O_{4}, and (.092 x 100)/3.04 = 3.02 per cent. N_{2}O_{4}. The

33 x 1.84 = 2.447). Wash into a large Erlenmeyer flask, carefully washing out the bottle, and also the stopper, &c. Add a drop of phenol- phthalein solution and titrate, with a half normal solution of sodium hydrate (use

45 : x = 95.64 per

the chimney shaft, and on the bottom of which was a lead pipe, bent in the form of a circle, and pierced with holes, through which the compressed air was made to pass; but the process was not found to be of a very satisfactory nature, and it is ce

d, be poured into a tank and mixed, and subsequently allowed to flow into an acid egg or montjus, to be afterwards forced up to the nitrating house in the danger area. The montjus or acid egg is a strong cast-iron tank, of either an egg shape, or a cylinder with a round end. If of the former shape, it would lie on its side, and upon the surface of the ground, and would have a manhole at one end, upon which a lid would be strongly bolted down; but if of the latter shape, the lid, of course, is upon the to

to a certain mark, just enough of the mixed acids for one nitration. The object of this tank is, that as soon as the man in charge knows that the last nitration is finished, he refills this smaller tank (which contains just enough of the mixed acids), and allows its contents to flow down into the nitrating house and into the nitrator, ready for the next nitration. The nitration is usually conducted in a vessel constructed of lead

hich is a small glass window, through which the progress of the nitrating operation can be watched. From the top of this dome is a tube of lead which is carried up through the roof of the building. It serves as a chimney to carry off the acid fumes which are given off during the nitration. The interior of this tank contains at least three concentric spirals of at least 1-inch lead pipe, through which water can be made to flow during the whole operation of nitrating. Another lead pipe is carried through the dome of the tank, as far as the bottom, where it is bent round in the form of a circle. Through this pipe, which is pie

ycerine give 227 lbs. nitro-gly

er Pipes for Cooling; C, Acid Mixture Pipe; E, Compressed Ai

harge, the former gives the temperature of the bottom, and the latter of the top of the mixture. The glycerine should be contained in a small cistern, fixed in some convenient spot upon the wall of the nitrating house, and should have

ratus. A large tap made of earthenware (and covered with lead) is fixed in the side of the nitrating tank just above the bottom, to run off the charge after nitration. This should be so arranged that the charge may be at option run down the conduit

lycerine tap is then partially opened, and the glycerine slowly admitted, and the compressed air turned on full, until the contents of the apparatus are in a state of very brisk agitation. A pressure of about 40 lbs. is about the minimum (if 247 lbs. of glycerine and 16 cwt. of acids are in the tank). If the glycerine tube is

dioxide are connected with the air pipes so that in the event of a failure

end to during the progr

registered by the

iven off (as seen through the little

s seen from a gauge fixed upon the air

The temperature, as shown by either of the two ther

e shut off, and the pressure of air increased for some few minute

bottom of the tank is opened, and the charge allowed to flow aw

sand, &c., may be at once removed. It is a good plan for the nitrator to keep a book in which he records the time of starting each nitration, the temperature at starting and at the finish, the time occupied, and the date and number of the charge, as this enables the foreman of the danger area at any time to see how many charges have

HNO_{3} = H_{2}SO_{4

ation of the process of nitratio

(in short lengths), in order that by lifting them at any point the condition of the conduit can be examined, as this is of the greatest importance, and the conduit requires to be frequently washed out and the sulp

.-SMALL NITRATOR. N,

mometer; W, Windows;

y. It should be made of stout lead (all lead used for tanks, &c., must be "chemical lead"), and may be made to hold 50 or 100 lbs. as found most convenient. This nitrator can very well be placed in the same house as the separator; in fact, where such a small quantity of nitro- glycerine is required, the whole series of operations, nitrating, separation, and washing, &c., may very well be performed in the same building. It will of cour

ion to direct the escaping air and fumes into a fume pipe where the flow of the latter may be assisted by an air injector. The lateral pipe in the separation cylinder is in connection with a funnel leading to the prewash tank. The drawing (Fig. 7) shows a vertical section of the apparatus; a is the nitrating vessel of usual construction, having at the bottom an acid inlet pipe with three branches, one leading to the de-nitrating plant, c leading to the drowning tank, and d, which extends upwards and has two branches, e leading to the nitrating acids tank, and f to the waste acid tank. On the sloped bottom of the nitrating vessel a lies a coil g of perforated pipe for blowing air, and there are in the vessel several coils h, three shown in the drawing, for circulation of cooling water. At the

ng. Pat. 15,98

) to the Waste Acids; (g) Coils for Compressed Air; (h) Pipes for Cooling Water; (i) Glass Cylinder; (j) Outlet to k; (k) leading to Prewash Tank; (l) Glass Dom

opped, and the glycerine supply vessel n is removed. The nitro-glycerine as it separates from the acids is raised by introducing by the pipe f waste acid from a previous charge, this displacing the nitro-glycerine upwards and causing it to flow by the outlet, j and pipe k to the prewash tank. When nearly all the nitro-glycerine has been separated in this manner the acids in the apparatus may be run off by the pipe b to an after separating vessel for fur

ion separation is commenced at a temperature such that when all the displacing acid has been added, and the separation of the nitro-glycerine is complete, the temperature of the contents of the nitrating vessel shall not be lower than 15° C. A sufficient quantity of the displacing acid is then run off through the waste-acid cock to allow of the remaining acids being air-stirred without splashing over the top. A small quantity of water, from 2 to 3 per cent. according to strength of acid; if waste consists of sulphuric acid (monohydrate), 62 per cent.; nitric acid (anhydrous), 33 per cent. and water 5 per cent.; temperature 15° C., then 2 per cent. of water is added; if waste acids contain less than 4 per

is carried up through the roof of the building, and acts as a chimney to carry off any fumes. A little glass window should be fixed in this pipe in order that the colour of the escaping fumes may be seen. The conduit conveying the nitro-glycerine enters the building close under the roof, and discharges its contents into

, bent in the form of a loop. It should lie upon the bottom of the vat. The object of this is to mix up the charge in case it should get too hot through decomposition. A thermometer should of course be fixed in the lid of the tank, and its bulb should reach down to the middle of the nitro-gl

-SEPARATOR. A, Compres

Nitrator; N, Nitro-gly

ide; S, Waste Acids to

es of Nitro-glycerine;

er Pipe; N, Nitro-glyc

in the same house, where it is washed three or four times with its own bulk of water, containing about 3 lbs. of carbonate of soda to neutralise the remaining acid. This smaller tank should contain a lead pipe, pierced and coiled upon the bottom, through which compressed air may be passed, in order to stir up the charge with the water and soda. After this preliminary washing, the nitro-glycerine is drawn off int

-FILTERING AND WASHING

L, Lid; S, Nitro-glyce

Tanks; B2, Ind

ng a compressed air pipe, just like the one in the small tank in the separating house. This tank is half filled with water, and the compressed air is turned on from half to a quarter of an hour after the introduction of the charge. The water is then drawn off, and fresh water added. Four or five washings are generally necessary. The nitro-glycerine is then run into the next tank (A), the top of which is on a level

time, than to use a lot of water and wash for half an hour. Plenty of compressed air should be used, as the compound nitric ethers which are formed are thus got rid of. As five or six charges are often in this house at one time, it is necessary to have as many tanks arranged in tiers, otherwise one or two refractory charges would stop the nitrating house and the rest of the nitro-glyc

pecific gravity a

ld nitr

ent matter, nor should any white flocculent matter (due to fatty acids) be formed wh

chlorine, and contain only trace

d organic residue together when evaporated in a platinum dis

ver te

it or separation of fatty acids when nitric peroxide gas is p

3 inches will rise to the surface or hang about in the nitro-glycerine, and at the point of contact between it and the mixed acids, and will afterwards be very difficult to get rid of by filtration. The material appears to be partly an emulsion of the glycerine, and partly due to fatty acids, and as there appears to be no really satisfactory method of preventing its formation, or of getting rid of it, the better plan is not to use any glycerine for nitrating that has been found by experiment u

d shaken with a little distilled water. This should be repeated, and the washings (about 400 c.c.) run into a beaker, a drop of Congo red or methyl orange added, and a drop or so of N/2 hydrochloric acid added, when it should give, with two or three drops at most, a blue colour with the Con

erience does not warrant the assumption that free acid is a source of danger in nitro

little water it still contains to rise to the surface. In order to accomplish this, it is sufficient to allow it to stand in covered-in tanks of a conical form, and about 3 or 4 feet high. In many works it is previously filtered through common salt, which of course absorbs the last traces of water. It is then of a pale ye

ezable oil, less sensitive to percussion, friction, and increase of temperature, and to possess a greater solvent power for collodion-cotton than ordinary nitro-glycerine. It can thus be used for the preparation of explosives of high stabili

ies of nitro-glycerine, which must be separated, as it is impossible to run this liquid away (unless it can be run into the sea) or to recover the acids by distillation as long as it contains this substance. The mixture, therefore, is generally run into large circular lead-lined tanks, covered in, and very much like the nitrating apparatus in construction, that is, they contain worms coiled round inside, to allow of water being run through to keep the mixture cool, and a compressed air pipe, in order to agitate the mixture if necessary.

It should be taken to the filter house and treated along with another charge. The acids themselves may either be run to waste, or better treated by some denitration plant. This house probably requires more attention than any other in the danger area, on account of the danger of the decomposition of the small quantities of nitro-glycerine, which, as it is mixed with such a large quantity of acids and water, is very apt to become hot, and decomposition, which sets up in spots where a little globule of nitro-glyc

once be shut off and the air turned on full, but if it is seen that an explosion is likely to occur, the tank should at once be emptied by allowing its contents to run away into a drowning tank placed close outside the house, which should be about 4 feet deep, and some 16 feet long by 6 feet wide; in fact, lar

, together with nitrate of soda, in a fine stream, and the small quantity of nitro-glycerine, coming into contact with the hot mixture already in the retort, would

Acid from the Manufactur

mposition of these

erine and

te

d 70 per cent

acid 10

20 "

cid to stand for at least twenty- four hours in a big vessel with a conical top, where all the nitro- glycerine which will have separated to the surface is removed by skimming; or, better still, the "watering down process" of Col. Nathan may be employed. In Nathan's nitrator every existing trace of nitro-glycerine is separated from the acids in a few hours after the nitration, and any further formation of nitro-glycerine is prevented by adding about 2 per cent. of water to the waste acids, which are kept agitated during the addition. The waste acid, now free from nitro-glycerine, but which may still contain organic matter, is denitrated by bringing it into contact with a jet of steam. The waste acid is passed in a small stream down through a tower of acid-resisting stoneware (volvic stone), which is closely packed with earthenw

ugh examination, including a preliminary experimental nitration, should always be instituted. As regards the second, the sulphuric acid should not only be strong (96 per cent.), but as free from impurities as possible. With the nitric acid, which is generally made at the explosive

acture of Nitric Acid,"

h 18

that the fluid may pass continuously from one to the other. The nitric acid being continuously separated by distillation, the contents of each division vary-the first containing the full proportion of nitric acid, and each succeeding one less of the nitric acid, until from the overflow of the last one the bisulphate of soda flows away without any nitric acid. The nitrate of

to take place at different points of space, and these differences exist at one and the same points of time." It is possible with this plant to produce the full product of nitric acid of a gravity of 1.500, or to obtain the acid of varying strengths from the different still-heads. One of these stills, capable of produci