US2096089A - Explosive - Google Patents

Description

Patented Oct. 19, 1937 UNITED STATES PATENT OFFICE EXPLOSIVE No Drawing.

Application April 20, 1934,

Serial No. 721,545

7 Claims.

from crude cellulosic materials such as, for example, balsa wood, bagasse, oat hulls, wood flour, etc., which can be successfully formulated into highexplosives. The nitrated materials in accordance with this invention -will contain only from 9-11.5% nitrogen, and will accordingly be sufiiciently stable for satisfactory use. In formulating an explosive in accordance with this invention, the nitrated material as, for example, nitrated balsa, nitrated bagasse, nitrated oat hulls, nitrated wood flour, etc. will be impregnated with what may be termed an explosive oxidant, as, for example, ammonium nitrate, ammonium perchlorate, potassium chlorate, etc. The term explosive oxidant is meant to designate those materials, well known in the explosive art, which, while not themselves explosive in the ordinary meaning of the word, are capable of forming a. detonatable mixture when combined with organic materials, and which when present in. an explosive actually take part in the explosion. The explosive in accordance with this invention will accordingly comprise a nitrated cellulosic material impregnated with an explosive oxidant.

The nitrated cellulosic material in accordance with this invention may be produced by nitration 40 of the comminuted raw material, as, for example,

balsa pulp, bagasse pulp, oat hulls, wood flour, etc. with mixed nitric and sulphuric acids in the manner well known to. the art, for example, as

flaked starch is nitrated. (See U. S. Pat. 1,908,857 to George M. Norman.) Themixed acids are chosen to give a product of from about 9% to about 11.5% nitrogen.

The nitrated cellulosic material will be found to retain essentially the same physical appearance and properties as the raw product from which it was made, and will accordingly be highly absorptive. The impregnation of this nitrated material with an explosive oxidant can be accom- .plished in various ways.

Thus, in accordance with this invention, the

explosive oxidant may be dissolved in water to form a concentrated solution, the nitrated cellulosic material stirred into this solution until the liquid has been all absorbed, and the result ant product dried until it becomes crisp and free 5 flowing. For example, 20 grams of ammonium nitrate may be dissolved in 3 to 4 cc. of water at -80 C., and 5 grams of dry nitrated balsa pulp are then stirred into the solution. The product is then dried to 105.F. until it becomes crisp and free-flowing. The explosive so produced may be detonated by a #6 electric blasting cap, and has a. weight strength of 63.3%.

In order to avoid the necessity of drying the nitrated cellulosic material before the impregnation (which presents some fire hazard owing to the dusty nature of the dry material), the wet nitrated material as taken from the final stabilizing wash or boil may be mixed with the finally ground explosive oxidant, the residual water acting as a solvent for the salts and effecting impregnation. The product may then be dried as described above. For example, wet nitrated balsa pulp may be thoroughly mixed with four times its dry weight of ammonium nitrate, or of .equal parts ammonium and sodium nitrates, and then dried at 105 F. until crisp and free flowing. The use of ammonium-nitrate alone gives an explosive having a lb. count of509 and a weight strength of 65.3%. The explosive containing sodium nitrate has a 100 lb. count of 498 and a weight strength of 28.3%.

By using this method water-insoluble materials may also be incorporated. For example, an ex-' plosive may be made from wet nitrated balsahaving the following composition and properties:

Per cent Nitrated balsa (dry weight) 10 Ammonium nitrate 10 Sodium nitrate 65 Charcoal 8 Sulfur 7 Count per 100 lbs 440 Weight strength 9.5

nated material at an elevated temperature. 55

Per cent Nitrated balsa pulp 20 Ammonium nitrate '70 Nitroglyicer 10 In addition to the nitrated crude cellulosicmaterials, as balsa wood, bagasse, oat hulls, 'wood flour, etc., already referred to, nitrated starch flakes and nitrocellulosecan also be impregnated with the explosive oxidant in producing explosives in accordance with this invention.

- While ammonium nitrate has been indicated as the explosive oxidant used in the examples given, other explosive oxidants, as for example, ammonium perchlorate, etc. may be used to replace the ammonium nitrate either in whole or in part. For example, explosives in accordance with this invention may be composed of 20% and the remainder ammonium perchlorate or a mixture of ammonium perchlorate and ammonium nitrate.

By way of recapitulation the following table shows, solely as examples, various types of explosives produced in accordance with this invention:

Detonates Percent Weight Material Percent Dens. with NH4NO; E- B mp Smilgth Percent Nitratad balsa 20 80 33 Yes 65.34 26 74 35 do. 68. 78 33% 66% 22 do. l4. i6 20 so 41 do 20 80 36 do. 71. 33 Nitrated starch flakes 25 75 46 do. 70. 33 a N itrated cotton 20 80 .44 do. 70.99

in accordance with this invention to form a powerful explosive. Their natural absorbency, however, is not as great as that of the crude cellulosic materials.

However, since these carbonaceous materials (starch and cotton) can be obtained in a substantiaily pure form, they may be nitrated to give products having more nitrogen than 11.5% without becoming unstable.

Thus, for example, 75 g. of ammonium nitrate may be dissolved at 75-80" C.- in a minimum of water, and 25 g. of dry nitrated starch flakes, produced, for example, by the method described in U. S. Pat. 1,908,857 to Normammay be stirred into the solution. The material, when dried at about 105 F., is granular and free flowing and has a weight strength of 70.3%.

Also, wet nitrostarch flakes may be treated with the finely ground explosive oxidant in the manner i heretofore described. By this method an explosive of the following composition was produced:

) Per cent Nitrostarch flakes (dry weight) 15 Ammonium nitrate; 25 Sodium nitr 56 Balsa pulp 4 The balsa pulp is added to increase the absorptiveness of the mixture and so to aid impregnation.

of explosives other A solution of g. 'of ammonium nitrate in a.

minimum of water may be used to impregnate 20 g. of drynitrocotton (13%N). The dried prod-, uct has a weight strength of 70.9%.

example, sodium nitrate, trated wood pulps, may

'ingly may be readily cartridged, or,

cellulosic material containing from The explosives in accordance with this invention have many desirable properties. They are powerful, relatively insensitive to shock yet easily detonated by proper means, inexpensive, and ,(if they do notcontains nitroglycerin or the like) non-freezing and non-headache-producing.

Explosives in accordance with this invention will also be found to be free-flowing and accordif desired, may be poured directly into bore holes.

What I claim and desire to protect by Letters Patent is:

1. An explosive comprising a nitrated crude cellulosic material containing from about 9% to about 11.5% nitrogen impregnated with an explosive oxidant.

2. An-explos'ive comprising a nitrated crude about 9% to about 11.5% nitrogen impregnated with ammonium nitrate.

3. An explosive comprising a nitrated crude cellulosic material containing from about 9% to about 11.5% nitrogen impregnated with ammonium perchlorate.

4. An explosive comprising nitrated balsa pulp containing from about 9% to about 11.5% nitrogen impregnated with an explosive oxidant.

5 An explosive comprising nitrated bagasse containing from about 9% to about 11.5% nitrogen impregnated with an explosive oxidant.

6. An explosive comprising nitrated oat hulls containing from about 9% to about 11.5% nitrogen impregnated with an explosive oxidant.

'1. An explosive comprising a nitrated crude cellulosic material containing from about 9% to about 11.5% nitrogen impregnated with a WILLARD D! C. CRA'I'EQR.

nitrated b'alsa I