US2314808A - Explosive composition - Google Patents

Description

Patented Mai-.23, 1943 2,314,808 EXPLOSIVE comosirron Clarence H. Winning and Ross J. Miller, Woodbnry, N. J., assignors to E. I. du Pont de Nemonrs & Company, Wilmington, DeL, a corporation of Delaware No Drawing. Application December Serial No. 370,488

Claims. (o1. 52-l1) This invention relates to explosive compositions containing a water-soluble inorganic salt,

to ammonium nitrate exadheres to the grain and is not removed in threshing. The above species of wheat differ markedly from the common form of .wheat (Triticum vulaare) such as to give importantly diflerent characteristics to explosives containing them where a water-soluble salt is present.

Our invention is applicable with advantage to all explosive compositions containing a waterit has a great amnity for water. Because of this fact, there is a tendencyior explosive compositions high in ammonium nitrate to become hard and set on storage in the presence of even small 'amounts of moisture. This brings about a decreased sensitiveness of the explosive and a lesser degree of uniformity in performance. The water resistance of ammonium nitrate explosives is generally low because of the presence of this very soluble salt.

Anobject of the present invention is an explosive composition containing at least one watersoluble salt and having improved water resistance. A further object is an ammonium nitrate explosive of enhanced waterresistance. A still further object is an explosive containing ammonium nitrate wherein an ingredient is present which tends to prevent the harmful penetration of water. Additional objects will be disclosed as the invention is described more at length hereinafter. We have found that the foregoing objects are accomplished by including spelt meal as an ingredient in explosive compositions containing at least one water-soluble salt, said spelt meal or flour being capable of functioning as a protective agent against water for said salt.

By the term spelt meal we intend to designate the finely divided form of that variety of wheat known as spelt or any of its variations.

western states of the United States, as well as in central and southern Europe. The botanical classification of this species is not wholly exact and the term spelt frequently is applied to the variety of wheat more properly named emmer. By the term spelt therefore we intend to include not only the true spelt" (Triticum spelta) out also emmer" (Triticum dicoccum). It is a characteristic of Triticum spelta. that the chaff This species of wheat is grown in various midsoluble salt, whether this salt is ammonium nitrate, sodium nitrate, a chlorate or perchlorate,

or other soluble salt. We find it particularly H important in the case of ammonium nitrate explosives, and especially in such compositions containing an explosive nitric-ester, nitroglycerin, for example. It should be understood, however, that the invention is applicable as. well to explosive compositions which contain no ingredient which is itself an explosive, for example, compositions containing non-explosive sensitizing agents.

Many compositions, for instance, contain ammonium nitrate or other oxidizing agent sensi tized with materials such as aluminum or other finely divided metals. .Likewise, certain ammonium nitrate explosives are sensitized with various forms of carbon, hydrocarbons and hitrated hydrocarbons, for example, paramn, char- .coal, dinitrotoluene, and the like. Our invention is equally applicable to these compositions, since they contain the water-soluble salt which must be protected from wet conditions in the field.

The advantages of. our invention are illustrated by tests on the following specific embodiments,

in which A and B represent onia dynamites .of similar compositions, A containing ordinary carbonaceous combustibles and B spelt meal:

14.0 no 88.6 ass 0. 3 0. 3 sea am; so 0.9, so

c o co co 0. s; o. a

- 100.0 100.0 Density-wtga/M lbs.l% x 8"; 113 108 The foregoing dynamitesA and B, in cartridges of 4" x 10" dimensions, were subjected to a leaching test under pressure. In each cartrie four holes were made of %f diameter in the side wall at each end. These cartridges were'then exposed to a water pressure of 15 lbs. per square inch for 24 hours. At the end of the test. the

sample A, containing meals of the prior art, consisted only of a 2 /2 x 7" column of highly wetted material. The weight of the cartridge had been reduced by leaching from 2506 to 1754 grams. In the case of the sample B, containing spelt meal,

the weight of the powder after the leaching treatment had actually-increased from 2678 to 2725 grams, and a core of completely dry material was present at the center. While the material at the ends of the cartridge had become wetted, it had not been leached out in a manner even appreaching that of sample A.

The spelt meal, when present inexplosives of the type described, is capable of forming a cohesive and protective paste with the more or less rapid separation of the flour, meal, starch, or the like. Spelt flour acts differently in that the greater part of the material remains colloidally dispersed and suspended on dilution of a relatively dry material with dilute nitrate solution even though no heat has been applied at any time.

When spelt meal according to our invention is used in composition such as ammonia dynamites, it appears that the entrance of the first traces of water brings about a paste or gel formation. This gelatinization in the outer portion of the explosive retards the rate of water penetration toward the interior of the explosive column. The gelatinous structure formed also prevents segregation of liquid or solid ingredients of the explosive such as would be caused by water penetration and softening of the composition. The cohesive gel or paste also decreases the loss of solid or liquid ingredients from partly opened cartridges by reason of gravity flow. The leaching ofsoluble salts is likewise lessened by the presence of the paste, as has been shown in the example cited.

It will be understood that, in1order to obtain the most favorable results, thespelt meal or fiour should be in, finely divided condition. Preferably, said meal should be in a state of subdivision such that -the major portion, that is more than 50%, will pass a 60-mesh screen. Furthermore, the spelt flour is preferably included in the explosive composition in pulverulent form during the manufacture of the explosive composition, no' paste/,being formed at that; time.

' We do not inten to be limited to meal of this degree of fineness, however. Likewise, we may wish to introduce into the explosive composition a small amount ofa water-insoluble metal soap,

such as calcium stearate, which will have aprotective and coating effect on the ammonium nitrate against water or moisture. The presence of this latter ingredient, together with the spelt flour, gives very beneficial results. The shell; flour is effective, however, without the presence of the water-insoluble soap. Preferably, said spelt flour will be used in an amount not greater 7 than 15%, and we find a quantity between 1% and 9% to be advantageous.

It will be understood that we may use a. meal made from the entire spelt kernel or portions of said kernel which have a higher protein content, or otherfractions of the type.

The invention is applicable with great advantage in ammonia dynamites containing ammonium nitrates and nitroglycerin in amounts not exceeding 25%, for example, between 3% and 25%. It has important applications also in the case of compositions containing other high explosive compounds, such as nitrostarch, trini trotoluene, and the like, in the presence of ammonium nitrate or other water-soluble salt. Furthermore, it is effective in the case of compositions in which the ammonium nitrate is sensitized by means of paraflin, dinitrotoluene, carbon, aluminum, other powdered metals and alloys, and many other materials.

The spelt flour, according to our invention, has been stated to be present preferably in pulverulent form during the manufacture of the explosive, since in this form the meal or flour functions in the peculiarly eifective manner desired in protecting the explosive against water penetration.

Our invention has been described in detail in the foregoing. It will be apparent, however, that many variations may be introduced in methods of application or in compositions without departure from the scope of the invention. We intend to be limited therefore only by the following patent claims.

We claim:

1. An explosive composition comprising a water-soluble oxygen-supplying inorganic salt, a

sensitizing agent, and spelt meal in pulverulent form. 1

2. An explosive composition comprising ammonium nitrate, a sensitizing agent, and spelt meal in pulverulent form.

3. An explosive composition comprising ammonium nitrate, an explosive sensitizing agent, and spelt meal in pulverulent form.

4. The explosive composition of claim 3, wherein the sensitizing agent comprises nitroglycerin.

5. The explosive composition of claim 3, wherein the sensitizing agent comprises an aromatic nitrocompound.

8. An explosive composition comprising ammonium nitrate, a non-explosive sensitizing agent, and spelt meal in pulverulent form.

7. The explosive composition of claim 6, wherein the sensitizing agent comprises a powdered metal.

8. An explosive composition comprising ammonium nitrate, between 3% and 25% nitroglycerin, and not more than 15% spelt meal in pulverulent form.

9. The explosive composition of claim 8, in

which the spelt meal is. present in a. degree of fineness such that more than 50% thereof will pass a GO-mesh screen.

10. The explosive composition of claim 8,. in which the spelt meal is present in an amount between 1% and 9%.

CLARENCE H. WINNING. ROSS J. MILLER.