US3184351A - Liquid chlorinated organic compound sensitizing agents - Google Patents

Description

United States Patent tion of Ohio No Drawing. Filed Maro 27, 1963, er. No. 268,453 23 Claims. (El. 149-4) This invention relates to novel low cost explosives and a method for their manufacture. More particularly, this invention relates to novel explosives containing a major quantity of an oxidizer and in addition a sensitizer mixture comprising a liquid chlorinated organic compound.

In the use of explosives, the need for safety is a problem which is ever present with workers in the field. Many explosives used in the field are compounded into a finished form at the factory and shipped from there to the point of use. During shipment, special precautions must be taken. Frequently, these precautions involve limitations on the routing of the explosives and the type of carrier, etc. Further, there are limitations as to the manner in which the explosives can be shipped and stored.

As a result of these requirements regarding shipping, storage, etc. dynamite and other sensitive explosives are quite expensive to ship and store. This is reflected by relatively high cost of the explosive material which must be borne by the ultimate user.

In many applications in the field, it is desirable to detonate an explosive in a small bore hole which is drilled in the rock or other material to be blasted. Since am monium nitrate-fuel oil explosive require a large diameter bore hole (in excess of 2 inches in diameter) they are unsuitable for such operations. stances, dynamite must be employed since it will detonate in a small diameter bore hole.

In present blasting operations, it is frequently necessary to have on hand two types of explosives. The first type is the ammonium nitrate-fuel oil explosive which requires a relatively large diameter hole in which to detonate and which requires a booster charge of dynamite or other sensitive material for initiation. The second type of explosive is dynamite which is relatively expensive and dangerous to work with. This explosive is frequently used as a booster for ammonium nitrate-fuel oil explosives and is further used alone for blasting operations which require the use of small diameter bore holes. Thus, present blasting operations always require the presence of large quantities of relatively sensitive explosives such as dynamite which must be transported and stored as explosive. This creates constant safety hazards. Also because they should be stored separately, the use of two types of explosives creates storage and handling problems at the blasting site.

Many explosives are solids which are formed in a given shape in their manufacture. An illustration of this is the fact that dynamite generally comes in the form of sticks. By reason of their shape, it is frequently di ncult to get the desired quantity of explosive into the bore hole. In order to meet this problem, it is common practice in the field to slit the dynamite cartridges and tamp the explosive after it is inserted in the bore hole. This breaks down the sticks and forces the explosives into contact with the Walls of the hole to give maximum packing density in the hole. Tamping is a time consuming and inherently dangerous operation since many explosives are somewhat shock sensitive.

In order to meet the above problems, it is an object of our invention to provide a low cost, multi-purpose explosive which is as cheap as ammonium nitrate-fuel oil explosives from a cost effectiveness standpoint (amount In these ina of rock removed per cost of explosive, drilling the bore holes, etc.) but which at the same time as properties that make it useful for applications now performed by dynamite. lt is a further object of this invention to provide an explosive composed of ingredients which in themselves are not explosives so that they can be shipped and stored as ordinary articles of commerce. A still further object of this invention is to provide an explosive which does not require a sensitive, high explosive booster, which will propagate readily in a small diameter bore hole, and which is free flowing so that it normally does not require tamping. Another object of this invention is to provide a method for compounding an explosive which method can be readily practiced in the field by inexperienced personnel without the use of elaborate mixing equipment. Additional objects will become apparent from the specification and claims which follow.

Oxidizers which are applicable in the explosive of this invention are those oxygen-containing solids which readily give up oxygen and include, for example, solid inorganic oxidizing salts such as ammonium, alkali metal, and alkaline earth metal salts of nitric, perchloric, sulfuric, and chloric acids and mixtures thereof. Specific oxidizers include ammonium nitrate, sodium nitrate, potassium perchlorate, ammonium perchlorate, calcium nitrate, calcium sulfate and magnesium sulfate. Mixtures of oxidizers are also applicable. Ammonium nitrate is the preferred oxidizer of this invention.

The ammonium nitrate used for the explosive compositions of our invention may be in the form of fines, crystals, grains or prills. Generally prills are preferred because they lend themselves to obtaining more intimate mixing in the field without elaborate field mixing equipment. When using ammonium nitrate prills, the prills are from about 25 to about percent saturated (if 100 percent, the prills are first evacuated in vacuo) with a sensitizer which comprises a liquid chlorinated organic compound; or a mixture of a liquid chlorinated organic compound and a hydrocarbon or a substituted hydrocarbon.

Depending upon the particular type of ammonium nitrate employed, the sensitizer comprises from about 5 to about 30 percent by weight of the total explosive formulation. When prills are employed, the sensitizer comprises from about 10 to about 30 percent by weight of the total explosive formulation, the range of the saturation point of ammonium nitrate prills.

In order that the sensitizer component of our explosives is more uniformly distributed with the oxidizer, it is preferred that the sensitizer exist as a liquid. In certain instances a mixture of a chlorinated organic compound and a substituted or non-substituted hydrocarbon exists as a liquid. In other instances, however, the components do not. In these instances a third component may be employed in the sensitizer which is a solvent for the nonliquid components. The function of the solvent is to solubilize the non-liquid sensitizer components so as to form a sensitizer which is liquid throughout.

Typical solvents which may be employed in our explosive compositions are solvents such as alcohols, ketones, ethers, aromatics such as benzene and naphthalene, and mixtures of these. Preferred solvents are the organic ketones which are preferably dialkyl ketones. More preferably, the alkyl groups are lower alkyl groups such as methyl, ethyl, propyl, butyl, amyl and hexyl. Typical solvents include dimethyl ketone, methyl ethyl ketone, cliethyl ketone, diisopnopyl ether, methyl alcohol, butyl alcohol, methyl isobutyl ketone and the like. The solvent can be present up to about 50 percent by Weight of the sensitizer material. Preferably, however, the solvent is present from about 5 to about 20 percent by weight of the total sensitizer material.

In some cases, we may employ sufficient sensitizer to flood the oxidizer. Although this has the disadvantage of reducing the sensitivity and making the explosive more difiicult to detonate, it increases the bulk density of the explosive. This has the advantage of putting more explosive in a given volume. Also, it has advantage in underwater demolition, since an increase in the bulk density of the explosive above that of the surrounding water makes the explosive sink. In underwater demolition we may place our explosive in a water-resistant container, preferably a plastic bag such as polyethylene. This prevents the water from coming into contact with it and having an adverse effect upon its properties.

The liquid chlorinated organic compound employed is a compound or mixture of compounds having the formula R(Cl) wherein R is a radical selected from the group consisting of alkyl, aryl, cycloalkyl radicals or radicals which contain combinations of the above groups as aralkyl, alkaryl or cycloalkyl aryl radicals. Preferably, the lower members of each of the above groups are employed, that is, radicals containing from one to about six carbon atoms. n is an integer, preferably from one to about 10.

Typical of such liquid chlorinated organic compounds are trichlorocthylene, perchloroethylene, trichloroethane, carbon tetrachloride, chlorobenzene, chlorotoluene, chloronaphthalene, chlonostyrene, trichlorobenzene, trichloropropane, ch'lorocyclohexane and nitro-substituted chlorinated organic compounds such as nitro-chloroform. The chlorinated organic compound comprises at least percent of the sensitizer mixture and preferably at least about 65 percent is utilized to get desirable sensitivity.

The hydrocarbon as defined above which may be admixed with the chlorinated organic compound may be a solid or a liquid. Generally, a liquid is preferred because the use of a liquid component makes mixing in the field an easier job. However, solid hydrocarbons or substituted hydrocarbons may be employed.

The hydrocarbon material may be an aroma-tic, a'liphatic, or an alicyclic compound or a compound which contains combinations of the above groups such as aralkyl, alkaryl or cycloalkyl aryl groups. Preferred groups are the lower members of each of the above groups, that is, those containing from one to about 6 carbon atoms. Typical of such hydrocarbons are benzene, naphthalene, toluene, xylenes (either pure or mixed) hexane, octane, heptane, cycloheptane, methylcyclohexane, graphite and the like. Also typical of such hydrocarbons are mixed petroleum products such as gas oils, furnace oils, residual fuel oils, natural gasoline, jet fuels, diesel oils, kerosene, ligroin, Waxes, jellies, and the like. In addition, substituted aromatic, aliphatic, or alicyclic compounds may be used such as methanol, phenol, methyl ethyl ketone, diethyl ether and diethyl ketone,

Although not bound by any theory, it is our belief that our explosive compositions, when ammonium nitrate prills are employed, are formed through an absorption mechanism in which the sensitizer material comprising a liquid chlorinated organic compound migrates from the exterior surfaces of the ammonium nitrate prills into their interior portions. The liquid component of our explosive is thus uniformly distributed through the interior of the solid ammonium nitrate prills. As a result our explosives are extremely powerful, easy to detonate and vastly superior to prior art explosives in which ammonium nitrate is admixed with a fuel roll.

The ammonium nitrate used in our explosives is a standard item of commerce used widely as a fertilizer. By prills we mean that the ammonium nitrate takes the form of spheroids as produced by dropping a super-saturated solution of ammonium nitrate through a shot tower, through a countercurrent flow of dry air. The individual spheres of ammonium nitrate generally range in size from about'2000 to about 5000 microns in diameter. Although the particles are not completely uniform, they are generally spherical in nature and are porous with respect to our liquid sensitizer. As purchased, the ammonium nitrate prills are generally coated with an anticaking agent. The anticaking agent generally has little if any effect on the elfectiveness :of our explosives. Thus, our invention encompasses explosives in which either coated or uncoated prills of ammonium nitrate are used. Preferably, the ammonium nitrate prills are relatively uniform in size since we have found that such prills give a superior explosive.

The explosive compositions of our invention have an oxygen balance ranging from about 25 to about +25 preferably about 0. Thus, when using a mixture of a liquid chlorinated organic compound and a hydrocarbon, a large enough percentage of an oxygen-rich chlorinated hydrocarbon, e.g., trichloroethylene, is employed to coun ter balance oxygen-poor ingredients in our explosive. Our explosives are readily mixed at the site by pouring the sensitizer as defined above onto the oxidizer. Preferably, sufiicient sensitizer is added so as to substantially saturate the oxidizer. This can readily be accomplished by adding excess liquid and pouring off the excess after the oxidizer has soaked for a few minutes or longer. When a liquid sensitizer and ammonium nitrate prills are employed, the quantity of liquid adsorbed by the prills is determined by their porosity and it is not necessary for the worker to weigh the ingredients or perform any calculation in formulating the explosive. Rather, all he has to do is add the liquid sensitizer until the prills are saturated and then pour off the excess liquid. In one typical case, approximately 0.8 gal. of sensitizer per 50 pounds of ammonium nitrate prills gives an acceptable explosive.

The explosive composition can also conveniently be mixed at the site in any standard mixing apparatus such as a cement mixer by charging the mixer with measured amounts of oxidizer and liquid.

In order to obtain best results, out explosive compositions should not be allowed to stand for any prolonged period of time in contact with air. When this happens some of the liquid sensitizer can evaporate off to give a less effective explosive. In order to prevent this from happening the explosive should be used within several hours after mixing or else stored in a vapor-tight container to prevent evaporation of the liquid sensitizer.

In order to further illustrate our invention, there are presented the following examples in which all parts and percentages are by weight unless otherwise indicated.

Example I To 83 parts of prilled ammonium nitrate were added 17 parts of a liquid sensitizer comprising 83 percent trichloroethylene and 17 percent Cutter Stock fuel oil sold by the Powerine Oil Company (a mixture of C -C hydrocarbons).

Colum nar propagation and plate dent.A 12-inch long galvanized steel water pipe having an interior diameter of 2 inches and wall thickness of 0.138 inch was filled with the explosive. Following this, an g. tetryl pellet was inserted in the top of the explosive column and the material was detonated. The galvanized steel water pipe rested on a l-iuch plate of cold-rolled steel backed up by 6 inches of steel armor plate. Upon detonation, it was found that a dent having a maximum depth of 0.166 inch was made in the 1-inch cold-rolled steel plate.

Impact sensitivity (Picatinny Arsenal).Tests were conducted using a Picatinny type apparatus where a two kilogram weight is dropped on a small amount of explosive placed on an anvil. Results are quoted as the distance in inches the two kilogram weight must fall to cause the explosive to detonate in 50 percent of the trials. The explosive prepared above did not detonate at the 70-inch maximum drop limit of the apparatus. percent dynamite detonated 50 percent of the time with a 7-inch drop. Picatinny Arsenal quotes impact sensitivity of RDX, a conventional insensitive military explosive at 8 inches.

Sixty Flame sensitivity.-A 2%-inch diameter thin-wall polyethylene tube approximately one-foot long was filled with the explosive prepared above. The tube was vertically suspended and an oxyacetylene flame of welding intensity was used to cut the tube in half. The explosive did not detonate and did not continue burning after the torch was removed. The same type of test was conducted using a Aa-inch wall aluminum tube. The torch burned a large hole through the wall of the tube but the explosive did not detonate.

When Example I is repeated using other hydrocarbons such as fuel oil, kerosene, graphite, hexane, heptane, toluene, xylenes (pure or mixed), petroleum waxes or jellies, or isooctane similar explosives are obtained.

Example 11 To 82.2 parts of prilled ammonium nitrate were added 17.8 parts of a liquid sensitizer comprising 84.7 parts of trichloroethylene and 15.3 parts of methanol.

In a plate dent test similar to that performed in Example I above, except that the galvanized steel water pipe had an interior diameter of 4 inches, a dent having a maximum depth of 0.209 inch was made in the oneinch cold-rolled steel plate.

Example 111 To 79.6 parts of prilled ammonium nitrate were added 20.4 parts of a liquid sensitizer comprising 81.8 parts perchloroethylene and 18.2 parts benzene. Using the plate dent test performed as shown in Example II above, a dent having a maximum depth of 0.192 inch was made in the one-inch cold-rolled steel plate.

When trichloroethylene was used in place of perchloroethylene in Example III above, a dent having a maximum depth of 0.221 inch was obtained.

Example IV To 84 parts of prilled ammonium nitrate were added 16 parts of trichloroethylene. A plate dent having a maximum depth of 0.163 inch was obtained upon performance of the test described in Example II above.

Example V To 83.2 parts of prilled ammonium nitrate were added 16.8 parts of a liquid sensitizer comprising 73 percent perchloroethylene and 27 percent Cutter Stock fuel oil. The plate dent test described in Example I was carried out and a dent having a maximum depth of 0.152 inch was obtained in the one-inch cold-rolled steel plate.

In another and separate aspect of the invention the sensitizer for the ammonium nitrate comprises a mixture of a liquid chlorinated organic compound as described above with a lower nitroalkane; or a mixture of the chlorinated organic compound, a nitroalkane and a substituted or non-substituted hydrocarbon in the presence or absence of a solvent. In this aspect of the invention, the presence of the nitroalkane provides an explosive which, though slightly more expensive, has greater output than those explosives previously described.

The liquid nitroalkane employed is a compound or a mixture of compounds having the formula RNO in which R is a lower alkyl group such as methyl, ethyl, N-propyl and isopropyl. Compounds included within this formula are nitrornethane, nitroethane, l-nitropropane, 2-nitropropane and nitrobutane. Nitromethane is a preferred nitroalkane sensitizer since it has been found that our explosive compositions produced by using this compound have a higher brisance than other of our explosive compositions containing higher nitroalkanes. Generally, the nitroalkane comprises an effective amount from about a trace to about percent of the sensitizer mixture. When certain nitroalkanes are used, such as 2-nitropropane which is infinitely soluble in certain chlorinated organic compounds and mixtures of hydrocarbons and chlorinated organic compounds, up to 85 percent nitroalkane may be employed.

The liquid chlorinated organic compound and substituted or non-substituted hydrocarbon used in this aspect of the invention are those described previously.

The oxygen balance of the explosive compositions ranges from about -25 to about +25 preferably about 0. Thus, when using a mixture of a nitroalkane, a chlorinated organic compound, and a hydrocarbon, sulficient oxygen-rich material is used to counterbalance oxygenpoor ingredients.

Example VI To 83.6 parts of prilled ammonium nitrate were added 16.4 parts of a liquid sensitizer comprising 63 percent trichloroethylene, 20 percent nitromethane and 17 percent Cutter Stock fuel oil. A plate dent test was carried out as set forth in Example I above. A plate dent having a maximum depth of 0.201 inch was obtained in the oneinch cold-rolled steel plate.

A satisfactory explosive was also obtained when 84 parts of prilled ammonium nitrate were added to 16 parts of a liquid sensitizer comprising 90 percent trichloroethylene and 10 percent nitromethane. This explosive was detonated with a g. tetryl pellet.

When Example VI is repeated using other liquid chlorinated compounds such as perchloroethylene, chlorobenzene, trichloroethane and chloronaphthalene, good explosives are obtained.

When Example VI is repeated using other hydrocarbons such as kerosene, hexane, toluene, methanol and heptane good explosives are obtained.

As set forth in the foregoing description, our explosives generally serve a dual function since they can be used in place of dynamite but yet at the same time are cheaper than dynamite on a pound-per-pound basis, and from a cost effectiveness standpoint they are cheaper than ammonium nitrate-fuel oil mixtures. Further, our explosives are readily formed in the field and are composed of ingredients that are not in themselves explosives. Thus, the ingredients forming our explosives can. be shipped and stored as ordinary articles of commerce. This results in our explosive being both cheap and safe to ship and store.

In addition to being cheap and safe, our explosives are quite powerful. Thus, it has been observed in field testing that our explosives are more powerful than dynamite. This, coupled with their free-flowing properties and ability to detonate in small diameter bore holes, makes them admirably suitable for a number of applications where dynamite is presently employed.

Having fully defined our explosive compositions and their mode of preparation, we desire to be limited only within the lawful scope of the appended claims.

We claim:

1. An explosive composition having an oxygen balance ranging from about 25 to about +25 consisting essentially of an inorganic oxidizer component and a sensitizer selected from the group consisting of a liquid chlorinated organic compound having the formula R(Cl) and a mixture of a liquid chlorinated organic compound having the formula R(Cl) with a compound selected from the group consisting of a hydrocarbon and a substituted hydrocarbon wherein R is selected from the group consisting of alkyl, aryl, cycloalkyl, aralkyl, alkaryl, and cycloalkyl aryl radicals and n is an integer from one to about 10.

2. The composition of claim 1 wherein said substituted hydrocarbon is diethyl ether.

3. The composition of claim 1 wherein said substituted hydrocarbon is methanol.

4. The composition of claim 1 wherein R is a lower member of the respective groups recited.

5. The composition of claim 4 wherein said sensitizer is a liquid chlorinated organic compound.

6. The composition of claim 5 wherein said chlorinated organic compound is trichloroethylene.

7. The composition of claim 4 wherein the sensitizer is a liquid hydrocarbon in admixture with a liquid chlori- 2 nated organic compound and the oxidizer is ammonium nitrate prills.

8. Thecomposition of claim 7 wherein the chlorinated organic compound is trichloroethylene.

9. The composition of claim 7 wherein the explosive composition has an oxygen balance of about 0.

10. The composition of claim 7 wherein the liquid sensitizer is a mixture of trichloroethylene and fuel oil.

11. The composition of claim 7 wherein a mutual solvent for the liquid components is present in the liquid sensitizer composition.

12. The composition of claim 5 wherein said chlorinated organic compound is a liquid ni-tro substituted chlorinated organic compound.

13,. An explosive composition having an oxygen balance ranging from about 25 to about +25, consisting essentially of ammonium nitrate prills which are from about 25 to about 10.0 percent saturated with a sensitizer selected from the. group consisting of a liquid chlorinated organic compound having the formula R(Cl) and a liquid chlorinated organic compound having the formula R(Cl) with a compound selected from the group consisting of a hydrocarbon and a substituted hydrocarbon, wherein R is selected from the group consisting of alkyl, aryl, cycloalkyl, aralkyl, alkaryl, and cycloalkyl aryl radicals and n is an integer from one to about 10.

14. The composition of claim 13 wherein R is a lower member of the, respective groups claimed.

15. The composition of claim 14 wherein the sensitizer is a liquid hydrocarbon in admixture with a liquid chlorinated organic compound.

16. The. composition of claim 15 wherein the explosive composition has an oxygen balance of about 0.

g 17.. The composition of claim 15 wherein the liquid chlorinated organic compound is trichloroethylene.

ranging from about 25 to about, +25 consisting of an inorganic oxidizer component and a sensitizer selected from the group consisting of a liquid chlorinated organic compound having the formula R(Cl') and a mixture of a liquid chlorinated organic compound having the formula R(Cl) with a compound'selected from the group consisting of a hydrocarbon and. a substituted hydrocarbon wherein R is selected from the group consisting of alkyl, aryl, cycloalkyl, aralkyl, alkaryl, and cycloalkyl aryl radicals and n is an integer from one to about 10.

' References Cited by the Examiner UNITED STATES PATENTS 2,829,036 4/58 Berthrnann et a1 149-62 2,952,530 9/60 John 149-60 X 3,027,283 3/62 Bice 149-76 X 3,046,888 7/62 Gordon 149-76 X 3,047,440 7/ 62 Hughes et a1 149-76 X 3,067,074 12/62v Gey 1*49-76 X CARL D. QUARFORTH, Primary Examiner.

Claims (1)

1. AN EXPLOSIVE COMPOSITION HAVING AN OXYGEN BALANCE RANGING FROM ABOUT -25 TO ABOUT +25 CONSISTING ESSENTIALLY OF AN INORGANIC OXIDIZER COMPONENT AND A SENSITIZER SELECTED FROM THE GROUP CONSISTING OF A LIQUID CHLORINATED ORGANIC COMPOUND HAVING THE FORMULA R(CL)N; AND A MIXTURE OF A LIQUID CHLORINATED ORGANIC COMPOUND HAVING THE FORMULA R(CL)N WITH A COMPOUND SELECTED FROM THE GROUP CONSISTING OF A HYDROCARBON AND A SUBSTITUTED HYDROCARBON WHEREIN R IS SELECTED FROM THE GROUP CONSISTING AF ALKYL, ARYL, CYCLOALKYL, ANALKYL, ALKARYL, AND CYCLOALKYL ARYL RADICALS AND N IS AN INTEGER FROM ONE TO ABOUT 10.