US3369944A - Thickened aqueous detonator composition containing a brisant explosive - Google Patents

Description

United States Patent Ofiice 3,369,944 Patented Feb. 20, 1968 3,369,944 THICKENED AQUEOUS DETONATOR COMPOSI- TION CONTAINING A BRISANT EXPLOSIVE Adolf Berthmann, Leverkusen, and Paul Lingens, Co-

logne-Maricnburg, Germany, and Clemens Franze, deceased, late of Leverkusen, Germany, by Anneliese Franze, heiress, Leverkusen, Germany, assignors to Dynamit Nobel Aktiengesellschaft Patentabteilung, Troisdorf, Bezirk Cologne, Germany, a corporation of Germany No Drawing. Filed June 8, 1964, Ser. No. 374,229 Claims priority, application Germany, June 12, 1963, D 41,752 8 Claims. (Cl. 14939) This invention relates to detonation charges for blasting explosives, and more particularly this invention relates to detonation charges for blasting explosives that are relatively non-sensitive in handling and non-hazardous during the manufacture and packing of the same into cartridges or the like, but which can readily be brought to detonation and which are prepared from mixtures of at least one brisant explosive with water or another aqueous solution.

Explosive compositions, such as mixtures of ammonium nitrate, trinitrotoluene and water, mixtures of ammonium nitrate and diesel oil, and cast charges of TNT, for which brisant detonating charges (primers) are required to initiate the detonation instead of blasting caps or instantaneous fuses, are already known. Cast or pressed bodies of solid brisant explosives, such as cast charges of TNT and Hexogen (cyclotrimethylenetrinitroamine), pressed bodies of desensitized PETN (pentaerythritol tetranitrate) or tetryl (tetranitromethylaniline), etc. or of nitric acid esters and ammonium nitrate are usually used as the detonators.

The conventional detonating charges, however, are extremely sensitive to shock and impact. For example, when drilling into charges that have not been completely detonated in blast holes, there is the ever present danger of producing detonation. In long bore holes having relatively small cross-sections, solid, rigid detonating charges are difficult to insert because of the possibility of canting. Gelatinized blasting explosives cannot reliably be brought to their maximum speed of detonation by establishing contact therewith with an instantaneous fuse, but are usually brought only to their lowest speed of detonation, which is not always sufiicient for the initiation of the explosive charge.

It is one of the objects of the present invention to teach a practical utilization of charges of mixtures of brisant explosives with water or another aqueous solution in initiating detonation in bore hole blasting.

It is another object to teach efficient detonating compositions for use in bore hole blasting, wherein charges of mixtures of brisant explosives with water or another aqueous solution, accomplish detonation results beyond the expectations of conventional blasting.

It is still another object to teach efiicient detonation compositions for use in bore hole blasting, wherein explosive handling is greatly simplified and blasting effectiveness is vastly increased.

Further objects and advantages will become apparent to those skilled in the art as the description proceeds.

'In accordance with the invention it has now surprisingly been found that mixtures of brisant explosives with water or an aqueous solution, such as have been described in the literature (M. A. Cook, Science of High Explosives, Reinhold PublishingCorp 1958, pp. 316 et seq), can be used as detonating charges. The detonating charges are required to be of a composition that is determined empirically, so that they can be brought reliably to a sufficiently high speed of detonation (e.g., greater than 5000 m./sec.) by means of an instantaneous fuse applied to them.

Brisant explosives, which are practically insoluble in water, and which have been found particularly suitable for the manufacture of the detonating charges of the present invention include compounds such as solid nitric acid esters, e.g., pentaerythritol tetranitrate, nitro mannitol, nitro starch, nitrated aromatic compounds, e.g. tn'nitrotoluene, and nitramines, e.g., cyclotrimethylene trinitramine, cyclotetramethylene tetranitramine, trinitrophenyl-methylnitramine and the like. Mixtures of the above mentioned brisant explosives can also be used to great advantage. The lower limit of the brisant component of the detonator charge amounts to approximately 50 percent by weight. This limit is determined substantially by the particular speed of detonation required (above 5000 rn./sec.). The brisant explosives are used in amounts varying from 50 to 85% of weight, and preferably from 60 to of weight.

In place of water, aqueous solution can also be used in accordance with the invention, which contain in addition to salts (salts which participate in the detonation, such as alkali and alkaline earth metal nitrates and perchlorates, or inert salts of the type alkaline earth metal chlorides), swelling agents. The water content or the content of the aqueous solution in the detonating charge should advantageously amount to not less than 5 percent by weight at the very least. An amount of water varying from 15 to 30% of weight, and preferably from 20 to 30% of weight is generally applied, when water is used without addition of salts. In the case of aqueous solution of salts the amount of water is varying from 5 to 20% of weight, and preferably from 5 to 12% of weight. While amounts of salts varying from 10 to 45% of weight, and preferably from 15 to 30% of weight are used.

Swelling agents applied in accordance with the present invention may include compounds of the group consisting of guar flour, alginates, agar-agar, cellulose, carboxymethylcellulose and the like. These swelling agents are added in amounts varying from 0.1 to 5% of weight, and preferably from 0.1 to 2% of weight.

Powdered metals can also be added to the new detonating charges. Prepared aluminum and magnesium powders and powdered alloys thereof have proven to be particularly advantageous in this regard. The amounts of powdered metals may vary from 1 to 35% of weight. The range preferred varies from 5 to 20% of weight.

The novel detonating charges can be used for initiating the detonation of high explosives in the same quantities as have conventionally been used hitherto in the explosive industry for other detonating charges. The detonator is most advantageously used in cartridge form. One not inconsiderable advantage of the detonators in accordance with the invention is that they can be brought in fairly large quantities to the site of the explosion and can there be loaded in the quantity required for the explosion. Thus, at that point they can be loaded into metal, plastic, or like canisters, and be used in that form. They can also be cartridged in tubes, bags or other such containers, constructed of plastic or waterproof paper of the type conventionally used in the explosive art.

The use of the detonator charges of the present invention has still further advantages over those charges presently usedln comparison with pressed or cast charges of solid, high explosives, and in comparison with gelatinous explosives prepared on the basis of nitric acid esters, safety in handling is considerably improved. While pentolite (mixtures of trinitrotoluene and pentaerythritol tetranitrate) and ammonium gelites can be brought to detonation six times out of six, using a drop hammer having a hammer weight of 1 kg. and a drop height of 50 cm.,

the detonating charge as described in Example 1 (infra) requires kg. of hammer weight for the same drop height under substantially identical conditions. Furthermore, due to their water content, the detonation charges of the invention are characterized by a reduced infiammability. In spite of their greater handling safety, the new detonating charges of the invention are brought, without any difficulty, to a high speed of detonation by an attached instantaneous fuse.

Further, due to their plasticity, the detonation charges of the invention can be applied wherever and whenever the use of rigid explosive bodies encounters difliculties or is contra-indicated.

The invention will be further illustrated by detailed description in connection with the following specific examples of the practice of it.

EXAMPLE 1 Composition:

70 wt. percent pentolite (50/50), grain size 1 30 wt. percent thickened solution of:

10.4 parts Ca(NO 11.9 parts NH NO 7.5 parts H O, 0.2 part guar flour.

Explosive characteristics: Density: 1.52 g./cc. Trauzl lead block expansion:

325 cc. Speed of detonation:

6600 to 6800 m./sec.

The high speed of detonation was achieved, most surprisingly, even though initiation of the explosive charge column was brought about by a PETN fuse from a distance of half a centimeter, the explosive having been contained in a plastic tube having a wall thickness of 0.15

Use.The above-described explosive was used successfully as a detonating charge for mixtures of ammonium nitrate, TNT and water in large bore-hole blasting in massive basalt. The detonating charge was contained in a cartridge constructed of flexible plastic tubing and having a length of 200 mm. and a diameter of 50 mm. which easily inserted into the bore hole because of its flexibility. Explosions carried out under the same conditions using a gelatinous rock blasting explosive (Ammongelit described in Chemische Technologie' by Winnacker and Weingartner, Carl Hanser Verlag, Munich, 1960, vol. 4, pp. 754) as the detonating charge resulted in a far lesser explosive eflt'ect.

EXAMPLE 2 Composition:

65 wt. percent pentolite (50/50), grain size 1 mm., 35 wt. percent thickened solution of:

12.2 parts Ca(NO 14 parts NH NO 8.6 parts H O, 0.2 part guar flour.

Explosive characteristics:

Density: 1.55 g./cc. Trauzl lead block expansion:

300 cc. Detonation speed:

6300 to 6400 m./sec.

Use. A mixture of 44% nitrocellulose powder (consisting of 85 wt. percent nitrocellulose and 15 wt. percent stabilizer and plasticizer in the form of cord grains having 4.8 mm. diam. and a length of 11.8 mm.), 24% NH NO 31.9% of a salt solution saturated with Ca(NO and NH NO and 0.17 guar flour was prepared. 400 g. of the detonating mass as above described were placed in a cartridge made of flexible plastic tubing 4 (50 mm. diam.) which in turn were placed in an iron pipe having a length of 700 mm., a diameter of 65 mm., and wall thickness of 4 mm., closed at one end, and were detonated with an instantaneous fuse applied to them. The entire iron pipe was fragmented. Under the same experimental conditions, using, however, various rock blasting explosives (Ammongelit) as the detonating charge, the iron pipe was intact, and only the piece in which the detonating charge 'was contained was destroyed. In the case of initiation by an attached instantaneous fuse, the detonating charges made of explosives based on nitric acid esters detonated with a speed of 2 to 3 thousand meters per second, while the detonating charge of pentolite and aqueous solution had a detonation speed of 6300 m./sec.

EXAMPLE 3 Composition:

61 wt. percent pentolite (50/ 50), grain size 0.1

mm., 8.7 wt. percent aluminum, 30.3 wt. percent thickened solution of:

10.5 parts Ca(NO 12.0 parts NH NO 7.6 parts H O, 0.2 part guar flour.

Explosive characteristics:

Density:

1.60 g./ cc. Trauzl lead block expansion:

350 cc. Speed of detonation:

6500 to 6800 m./sec.

Use.-There was placed in an iron pipe (length 1 m., diam. 50 mm., wall thickness 4 mm.) a mixture of ammonium nitrate and diesel oil (94 parts and 6 parts), which could not be brought to detonation with a blasting cap, and 100 grams of the above-described detonating charge. The initiation was carried out with a No. 8 aluminum blasting cap. The iron pipe was fragmented over its entire length.

EXAMPLE 4 Composition:

76.5 wt. percent of a mixture of 60 parts hexogen and 40 parts TNT (grain size 1 mm.) 23.5 wt. percent of a thickened solution of:

8.1 parts Ca(NO 9.3 parts NH NO 5.9 parts H O, 0.2 part guar flour.

Explosive characteristics:

Density:

1.58 g./cc. Trauzl lead block expansion:

350 cc. Speed of detonation:

7 100 m. /sec.

Use.This detonating charge was used for the purpose of detonating a ground nitrocellulose powder in cartridges made of flexible plastic tubing of a length of 700 mm. and a diameter of 65 mm. placed in a blast hole having a length of 10 m. and an mm. diam. in passive limestone. The resulting explosion was entirely successful. The debris after the explosion was indesirable form.

EXAMPLES 5 TO 8 The effect of additional detonating charges, having a length of 50 mm. and a 30 mm. diam. was evaluated on cast TNT bodies (length 200 mm., diam.- 50 mm). In all cases, the TNT bodies were brought'to detonation.

The compositions and explosive characteristics of the detonating charges are given in the following table:

6 5.9 parts H O, 0.2 part guar flour.

TABLE Examples DETONA'IING CHARGES Composition (wt. percent):

Pentolite (grain size 0.1 mm.) 72. 3 61 PETN 70 0. I III: I: 0.

11. 9 7. 6 6. 4 17. 9 Guar flour 0. 2 0. 2 0. 2 0. 2 Explosive characteristics:

Density, g./ec 1. 32 1. 50 1. 64 1. 57 Trauzl lead block expansion in cc 5 35 330 Detonation speed, rn./see.

EXAMPLE 9 Composition:

70 wt. percent pentolite (50/50), grain size 1 mm. 30 wt. percent thickened solution of:

parts NaClO 14 parts H 0, 1 part agaragar.

Explosive characteristics:

Density:

1.50 g./-cc. Trauzl lead block expansion:

330 cc. Speed of detonation:

6600 m./ sec.

Use.This detonating charge was used successfully in a test explosion according to Example 1.

We claim:

1. A detonator composition of reduced hazard during manufacture and of substantially full sensitivity to detonation at the time of use, the composition consisting of:

70 Wt. percent pentolite (50/ 50), grain size 1 mm.,

wt. percent thickened solution of:

10.4 parts Ca(NO 11.9 parts NH NO 7.5 parts H O,

0.2 part guar flour.

2. A detonator composition of reduced hazard during manufacture and of substantially full sensitivity to detonation at the time of use, the composition consisting of:

65 wt. percent pentolite (50/50), grain size 1 mm.,

Wt. percent thickened solution of:

12.2 parts Ca(NO 14 parts NH NO 8.6 parts H O,

0.2 part guar flour.

3. A detonator composition of reduced hazard during manufacture and of substantially full sensitivity to detonation at the time of use, the composition consisting of:

61 wt. percent pentolite (/50), grain size 0.1 mm.,

8.7 Wt. percent aluminum,

30.3 wt. percent thickened solution of:

10.5 parts Ca(NO 12.0 parts NH NO 7.6 parts H O,

0.2 part guar flour.

4. A detonator composition of reduced hazard during manufacture and of substantially full sensitivity to detonation at the time of use, the composition consisting of:

76.5 wt. percent of a mixture of parts hexogen and 40 parts TNT (grain size 1 mm.),

23.5 wt. percent of a thickened solution of:

8.1 parts Ca(NO 9.3 parts NH NO 5. A detonator composition of reduced hazard during manufacture and of substantially full sensitivity to detonation at the time of use, the composition consisting of:

72.3 wt. percent of pentolite,

27.5 wt. percent of water, and

0.2 wt. percent guar flour.

6. A detonator composition of reduced hazard during manufacture and of substantially full sensitivity to detonation at the time of use, the composition consisting of:

61 wt. percent of pentolite,

10.6 wt. percent of Ca(NO 7.6 wt. percent of water,

20.6 wt. percent of NH NO 0.2 wt. percent guar flour.

7. A detonator composition of reduced hazard during manufacture and of substantially full sensitivity to detonation at the time of use, the composition consisting of:

74.3 wt. percent of cyclotrimethylenetrinitroamine,

8.9 wt. percent Ca(NO 10.2 wt. percent NH NO 6.4 wt. percent water,

0.2 wt. percent guar flour.

8. A detonator composition of reduced hazard during manufacture and of substantially full sensitivity to detonation at the time of use, the composition consisting of:

70 wt. percent PETN,

11.9 wt. percent CaCl 17.9 wt. percent water,

0.2 Wt. percent guar flour.

References Cited UNITED STATES PATENTS Re. 26,115 11/1966 Schwoyer 14941 2,942,965 6/1960 Westheimer et a1 14939 2,982,641 5/1961 Dawson et a1. 149-39 3,222,232 12/1965 Schwoyer 14938 3,062,143 11/1962 Savitt et a1. 149-93 XR 3,096,223 7/1963 Cook et a1. 149-105 XR 3,155,038 11/1964 Smith 14993 XR 3,299,811 1/1967 Gates 14992 XR 3,326,731 6/1967 Noddin 14992 XR OTHER REFERENCES Mellor, J. W., Mellors Modern Inorganic Chemistry, Longmans, Green and Co, New York, 1951, QD5, M52, 04 (p. 422).

CARL D. QUARFORTH, Primary Examiner.

BENJAMIN R. PADGETT, Examiner.

S. J. LECHERT, JR., Assistant Examiner.

Claims (3)

1. 3. A DETONATOR COMPOSITION OF REDUCED HAZARD DURING MANUFACTURE AND OF SUBSTANTIALLY FULL SENSITIVITY TO DETONATION AT THE TIME OF USE, THE COMPOSITION CONSISTING OF: 61 WT. PERCENT PENTOLITE (50/50), GRAIN SIZE <0.1 MM., 8.7 WT. PERCENT ALUMINUM, 30.3 WT. PERCENT THICKENED SOLUTION OF: 10.5 PARTS CA(NO3)2, 12.0 PARTS NH4NO3, 7.6 PARTS H2O, 0.2 PART GUAR FLOUR.
2. 4. A DETONATOR COMPOSITION OF REDUCED HAZARD DURING MANUFACTURE AND OF SUBSTANTIALLY FULL SENSITIVITY TO DETONATION AT THE TIME OF USE, THE COMPOSITION CONSISTING OF: 76.5 WT. PERCENT OF A MIXTURE OF 60 PARTS HEXOGEN AND 40 PARTS TNT (GRAIN SIZE <1MM.), 23.5 WT. PERCENT OF A THICKENED SOLUTION OF: 8.1 PARTS CA(NO3)2, 9.3 PARTS NH4NO3, 5.9 PARTS H2O, 0.2 PART GUAR FLOUR.
3. 7. A DETONATOR COMPOSITION OF REDUCED HAZARD DURING MANUFACTURE AND OF SUBSTANTIALLY FULL SENSITIVITY TO DETONATION AT THE TIME OF USE, THE COMPOSITION CONSISTING OF: 74.3 WT. PERCENT OF CYCLOTRIMETHYLENETRINITROAMINE, 8.9 WT. PERCENT CA(NO3)2, 10.2 WT. PERCENT NH4NO3, 6.4 WT. PERCENT WATER, 0.2 WT. PERCENT GUAR FLOUR.