DE1216749B - Stabilized slurry-type explosive composition - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN -007ITW 'PATENT OFFICE Int. α .:

C06b

EDITORIAL

C08b

German class: 78 c-17

Number: 1216 749

File number: C 33864 VI b / 78 c

Filing date: September 11, 1964

Opening day: May 12, 1966

The invention relates to improved slurried explosives which primarily from one or more organic explosives and one or more inorganic ones There are oxygen-releasing salts in an aqueous solution of said inorganic oxygen-releasing Salts are slurried. Thus this is in an amount between about 8 and 26 percent by weight present water is an essential component of such explosive compositions.

The aforementioned slurried explosives are already well known, and some of them, which contain trinitrotoluene (TNT), ammonium nitrate (AN) and water are, for example, in the Canadian Patent 619,653. They have had widespread uptake and in recent years Found use, especially in open pit mining, quarrying and construction work. they are safe to use because of their insensitivity to blast vibrations, economical and have a high explosive power because of their high borehole loading density.

It has been found, however, that aqueous slurried explosive compositions containing inorganic oxygen-donating salts and particulate organic explosives have very poor storage properties, even when they contain gelling agents such as e.g. The mannogalactans suggested in Canadian Patent 617,006. In a relatively short time, especially when large temperature differences occur during storage, such as. B. between day and night, the gel is diluted by the salts, which go into solution during warmer periods; this dilution causes the slurries to separate into solids and an overlying liquid layer. This separation, of course, destroys the homogeneity of the mixture, which can easily lead to misfiring in the wells which are driven into the reservoir. Furthermore, a homogeneous gelled slurry has excellent resistance to water, which may be present in boreholes, for example, as shown in the above-mentioned patent. If, however, separation of the slurry occurs, the resistance to water exposure and water penetration is reduced, and this in turn reduces the sensitivity of the mass and can cause misfires in use. The salts also crystallize out again during cooler times after the separation and form bridges, whereby Stabilized Explosive Composition from
Slurry type

Applicant:

Canadian Industries Limited,

Montreal (Canada)

Representative:

Dipl.-Ing. H. Bohr, Dr. H. Fincke

and Dipl.-Ing. S. Staeger, patent attorneys,

Munich 5, Müllerstr. 31

Named as inventor:

Joseph Francis McLean Graig, Beloeil;

Errol Linton Falconer, St. Hilaire;

Gordon Towell, Otterburn Heights (Canada)

Claimed priority:

Canada September 13, 1963 (884 510)

the slurries lose their fluidity to a great extent. However, this property is - as already mentioned - essential for achieving the optimal borehole loading density. Furthermore, a loss of the Flowability an introduction of the slurries, e.g. B. by pouring into the holes, which in the Deposit are difficult. As a result, factory made explosives slurries have become in trade only under conditions of very short-term storage at relatively low levels Room temperatures proved attractive. The latter factor has little influence on the reduction the separation of the solid and liquid components. In particular, it was found that under tropical climatic conditions these slurries have a reduced storage life because the constituents tend to to separate faster than in more temperate climates. In the aforementioned patent 617 006 was to solve the problem of separating the stock

609 568/178

3 4

parts proposed to create a critical amount of borax that would oppose separation of the constituents

add mannogalactan-containing slurries while being stable over longer periods of storage. Other

to get a more cohesive gel. It is believed that objects of the invention are to be derived from the following

men that the borate ions in the borax see through.

Mannogalactan thickened slurries are thus stabilized according to the invention wets «, with an improved cohesiveness and thus an explosive composition of the slurry type on the a product of improved resistance to - based on inorganic oxidizers, especially from is obtained via the separation into the constituent parts. Nitrates of Ammonium, Sodium, Potassium, Ba-During however, the addition of borax under sodium and / or calcium in a mixture with particle-fold controlled conditions a satisfactory- io-shaped organic explosives, such as TNT, cohesive gelled slurry, such as Pentolyt, PTEN, Hexogen and / or smokeless powder but found that it was on an industrial scale, a gel-forming polysaccharide and water stab was unable to produce the best product suggested, which is identified by the because either the gel is not affected at all, addition of a metal chromate, namely a sodium if the borax is added before the mannogalic or potassium dichromate in amounts of 0.005 to 0.1, actan swells, or the slurry quickly becomes a zinc chromate in amounts of 0.05 to 0.1 or firm and cohesive that it will soon no longer flow a barium chromate in amounts of 0.01 to 1%> and no longer printed in the packs or based on the total weight of the explosive cast can be. In the Canadian patent composition of matter.

font 658 202 is the use slowly 20 It is already known from the USA patents of dissolving annealed glassy tetraborates instead of 2,997,377 and 2,988,437, dry. Nitrate borax suggested. These tetraborates result in an explosive addition of chromates. The additive serves to delay the crosslinking effect, but the tetraborate but to promote the combustion. The advantageous slurries tend - similar to the borax-like effect of the addition of chromates to slurry-crosslinked slurries - to a lower level of explosives, however, it is not disclosed.
Sensitivity to explosion _{ignition as Di 6} addition of the above metal chromates or slurries which do not contain borate ions. -dichromates in the specified amounts to one

In another way, the problem of separating explosives sludge has the desired effect,

of the components in slurried explosives - that almost completely any tendency of the sludge

Arriving, some consumers are on a mixing 3 ° mes, when storing in solid and liquid

Separating the slurries in place with immediate layers is turned off because that

Subsequent introduction into the boreholes of overmetallic chromate has a crosslinking effect

went. However, even in these methods, one may exert the gel-forming polysaccharide, thereby creating a

Separation of the constituents in the wells instead of slurry is obtained, which compared to the

find, if not, the charged boreholes to be extremely resistant without penetration of water

Delay be detonated. Furthermore is. However, it has been found to be effective

this mixing of the slurries in place and crosslinking in the absence of crosslinking

On an economic basis, usually only reluctantly add these to the separation.

in the case of large consumers of explosives, grain-hindering additives to an explosives slurry should be considered

men. The small explosives consumer who is normally _{delayed at least V 2} hours before the 40th

Cost of on-site mixing and raw material, d. H. until the point in time at which the

cannot carry material storage facilities and saccharide gelling agent has had an opportunity to have one

still take advantage of the additional explosive power and the corresponding amount of water

the low cost of such explosive slurry sleepers. When the networking and the separation

The use of a preventive additive must be incorporated before use

factory made and packaged product the gelling agent is appropriately swollen so

can fall back on. there will either be no thickening at all, or that

The problem of component separation and the rate of thickening is greatly altered Disadvantages of the explosives slurries can be reduced. If on the other hand the networking partly by increasing the amount of gelling agent approximately one-half hour after the addition of the agent and / or by reducing the amount of gelling agent is added, it stiffens Water that gel used in the slurry mixture almost instantaneously, so it is only extremely will come along. Either or both of these measures is difficult to pack. In addition, she has such skill the effect of forming a thick, solid retardation for the purpose of water absorption Product result in which the separation 55 of the gelling agent has a deleterious effect During longer storage times, even at elevated temperatures, the effectiveness and the costs of production temperature resists. Such a measure reduces the amount of slurried explosives. Because the Schlämjedoch the fluidity of the slurry so much that the mung has already become very thick at this point if it is usually not on in the desired manner, mixing at this stage has an inclusion can be turned; d. that is, it becomes difficult in the 60's of air and a decrease in sensitivity Boreholes must be drilled and will not result in "swamping" of the mud.

and fill the drill holes. In addition, the other hand, it was surprisingly discovered

The cost of the product necessarily as a result of the addition of a crosslinking retarder increased component costs and also the resulting beneficial effect in the specified quantities associated more difficult production and packing 65 delaying the crosslinking effect of the metal

rise. has chromations on the polysaccharide,

The aim of the present invention is to provide a while the slurry for a time, which for improved slurried explosives composition sufficient to provide convenient packaging that remains free flowing.

5 6

The crosslinking retardant acts to make it appropriate to be included in this specification the normal swelling of the gelling agent does not denote "particulate". With the expression "partially disturbs, but only the cross-linking effect of the “chrochen-shaped” is intended, liquid explosives such as mations delayed. It is therefore not necessary to B. nitroglycerin and nitroglycol to exclude processing of the cross-linking and the separation of 5 and to indicate that the explosives in a powder-preventing Additive in the composition so ized, granulated, flaky or pelletized form to postpone long until the networking delay should be present. A very suitable organic explosive has been added to the slurry. substance is TNT (trinitrotoluene), although a large one The packing of the slurry should be prepared immediately by preparation grade in particulate form a homogeneous and sufficiently thickened ionic explosives for the mixture according to the invention take place, usually within application, either as such of 5 minutes after the polysaccharide addition. Appropriated or mixed with TNT or in a mixture Crosslinking retardants are metal one another, but in general these prove to be citrate, citric acid, tartaric acid and gluconic acid. more expensive than TNT. This class includes e.g. B. Penta-

Thus it is now possible to produce valuable and explosive erythritol tetranitrate (PETN), tetryl, cyclotrimethylene Slurries in explosives manufacturing be- trinitramine (RDX), pentolite (this is a mixture of drove under controlled and safe conditions approximately equal parts of TNT and PETN) and Prepare and mix during longer Composition B (this is a mix of un times To store 60 percent by weight RDX and about 40 frame parts without separating the solid and liquid substances. The 2% weight percent TNT produced in this way and a small amount of wax). Slurries possess the additional and beneficial- smokeless powder is used for the purposes of achieving Property that it is cohesive and yet completely flowable as an organic explosive stay, but still strive for the deepest.

The temperatures encountered in the deposits form the gel-forming or thickening polysaccharides

Loading of the boreholes with optimal density possible 25 are preferably mannogelactans, such as. B. guar gum

is. Equally beneficial - as already he or carob tree seeds.

mentions - is the property of delayed wetting. The slurried explosives composition of the slurries, which can be an economical measure of the invention in any suitable mixing-mixing, Handling and packaging can be made in the explosives device, but preferably factory allowed. In addition, it was found that the mixer should not have any fast-moving parts that using the delayed chromate possess and should have a shifting effect combined systems networked slurries, as opposed to lifting the material from the bottom of the own the in the aforementioned Canadian patent mixer to the top. For this purpose it is 658 202 specified borate-crosslinked slurry - conventional "ribbon-like" mixers (ribbon type mings, which as a rule are particularly suitable compared to ignition 35 mixer). A preferred mixed less Are sensitive, a slightly higher procedure is the dry inorganic Sensitivity than non-crosslinked slurries oxygen-releasing salts, the metal chromate and exhibit. Mix the water together. After a few minutes

Preferred slurried explosive compositions may contain particulate organic explosive tongues according to the invention, 30 to 75 substances are added and distributed among the mass, weight percent of at least one inorganic acidic then added the crosslinking retardant substance-releasing salt, 15 to 40 percent by weight can be. The gelling or thickening agent a particulate organic explosive, can then as a dry powder or in admixture with 0.2 to 2.0 percent by weight of a gel-forming or a small amount of ethylene glycol or glycerin as thickening polysaccharide, 0.01 to 0.5 weight 45 dispersion medium, whereupon the percent of the crosslinking and the separation preventing the entire composition is mixed until it detergent additive, 0.005 to 0.05 percent by weight is homogeneous. The desired end temperature of the cent of a crosslinking retardant and 8 bis mixture should be between 4 and 60 ° C so 25 percent by weight water. packed the slurry in a satisfactory manner

A very suitable inorganic, oxygen-depleting 50 can be. To get the desired final temperature Giving salt for incorporation into the invention, it may be necessary that the water-based explosive composition is hot or as a hot solution of an ammo additive nium nitrate. In some cases it is advantageous to use one of several of the inorganic oxygen-releasing substances Part, suitably up to 50% or the total salts is added. A heated mixer can amount of ammonium nitrate by other metal 55 can also be used.

nitrates, such as B. sodium, barium, potassium and calcium nitrate, to replace the following table and the following graphs, for example to explain a representation to achieve the increased strength or flowability according to the invention. An improved explosive composition; The inventive mixture can also be achieved through the use of urea, but this is not intended to result in a small percentage of urea as described. 6 ° embodiments are limited.
The particle size of the inorganic oxygen-releasing salts is not critical, and powdered, granulated, lumpy or crystalline form can be produced according to the first type indicated above and used in a 50 cm high glass or the total cylinder can also be given. The amount of the separated amount of liquid or some of the salts completely or partially at the top of the column must be predissolved in the water after storage. at 32 ⁰ C during the specified time in MiUi-

The organic explosives specified for the mince. The compositions are as

Application expressed in the explosives according to the invention as percentages by weight of the total mass.

Components

Mix. L Mix. 2 mix. 3 mix. 4 mix. 5 mix. 6 mix. 7 mix. 8 mix. 9 mix. 10 mix. 11

Ammonium nitrate

Sodium nitrate

water

TNT flakes

TNT pellets

Smokeless powder

PETN

Composition B

Guar flour

Glycol

Zinc chromate

Potassium dichromate

Potassium tartrate

Tartaric acid

Barium chromate,

Gluconic acid,

Storage temperature, ° G

Storage time, days,

Separation in one
50 cm column, mm

55.5 8.0 14.9 10.0 10.0

0.6 1.0

32
26th

55.4 8.0 14.9 10.0 10.0

0.6 1.0 0.1

0.005

32 47

no

37.6 23.3 12.6 12.5 12.5

0.5 1.0

32 28

25th

37.5 23.3 12.6 12.5 12.5

0.5 1.0 0.1

0.005

32 68

no

37.5
18.3
12.6

15.0
15.0

0.5
1.0
0.1

0.005

32
50

3.2

37.5
23.3
12.6
12.5
12.5

0.5
1.0

0.1
0.047

32
35

no

48.0

7.9

11.1

31.4
0.5
1.0
0.1

0.005

32
50

3.2

51.9

8.0

13.5

16.0

9.0

0.5
1.0
0.1

0.005

32
42

no

37.4
23.3
12.6
25.0

0.5
1.0

0.03
0.2

32
10

9.5

37.5
23.3
12.6
25.0

0.03
32
10

F i g. Figure 1 illustrates the change in viscosity of two similarly crosslinked slurries, one containing a crosslinking retarder and the other not containing a crosslinking retarder. The compositions used were the same as Mix's. 2 in the table. Only laboratory-scale approaches on the beaker scale were used. The viscosity of the compositions was determined at 3 to 5 minute intervals after the addition of the gelling agent using a Brookfield viscometer. Lines illustrates the sudden change in the viscosity of a slurry when the crosslinking and separation preventing additive (zinc chromate) is added to a thickened slurry about 30 minutes after the addition of the gelling agent (guar flour), i.e. after the guar has had an opportunity To absorb water and swell. It can be seen that this viscosity change occurs almost instantaneously, reflecting sudden crosslinking and making the slurry too cohesive and too stiff to be conveniently packed. The dashed branch of the ruled line (referred to as line 4-1) represents the gradual increase in the viscosity of a slurry when only a thickening agent (guar flour) is added. Such a slurry does not cross-link and breaks up into solid and liquid layers within a short time after production (see table - Mix. 1). Line B shows the gradual increase in viscosity of a slurry which contains zinc chromate as a crosslinking and separation preventing additive and tartaric acid as a crosslinking retarder. The increase in the viscosity of such a composition occurs (as a result of the start of crosslinking) approximately between 8 and 24 hours after the addition of the guar flour and is therefore outside the graph. The composition relating to line B remained cohesive for a long time after production and resistant to separation into its constituent parts (see Table — Mix. 2). However, it remained sufficiently free flowing that it could be easily packed. Line C represents the decreased rate of increase in viscosity of a slurry composition when the poorly soluble zinc chromate and guar meal are added to the slurry at the beginning of the mixing cycle and when no crosslinking retardant is used. It appears that the lack of the crosslinking retardant affects the ability of the guar meal to take up water and form a cohesive gel. It can be assumed that the zinc chromate inhibits at least part of the gelling agent, which prevents a corresponding thickening. Although such a slurry may thicken and crosslink, there is a risk of separation before crosslinking occurs because of the lower viscosity during and immediately after packing. Line D represents the near complete absence of thickening and instantaneous separation of a slurry composition when fully soluble sodium dichromate and guar meal are added to the slurry at the beginning of the mixing cycle and when no crosslinking retardant is used. It appears that the absence of the crosslinking retardant results in an instantaneous inhibition of all of the decongestant, thereby almost completely preventing thickening.

F i g. Fig. 2 illustrates a similar effect, which is similar to that of Fig. 1, with the difference that various combinations of crosslinking and separation preventing additives] and crosslinking retardants are applied. Lined explains the sudden change that occurred in the Viscosity of a slurry occurs when the crosslinking and separation preventing additive (Potassium dichromate) about 30 minutes after adding the gelling agent (guar flour) to a added to thickened slurry, d. H. after the guar had had an opportunity Absorb water and swell. It can be seen that this change in viscosity is almost instantaneous what occurs is sudden networking

and makes the slurry too cohesive and stiff to be conveniently packed. The dashed branch of the lines (denotes line A- 1) shows the gradual increase in the viscosity of a slurry if only a thickening agent (guar flour) is added. Such a slurry does not cross-link and breaks up into solid and liquid layers within a short time after production (see table - Mix. 1). Line B shows the gradual increase in viscosity of a slurry which contains potassium dichromate as a crosslinking and separation preventing additive and potassium tartrate as a crosslinking retarder. The increase in the viscosity of such a composition occurs (as a result of the start of crosslinking) approximately between 13 and 17 hours after the addition of the guar flour and is shown in FIG. 3 shown. The composition corresponding to line B remained cohesive for a long time after production and resistant to separation into its components (see table - Mix. T).

10

Claims (1)

Claim: Stabilized slurry-type explosive composition based on inorganic oxidizers, especially nitrates of ammonium, sodium, potassium, barium and / or calcium in admixture with particulate organic explosives such as TNT, pentolyte, PTEN, hexogen and / or smokeless powder, a gel-forming polysaccharide and water, characterized by the addition of a metal chromate, namely a sodium or calcium dichromate in amounts from 0.005 to 0.1, a zinc chromate in amounts from 0.05 to 0.1 or a barium chromate in amounts from 0.01 to l ° / ₀ , based in each case on the total weight of the explosive composition. Considered publications:
German Auslegeschriften No. 1009990, 1082842; U.S. Patent Nos. 2,988,437, 2,997,377, 072,509, 3,091,559, 3,094,443. 1 sheet of drawings