FI56821C - VAETSKEFORMIG SPRAENGMEDELSKOMPOSITION - Google Patents

Description

rftl ADVERTISEMENT C c Ο O «[B] (11) UTLÄGGNI NGSSKRIFT 8oo2l C (45) ra'vcniti myynnene · -tr 10 -ivOO ^ T ^ (51) KY.Ik. * / lnt.CI. · C 06 B 29/02 FINLAND — FINLAND (21) p * wnttlh * k * mu * -p * t, nWn * öknln * 3010/70 (22) H »k« mi * ptlvi - An * eknlnj »d« f (23) ALkupUvI — Glhl | h «$ d» f 09.1170 (41) Become public —Bllvlt off «ntli | ,

Patent · and registration iti »Nihtlvlkslp * ™ |, date of publication-‘ 5 ’? 1

Patent and Regulatory Authority '' Ansöksn utlagd och utl. * Kriften publlcersd 31.12.79 (32) (33) (31) Claim claimed — Bejlrd priority 13.11.69 USA (US) 876576 (71) Ireco Chemicals, 726 Kennecott Building, Salt Lake City, Utah 8U 111, USA (72) Albert Gail Funk, Salt Lake City, Utah, Boyd LaMar Hansen, Salt Lake City, Utah, Melvin Alonzo Cook, Salt Lake City, Utah, USA (7) This invention relates to a liquid explosive composition having a self-explosive liquid solution and containing 5 ~ 30% by weight of a water-miscible organic liquid having a calorific value of at least 3900 kcal / kg and capable of dissolving. * 0 Berggren Oy Ab (5 ^ 0 Liquid explosive mixture - Vätskeformig sprängmedelskomposition an oxidizing salt, 0 to 25% by weight of water, more than 50% by weight of an oxidizing salt or a mixture of such salts, which oxidizing salt is ammonium, alkali metal and / or alkaline earth metal nitrate and / or perchlorate, small sealed gas bubbles and, if desired , finely divided solid combustible material and s akeut us substance.

In recent years, many liquid explosives have been developed which contain an aqueous continuous phase, usually an aqueous solution of ammonium nitrate or a concentrated aqueous solution of ammonium nitrate to which nitrate of sodium or another alkali or alkaline earth metal or a similar inorganic salt with high acidity has been added. where particulate combustibles and / or sensitizers are suspended. Usually part of the oxidant is also suspended. Chlorates and perchlorates come to mind as oxidant components, but these have rarely been used. Thickeners such as guar gum or similar polysaccharides, starches and the like are commonly used as thickeners and / or gelling agents to increase the viscosity of the liquid phase and / or to provide it with sufficient tightness to prevent gravity-induced separation of suspended particles.

When muddy explosives and the above-mentioned similar substances are highly satisfactory, especially when high-flux rods or charges are used and where a relatively low explosive sensitivity is useful, they are often completely unsuitable for other purposes. One reason is that they often have too low an explosion sensitivity as thin rods. There is a real need to provide a mobile liquid or pumpable explosive, i.e. a liquid or sludge-type explosive which is sufficiently sensitive to explode as a small-diameter mass or rod at low temperatures by means of an ordinary detonator or a conventional PETN-filled filament. Where the slurry must be gravity-driven to a location where it is to be used or where it can be pumped into a relatively thin column, an explosive mixture with a very small critical cross-section may be required, in no case larger than the borehole diameter and preferably considerably smaller.

As a further example, there is a need for a time-flowing liquid or muddy explosive that can be applied, for example, as well as a regular toothpaste from a compressible bottle or container with a 6.3-12.7 mm orifice. In some cases, explosives must be usable at temperatures as low as -40 ° C. It may be desirable for such a slurry to be sensitive enough to be blasted at such a temperature by means of a detonator. Such requirements are very difficult to meet. Not all of the compositions of this invention satisfy all of them, but some do. Most of these explosive mixtures meet most of the essential requirements.

In the past, many attempts have been made to produce a "teddy-sensitive" slurry, i. one that can be used in very small boreholes like dynamite rods, which is about 25-30 irm in diameter in rods. However, such an explosive must have a very low water or other liquid content. Some of these are not mobile sludges at all or, if they could be called sludges, they are so solid that they do not flow easily. Fluid mobility is desired in many cases and is usually required for the purposes of this invention. Preferably, it should flow by gravity or it should be able to be pumped mechanically through hoses, pipes or other tubular conduits.

It has also been found in the past that water, an ordinary liquid in which the oxidant is dissolved, could be diluted by adding to the water a suitable organic liquid having a calorific value. However, the use of organic liquids in such cases is somewhat different from where the organic liquids of this invention operate. The liquids added here should have a significant calorific value and good solubility of the oxidants used.

The use of particulate, molecular-type explosives such as TNT and nitrocellulose (smokeless gunpowder) has also been previously described in the art. In such cases, the explosive particles are usually quite large and some are completely unsuitable for use in thinner columnar explosive charges. This invention contemplates the use of much finer ground molecular type explosive particles, e.g., finely divided RDX or PETN.

More flammable sludge type. The explosives have been made using considerable amounts of heat-generating metals, in particular using very fine-grained aluminum metal such as finely divided particle sizes or so-called paint-grade aluminum. These can be used as auxiliary fuel sensitizers in this invention. However, even with paint-grade aluminum, the sensitivity of typical prior art sludge explosives, usually based on ammonium nitrate or AN + sodium nitrate, is generally not sufficient for the purposes of this invention.

It has now been found that the sensitivity of an explosive sludge depends to some extent not only on the temperature at which the sludge is ignited, but also on the solubility of the inorganic oxidant salts in the liquid phase at that particular temperature. The saline solution, of course, acts as the liquid uniform backbone phase of a typical slurry. The effect of temperature on sensitivity is described by a typical explosive slurry mixture having a critical diameter of 51 mm at 25 ° C but increasing the critical diameter to at least 6 mm when the temperature drops to 5 ° C. Many or possibly most previous explosive liquids generally have a very significant change in critical diameter over a small temperature range. This is thought to be due, at least in large part, to the fact that when the actual solution of the oxidant, usually ammonium nitrate, is present at a higher temperature, at a moderately lower temperature, some of the oxidant salt has precipitated from the solution. The solubility of ammonium nitrate in water decreases very rapidly as the temperature decreases. This is true to varying degrees for most other strong oxidant salts. In those cases where there is indeed a real solution of oxidant and combustible substance which can be stored within the operating temperature limits and where the oxidant and combustible substance are in close contact, i. substantially in molecular contact with each other in the liquid despite temperature changes, the detrimental effect of temperature on the sensitivity and critical diameter of the mixture 56821 can either be substantially eliminated or at least very significantly reduced.

Therefore, it is important to keep the oxidant salt in solution at the temperature range where difficulties are most likely to occur in practice. In fact, it will be appreciated that the sensitivity of the oxidant solution, among other things, can be greatly increased and maintained at a useful level at a reasonable temperature in accordance with this invention by appropriately selecting a solvent or solute or mixtures thereof, even using relatively poor combustibles or oxidants. Preferably, the effective combustible material and substantially all of the oxidant should remain in solution together and thus in molecular contact at the desired temperature range.

It is an object of the present invention to provide a flowable liquid or sludge-type explosive having a degree of sensitivity as close as possible to that of conventional solids, i.e., the general degree of sensitivity and range of molecular-type explosives such as TNT, RDX and the like. Liquid mixtures or sludges are prepared in such a way that at least a substantial portion of the essential combustible substances and oxidants remain in solution together. Therefore, these mixtures are not substantially affected by ordinary temperature changes because the necessary molecular contact between the combustible material and the oxidant is maintained. Of course, oxidants must be appropriately selected as well as combustibles. By finding the eutectic points of two or more salt-type oxidants taken from a selected group, it is possible according to the present invention to obtain an even better solubility of the oxidants in the solvent solution of the combustible substance, i. a wider thermal space range than is possible with private salt. At the same time, it is possible to achieve the benefits of maximum intermolecular contact in a mixture in which most or substantially all of the oxidant and at least a substantial portion of the combustible material are in a single true solution. In this way, a liquid is obtained which is explosive in itself.

The explosive mixture according to the invention contains the majority of the oxidant salt perchlorate and the total liquid content is at least 25% by weight.

The present invention has the advantage that when the perchlorate is dissolved and in molecular contact with the organic liquid fuel or an aqueous solution containing it, a highly sensitive explosive mixture is formed without the need for any sensitizing admixtures. This was a completely new and surprising phenomenon. In addition, the combination of perchlorate and liquid fuel provides the following additional advantages: (a) the perchlorate slurry has a higher density and thus a higher concentration of 56821 than the nitrate slurry, and (b) the perchlorate slurry has a higher sensitivity at low temperatures than the nitrate slurry.

The amount of water required can be reduced to or close to the practical minimum. A sufficient total amount of solvent, water and other liquid, is needed to maintain the actual solution at the operating temperature. Water can and often takes part in the reaction with or in the presence of finely divided aluminum or another metal such as magnesium, silicon or boron as a strong component. This is provided that the required reaction temperature and other conditions can be achieved and maintained. See. Cook, "The Science of High Explosives," ACS Monograph No. 139 (1958), page 304.

Example 1

An alkaline explosive solution was prepared by combining 52 wt% sodium perchlorate, 18.5 # water, 5.5% sodium nitrate and 24 # ethylene glycol. With this mixture, the density was quite high, 1.58 g / cm 2. This is advantageous when it is desired to obtain as much heavy explosive as possible and thus maximum energy in a given volume. The density can, of course, be easily reduced and the mixture made more sensitive by impregnating it with air or other gas in the form of fine fine bubbles. This particular mixture, which was liquid without suspended solids, was not sensitive to this density, but was completely explosive in itself. Its critical diameter was 25 mm at 25 ° C, which increased to 64 mm at 5 ° C. It was found possible to ignite an explosion of the same liquid by slurrying considerable amounts of particulate molecular type explosive. For example, sixty parts by weight of the above solution were combined with forty parts by weight of particulate pentaerythritol pentanitrate (PETN) using a small amount of guar gum, 0.2% by weight of the total, to thicken the solution so that the suspended solid PETN particles could not be reduced by weight. The density of this slurry mixture was 1.78 g / cm 2. It was tear-sensitive in relatively small pieces and 13 mm in infinite column diameter (paper tube). It exploded with a detonator No. 6 at various temperatures ranging from 40 ° C as low as -30 ° C.

Example 2

The second example slurry, made according to the above principles, contained 90 parts by weight of the solution described in Example 1, i. solution of sodium perchlorate, water, sodium nitrate and ethylene glycol. To this was added 8 parts by weight of fine aluminum and 2 parts by weight of even finer aluminum. The resulting slurry was brazed from 6,50621, which was obtained by adding 0.2 # of thickening guar gum and using 0.1 # of branching agent.

Z

H ^ ^ BO: a. The density of the mixture was 1.43 g / cm. The density indicates that a considerable amount of air had probably penetrated it in the form of small bubbles. The mixture was sensitive to 9 * 5 mm in diameter. It exploded with a detonator No. 6 up to a temperature of 0 ° C. At 12.7 mm in diameter, it exploded with a similar detonator at -15 ° C. It exploded at -30 ° C to a diameter of 25.4 mm by adding 40 g of 50/50 pentolite.

The comparison of explosion rates is interesting. The explosion rate of the liquid alloy itself was 2300 m / s, while the explosion rate of the same alloy when added with aluminum was 5300 m / s.

The slurry made from the liquid of Examples 1 and 2 in an amount of $ 60 with 40 # of PETN suspended in it and free did not explode from a 30.06 caliber rifle bullet. However, the aluminum alloy of Example 2 exploded when hit by such a bullet. The solution itself, without PETN and aluminum, was found to withstand various thermal analyzes up to 300 ° C. It proved to be exothermic when PETN was added at 170 ° C and exploded spontaneously at 178 ° C. The aluminum alloy lasted at 265 ° C.

Example 3

A second mixture was prepared containing 31.2 wt.% Sodium perchlorate, 11.1 # water, 3.3 # sodium nitrate and 14.4 # ethylene glycol as solvent and 0.1 # thickening guar gum and an additional 40 # particulate matter. PETN obtained from a Swedish source. The solution without PETN was explosive in itself. The calculated energy Q of this PETN-containing slurry was 1080 cal / g and the density was 1.78 g / cm 2. The PETN used here was made to a particle size of about 90 # ranging from 35 to 100 mesh. Attempts to obtain the same composition, but with finer PETN, of which 40 # would pass through a 325 mesh screen, failed, probably because the mixture became too thick to flow and became semi-gel at -40 ° C. The solution itself required a much stronger igniter than detonator No. 6 to detonate it as a 76 mm diameter column at 30 ° C.

It will be appreciated that in some circumstances explosives other than PETN such as RDX or TNT may be used. However, experiments found that finely divided RDX was less satisfactory than PETN at very low temperatures. Assume that TNT, which is less sensitive, would be even less satisfactory.

7 & 6 821

Example 4

A mixture was made containing 22 wt.% Sodium perchlorate, 17 # water, 3 # sodium nitrate, 8 # ethylene glycol, all in a solution to which 0.2 # thickening guar gum and 50 wt.% Fine PETN were added. Blasting of this slurry failed at 20 ° C as 12.7 mm statues with both detonator # 6 and # 8. As a 25.4 mm statue, it failed with detonator # 6, but exploded satisfactorily with detonator # 6. 8. The explosion made quite a dent in 12.7 mm 7 steel plates. This slurry had a density of 1.77 g / cm 2 and was very thick flowing at 20 ° C.

Example 5 Using 60 # of the same liquid mixture as in Example 1, which itself has an oxygen balance of -1.3 # with 40 # by weight of finely ground PETN (of which about 40 # passed through a 325 mesh Tyler wire), a mixture was obtained which was mobile enough to flow slowly, i.e. could be squeezed out of the press bottle, but it was almost too dry to be called a slurry, at 20 ° C. At -40 ° C it became solid. It exploded with a detonator No. 6 as a 9 * 5 mm statue. When 50 # of the same liquid and 50% by weight of the same PETN were used, the mixture was completely too dry to be called a slurry. The mixture of 65 μl of solution and 35 # of fine PETN was somewhat more liquid-ended than the 60-40 mixture, but still completely putty in solidity. Its density was 1.81 g / cm 2. This PETN contained 40 # fine enough particles to pass through a 325 mesh * Tyler wire. The 65-35 eeos exploded at 12.7 mm in diameter at -125 ° C. When 5 # earth-grade aluminum was added, the alloy was too dry to flow and did not explode with a detonator. This indicates that mixtures in which both the oxidant and the combustible substance are mostly or completely in solution may be more sensitive than drier mixtures. In general, drier sludges are easier to blow up than wet ones.

Example 6

A mixture was made of the following substances, weight #:

Sodium perchlorate 19 #

Water 15.0

Sodium nitrate 2.6

Ethylene glycol 3.4

Boric acid 0.05

Guar gum 0.2

Fine aluminum 10.0 PETN - finely ground 50.0 8 50821 This was too dry at 20 ° C to be called a slurry. Its density at 20 ° C was 1.82 g / cm -1 and it exploded as a 12f7 mm statue with detonator No. 6, making a dent in a 12.7 mm thick steel plate. It also exploded at 20 ° C as a 6.3 mm statue with a similar detonator No. 6. The PETN used here was a medium ground product of which 40 ° passed through a 325 mesh wire.

Example 7

A mixture was prepared containing 33 → 3 wt.% Sodium perchlorate, 3.5 $ sodium nitrate, 11.8 ° water, 15.4 g ethylene glycol, $ 1> thickening guar gum and $ 33 and $ 2, respectively. fine and very fine aluminum, which are described in Example 2. This 7 alloy, with an oxygen balance of $ -33.4, had a density of 1.65 g / cnr and an explosion rate of 5390 m / s.

Example 8

A mixture of 47 parts by weight of sodium perchlorate, 5 parts of sodium nitrate, 24 parts of water and 21 parts of ethylene glycol was prepared. To this solution was added 1 part thickening guar gum and small amounts of gas generating agents to saturate the slurry with gas and reduce its density. The properties of the initial solution and the thickened and gas-saturated solution are compared below;

A solution of pak-Sun and gas

Solution alone substances

Density (g / cm -1) 1.54 1.25

Critical diameter (mm) 76 (minimum) 19 Explosion rate (m / s) less than 2500 4800

Minimum additives 30 g pentolite ignition detonator No. 6

When the previous examples mainly concern explosives based on sodium perchlorate and sodium nitrate, i. in which sodium perchlorate is used in solution as the main oxidant, they may be partially or completely replaced by other perchlorates and nitrates.

Calcium nitrate, although less sensitive in most cases than perchlorates, is a particularly desirable substance for liquid explosives containing methyl alcohol. Calcium nitrate is highly soluble in water, methyl alcohol, ethyl alcohol and ethylene glycol even at low temperatures. Alone or in combination with 9 £ 6621 sodium perchlorate, it has a low eutectic solubility point. At doses as high as 70-75 1 ° of the total solution, commercial calcium nitrate, which contains 14-16 # of water of crystallization and normally contains a few percent ammonium nitrate, has a better (i.e., lower) crystallization point than the dilute ammonium nitrate solutions in combination with sodium nitrate. See. U.S. Patent No. 3,249,476. The values are given in Table I.

Table I

Ammonium-Sodium-Ethy-Crystalline-Nitrium-Nitium-Nitlene-Methethylate Rate Rate * HgO Glycol nol Point Density a. - - 75 - - 25 10 ° C 1.48

h. - - 75 10 - 15 -15 ° C

c. - - 70 - 10 15 10 ° C 1.57

d. - - 70 5 10 15 0 - 15 ° C

mp 40 15 - 22 10 - 13 ° C

* Calcium nitrate contains 5% by weight of ammonium nitrate and 16 # of water of crystallization.

Calcium nitrate clearly has the desired properties, which is why it is desired to keep it as an oxidant in solution (low crystallization point) as required in this invention.

The preferred explosive mixture is seen to contain both a combustible substance and an oxidant in solution, and preferably all or substantially all of the oxidant is dissolved. This mixture contains as little as 20 to about 60% by weight of oxidant and preferably contains at least one perchlorate selected from the group consisting of ammonium chlorate, alkali metal chlorates and alkaline earth metal perchlorates. Perchlorate is the main oxidizing component, but may be accompanied by a small amount of at least one other strong oxidizing salt, preferably a nitrate selected from the group consisting of ammonium, early metal and alkaline earth metal nitrates. «Salts should be selected to give a low eutectic solubility or crystallization temperature. that they do not crystallize from the mixture to a large extent at operating temperature.

The liquid may contain 0-25 # of water and 5-30 # of combustible material. At least part of the combustible material is water soluble. Ethylene glycol is generally considered good, but can sometimes be replaced or supplemented with simple alcohol. A mixture of about 6621 10 0-20 # of water and a little more glycol or other organic solvent, say 15-25 #, is highly desired to form the explosive solution itself. The calorific value of the selected organic liquid should be at least reasonably high, 3900 kcal / kg or higher. Diethylene glycol has a value of about 4,200 kcal / kg, methyl alcohol about 5,270 kcal / kg, and ethyl alcohol about 7,530 kcal / kg, but glycol is generally preferred for this invention.

To keep it intact, this liquid is preferably thickened at least moderately by the addition of a small amount of thickener. Guar rubber in an amount of 0.10 to 0.1 by weight is particularly suitable. Starches can be used in larger quantities. Cellulose gums and their derivatives are useful in some cases, such as methylcellulose or hydroxyethylcellulose. The rubber or starch is preferably converted to a branched chain using a substance such as boron or alkali metal dichromate. Branch rooting not only protects against excessive water penetrating from external sources, · it helps to keep suspended combustible substances or molecular type explosive particles in place against settling. Small bubbles of air or other gas, which is needed to increase the sensitivity, can also be introduced into and stored in the liquid phase. Such air or other gas may be introduced by mixing or agitating the thickened liquid itself or by mixing fine solids with the liquid. Particles of combustible materials and / or molecular type explosives such as aluminum and / or finely divided PETN, RDX, TNT, etc. may be added. The liquid mass itself is a strong explosive and is substantially oxygen balanced without these fine combustible materials or molecular type explosives. In this respect, it is quite different from previous sludge explosives.

When non-explosive combustibles are used, the better ones include aluminum, sulfur, and carbonaceous solids such as coal or gilsonite. Better molecular type explosives are PETN, RDX, Composition B, EDNA (ethylenediamine dinitrate) or TNT. These should be selected and used in appropriate amounts to give the desired sensitivity and to keep the oxygen balance within reasonable limits, in any case between -50 and +10 #. In the case of fine-grained aluminum, amounts up to 45 # of the total weight of the alloy can be used. Quantities of 20-40 # are better when maximum power is required. Some of this aluminum may be paint-quality fine loaded aluminum. Amounts of 1-2 # of the latter help with sensitivity. Sensitive molecular type explosives 11,56621 such as PETN can be used in amounts up to 65% by weight of the total weight of the slurry. Of course, mixtures of PETNs, RDXs, Composition B, TNTs, and aluminum, or mixtures of two or more of these, may be used. Because the liquid phase itself is very oxygen-balanced, fines should contain at least a portion of their own oxygen (such as molecular-type explosives) or should react with water (such as aluminum under favorable conditions when water is present), or some solid oxidant should be present in the particulate phase or suspension. This may be from the main oxidant (perchlorate) precipitated from the liquid or added separately, or it may be a separate or different oxidant salt such as ammonium nitrate, sodium nitrate, calcium nitrate, etc., added separately. As already mentioned, the use of a small amount of one or more of these salts helps because it lowers the crystallization point.

The compositions of this invention are very versatile. They can be made "to size" with respect to both the desired sensitivity and the desired power by appropriately selecting the types and amounts of components. Liquid components containing large amounts of dissolved sodium perchlorate or other perchlorate and large amounts of ethylene glycol or other dissolved organic flammable substances whose molecules are close to each other are quite sensitive in themselves. By adding significant amounts of more sensitive finely ground molecular type explosives, the oxygen balance is reasonable in itself, as in PETN weather, even more sensitive products are obtained. These can transmit the ignition shock in a very narrow column, e.g. in a column as small as 12.7 mm or less in diameter or average cross-section.

Where such highly sensitive explosives are not required, the amount of a molecular type explosive such as PETN can be reduced or eliminated altogether. Alternatively, this separate molecular type explosive may be replaced in whole or in part by one or more of the molecular type explosives mentioned above and / or aluminum powder.

In many cases, it is desirable to add a small amount of very fine aluminum, especially paint grade aluminum, because of its high calorific value. It has a very significant effect, generating high sensitivity even in well-balanced liquid mixtures. It is also desirable because of the mechanical handling properties it imparts to the mixture. It helps the lubricant mixture flow through pipelines and nozzles as it is distributed through valves, pumps, hoses and other piping equipment.

12 56821

Two additional examples were made. The first contained 73.5 # calcium perchlorate and 26.5 methyl alcohol. This solution itself had a density of 1.54 g / cm 2 and was blown up as a 19 mm diameter column with a 9 gram Pentolite igniter. The other contained $ 60 lithium perchlorate and $ 40 formamide. The intrinsic density of this solution was

• Z

1.56 g / cnr and exploded as a 25.4 mm diameter column with a 9 gram Pentolite igniter.

It is to be understood that the foregoing and other modifications which come to mind to one skilled in the art may be made within the spirit and scope of the invention.

Claims (4)

13 56821 1. The value of the explosive composition of the compound and the explosive content of the organic matter is 5 ** 30 times the weight of the organic compound, the weight of which is not more than 3900 kcal / kg and the weight of the oxidation medium, 0.25 times vikt- # oxidationsmedelsalt eller en blandning av dylika salter, vilket oxidationsmedelsalt är en ammonium-, alkalimetall- och / eller jordalkalimetallnitrat och / eller -perchlorat, smä innslutna gasbubb-lor och,, as kännetecknad av att huvuddelen av oxidationsmedelsaltet utgöres av perklorat och att vätskans totala hait är ätminstone 25 vikt- #. A liquid explosive mixture having a self-explosive liquid solution containing 5 to 30% by weight of a water-miscible organic liquid having a calorific value of 3900 kcal / kg or more and capable of dissolving an oxidizing salt, 0.25% by weight of water, of more than 50% by weight. # ha-bed salt or a mixture of such salts, which oxidant salt is ammonium, alkali metal and / or alkaline earth metal nitrate and / or perchlorate, small closed gas bubbles and, if desired, a finely divided solid combustible substance and thickener, characterized in that the majority of the oxidant salt is perchlorate and that the total liquid content is at least 25% by weight. 2. A composition according to claim 1, comprising organic organic glycol. Mixture according to Claim 1, characterized in that the organic liquid is glycol. 3. A composition according to claim 1, which comprises 20 to 60 sodium perchlorates and up to 10 sodium nitrates. Mixture according to Claim 1, characterized in that it contains 20 to 60% by weight of sodium perchlorate and at most 10% by weight of sodium nitrate. i, j. Mixture according to Claim 1, characterized in that the organic liquid combustible substance is methyl alcohol and in that the mixture contains at least 20% by weight of calcium nitrate. 4. A composition according to claim 1, comprising organic brandy or methyl alcohol and a compound containing 20 sodium calcium nitrates.