FI62279B - VAT TREATMENT - Google Patents

Description

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Norway-Norway (NO) 750887 (71) Eyno Industrier AS, Tollbodgaten 22, Oslo 1, Norway-Norway (NO) (72) Tore B. Nielsen, Drammen, Oddvar Aim, Drammen, Norway-NO (7I +) Berggren Oy Ab (5I +) Aqueous Explosive Mixture - Vattenhaltig sprängSmnesblandning

The present invention relates to mixtures of explosives, often referred to as "sludge explosives", which form an aqueous mixture of oxygen-donating salts and various combustible substances.

In particular, it applies to mixtures of explosives in which the flammable substances are or contain liquids which are substantially insoluble in water.

Oxygen consuming or combustible components are so-called a wide variety of substances have been proposed in the patent literature for sludge explosives. Of the solids, which are not explosives themselves, it has been proposed for use and introduced e.g. bituminous substances, various organic substances and metals. What all of these have in common is that the degree to which these combustible substances are finely divided is relevant to the properties of the explosive made from them.

A new class of sludge explosives can be considered to be those which contain a fluid, substantially water-insoluble substance. Most sludge explosives in this category contain various hydrocarbons, usually petroleum fractions, called fuel oils or diesel oils, as the combustible component of the mixture.

Thus, it is known from U.S. Patent No. 3,651 to manufacture such an explosive. It also discloses the use of a hydrophobic emulsifier capable of forming an emulsion of water in oil, which is a characteristic feature of this explosive. AT Patent 281,537 describes similar explosives and the use of anionic surfactants therein. Such explosives, which contain a fluid, substantially water-insoluble, combustible material, usually also contain known thickeners, preferably guar gum, and may, of course, also contain r) other ingredients. U.S. Pat. No. 3,096,069 thus describes explosives containing aluminum powder in combination with

with fuel oil. J

When using liquid fuels, the extent to which it is finely divided is of course also relevant to the properties of the explosive produced, i.e. what kind of fuel and aqueous saline emulsion is obtained, and also that this is stable. Thus, for example, it has been suggested that the emulsifiers used should be hydrophobic and stable in an aqueous oil emulsion. It has also been proposed to soak the fuel in ammonium nitrate, which is in the form of porous particles, before using them in the preparation of the final mixture.

The present invention relates in part to the use of an ingredient in an explosive composition such that both the fluid fuel is very easily dispersed in aqueous brine and the resulting emulsion is very stable. It has surprisingly been found that lignosulfonates, which are present in so-called in the form of sulphite lyes obtained in the production of wood cellulose by the sulphite cooking process are a component which is very well suited for the production of sludge explosives containing liquid fuel. These lignosulfonates are water-soluble in contrast to the previously proposed emulsifiers for slurry fuels containing liquid fuels, and it is assumed that the lignosulfonates stabilize an oil-in-water emulsion. The emulsifying and stabilizing effect of lignosulfonates is known per se, but it is not known that this effect is so strong in a system in which the aqueous phase is formed by a saturated solution of oxygen-donating salts, preferably nitrates.

It is previously known from Norwegian patent publication 112,484 to use lignosulfonate in sludge explosives. This patent discloses only sludge explosives in which the fuel is formed by solids or water-soluble substances, and thus does not disclose any use of lignosulfonates or their advantages in connection with running, water-insoluble fuels, which is a characteristic feature of the present invention.

The above-mentioned Norwegian patent refers to lignosulfonates as "sensitizers", i.e. as a substance that increases the sensitivity of the fuel to the initiators without, however, providing any explanation or theory as to why such a sensitizing effect results.

Norwegian Patent Publication 118,534 discloses a sludge-type explosive in which a water-soluble oxidizing salt and fuel are suspended in an aqueous medium. The fuel can be e.g. fuel oil or water-soluble lignosulfonate. The explosive contains a liquid, non-explosive aliphatic mononitrate having 3-5 carbon atoms as a sensitizing ingredient.

One feature of the present invention is that such a sensitizing effect is clearly evident when the fuel of the explosive is a fluid. The invention is thus mainly based on the fact that the same substance is both an effective emulsifier in running fuels and a sensitizer in the mixture.

The invention therefore relates to a slurry-type aqueous explosive mixture consisting of at least one inorganic oxygen donor, at least one combustible substance and at least one thickener, but which does not contain nitric acid blades or an organic nitro compound. The invention is characterized by such a combination that the at least one combustible substance is a liquid petroleum fraction, commonly referred to as fuel oil, and that the aqueous phase of the fuel mixture contains lignosulfonate in an amount of up to 5% by weight of the explosive mixture.

Lignosulfonates have advantageous effects over previously used emulsifiers in sludge explosives containing liquid fuels. In many cases, it is expedient to convert an aqueous, thickened saline solution in explosives into a gel using a so-called thickener molecule for thickener. cross-linking agents, because in this case e.g. significantly better water resistance of the explosive. In particular, compounds of heavy metals of groups 4, 5 and 6 of the Periodic Table at their highest degree of valence, such as chromates, antimonates or titanates, can be used as crosslinking agents. It is known per se that the reactions which give rise to such cross-linking or gel formation take place more rapidly or more completely in the presence of reducing agents. Lignosulfonates are also suitable as such gelling aids, unlike the previously proposed emulsifiers. Overall, it has thus surprisingly been found that lignosulphates have a total of three distinct beneficial effects in said category of explosives, which makes it unnecessary to use different ingredients for each such activity or effect.

The use of lignosulfonates in combination with flowable explosives also provides significant economic benefits. Lignosulfonates are significantly less expensive than most known emulsifiers proposed for use in liquid explosive slurry explosives. They are also less expensive than those reducing agents that have been proposed as excipients for cross-linking reactions with chromates and antimonate. Compared to use with solid fuels, the present invention has the advantage that all the costs of grinding solids are eliminated because the fines of the liquid fuels are finely divided by the blending treatment which produces the finished explosive. Besides, the economic advantage is that ordinary fuel oil is cheaper than most of the solids that have so far been proposed for use as fuels in sludge explosives.

In carrying out the present invention, no method is critical and mixing of the explosive components can be accomplished in a variety of ways. One preferred method is to prepare an aqueous solution of oxygen-donating salt or salts, thickeners and lignosulfonates and then add liquid fuel using a simple mixing process, whereby certain amounts of insoluble salts and other combustible substances such as metal powder or the like can also be added. Small amounts of additives to control the density and consistency of the explosive, such as gas-cleaving reagents, for example sodium nitrite, and a cross-linking reagent, such as chromates, titanates or antimonate, may be added in the same mixing treatment, if desired.

This mixing treatment and the equipment with which it is carried out are not critical to the practice of the invention, but the intensity of the mixing has a certain effect in some cases on the uniformity of the quality of the explosive, which is very important when it comes to explosives.

Thus, the resulting solution of oxygen-donating salts, thickeners 6 62279 and lignosulfonate can be mixed with running fuel and other possible ingredients in a plastic bottle and shaken by hand to provide a sufficiently thorough mixture in less than a minute that can be easily removed from the plastic bottle into suitable sleeves or the like. detonate using standard initiators. It is natural that the same mixing treatment can be carried out batchwise in any mixing device on a larger or smaller scale, in which case mixing times of one to a few minutes are generally sufficient.

A very preferred way of carrying out the mixing treatment is to allow the aqueous solution of oxygen-donating salt or salts, thickeners and aqueous lignosulfonate to run continuously in contact with the running fuel, possibly simultaneously adding certain amounts of dissolved salt and solid combustibles and other excipients to each mixing chamber. with a mixing device from which the finished explosive continuously drains and is further pumped either directly into the borehole or into a charging device of suitable quality.

When using such a continuous mixing treatment, which avoids the accumulation of larger amounts of finished and explosive explosive, the volume of the mixing chamber can be as small as 1-2 liters, whereby the flow volume of the finished explosive is of the order of 20 liters per minute. This means that the mixing treatment can be carried out in about 3 * 6 seconds, with such efficient emulsification of the flowing fuel in brine that the explosive produced is completely satisfactory for use in a borehole with a diameter of more than about 50 mm.

It is not important in the practice of the invention what kind of lignosulfonates are used or in what form they are present. Thus, for example, the so-called sulphite waste solutions which have been evaporated to a dry matter content of about 50% with the remainder being mainly water, or substances which have been evaporated to dryness and which are in the form of a powder may be used. Sodium, calcium, magnesium and ammonium lignosulfonates can also be used, depending on which base has been used in the preparation of sulphite cellulose. Nor is it in any way critical to the practice of the invention that the lignosulfonate formulation contains various other water-soluble ingredients, such as various sugars dissolved from the raw material for the manufacture of cellulose, or that these sugars have been removed by fermentation to about 50% before evaporating the lye. or almost dry.

The lignosulfonates used according to the invention in the finished explosive mixture are used in amounts of up to 5% of the total mixture, and preferably in amounts of between 0.5 and 2%.

In order to further illustrate the invention, the following examples of some embodiments thereof are presented, wherein both the mixing treatments have been performed in different ways and in a few examples the treatment has been performed without lignosulfonate to allow comparison of the results.

eXAMPLES

A total of 5 examples are shown in the table below, of which numbers 4 and 5 do not fall within the scope of the invention and are given by way of comparison because they do not contain lignosulphate and a fluid explosive at the same time.

The methods of preparation also vary, but what is common to all examples is that the solution containing essentially nitrates and water is first prepared and maintained at a temperature of about 45 ° C until mixing with the other ingredients occurs. This solution also contains, as a thickener, guar gum, which is first dispersed in glycol to prevent agglomeration, further thiourea, which is a reaction partner of the nitrite excipient so that a certain amount of nitrogen develops finely divided in the free mixture, and the antifoam "Foamaster 50 D" marketed by Nopco. to avoid the formation of varying amounts of air in the explosive mixture. The solution in all examples, with the exception of number 4, further contains lignosulphate, namely the commercial product "Totanin MG" manufactured by A / S Toten Cellulosefabrikk, Nygard, Norway.

The ammonium nitrate used is of commercial grade, which occurs in the so-called in the form of spheres. The lime soda used is also a commercial type in the form of spheres and contains about 15% water and about 6% ammonium nitrate in addition to calcium nitrate.

Conventional diesel is used as fuel. Comparative Example No. 5 contains finely ground gilsonite as a fuel, which is a carbon-rich, low ash-containing natural asphalt.

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The excipients, sodium dichromate for crosslinking the guar gum and sodium nitrite for nitrogen formation, are added during the single-stage mixing treatment in the form of separate aqueous solutions at concentrations of 50% and 25%, respectively. All figures in the table are given as percentages by weight.

table 1

Mixture No. 12 3 ^ 5

Solution:

Ammonium nitrate 29.00 29.00 29.00 29.33 29.00

Lime soda, technical grade 28.18 28.18 28.18 28.18 28.18

Water 6.29 6.29 6.29 6.29 6.29

Thiourea 0.13 0.13 0.13 0.13 0.13

Guar gum 0.36 0.36 0.36 0.36 0.36

Lignosulfonate 0.53 0.53 0.53 - 0.53

Glycol 0.78 0.78 0.78 0.98 0.78

Defoamer 0.03 0.03 0.03 0.03 0.03

fuels:

Diesel oil 6.50 6.50 6.50 6.50

Gilsonite - 6.50

Dissolved ammonium nitrate: 28.00 28.00 28.00 28.00 28.00

excipients:

Sodium dichromate 0.10 0.10 0.10 0.10 0.10

Sodium nitrite 0.10 0.10 0.10 0.10 0.10

Different mixing methods have been used in different embodiments.

In Example 1, the solution, fuel, dry ammonium nitrate, and excipients are combined in that order in a plastic bottle having a volume of about 2 liters and shaken together for about 15 seconds. The resulting mixture is then added to the cartons of different diameters before the complete crosslinking of the guar gum to test the explosive quality values.

In Example 2, mixing is performed in a mixing machine commonly used in the bakery industry with a mixing device having a volume of about 25 liters. After the addition of the solution, fuel (diesel oil) was added and stirring was therefore continued until the mixture appeared homogeneous, which took about 1 minute. At the same time, dry ammonium nitrate and excipients were added with some vigorous stirring and stirring was continued for about 1 minute. The finished mixture was then added to the cartridges as described in Example 1.

In Examples 3, 4 and 5, a continuous mixing method was used, in which the ingredients were introduced into a mixing chamber with a volume of about 1 liter. The feed rate was about 10 kg per minute and the run-off finished mixture was sampled into cardboard cores of varying diameters to determine the critical diameter. The specific weight of the product was in all cases about 1.15 kg / cm 2. The results obtained are shown in Table 2. The critical diameter of the explosive mixtures shown is the smallest core diameter in which a cartridge 6 times its diameter explodes completely after cooling in ambient air to 5 ° C after use of the initiator. 32 g of trinitrotoluene, indicated by the letter A in the table, was used as the initiator with a cartridge diameter of less than 84 mm, while 36% g of pentolite (55% of pentrite; 45% of trinitrotoluene) was used with larger cartridge diameters, and this is indicated by the letter B.

Table II

Example No. 1 2 3 4 5

Detonator A A A B B

Critical diameter 50 69 69 100> 144 From these results, it can be concluded that when diesel fuel is used, lignosulfonate provides a critical diameter of less than 70 mm, whereas in the absence of lignosulfonate but all other conditions remain the same, the critical diameter is more than 100 mm even if a stronger detonator is used. All lignosulfonate preparations have obtained similar results to those obtained with “Totan MG.” When using a solid fuel, gilsonite, the lignosulfonate gives a critical diameter of more than 144 mm, which was the largest diameter tested.

It can also be seen that rapid mixing by shaking in a plastic bottle provides a somewhat lower critical diameter than mechanical mixing, while continuous mixing is equivalent to mechanical intermittent mixing.

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A series of experiments were further performed using emulsifiers other than lignosulfonate. According to the producers, the substances studied were effective oil emulsifiers in saline water and the results are shown in Table III.

Table III

Product Manufacturer "LDC Base" Firma Nopco Senco, Drammen, Norway "1225" L "" "" "" "" 1186 A "" "" "" "" Type 09 "Hexamin Produkter, Röyken, Norway" Type 79/02 "" " "" "Berol 525" Berol Kemi AB, Stenungsund, Sweden "Berol 259" "" "" "

Nonylphenol Imperial Chemicals Ltd., London, England Using the same mixing conditions as in Examples 1 and 6 and components similar to Example 4, none of the commercial emulsifiers shown provided homogeneity close to that obtained with lignosulfonate because regularly an emulsifiable oil could be observed floating freely on the mixture. In no case was the critical diameter of these mixtures less than 100 mm.

Furthermore, it can be stated that the explosive mixture having the same composition as in Examples 1, 2 and 3 was prepared using the continuous mixing method shown in Example 3 »but with a larger device with a mixing chamber volume of about 8 liters and a feed rate of 150 kg / min. The effluent from the mixing chamber was pumped through a hose with an inner diameter of 38 mm and a length of 25 meters directly into the borehole of the iron ore mine. The diameter of the borehole was 20-30 cm. When detonated with two 360 g pentolite detonators, an explosion occurred perfectly in each borehole and the explosion results were very satisfactory.

Claims (3)

11 6 2 2 7 9 1. Vattenhaltig sprängämnesblandning av uppslamningstyp bestä-ende av minst et oorganiskt syreavgivande ämne, minst bränn-Bart ämne och minst et fertjockningsmed, the petroleum fraction of the petroleum fraction does not fall within the scope of this Regulation, and in that case it is used to reduce the amount of lignosulphonate to a maximum of 5% by weight. A slurry-type aqueous explosive mixture comprising at least one inorganic oxygen donor, at least one combustible substance and at least one thickener, but not containing a nitric acid ester or an organic nitro compound, characterized in that the at least one combustible substance is a liquid petroleum fraction which is designated as fuel oil, and that the aqueous phase of the fuel mixture contains, in solution, no more than 5% by weight of ligosulphonate based on the weight of the explosive mixture. 2. The use of lignosulfonate according to claim 1 is limited to 0.5-2% of the yield of lignosulphonates. Aqueous explosive mixture according to Claim 1, characterized in that it contains lignosulfonate 0.5 to 2% by weight of the explosive mixture. Aqueous explosive mixture according to Claim 1, characterized in that it is provided with a gel structure by means of a crosslinking agent comprising a heavy metal compound belonging to Group 4, 5 or 6 of the Periodic Table and having the highest degree of valence. 3. A power supply according to claim 1, which comprises the arrangement of a bridging structure with the resultant of the use of an encapsulating material in the form of a periodic metal system according to groups 4, 5 or 6, respectively.