CN1271336A - Explosive gasser composition and method - Google Patents

Abstract

A gassing composition for gassing explosive compositions wherein, the gassing composition comprises a gassing agent and a metal salt having a divalent cation.

Description

Explosive gasser compositions and methods

This invention relates to improved chemical gassing properties of explosives, and more particularly to a gassing composition for explosives. The invention also relates to a method of manufacturing an explosive and an explosive composition.

The civilian mining, quarrying and extracting industries generally use explosives in bulk or in packaged form as the primary method of blasting rock and ore during mining, tunneling, digging and similar activities.

Explosive compositions such as emulsion explosives have been chemically degassed in practice with chemical gassing agents such as sodium nitrite. Under certain conditions, these gassing agents take a considerable amount of time to generate the required gas and form a suitable gassed explosive. In commercial practice, it is desirable to generate the gas rapidly to detonate the explosive. One problem associated with gasser systems in the prior art is that the maximum rate of gasser currently achievable is not fast enough for some applications. For example, loading bulk explosives into bulky blastholes is particularly disadvantageous in cold climates, since it may take several hours to inflate the bulk explosives. Attempts have been made to overcome this problem by maintaining a very high emulsion temperature and thus a high gasser rate, however using high emulsion temperatures tends to slow down the filling of the emulsion into the blast hole, especially the emulsion pump Demulsifies the emulsion when sent to the blast hole.

It is preferred to start the gasser reaction immediately after loading the mixture of gasser composition and bulk emulsion into the blast hole and to reach completion quickly. Mining operations are usually run on tight schedules, minimizing delays in order to maximize efficiency. It is therefore economically advantageous to minimize the delay time between complete charge and detonation of the blasthole. This is particularly important for underground blasting where entire mine tunnels must be evacuated and where many activities over large areas must be stopped while blasting is in progress. Carry out above-mentioned multiple above-ground and underground mine blastings at a time set every day and if the blast holes and explosives are not ready at the set time, you have to wait 24 hours to have the next chance to detonate the blast holes.

We have now found that the gassing properties of explosive compositions can be improved, including a much wider range of gassing rates and higher maximum gassing rates, by the use of one or more divalent cation-containing metal salts. Accordingly, the present invention provides a gasser composition for use in a gassed explosive composition, wherein the gasser composition comprises a gasser and a divalent cation-containing metal salt.

The present invention also provides a method of degassing an explosive composition, the method comprising the steps of:

i) making a gasser composition comprising a gasser and a divalent cation-containing metal salt; and

ii) Dispersing the gassing composition into the explosive composition.

In addition, the present invention also provides a gassed explosive composition containing an explosive composition which is gassed by dispersing the gassed composition into said explosive composition, wherein the gassed composition comprises a gassing agent and a divalent cation-containing of metal salts.

Metal salts can be any conventional salts containing divalent metal cations, which include simple salts, double salts, complexes and any other conventional salts.

The divalent cation may be a divalent cation of any main group metal, transition metal, lanthanide or actinide. The divalent cations are preferably formed from main group metals or transition metals of II, III, IV or V or mixtures thereof. Divalent cations are more preferably selected from Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Ti ²⁺ , Zr ²⁺ , Hf ²⁺ , V ²⁺ , Cr ²⁺ , Mn ^{2 +} , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Zn ²⁺ , Ag ²⁺ , Hg ²⁺ , Cd ²⁺ , Al ²⁺ , Sn ²⁺ , Pb ²⁺ and their mixtures. The most preferred divalent metal cations are Mg ²⁺ and Ca ²⁺ .

The one or more anions of the metal salt may be any suitable monovalent, divalent or trivalent anion. Metal salts may contain more than one monovalent anion. Metal salts may be double salts. The anion of the metal salt may preferably be selected from halides, nitrates, sulfates, phosphates, chlorates, perchlorates and combinations thereof. The anion of the metal salt is more preferably nitrate.

The gasser composition may be in any convenient form, preferably in the form of a solution. The solution may be dispersed in the explosive, or it may be first placed in the form of a water-in-oil emulsion, an oil-in-water emulsion, a foam emulsion, a microemulsion, or a combination thereof, so that the gassing composition is dispersed in the explosive assembly. in things. Generally, gasser compositions comprise a chemical gasser and a divalent metal salt dissolved in a solvent or solvent mixture. The solvent can be any suitable liquid that dissolves the chemical gassing agent and the divalent metal salt, such as water. The gasser composition is preferably prepared from separate solutions of the gasser and the metal salt which are dispersed in the explosive immediately after mixing the two solutions.

Gasser is a reagent suitable for in situ chemical generation of gas bubbles, which includes peroxides such as hydrogen peroxide, nitrites such as sodium nitrite and potassium nitrite, nitrosamines such as N,N'-dinitros pentamethylenetetramine, diazonium ions/salts, alkali metal borohydrides such as sodium borohydride and bases such as carbonates including sodium carbonate.

Nitrite, more preferably sodium nitrite, is suitable for use in the present invention. Nitrite reacts under acidic pH conditions, producing nitrogen bubbles.

Accelerators such as thiocyanate, iodide, sulfamic acid or its salts, or thiourea may be used in the gassing composition to accelerate the gassing reaction.

In general, the gasser composition of the present invention may contain 0.5-45% by weight of the gasser composition of the gasser and 1-45% by weight of the gasser composition of the divalent metal salt. The gasser composition preferably comprises 0.5-25% by weight of a gasser and 10-40% by weight of a divalent metal salt. The gasser composition preferably comprises 0.5-20% by weight of gasser and 20-40% by weight of divalent metal salt. Optional accelerators such as thiocyanate may be present in the gasser composition in an amount of 0.05-20% by weight of the gasser composition, preferably 0.5-10% by weight.

The explosive composition is preferably gassed by dissolving the gasser, the metal salt containing a divalent cation, and any optional additives in a solvent to form a gasser composition, and the gasser composition is uniformly dispersed throughout the explosive composition. The gassing composition then reacts to generate gas bubbles in the explosive composition.

The gassing composition may be dispersed in the explosive composition in an amount of 0.5-10% by weight, more preferably 0.5-5% by weight of the total composition.

The gassing compositions of the present invention can be used in various explosive compositions including water-in-oil emulsions, oil-in-water emulsions (or slurries). The water-in-oil emulsion includes, for example, compositions in which the emulsion is a water-in-oil emulsion, a melt-in-fuel emulsion, and a melt-in-oil emulsion. The water-in-oil type emulsion explosive related to the present invention will now be described. However, it will be readily apparent to those skilled in the art that modified gasser compositions can be used with other forms of explosive compositions to accommodate the chemistry between the gasser composition and the explosive composition.

The gassing rate of a gasser composition dispersed in an emulsion can be affected by various factors including emulsion temperature, ambient temperature, ground temperature, concentrations of components in the gasser composition, explosive composition composition etc.

Water-in-oil emulsion explosive compositions were previously disclosed in U.S. Patent 3,447,978 to Bluhm, which comprise (a) a discontinuous aqueous phase containing individual droplets of an inorganic oxygen-releasing saline solution; a continuous water-immiscible organic phase; and (c) an emulsifier capable of forming an emulsion of the oxidizer salt solution throughout the continuous organic phase. When these types of emulsions contain only very small amounts of water or extraneous water in the discontinuous phase, they are more properly referred to as melt-in-fuel type emulsion explosives.

Emulsions suitable as explosive emulsions are preferably water-in-oil or melt-in-oil emulsions or melt-in-fuel emulsions. Suitable oxygen releasing salts for use in the aqueous phase of the emulsions of the present invention include alkali and alkaline earth metal nitrates, chlorates and perchlorates, ammonium nitrate, ammonium chlorate, ammonium perchlorate and mixtures thereof. Preferred oxygen releasing salts include ammonium nitrate, sodium nitrate and calcium nitrate. More preferred oxygen releasing salts include ammonium nitrate or a mixture of ammonium nitrate and sodium or calcium nitrate.

Generally, the oxygen-releasing salt component of the composition of the present invention accounts for 45-95% by weight of the whole emulsion composition, preferably 60-90% by weight. In compositions where the oxygen-releasing salt comprises a mixture of ammonium nitrate and sodium nitrate or calcium nitrate, a preferred compositional range for this mixture is 5-100 parts of sodium nitrate or calcium nitrate per 100 parts of ammonium nitrate calcium nitrate.

The amount of water used in the compositions of the present invention is generally from 0 (for melt-in-fuel emulsions) to 30% by weight of the total emulsion composition. The amount is preferably 4-25% by weight, more preferably 6-25% by weight.

The continuous water-immiscible organic phase of the emulsion composition of the present invention comprises the continuous "oil" phase of the emulsion composition, which is the fuel. Suitable organic fuels include aliphatic, cycloaliphatic and aromatic compounds and mixtures thereof which are liquid at the temperature of formulation. Suitable organic fuels may be selected from fuel oils, diesel oils, distillates, furnace oils, kerosene, naphtha, vegetable oils, waxes such as microcrystalline waxes, paraffin waxes and slack waxes, paraffin oils, benzene, toluene, xylene, bituminous materials ; polymeric oils such as low molecular weight olefin polymers, animal oils, fish oils and other mineral oils, hydrocarbon oils or fatty oils and mixtures thereof. Preferred organic fuels are liquid hydrocarbons commonly referred to as petroleum distillates such as gasoline, kerosene, heating oil and paraffin oil.

The organic fuel or continuous phase of the emulsion generally constitutes 2-15% by weight of the total composition, preferably 3-10% by weight.

In emulsion explosives, emulsifiers are used to reduce the interfacial tension between the water and oil phases. The emulsifier molecules are located at the interface between the aqueous liquid droplets and the continuous hydrocarbon phase. The emulsifier molecules are oriented so that their hydrophilic head groups are in the aqueous droplet and their lipophilic tails are in the continuous hydrocarbon phase. Emulsifiers stabilize emulsions, preventing coalescence of aqueous droplets and phase separation. The emulsifier also prevents crystallization of the oxidizer salt in the aqueous droplets, which would break the emulsion and reduce the detonation sensitivity of the emulsion explosive composition.

The emulsifier of the emulsion composition of the present invention may comprise an emulsifier selected from a variety of emulsifiers known in the art for use in the preparation of emulsion explosive compositions. A particularly preferred emulsifier for use in the emulsion compositions of the present invention is a well-known emulsifier based on the reaction product of poly[alk(en)yl]succinic anhydrides and alkylamines, which include poly(alkanolamines) Isobutylene succinic anhydride (PiBSA) derivatives. Particularly preferred emulsifiers include the condensation products of poly[alk(en)yl]succinic anhydrides with amines such as ethylenediamine, diethylenetriamine and ethanolamine. Another preferred emulsifier for use in the emulsion compositions of the present invention is a mixture of PiBSA-based and sodium monooleate-based emulsifiers. Other suitable emulsifiers for use in the emulsions of the present invention include alcohol alkoxylates, phenol alkoxylates, poly(oxyalkylene) glycols, polyfatty acid (oxyalkylene) esters, amine alkoxylates, sorbitol and Fatty acid esters of glycerin, fatty acid salts, sorbitan esters, poly(oxyalkylene) sorbitan esters, fatty amine alkoxylates, poly(oxyalkylene) glycol esters, fatty acid amines, fatty acid amide alkoxylates Alkyl compounds, fatty amines, quaternary amines, alkyl oxazolines, alkenyl oxazolines, imidazolines, alkyl sulfonates, alkyl aryl sulfonates, alkyl sulfosuccinates, alkyl aryl sulfonates alkyl esters, alkyl sulfosuccinates, alkyl phosphates, alkenyl phosphates, phosphate esters, lecithin, copolymers of poly(oxyalkylene) glycols and poly(12-hydroxystearic acid), and their mixture.

Generally, the emulsifier in the emulsion comprises up to 5% by weight of the emulsion. Higher proportions of emulsifiers can be used as supplementary fuel to the composition, but it is generally not necessary to add more than 5% by weight of emulsifier to achieve the desired effect. Lesser amounts of emulsifiers can be used to form stable emulsions, and for economic reasons it is preferred to keep the amount of emulsifier to the minimum required to form the emulsion. The preferred amount of emulsifier is 0.1-3.0% by weight of the water-in-oil emulsion.

In addition to the water-immiscible organic fuel phase, other optional fuel substances, hereinafter referred to as auxiliary fuels, may be added to the emulsion if desired. Examples of such auxiliary fuels include finely divided solids and water-miscible organic liquids, which can be used to partially replace water as a solvent for oxygen-releasing salts or to extend aqueous solvents for oxygen-releasing salts. Examples of auxiliary fuel solids include finely divided substances such as sulfur, aluminum, urea and carbonaceous materials such as natural pitch, pulverized coke or charcoal, carbon black, resin acids such as abietic acid, sugars such as glucose or dextrose and plant products such as Starches, nut flours, grain flours and wood pulp. Examples of water-miscible organic liquids include alcohols such as methanol, diols such as ethylene glycol, amides such as formamide and urea, and amines such as methylamine.

In general, the optional auxiliary fuel component of the compositions of the present invention comprises from 0 to 30% by weight of the total composition.

Emulsions themselves are usually not detonable, and to form explosive emulsions must be mixed with sensitizers such as auto-explosives (eg trinitrotoluene or nitroglycerin) or with a discontinuous phase of void agents. Sensitization using such explosives has been replaced by sensitization methods using non-explosive sensitizers. For example, the introduction of small pores in emulsions that act as conductive detonation hotspots can be used to sensitize emulsions to obtain detonable explosives.

It is also possible to add to the emulsion other substances or mixtures of substances which are oxygen-releasing salts or which are themselves suitable materials for use as explosives. For example, emulsions can be mixed with granular or granulated ammonium nitrate or ammonium nitrate/fuel oil mixtures to produce so-called heavy ANFO (or HANFO).

However, it will be apparent to those skilled in the relevant art that certain divalent cation salts within the ranges described above may produce the desired effect on the gasser rate of the emulsion, but they are not useful for gasser Solution or emulsion explosives recipes may not be as good. For example, the addition of _FeSO4 to the formulation of emulsion explosives containing nitrate ions may produce large amounts of harmful fumes. Copper nitrate may also be an unsuitable additive in emulsion explosive formulations due to the possible formation of undesirable by-products including contact sensitive explosives such as tetraamine copper nitrate. Certain salts such as ferric nitrate and aluminum nitrate are also unsuitable if added to the emulsion explosive formulation in an amount which lowers the pH of the gasser solution to an undesired extent.

The final density of the gasser emulsion will depend on the concentration of the components in the gasser composition, but generally the final density will be from 0.2 to 1.5 g/cc. The final density is preferably 0.5-1.3 g/cc, or more preferably 0.6-1.2 g/cc.

Water-in-oil emulsion compositions can be prepared in a number of different ways. A preferred preparation method comprises: dissolving the oxygen-releasing salt in water at a temperature higher than the fudge point of the saline solution, preferably at a temperature of 20-110° C., to obtain an aqueous solution of the salt; Combine the aqueous salt solution, the water-immiscible organic phase, and the emulsifier in a rapid-mix fashion to form a water-in-oil emulsion; mix until the emulsion is homogeneous.

Unless the context requires otherwise, throughout this specification and the following claims the word "comprise" and variations thereof such as "comprises" and "comprises" will be understood to mean including stated integers or steps or integers or steps without excluding any other wholes or steps or groups of wholes or steps.

The present invention is now illustrated by the following examples, but the present invention is by no means limited to these examples.

Example 1

In this example, a number of different divalent salts were used in the gasser composition of the present invention, which were added to each portion of the water-in-oil emulsion. The outgassing rate of each emulsion was then measured.

Preparation of water-in-oil emulsions

The water-in-oil type emulsion of preparation following composition is used in this embodiment;

Oxidizer solution - 91 w/w %, which contains:

Ammonium nitrate (78.9w/w%)

Water (20.7w/w%)

Buffer (0.4w/w%)

Fuel phase - 9 w/w %, it contains hydrocarbon oil/emulsifier mixture.

The emulsifier system comprises a mixture of sorbitan-oleate derivatives (SMO) and uncondensed amides prepared by reaction of alkanolamines with poly(isobutylene)succinic anhydride (PiBSA). An emulsion was prepared by dissolving ammonium nitrate in water at elevated temperature (98°C) and then adjusting the pH of the oxidant solution to 4.2. The microcrystalline wax is then melted and mixed with the hydrocarbon oil/emulsifier system mixture to produce the fuel phase. The oxidizer phase was then added to the fuel phase in a slow flow with rapid stirring at 98°C to obtain a uniform water-in-oil emulsion.

The emulsion is then divided into equal mass portions.

Preparation of Gasser Compositions

A series of gasser compositions were prepared by dissolving sodium nitrite and divalent metal salts in water. All gasser compositions contained 5% by weight sodium nitrite and 35% by weight divalent salt (except calcium chloride which was 32.5% by weight and magnesium sulfate which was 33.6% by weight). A reference gasser composition was prepared by dissolving sodium nitrite (5% by weight) in water.

Adding the gasser composition to the emulsion

Divide the water-in-oil emulsion into portions. Each gasser composition was mixed into separate emulsion portions at 30°C, the gassing rate was measured, and the relative rate constant at 30°C was calculated. The relative rate constant is the measured rate constant divided by the rate constant of the reference sample. The relative reaction rate constants for gasser compositions containing different divalent metal salts are listed in Table 1.

Table 1 Metal salts in gassing agents Relative rate constant, k Reference (without divalent metal salts) 1.0 Sodium Nitrate (NaNO ₃ ) 0.9 Magnesium nitrate (Mg(NO ₃ ) ₂ ·6H ₂ O) 4.4 Calcium nitrate (Ca(NO ₃ ) ₂ 4H ₂ O) 4.1 Strontium nitrate (Sr(NO ₃ ) ₂ ) 1.8 Manganese(II) nitrate (Mn(NO ₃ ) ₂ ·4H ₂ O) 6.4 Zinc nitrate (Zn(NO ₃ ) ₂ ·6H ₂ O) 3.4 Calcium chloride (CaCl ₂ 6H ₂ O) 2.7 Magnesium Sulfate (MgSO ₄ 4H ₂ O) 1.6

The results in Table 1 show that the gasser composition comprising a divalent metal salt greatly increases the gasser rate compared to the gasser composition comprising a divalent metal salt or no metal salt. The presence of a divalent metal salt in the gasser composition appears to increase the gasser rate by up to a factor of 6. Of particular note is the lower gassing rate of the gasser composition comprising the monovalent metal salt (sodium nitrate) and sodium nitrite than the gasser composition comprising only sodium nitrite. It thus appears that the presence of the monovalent metal salt may have reduced the reaction rate.

Again, for these salts, the catalytic effect decreases down one column of the periodic table, eg magnesium nitrate is more effective per mole than calcium nitrate which in turn is more effective than strontium nitrate. Across one row of the periodic table, magnesium nitrate and zinc nitrate had a better effect on gasser rates than calcium nitrate. These results tend to suggest that the increase in gassing rate appears to be roughly inversely proportional to the molecular weight of the salt or the size of the cation.

Example 2

In this example, the gasser composition of the present invention was added to a water-in-oil emulsion containing a PiBSA-based emulsifier system and compared to Example 1 (wherein the gasser composition was added to The results obtained in emulsions containing mixed PiBSA/SMO-based emulsifier systems) were compared.

Preparation of water-in-oil emulsions

The water-in-oil emulsion was prepared according to the method described in Example 1, except that only PiBSA was used as the emulsifier instead of the PiBSA/SMO emulsifier system. The emulsion of this formula is suitable for making explosive emulsion.

Preparation of Gasser Compositions

Two gasser compositions were prepared. A first gasser composition comprised 35% by weight calcium nitrate and 5% by weight sodium nitrite dissolved in water. The second, reference gasser composition, contained 5% by weight sodium nitrite dissolved in water.

Adding the gasser composition to the emulsion

Divide the water-in-oil emulsion into two parts. Each of the two gasser compositions was mixed into separate emulsion portions at 30°C, the gasser rates were measured, and the relative rate constants at 30°C were calculated. The relative rate constant is the measured rate constant divided by the rate constant measured for the reference sample. The reaction rate constants for the two gasser compositions are listed in Table 2.

Table 2 Metal salts in gassing agents Relative rate constant, k Reference (without divalent metal salts) 1 Calcium nitrate (Ca(NO ₃ ) ₂ 4H ₂ O) 2.5

The presence of a divalent metal salt (calcium nitrate) in the gasser composition increased the gasser rate to 2.5 times that of the reference gasser composition. It is noteworthy that the gassing rate of the emulsion containing PiBSA-based emulsifier was lower than that of the equivalent emulsion containing PiBSA/SMO mixed emulsifier system (Table 1).

Example 3

In this example, the reaction rates of gasser compositions of the present invention comprising divalent metal salts and/or accelerators are compared.

Preparation of water-in-oil emulsions

Water-in-oil emulsion was prepared according to the method described in Example 1.

Adding the gasser composition to the emulsion

A series of gasser compositions were prepared and added to separate portions of the water-in-oil emulsion. Each of the two gasser compositions was mixed into separate emulsion portions at 30°C, the reaction rate was measured, and the rate constant at 30°C was calculated. The relative rate constant is the measured rate constant divided by the rate constant of the reference sample. The relative reaction rate constants for the two gasser compositions are listed in Table 3.

table 3 Composition of gasser Relative rate constant, k Reference - 5% by weight NaNO ₂ , no NaSCN, no divalent metal salts 1.0 5 wt% _NaNO2 10 wt% NaSCN 1.2 5% by weight NaNO ₂ 35% by weight Ca(NO ₃ ) ₂ ·4H ₂ O 4.1 5 wt% NaNO ₂ 10 wt% NaSCN 35 wt% Ca(NO ₃ ) ₂ 4H ₂ O 10.0

Note that the final density of the gassed emulsion was 1.0 ± 0.1 g/cc for each of the four samples.

The results in Table 3 show that the mere addition of thiocyanate to the sodium nitrate gasser composition solution provided little increase in the reaction rate. Thiocyanate alone is a relatively poor gasser catalyst. However, when thiocyanate was added to the gasser composition containing divalent metal salts, the reaction rate was significantly increased; the reaction rate increased to about 10 times the rate of the gasser using the reference sample, and compared to 2.5 times faster using only divalent metal salts.

Example 4

The test described in Example 3 at 30°C was repeated using the emulsion and gasser composition at 5°C. The gassing rate of the gasser composition comprising divalent metal salt and thiocyanate was still 10 times higher than the reaction rate using the reference sample, and faster than the reaction rate of the gassing agent composition comprising only divalent metal salt 2.5 times faster.

Example 5

The deflation time was also measured for the test described in Example 3 and the results are listed in Table 4. The gassing time is the length of time when the reaction of the gassing agent in the emulsion at 30°C reaches completion.

Table 4: Composition of gasser deflation time Reference - 5% by weight NaNO ₂ , no NaSCN, no divalent metal salts 60 minutes 5 wt% _NaNO2 10 wt% NaSCN 52 minutes 5% by weight NaNO ₂ 35% by weight Ca(NO ₃ ) ₂ ·4H ₂ O 17 minutes 5 wt% NaNO ₂ 10 wt% NaSCN 35 wt% Ca(NO ₃ ) ₂ 4H ₂ O 8 minutes

The results in Table 4 show that very fast gasser times can be achieved using the gasser compositions of the present invention.

Example 6

Gasser compositions were prepared using 5 wt% _NaNO2 and different concentration ranges of divalent cation salts. The gasser composition was added to separate portions of the emulsion prepared in Example 1 and the gasser rate was measured. The measured reaction rates indicated that the rate of gasser enhancement was approximately proportional to the square of the nitrite concentration. Without wishing to be bound by theory, it is believed that divalent cations participate twice in the rate-limiting step of the gassing reaction mechanism.

Example 7

In this example, the gasser composition of the present invention comprising different amounts of divalent cation salts was added to a water-in-oil emulsion containing a PiBSA/SMO-based emulsifier system, and the final density of the gassed emulsion was measured .

Preparation of water-in-oil emulsions

Water-in-oil emulsion was prepared according to the method described in Example 1.

Preparation of Gasser Compositions

A gasser composition of the following composition was prepared:

table 5: Composition of gasser Emulsion density, g/cc Reference - 5% by weight NaNO ₂ , no NaSCN, no divalent metal salts 0.98 5% by weight of NaNO ₂ 10% by weight of Mg(NO ₃ ) ₂ ·6H ₂ O 0.97 5% by weight NaNO ₂ 15% by weight Mg(NO ₃ ) ₂ ·6H ₂ O 0.98 5% by weight NaNO ₂ 25% by weight Mg(NO ₃ ) ₂ ·6H ₂ O 0.98 5% by weight NaNO ₂ 30% by weight Mg(NO ₃ ) ₂ ·6H ₂ O 0.97

The results show that the amount of divalent cations added has a negligible effect on the final density of the emulsion.

Example 8

The test described in Example 7 was repeated with the only difference that all gasser compositions also contained 10% by weight NaSCN. The densities of the gassed emulsions were all measured in the range of 0.97-0.98 g/cc.

Additionally, the difference in the amount of divalent cation salt in the gasser solution containing sodium nitrite and sodium thiocyanate did not affect the final density of the gasser emulsion.

Example 9

A sample of the emulsion of Example 1 was mixed at 26°C with 2.9% by weight of the gasser composition formulated below. Gasser components refer to Gasser Composition T1 Gasser Composition T2 _NaNO2 (wt%) 15 15 15 NaSCN(wt%) 15 15 15 Ca(NO ₃ ) ₂ (wt%) 0 5 10 Water (wt%) 70 65 60

Gasser compositions T1 and T2 contained divalent cations Ca ²⁺ , while the reference gasser contained no divalent cations.

Samples of the three gasser compositions mixed with the emulsion were pumped into three separate containers of equal volume at a loading rate of 70 kg/min.

Density versus time for each gassed emulsion sample is plotted in FIG. 1 . Figure 1 illustrates that the emulsion samples gassed with gasser compositions T1 and T2 had faster gasser rates and lower final densities compared to the reference samples. Gasser composition T2, which contained twice as much divalent cation Ca2 ⁺ as gasser composition T1, also had a faster gasser rate.

While there have been described preferred embodiments of the invention, it is to be understood that various modifications thereto will become apparent to those skilled in the art from the reading of the description. It is therefore to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims.

Claims (37)

Claims 1. A gasser composition for a gassed explosive composition, wherein the gasser composition comprises a gasser and a divalent cation-containing metal salt. 2. The gasser composition of claim 1, wherein the cation is selected from divalent cations of any main group metal, transition metal, lanthanide or actinide. 3. The gasser composition as claimed in claim 1, wherein the divalent cations may be selected from Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Ti ²⁺ , Zr ²⁺ , Hf ²⁺ , V ²⁺ , Cr ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ^{2+ ,} Zn ²⁺ , Ag 2+ , Hg ²⁺ , Cd ²⁺ , Al ²⁺ , Sn ²⁺ , Pb ²⁺ . 4. The gasser composition of claim 1, wherein the divalent metal cation is selected from the group consisting of Mg2 ⁺ and Ca2 ⁺ . 5. The gasser composition of claim 1, wherein the one or more anions of the metal salt are selected from the group consisting of halides, nitrates, sulfates, phosphates, chlorates, perchlorates, and combinations thereof. 6. The gasser composition of claim 1, wherein the one or more anions of the metal salt are nitrate. 7. A gassing composition wherein the gassing agent is a nitrite. 8. A gassing composition wherein the gassing agent is sodium nitrite. 9. The gasser composition of claim 1, wherein the gasser and the metal salt are in solution. 10. The gasser composition of claim 1, wherein the gasser composition comprises 0.5-45% by weight of the gasser composition and 1-45% by weight of the gasser composition. metal salts. 11. The gasser composition of claim 1, wherein the gasser composition comprises 0.5-25% by weight of a gasser and 10-40% by weight of a divalent metal salt. 12. The gasser composition of claim 1, wherein the gasser composition comprises 0.5-20% by weight of a gasser and 20-40% by weight of a divalent metal salt. 13. The gassing composition of claim 1, wherein the explosive composition is a water-in-oil emulsion explosive. 14. A method of degassing an explosive composition, the method comprising the steps of: i) making a gasser composition comprising a gasser and a divalent cation-containing metal salt; and ii) Dispersing the gassing composition into the explosive composition. 15. A method of degassing an explosive composition as claimed in claim 14, wherein the cation is selected from divalent cations of any main group metal, transition metal, lanthanide or actinide. 16. A method of degassing an explosive composition as claimed in claim 14, wherein the divalent cations may be selected from Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Ti ²⁺ , Zr ²⁺ , Hf ²⁺ , V ²⁺ , Cr ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , ^{Ni 2+} , Cu ²⁺ , Zn 2+ , Ag ²⁺ , Hg ²⁺ , Cd ²⁺ , Al ²⁺ , Sn ²⁺ , Pb ²⁺ . 17. A method of degassing an explosive composition as claimed in claim 14, wherein the divalent metal cation is selected from the group consisting of Mg2 ⁺ and Ca2 ⁺ . 18. A method of degassing an explosive composition as claimed in claim 14, wherein the one or more anions of the metal salt are selected from the group consisting of halides, nitrates, sulfates, phosphates, chlorates, perchlorates and their The combination. 19. A method of degassing an explosive composition as claimed in claim 14, wherein the one or more anions of the metal salt are nitrate. 20. A method of gassing an explosive composition wherein the gassing agent is a nitrite. 21. A method of degassing an explosive composition wherein the gassing agent is sodium nitrite. 22. A method of gassing an explosive composition as claimed in claim 14, wherein the gassing agent and the metal salt are in solution. 23. A method of degassing an explosive composition, wherein a static mixer is used to disperse the gassing composition into the explosive composition while pumping the explosive composition. 24. A method of degassing an explosive composition as claimed in claim 23, wherein the explosive composition is a water-in-oil emulsion explosive. 25. A gassing explosive composition comprising an explosive composition gassed by dispersing a gassing composition into said explosive composition, wherein the gassing composition comprises a gassing agent and a metal salt containing a divalent cation . 26. A gassed explosive composition comprising an explosive composition gassed by dispersing the gassed composition in an explosive composition as claimed in claim 25, wherein the cation is selected from any main group metal, transition metal, Divalent cations of lanthanides or actinides. 27. A gassed explosive composition comprising an explosive composition gassed by dispersing the gassed composition in the explosive composition as claimed in claim 25, wherein the divalent cations can be selected from Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Ti ²⁺ , Zr ²⁺ , Hf ²⁺ , V ²⁺ , Cr ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Zn ²⁺ , Ag ²⁺ , Hg ²⁺ , Cd ²⁺ , Al ²⁺ , Sn ²⁺ , Pb ²⁺ . 28. A gassed explosive composition comprising an explosive composition gassed by dispersing the gassed composition into an explosive composition as claimed in claim 25, wherein the divalent metal cation is selected from the group consisting of Mg ^and Ca ²⁺ . 29. A gassed explosive composition comprising an explosive composition gassed by dispersing the gassed composition in an explosive composition as claimed in claim 25, wherein one or more anions of the metal salt are selected from Halides, nitrates, sulfates, phosphates, chlorates, perchlorates, and combinations thereof. 30. A gassed explosive composition comprising an explosive composition gassed by dispersing the gassed composition in an explosive composition as claimed in claim 25, wherein the one or more anions of the metal salt are nitric acid root. 31. A gassed explosive composition comprising an explosive composition gassed by dispersing a gassing composition into said explosive composition, wherein the gassing agent is a nitrite. 32. A gassed explosive composition comprising an explosive composition gassed by dispersing a gassing composition into said explosive composition, wherein the gassing agent is sodium nitrite. 33. A gassed explosive composition comprising an explosive composition gassed by dispersing the gassed composition in an explosive composition as claimed in claim 25, wherein the gassed agent and the metal salt are in solution. 34. A gassed explosive composition comprising an explosive composition gassed by dispersing the gassed composition in the explosive composition of claim 25, wherein the gassed composition comprises a gassed composition 0.5-45% by weight of the gasser and 1-45% by weight of the gasser composition of the divalent metal salt. 35. A gassed explosive composition comprising an explosive composition gassed by dispersing a gassed composition in an explosive composition as claimed in claim 25, wherein said gassed composition comprises 0.5-25 wt. % of gassing agent and 10-40% by weight of divalent metal salt. 36. A gassed explosive composition comprising an explosive composition gassed by dispersing a gassed composition in an explosive composition as claimed in claim 25, wherein said gassed composition comprises 0.5-20 wt. % of gassing agent and 20-40% by weight of divalent metal salt. 37. A gassed explosive composition comprising an explosive composition gassed by dispersing the gassed composition in the explosive composition of claim 25, wherein the explosive composition is a water-in-oil emulsion explosives.

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