CA1050276A - Aqueous explosive composition - Google Patents
Aqueous explosive compositionInfo
- Publication number
- CA1050276A CA1050276A CA238,034A CA238034A CA1050276A CA 1050276 A CA1050276 A CA 1050276A CA 238034 A CA238034 A CA 238034A CA 1050276 A CA1050276 A CA 1050276A
- Authority
- CA
- Canada
- Prior art keywords
- composition
- lignosulphonate
- fuel
- nitrate
- oxidant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B47/00—Compositions in which the components are separately stored until the moment of burning or explosion, e.g. "Sprengel"-type explosives; Suspensions of solid component in a normally non-explosive liquid phase, including a thickened aqueous phase
- C06B47/14—Compositions in which the components are separately stored until the moment of burning or explosion, e.g. "Sprengel"-type explosives; Suspensions of solid component in a normally non-explosive liquid phase, including a thickened aqueous phase comprising a solid component and an aqueous phase
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Liquid Carbonaceous Fuels (AREA)
- Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
- Agricultural Chemicals And Associated Chemicals (AREA)
Abstract
AQUEOUS EXPLOSIVE COMPOSITION
Abstract of the Disclosure The present invention relates to an aqueous explosive composition which consists of at least one inorganic oxygen-supplying substance, at least one combustible substance and at least one thickening agent, at least one of combustible substance being liquid and substantially water insoluble and the aqueous phase of the explosive composition having dissolved therein a lignosulphonate in an amount of up to 5 % of the weight of the explosive composition.
Abstract of the Disclosure The present invention relates to an aqueous explosive composition which consists of at least one inorganic oxygen-supplying substance, at least one combustible substance and at least one thickening agent, at least one of combustible substance being liquid and substantially water insoluble and the aqueous phase of the explosive composition having dissolved therein a lignosulphonate in an amount of up to 5 % of the weight of the explosive composition.
Description
~6)soz76 This invention relates to such explosive compositions frequently called slurry explosives consisting of an aqueous composition of oxygen-supplying salts and a fuel. More particularly, the invention relates to such explosive compositions in which the fuel is or comprises a liquid substance substantially insoluble in water.
In the patent literature substances of most various kinds have been discussed as oxidant and fuel components in the so-called slurry explos- :
ives. Among solid substances which are not self-explosive, bituminous sub-stances and many other organic substances and various metals have been sug-gested and put into use. These substances have in common that the degree to which these fuels are finely dispersed is important to the properties of the explosive manufactured therefrom.
Slurry explosives which contain a liquid, substantially water-insoluble fuel are known. The most frequently discussed slurry explosives of this group contain hydrocarbons of various kinds, normally petroleum fractions called fuel oils or diesel oils as the fuel component of the composition.
Thus, the manufacture of explosives of this kind is known from U.S. Patent Specification 3,161,551. In said specification the use of a hydro-phobic emulsifier is also suggested, in which the emulsifier is able to form a water-in-oil emulsion as a characterising feature of the explosive disclosed.
In Australian Patent 281,537 similar explosives have been disclosed and also the use of anionic surface active substances therein. Such explosives which contain a substantially water insoluble liquid fuel normally also contain thickening agents of known character, preferably guar gum and, naturally, also can contain other components. Thus, explosives which contain aluminium pow-der in addition to a fuel oil have been disclosed in IJ.S. Patent Specifica-tion 3,094,069.
Naturally, in the case also of such liquid fuel aqueous explos-ives, there are a number of important factors governing the properties of the product, namely: the extent to which such fuels are finely dispersed, how the emulsion of fuel and the aqueous salt solution is provided and the stability of the emulsion or dispersion. Thus, it has been stated that the emulsifiers ., ~
lOSOZ76 used should be hydrophobic and stabilize a water-in-oil emulsion. It has also been suggested to allow the fuel to be absorbed by the ammonium ni-trate in the form of porous prills before this is used in the production of the final composition.
The present invention is based on the discovery that lignosul- ;
phonates available from the so-called sulphite liquors in the production of wood pulp according to the sulphite cellulose process, is particularly well suited to the preparation of aqueous slurry explosives containing a liquid fuel, in that the liquid fuel is very easily dispersed in an aqueous salt solution containing such lignosulphonates and the emulsion obtained is very stable. These lignosulphonates are water soluble, in contrast to the pre-viously suggested emulsifiers for slurry explosives comprising liquid fuels, and it is presumed that the lignosulphonates stabilize an emulsion of the oil-in-water type. The emulsifying and emulsion stabilizing effect of lig-nosulphonates is previously known ~ se, but it has not been known that this effect is so evident in a system in which the water phase is a saturated solution of oxygen supplying salts, especially the preferred nitrates.
Using lignosulphonates in slurry explosives is previously known from Canadian Patent 784,636, issued May 7, 1968 to Canadian Industries Limited. In this patent there are disclosed only slurry explosives in which the fuel consists of solid substances or water soluble substances. The spe-' cification does not disclose any use of or particular advantages of lignosul-phonates in connection with watér-insoluble liquid fuels which is a character-ising feature of the present invention.
In said Canadian patent lignosulphonates are designated a sensi-f tizer, i.e. an agent which increases the sensitivity o~ the explosive to ini-~i tiators, however, without presenting any explanation of, or theory for, this ; sensitizing effect. This sensitivity increasing effect is present also when the fuel is a water-soluble liquid substance.
U.S. Patent 3,617,407 to Craig and Falconer, issued November 2, ,s 1971 refers to slurry explosives comprising a combination of cross-linked galactomannan with psyllium flour as a thickener. Certain examples of slurry explosive compositions containing ammonium lignosulphonate are given, but none includes this agent together with a liquid fuel. -Thus, the inventive concept resides mainly in the fact that the very same substance is both an effective emulsifier for liquid fuels and a sensitivity increasing component of the composition. Furthermore, it is a feature of the present invention that lignosulphonates have additional advan-tageous effects relative to previously known emulsifiers for slurry explos-ives comprising liquid fuels. In many cases it is advisable to convert the aqueous thickened salt solution of the explosive into a gel by means of a so-called crosslinking agent for the high polymer molecules of the thickener, thereby providing inter alia a considerably improved water resistance to the explosive. As crosslinking agents, compounds of heavy metals from Groups IV, V and VI of the Periodic System in their highest valence states are particularly mentioned, such as chromates, antimonates or titanates. It is known that such crosslinking reactions or gel formation proceed more ra-pidly or more completely in the presence of reducing agents. Thus, it is also a feature of the present invention that lignosulphonates are suitable as such reducing agents for promoting gel formation, a property not shared with previously suggested emulsifiers. Thus, considered as a whole, it has sur-prisingly been found that lignosulphonates have no less than three separate advantageous effects in the explosives of the present invention, which rend-ers the use of different components for each of said functions superfluous.
Finally, it is a feature of the present invention that the use of lignosulphonates in connection with liquid fuels gives rise to consider-able economic advantages. Lignosulphonates are much cheaper than most known or suggested emulsifiers for slurry explosives comprising liquid fuels. They are also cheaper than the reducing agents which have been suggested for crosslinking reactions with chromates and antimonates. Also, considered in , J~.
~(~SQZ76 relation to the use of solid fuels, the present invention means that all ex- -penses for crushing and grinding of the solids are avoided, since the disper-sion of the liquid fuels takes place during the mixing operation for preparing the finished explosive. Furthermore, an economic advantage lies in the fact that common fuel oil is cheaper than most solids which have been suggested up to now as fuels in slurry explosives.
Accordingly,the present invention provides an aqueous, slurry type explosive composition comprising an inorganic oxidant, a fuel, a thickener and a surface active agentJ said composition being free from any self-explosive component, the improvement which comprises using in combination a fuel com-ponent which is a liquid, substantially water-insoluble hydrocarbon and, as surface active agent, a lignosulphonate in an amount of about 0.5 to 5% by weight of the composition.
In the practice of the present invention no method is critically important and the mixing of the explosive components may be carried out in many different ways. A preferred method is to prepare an aqueous solution of the oxygen supplying saltts), thickener(s) and lignosulphonates and thereafter add the liquid fuel in a simple mixing operation, wherein certain quantities of undissolved salts and other combustible substances, such as metal powder or the like, may be added. Auxiliary agents in small quantities to control the density and consistency of the explosive, such as gas generating reagents, e.g. sodium nitrite and crosslinking agents such as chromates, titanates or antimonates, respectively, may be added in the same mixing operation, if de-slred.
The mixing operation and the equipment for carrying out the oper-ation are neither critical to the practice of the invention, but a certain effect of the mixing intensity can sometimes be observed on such quality parameters of the explosive as the critical diameter.
Thus, a prepared solution of oxygen supplying salts, thickeners and a lignosulphonate may be brought together with the liquid fuel and op-r~
~OS(~276 tionaLlly other components in a plastic bottle and shaken by hand, whereby within one minute a sufficiently intimate mixture is obtained which can be squeezed out of the plastic bottle into suitable tubes or the like and then successfully detonated by means of conventional initiators. Obviously, the same mixing operation may be performed chargewise in so to say any size mixing equipment whereby mixing periods of the order of one ~r a few minutes usually will be sufficient. A particularly preferred method in carrying out the mixing operation is to allow the aqueous solution of the oxygen supplying salt or salts, thickeners and the lignosulphonate to continuously run to-gether with the liquid fuel, optionally simultaneous supply of some quantities of undissolved salt and combustible solids and other agents, into a mixing chamber with a mechanical stirrer, from which chamber the ready prepared ex-plosive flows continuously and is pumped either directly into a blast hole or to a cartridging machine of suitable kind.
In such a continuous mixing operation whereby accumulation of large quantities of ready made and detonable explosive is avoided, the volume of the mixing chamber may be as small as 1 to 2 litres for a flow through of an explosive quantity with a volume of about 20 litres per minute. By such means the mixing operation may be carried out between 3 to 6 seconds as an average with such an effective emulsification of the liquid fuel in the salt solution that the explosive produced is fully satisfactory for application in blast holes of diameters above 2 inches.
W~en practising the invention it is not critical what kind of lig-nosulphonates are being used or in which form they are present. Thus, so-called sulphite liquors evaporated to a solids content of about 50%, the rest substantially being water or substances evaporated to dryness and present as powder may be used. Lignosulphonates of sodium, calcium, magnesium and am-monium may be used, dependent of which bases are used in the sulphite cellu-lose process. Nor is it critical in any way in practising the invention whether the lignosulphonate material contains various other water soluble com-A
~ - 6 -105~276 ponents, such as various sugars extracted from the raw material for the pro-duction of cellulose, or whether these sugars are removed by fermentation be-fore evaporating to about 50% or nearly to 100% dry content.
The lignosulphonates which according to the invention should be included in the final explosive composition are being used in amounts of up to 5% of the total composition and preferably in amounts of between 0.5 and
In the patent literature substances of most various kinds have been discussed as oxidant and fuel components in the so-called slurry explos- :
ives. Among solid substances which are not self-explosive, bituminous sub-stances and many other organic substances and various metals have been sug-gested and put into use. These substances have in common that the degree to which these fuels are finely dispersed is important to the properties of the explosive manufactured therefrom.
Slurry explosives which contain a liquid, substantially water-insoluble fuel are known. The most frequently discussed slurry explosives of this group contain hydrocarbons of various kinds, normally petroleum fractions called fuel oils or diesel oils as the fuel component of the composition.
Thus, the manufacture of explosives of this kind is known from U.S. Patent Specification 3,161,551. In said specification the use of a hydro-phobic emulsifier is also suggested, in which the emulsifier is able to form a water-in-oil emulsion as a characterising feature of the explosive disclosed.
In Australian Patent 281,537 similar explosives have been disclosed and also the use of anionic surface active substances therein. Such explosives which contain a substantially water insoluble liquid fuel normally also contain thickening agents of known character, preferably guar gum and, naturally, also can contain other components. Thus, explosives which contain aluminium pow-der in addition to a fuel oil have been disclosed in IJ.S. Patent Specifica-tion 3,094,069.
Naturally, in the case also of such liquid fuel aqueous explos-ives, there are a number of important factors governing the properties of the product, namely: the extent to which such fuels are finely dispersed, how the emulsion of fuel and the aqueous salt solution is provided and the stability of the emulsion or dispersion. Thus, it has been stated that the emulsifiers ., ~
lOSOZ76 used should be hydrophobic and stabilize a water-in-oil emulsion. It has also been suggested to allow the fuel to be absorbed by the ammonium ni-trate in the form of porous prills before this is used in the production of the final composition.
The present invention is based on the discovery that lignosul- ;
phonates available from the so-called sulphite liquors in the production of wood pulp according to the sulphite cellulose process, is particularly well suited to the preparation of aqueous slurry explosives containing a liquid fuel, in that the liquid fuel is very easily dispersed in an aqueous salt solution containing such lignosulphonates and the emulsion obtained is very stable. These lignosulphonates are water soluble, in contrast to the pre-viously suggested emulsifiers for slurry explosives comprising liquid fuels, and it is presumed that the lignosulphonates stabilize an emulsion of the oil-in-water type. The emulsifying and emulsion stabilizing effect of lig-nosulphonates is previously known ~ se, but it has not been known that this effect is so evident in a system in which the water phase is a saturated solution of oxygen supplying salts, especially the preferred nitrates.
Using lignosulphonates in slurry explosives is previously known from Canadian Patent 784,636, issued May 7, 1968 to Canadian Industries Limited. In this patent there are disclosed only slurry explosives in which the fuel consists of solid substances or water soluble substances. The spe-' cification does not disclose any use of or particular advantages of lignosul-phonates in connection with watér-insoluble liquid fuels which is a character-ising feature of the present invention.
In said Canadian patent lignosulphonates are designated a sensi-f tizer, i.e. an agent which increases the sensitivity o~ the explosive to ini-~i tiators, however, without presenting any explanation of, or theory for, this ; sensitizing effect. This sensitivity increasing effect is present also when the fuel is a water-soluble liquid substance.
U.S. Patent 3,617,407 to Craig and Falconer, issued November 2, ,s 1971 refers to slurry explosives comprising a combination of cross-linked galactomannan with psyllium flour as a thickener. Certain examples of slurry explosive compositions containing ammonium lignosulphonate are given, but none includes this agent together with a liquid fuel. -Thus, the inventive concept resides mainly in the fact that the very same substance is both an effective emulsifier for liquid fuels and a sensitivity increasing component of the composition. Furthermore, it is a feature of the present invention that lignosulphonates have additional advan-tageous effects relative to previously known emulsifiers for slurry explos-ives comprising liquid fuels. In many cases it is advisable to convert the aqueous thickened salt solution of the explosive into a gel by means of a so-called crosslinking agent for the high polymer molecules of the thickener, thereby providing inter alia a considerably improved water resistance to the explosive. As crosslinking agents, compounds of heavy metals from Groups IV, V and VI of the Periodic System in their highest valence states are particularly mentioned, such as chromates, antimonates or titanates. It is known that such crosslinking reactions or gel formation proceed more ra-pidly or more completely in the presence of reducing agents. Thus, it is also a feature of the present invention that lignosulphonates are suitable as such reducing agents for promoting gel formation, a property not shared with previously suggested emulsifiers. Thus, considered as a whole, it has sur-prisingly been found that lignosulphonates have no less than three separate advantageous effects in the explosives of the present invention, which rend-ers the use of different components for each of said functions superfluous.
Finally, it is a feature of the present invention that the use of lignosulphonates in connection with liquid fuels gives rise to consider-able economic advantages. Lignosulphonates are much cheaper than most known or suggested emulsifiers for slurry explosives comprising liquid fuels. They are also cheaper than the reducing agents which have been suggested for crosslinking reactions with chromates and antimonates. Also, considered in , J~.
~(~SQZ76 relation to the use of solid fuels, the present invention means that all ex- -penses for crushing and grinding of the solids are avoided, since the disper-sion of the liquid fuels takes place during the mixing operation for preparing the finished explosive. Furthermore, an economic advantage lies in the fact that common fuel oil is cheaper than most solids which have been suggested up to now as fuels in slurry explosives.
Accordingly,the present invention provides an aqueous, slurry type explosive composition comprising an inorganic oxidant, a fuel, a thickener and a surface active agentJ said composition being free from any self-explosive component, the improvement which comprises using in combination a fuel com-ponent which is a liquid, substantially water-insoluble hydrocarbon and, as surface active agent, a lignosulphonate in an amount of about 0.5 to 5% by weight of the composition.
In the practice of the present invention no method is critically important and the mixing of the explosive components may be carried out in many different ways. A preferred method is to prepare an aqueous solution of the oxygen supplying saltts), thickener(s) and lignosulphonates and thereafter add the liquid fuel in a simple mixing operation, wherein certain quantities of undissolved salts and other combustible substances, such as metal powder or the like, may be added. Auxiliary agents in small quantities to control the density and consistency of the explosive, such as gas generating reagents, e.g. sodium nitrite and crosslinking agents such as chromates, titanates or antimonates, respectively, may be added in the same mixing operation, if de-slred.
The mixing operation and the equipment for carrying out the oper-ation are neither critical to the practice of the invention, but a certain effect of the mixing intensity can sometimes be observed on such quality parameters of the explosive as the critical diameter.
Thus, a prepared solution of oxygen supplying salts, thickeners and a lignosulphonate may be brought together with the liquid fuel and op-r~
~OS(~276 tionaLlly other components in a plastic bottle and shaken by hand, whereby within one minute a sufficiently intimate mixture is obtained which can be squeezed out of the plastic bottle into suitable tubes or the like and then successfully detonated by means of conventional initiators. Obviously, the same mixing operation may be performed chargewise in so to say any size mixing equipment whereby mixing periods of the order of one ~r a few minutes usually will be sufficient. A particularly preferred method in carrying out the mixing operation is to allow the aqueous solution of the oxygen supplying salt or salts, thickeners and the lignosulphonate to continuously run to-gether with the liquid fuel, optionally simultaneous supply of some quantities of undissolved salt and combustible solids and other agents, into a mixing chamber with a mechanical stirrer, from which chamber the ready prepared ex-plosive flows continuously and is pumped either directly into a blast hole or to a cartridging machine of suitable kind.
In such a continuous mixing operation whereby accumulation of large quantities of ready made and detonable explosive is avoided, the volume of the mixing chamber may be as small as 1 to 2 litres for a flow through of an explosive quantity with a volume of about 20 litres per minute. By such means the mixing operation may be carried out between 3 to 6 seconds as an average with such an effective emulsification of the liquid fuel in the salt solution that the explosive produced is fully satisfactory for application in blast holes of diameters above 2 inches.
W~en practising the invention it is not critical what kind of lig-nosulphonates are being used or in which form they are present. Thus, so-called sulphite liquors evaporated to a solids content of about 50%, the rest substantially being water or substances evaporated to dryness and present as powder may be used. Lignosulphonates of sodium, calcium, magnesium and am-monium may be used, dependent of which bases are used in the sulphite cellu-lose process. Nor is it critical in any way in practising the invention whether the lignosulphonate material contains various other water soluble com-A
~ - 6 -105~276 ponents, such as various sugars extracted from the raw material for the pro-duction of cellulose, or whether these sugars are removed by fermentation be-fore evaporating to about 50% or nearly to 100% dry content.
The lignosulphonates which according to the invention should be included in the final explosive composition are being used in amounts of up to 5% of the total composition and preferably in amounts of between 0.5 and
2%.
To further illustrate the invention the following examples are given on some embodiments of the invention wherein both the mixing operations are carried out in different ways and wherein some examples have been carried out without lignosulphonates for comparison of the obtained results.
Examples In the following table a total of five examples are summarized, Examples 4 and 5 ~eing outside the scope of the invention and included for reasons of co~parison since they either do not contain lignosulphonate or do -not contain a liquid fuel.
The method of preparation is also varied, but all examples have in common that a solution consisting substantially of nitrates and water is first prepared and maintained at a temperature of about 45C. until the mixing 1 20 operation with the remaining components is taking place. In this solution ! there are also included: the thickener guar gum which is first dispersed in glycol to prevent lump formation; furthermore, thiourea as a reaction partner for the nitrite aerating agent so that a certain amount of nitrogen is gener-ated and finely distributed throughout the final mixture; and also the anti-foaming agent "Foamaster* 50D", marketed by the company Nopco Senco, to avoid , varying occlusions of air in the explosive composition. Finally, the solution according to all examples except Example 4 contains a lignosulphonate, viz., the commercial product denoted "Totanin MG" from A/S Toten Cellulosefabrikk, Nygard, Norway.
The ammoniu~ nitrate used is a commercial grade available in : *Trademark A
105~276 prilled form. The lime saltpeter being used is also a commercial grade in the iorm of prills containing about 15% of water and about 6% of ammonium nitrate in addition to calcium nitrate.
As fuel a diesel oil of normal commercial grade was used except Example 5, where the fuel was a finely ground gilsonite which is a high car-bon, low ash, natural asphalt.
The auxiliary substances sodium dichromate for crosslinking the guar gum and sodium nitrite for generating nitrogen are added during the final mixing operation in the form of separate solutions, 50% and 25% concen-tration, respectively. All figures in the composition table are given in weight percent.
TABLE I is Composition No. 1 2 3 4 5 Solution:
Ammonium nitrate 29.0029.00 29.00 29.33 29.00 Lime saltpeter, 28.1828.18 28.18 28.18 28.18 Commercial grade 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 Lignosulphonate 0.53 0.53 0.53 - 0.53 Ethylene glycol 0.78 0.78 0.78 0.98 0.78 Ant foaming agent 0.03 0.03 0.03 0.03 0.03 Fuels:
Diesel oil (fuel oil) 6.50 6.50 6.50 6.50 Gilsonite - - - - 6.50 Undissolved ammonium nitrate28.00 28.00 28.00 28.00 28.00 uxiliary substances:
,. .
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 mixture methods are used in the various embodiment examples.
.
In Example 1 the solution, fuel, dry ammonium nitrate and auxili- `
ary substances are brought together in the order mentioned in a plastic bottle having a volume of about 2 litres and shaken together for about 15 seconds.
Thereupon the prepared mixture, before a complete crosslinking of the guar gum has taken place, is transferred into cardboard tubes of various diameters for testing of the explosive quality parameters.
In Example 2 the composition has been prepared in a mixing appa-ratus commonly used for bakery purposes with a mixing vessel having a volume : -of about 25 litres. After charging the solution the fuel oil was added and stirred until the mixture looked homogeneous, which was obtained within about ~ -one minute. During somewhat more vigorous stirring dry ammonium nitrate and the auxiliary substances were added and stirring maintained for about one minute. Then the prepared mixture was put into cardboard tubes as in Example 1, In Examples 3, 4 and 5 a continuous mixing process was used where-in the components were passed into a mixing chamber having a volume of about 1 litre. The charging rate was about 10 kgs per minute and samples of the final mixture were brought into cardboard tubes of various diameters for the determination of the critical diameter. In all cases the density of the pro-duct was about 1.15 g/cm . The results are stated in Table II. The stated critical diameter for the explosive mixtures is the smallest diameter where a tube, having a length 6 times the diameter, detonates completely unconfined 1 having been cooled down to 5C. and initiated with a primer. As primer for ; tube diameters below 84 mm 32 g of trinitro-toluene has been used, in the table denoted as "A", whilst for larger tube diameters 360 g of pentolite (55% pentrite, 45~ trinitro-toluene), in the table denoted "B" has been used.
TABLE II
Example No. 1 2 3 4 5 I Primer, type: A A A B B
-' 30 Critical diameter, inches: 2 2 3/4 2 3/4 4 >5 3/4 .. , _ g _ .z~
lOSQ276 From the above results it can be seen that with diesel oil as fuel lignosulphonate provides a critical diameter below 3 inches whilst lack of lignosulphonate, all other conditions being unchanged, provides a critical diameter of 4 inches even with a substantially stronger primer. Other lig-nosulphonate compositions provided results nearly identical to those obtained with "Totanin MG". For a solid fuel, gilsonite, even with lignosulphonate it is obtained a critical diameter above 5 3/4 in. which was the largest diameter tested.
It will also be seen that the rapid mixing by shaking in a plas-tic bottle provides a somewhat lower critical diameter than a mechanical mix-ing whilst the continuous mixing and the mechanical chargewise mixing are of equal value.
A series of tests have been performed with emulsifiers other than lignosulphonate. The agents tested were stated by the suppliers to be effect-ive for emulsification of oil in water containing salts, and are presented in Table III.
TABLE III
Designation Supplier "LDC Base"~ Company Nopco Senco, Drammen, Norway "1225-L" " " " " "
"1186 A" " ll "Type 09" Hexamin Products, R~yken, Norway "Type 79/02" " " " "
"Berol 525" B~rol Kemi AB, Stenungsund, Sweden "Berol 259"
Nonylphenol Imperial Chemicals Ltd., London, England Using the same mixing conditions as applied for Example 1 and with componen~s otherwise as in Example 4, none of the commercial emulsifiers stated above produced a homogenity even approximating that achieved by the ~ ~ra~h . ~
~050276 lignosulphonate, and usually non-emulsified oil was observed floating freely on the surface of the mixture. In no case was a critical diameter determined below 4 inches for these mixtures.
Finally, it should be mentioned that an explosive mixture having a composition as in Examples 1, 2 and 3 was produced by a continuous mixing method according to Example 3 but in a larger apparatus having a mixing chamber volume of about 8 litres and with a feed rate of 150 kgs per minute.
The discharge from the mixing chamber was pumped through a hose of 1 1/2 inches bore and 82 feet long directly into a blast hole in an open cast iron ; 10 ore mine. The blast hole diameters were from 8 to 12 inches. Upon initiation with two pentolite primers of 360 g in each blast hole, such compositions de-tonated completely and showed very satisfactory blasting results.
. ~
.
,~ 11 -,~
To further illustrate the invention the following examples are given on some embodiments of the invention wherein both the mixing operations are carried out in different ways and wherein some examples have been carried out without lignosulphonates for comparison of the obtained results.
Examples In the following table a total of five examples are summarized, Examples 4 and 5 ~eing outside the scope of the invention and included for reasons of co~parison since they either do not contain lignosulphonate or do -not contain a liquid fuel.
The method of preparation is also varied, but all examples have in common that a solution consisting substantially of nitrates and water is first prepared and maintained at a temperature of about 45C. until the mixing 1 20 operation with the remaining components is taking place. In this solution ! there are also included: the thickener guar gum which is first dispersed in glycol to prevent lump formation; furthermore, thiourea as a reaction partner for the nitrite aerating agent so that a certain amount of nitrogen is gener-ated and finely distributed throughout the final mixture; and also the anti-foaming agent "Foamaster* 50D", marketed by the company Nopco Senco, to avoid , varying occlusions of air in the explosive composition. Finally, the solution according to all examples except Example 4 contains a lignosulphonate, viz., the commercial product denoted "Totanin MG" from A/S Toten Cellulosefabrikk, Nygard, Norway.
The ammoniu~ nitrate used is a commercial grade available in : *Trademark A
105~276 prilled form. The lime saltpeter being used is also a commercial grade in the iorm of prills containing about 15% of water and about 6% of ammonium nitrate in addition to calcium nitrate.
As fuel a diesel oil of normal commercial grade was used except Example 5, where the fuel was a finely ground gilsonite which is a high car-bon, low ash, natural asphalt.
The auxiliary substances sodium dichromate for crosslinking the guar gum and sodium nitrite for generating nitrogen are added during the final mixing operation in the form of separate solutions, 50% and 25% concen-tration, respectively. All figures in the composition table are given in weight percent.
TABLE I is Composition No. 1 2 3 4 5 Solution:
Ammonium nitrate 29.0029.00 29.00 29.33 29.00 Lime saltpeter, 28.1828.18 28.18 28.18 28.18 Commercial grade 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 Lignosulphonate 0.53 0.53 0.53 - 0.53 Ethylene glycol 0.78 0.78 0.78 0.98 0.78 Ant foaming agent 0.03 0.03 0.03 0.03 0.03 Fuels:
Diesel oil (fuel oil) 6.50 6.50 6.50 6.50 Gilsonite - - - - 6.50 Undissolved ammonium nitrate28.00 28.00 28.00 28.00 28.00 uxiliary substances:
,. .
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 mixture methods are used in the various embodiment examples.
.
In Example 1 the solution, fuel, dry ammonium nitrate and auxili- `
ary substances are brought together in the order mentioned in a plastic bottle having a volume of about 2 litres and shaken together for about 15 seconds.
Thereupon the prepared mixture, before a complete crosslinking of the guar gum has taken place, is transferred into cardboard tubes of various diameters for testing of the explosive quality parameters.
In Example 2 the composition has been prepared in a mixing appa-ratus commonly used for bakery purposes with a mixing vessel having a volume : -of about 25 litres. After charging the solution the fuel oil was added and stirred until the mixture looked homogeneous, which was obtained within about ~ -one minute. During somewhat more vigorous stirring dry ammonium nitrate and the auxiliary substances were added and stirring maintained for about one minute. Then the prepared mixture was put into cardboard tubes as in Example 1, In Examples 3, 4 and 5 a continuous mixing process was used where-in the components were passed into a mixing chamber having a volume of about 1 litre. The charging rate was about 10 kgs per minute and samples of the final mixture were brought into cardboard tubes of various diameters for the determination of the critical diameter. In all cases the density of the pro-duct was about 1.15 g/cm . The results are stated in Table II. The stated critical diameter for the explosive mixtures is the smallest diameter where a tube, having a length 6 times the diameter, detonates completely unconfined 1 having been cooled down to 5C. and initiated with a primer. As primer for ; tube diameters below 84 mm 32 g of trinitro-toluene has been used, in the table denoted as "A", whilst for larger tube diameters 360 g of pentolite (55% pentrite, 45~ trinitro-toluene), in the table denoted "B" has been used.
TABLE II
Example No. 1 2 3 4 5 I Primer, type: A A A B B
-' 30 Critical diameter, inches: 2 2 3/4 2 3/4 4 >5 3/4 .. , _ g _ .z~
lOSQ276 From the above results it can be seen that with diesel oil as fuel lignosulphonate provides a critical diameter below 3 inches whilst lack of lignosulphonate, all other conditions being unchanged, provides a critical diameter of 4 inches even with a substantially stronger primer. Other lig-nosulphonate compositions provided results nearly identical to those obtained with "Totanin MG". For a solid fuel, gilsonite, even with lignosulphonate it is obtained a critical diameter above 5 3/4 in. which was the largest diameter tested.
It will also be seen that the rapid mixing by shaking in a plas-tic bottle provides a somewhat lower critical diameter than a mechanical mix-ing whilst the continuous mixing and the mechanical chargewise mixing are of equal value.
A series of tests have been performed with emulsifiers other than lignosulphonate. The agents tested were stated by the suppliers to be effect-ive for emulsification of oil in water containing salts, and are presented in Table III.
TABLE III
Designation Supplier "LDC Base"~ Company Nopco Senco, Drammen, Norway "1225-L" " " " " "
"1186 A" " ll "Type 09" Hexamin Products, R~yken, Norway "Type 79/02" " " " "
"Berol 525" B~rol Kemi AB, Stenungsund, Sweden "Berol 259"
Nonylphenol Imperial Chemicals Ltd., London, England Using the same mixing conditions as applied for Example 1 and with componen~s otherwise as in Example 4, none of the commercial emulsifiers stated above produced a homogenity even approximating that achieved by the ~ ~ra~h . ~
~050276 lignosulphonate, and usually non-emulsified oil was observed floating freely on the surface of the mixture. In no case was a critical diameter determined below 4 inches for these mixtures.
Finally, it should be mentioned that an explosive mixture having a composition as in Examples 1, 2 and 3 was produced by a continuous mixing method according to Example 3 but in a larger apparatus having a mixing chamber volume of about 8 litres and with a feed rate of 150 kgs per minute.
The discharge from the mixing chamber was pumped through a hose of 1 1/2 inches bore and 82 feet long directly into a blast hole in an open cast iron ; 10 ore mine. The blast hole diameters were from 8 to 12 inches. Upon initiation with two pentolite primers of 360 g in each blast hole, such compositions de-tonated completely and showed very satisfactory blasting results.
. ~
.
,~ 11 -,~
Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In an aqueous, slurry type explosive composition comprising an inorganic oxidant, a fuel, a thickener and a surface active agent, said com-position being free from any self-explosive component, the improvement which comprises using in combination a fuel component which is a liquid, substan-tially water-insoluble hydrocarbon and, as surface active agent, a lignosul-phonate in an amount of about 0.5 to 5% by weight of the composition.
2. A composition as claimed in claim 1 wherein the oxidant is a nitrate.
3. A composition as claimed in claim 2 wherein the nitrate consists at least in part of ammonium nitrate.
4 A composition as claimed in claim 1, 2 or 3 wherein the amount of lignosulphonate is from about 0.5 to about 2% by weight of the composition.
5. A composition as claimed in claim 1, 2 or 3 wherein the lignosul-phonate is sodium lignosulphonate, calcium lignosulphonate, magnesium lignosul-phonate, ammonium lignosulphonate or any mixture thereof.
6. A composition as claimed in claim 1, 2 or 3 wherein the lignosul-phonate is in the form of a sulphite liquor evaporated to a solids content of about 50%.
7. A composition as claimed in claim 1 wherein the lignosulphonate is sodium lignosulphonate, calcium lignosulphonate, magnesium lignosulphonate, ammonium lignosulphonate or any mixture thereof and is present in an amount of from about 0.5 to about 2% by weight of the composition.
2. A composition as claimed in claim 1 wherein the lignosulphonate is in the form of a sulphite liquor evaporated to a solids content of about 50% and is present in an amount of from about 0.5 to about 2% by weight of the composition.
9. A composition as claimed in claim 1, 7 or 8 wherein the fuel com-ponent is a hydrocarbon fuel or diesel oil.
10. A composition as claimed in claim 1, 7 or 8 wherein the fuel com-ponent is a hydrocarbon fuel or diesel oil and the oxidant is a nitrate.
11. A composition as claimed in claim 1, 7 or 8 wherein the fuel com-ponent is a hydrocarbon fuel or diesel oil and the oxidant is a nitrate con-sisting at least in part of ammonium nitrate.
12. A composition as claimed in claim 1, 7 or 8 wherein the thickener is a high polymer substance used in combination with a crosslinking agent se-lected from compounds of heavy metals from Groups IV, V and VI of the Periodic System in their highest valence state.
13. A composition as claimed in claim 1, 7 or 8 wherein the thickener is a high polymer substance used in combination with a crosslinking agent se-lected from compounds of heavy metals from Groups IV, V and VI of the Periodic System in their highest valence state and wherein the oxidant is a nitrate.
14. A composition as claimed in claim 1, 7 or 8 wherein the thickener is a high polymer substance used in combination with a chromate, antimonate or titanate crosslinking agent.
15. A composition as claimed in claim 1, 7 or 8 wherein the thickener is a high polymer substance used in combination with a chromate, antimonate or titanate crosslinking agent and wherein the oxidant is a nitrate consisting at least in part of ammonium nitrate.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO750887A NO134945C (en) | 1975-03-14 | 1975-03-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1050276A true CA1050276A (en) | 1979-03-13 |
Family
ID=19882146
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA238,034A Expired CA1050276A (en) | 1975-03-14 | 1975-10-21 | Aqueous explosive composition |
Country Status (9)
| Country | Link |
|---|---|
| AU (1) | AU500535B2 (en) |
| CA (1) | CA1050276A (en) |
| FI (1) | FI62279C (en) |
| GB (1) | GB1538092A (en) |
| NO (1) | NO134945C (en) |
| RO (1) | RO71039A (en) |
| SE (1) | SE7602357L (en) |
| YU (1) | YU41421B (en) |
| ZA (1) | ZA76288B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3376482D1 (en) * | 1982-10-22 | 1988-06-09 | Ici Plc | Emulsion explosive composition |
| DE3378726D1 (en) * | 1982-10-29 | 1989-01-26 | Cil Inc | Emulsion explosive composition |
| MW2884A1 (en) * | 1984-02-08 | 1986-08-13 | Aeci Ltd | An explosive which includes an explosive emulsion |
| US4844756A (en) | 1985-12-06 | 1989-07-04 | The Lubrizol Corporation | Water-in-oil emulsions |
| US4708753A (en) | 1985-12-06 | 1987-11-24 | The Lubrizol Corporation | Water-in-oil emulsions |
| US4863534A (en) | 1987-12-23 | 1989-09-05 | The Lubrizol Corporation | Explosive compositions using a combination of emulsifying salts |
| US4840687A (en) | 1986-11-14 | 1989-06-20 | The Lubrizol Corporation | Explosive compositions |
| US4828633A (en) | 1987-12-23 | 1989-05-09 | The Lubrizol Corporation | Salt compositions for explosives |
| US5527491A (en) | 1986-11-14 | 1996-06-18 | The Lubrizol Corporation | Emulsifiers and explosive emulsions containing same |
| US5129972A (en) | 1987-12-23 | 1992-07-14 | The Lubrizol Corporation | Emulsifiers and explosive emulsions containing same |
-
1975
- 1975-03-14 NO NO750887A patent/NO134945C/no unknown
- 1975-10-21 CA CA238,034A patent/CA1050276A/en not_active Expired
-
1976
- 1976-01-19 ZA ZA760288A patent/ZA76288B/en unknown
- 1976-01-20 GB GB2132/76A patent/GB1538092A/en not_active Expired
- 1976-01-21 AU AU10447/76A patent/AU500535B2/en not_active Expired
- 1976-01-30 RO RO7684656A patent/RO71039A/en unknown
- 1976-02-06 YU YU283/76A patent/YU41421B/en unknown
- 1976-02-24 FI FI760466A patent/FI62279C/en not_active IP Right Cessation
- 1976-02-25 SE SE7602357A patent/SE7602357L/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| YU41421B (en) | 1987-06-30 |
| ZA76288B (en) | 1977-04-27 |
| YU28376A (en) | 1983-12-31 |
| NO134945C (en) | 1977-01-12 |
| SE7602357L (en) | 1976-09-15 |
| AU1044776A (en) | 1977-07-28 |
| AU500535B2 (en) | 1979-05-24 |
| GB1538092A (en) | 1979-01-10 |
| FI62279C (en) | 1982-12-10 |
| NO750887L (en) | 1976-09-15 |
| FI760466A (en) | 1976-09-15 |
| FI62279B (en) | 1982-08-31 |
| NO134945B (en) | 1976-10-04 |
| RO71039A (en) | 1981-06-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0161821B1 (en) | Gas bubble-sensitized water-in-oil emulsion explosive compositions | |
| US4448619A (en) | Emulsion explosive composition | |
| US6165297A (en) | Process and apparatus for the manufacture of emulsion explosive compositions | |
| PL117150B1 (en) | Water explosive mixture of inverted phase and method of making the samerigotovlenija vodnojj wzryvchatojj smesi z obratnojj fazojj | |
| AU2012286593B2 (en) | Improved explosive composition | |
| CA1050276A (en) | Aqueous explosive composition | |
| US4936933A (en) | Process for preparing explosive | |
| IE50170B1 (en) | Slurry explosive composition | |
| EP0194775A1 (en) | Stable nitrate/slurry explosives | |
| AU2015337861A1 (en) | Explosive composition and method of delivery | |
| EP0276934A2 (en) | Explosive composition | |
| CA2386345C (en) | Reduced energy blasting agent and method | |
| AU609930B2 (en) | Chemical foaming of emulsion explosives | |
| EP1002777B1 (en) | Process and mechanism for in situ sensitization of aqueous explosives | |
| CA2045757C (en) | Chemically gassed emulsion explosive | |
| US4718954A (en) | Explosive compositions | |
| US4084994A (en) | Aqueous hydrocarbon oil-soluble lignosulphonate explosive composition | |
| US4853050A (en) | Oil-in-water explosive composition containing asphalt | |
| AU690398B2 (en) | Method of reducing nitrogen oxide fumes in blasting | |
| CA1096173A (en) | Water-in -oil emulsion blasting agent | |
| CA2363212C (en) | Blasting method for reducing nitrogen oxide fumes | |
| CS200185B2 (en) | Explosive composition | |
| EP0097030B1 (en) | A water-in-oil emulsion explosive composition and a process for the preparation thereof | |
| NZ250912A (en) | Ammonium, sodium and/or calcium nitrate explosives with increased sensitivity | |
| RU2222519C2 (en) | Packaged explosive energetic emulsions |